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UBC Theses and Dissertations

Development of marine benthic algal communities on Juan de Fuca Strait, British Columbia Lee, Robert Kui Sung 1965

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The  U n i v e r s i t y of B r i t i s h  Columbia  FACULTY OF GRADUATE STUDIES  PROGRAMME-OF THE FINAL ORAL EXAMINATION FOR THE  DEGREE OF  DOCTOR OF PHILOSOPHY  of  ROGERT KUI SUNG LEE  B.A., U n i v e r s i t y of Hawaii, 1959 M.Sc.  3  U n i v e r s i t y of Hawaii, 1962  THURSDAY, OCTOBER 21, 1965, at 3;30  P.M.  ROOM 3332, BIOLOGICAL SCIENCES BUILDING  COMMITTEE IN CHARGE Chairman: I . McT« Cowan V. J . K r a j i n a G. L. P i c k a r d G. E„ Rouse  R. F. Scagel W. B. S c h o f i e l d T M. C. T a y l o r G. H. N. Towers  External  0  Examiner:  M. S. Doty  U n i v e r s i t y of Hawaii Honolulu Hawaii  DEVELOPMENT OF MARINE BENTHIC ALGAL COMMUNITIES ON JUAN DE FUCA STRAIT, BRITISH COLUMBIA ABSTRACT Developmental s t u d i e s were made on c e r t a i n i n t e r t i d a l a l g a l communities at t h r e e s i t e s on Juan de Fuca S t r a i t , B.C. The o b j e c t was t o d e s c r i b e the form and s t r u c t u r e of t h e s e communities and t o p r o v i d e an i n t e r p r e t a t i o n t h a t would account f o r the manner i n which they occur. P e r i o d i c o b s e r v a t i o n s were made on communities d e v e l o p i n g on denuded rock s u r f a c e s and on i n s i t u communities. By u s i n g the denuded-quadrat method, a method f a m i l i a r to t e r r e s t r i a l p l a n t e c o l o g i s t s , s p e c i e s d i s t r i b u t i o n i n d i c e s of frequency and abundance were taken to q u a n t i t a t i v e l y d e s c r i b e the stages of r e c o l o n i zation. Data r e l a t i v e to the developmental process, such as l i f e span and p e r i o d of r e p r o d u c t i o n of the s p e c i e s i n v o l v e d , were a l s o g a t h e r e d . The experimental data r e v e a l a p a t t e r n of development t h a t i s c o n s i s t e n t and p r e d i c t a b l e . D e s p i t e the presence of an o r d e r l y sequence of events, t h e r e i s no evidence i n i n d i c a t e t h a t t h i s i s an e x p r e s s i o n of e c o l o g i c a l s u c c e s s i o n . The p a r t i a l or even t o t a l e l i m i n a t i o n of a p o p u l a t i o n i s concluded not to be due to any changes i n h a b i t a t o r i g i n a t e d by t h a t p o p u l a t i o n . Instead i t s e l i m i n a t i o n , p a r t i a l or otherwise, i s c o n s i d e r e d to be a consequence of the degree of e s t a b l i s h m e n t of the preceding p o p u l a t i o n . The s u c c e s s i o n a l phenomenon, which can be a l t e r e d by seasonal populants, i s r e l a t e d to the m o r p h o l o g i c a l nature of the c o l o n i z i n g s p e c i e s . U n i c e l l u l a r forms appear b e f o r e f i l a m e n t o u s ones, and f i l a m e n t o u s forms appear b e f o r e parenchymatous ones. Such a s u c c e s s i o n i s i n t e r p r e t e d as b e i n g i n d i c a t i v e of the r e l a t i v e growth r a t e s and l i f e spans of the growth forms. The l e n g t h of time i n which a p o p u l a t i o n occupies an area i s d e t e r mined by these f a c t o r s . The presence or absence of growth space can be a main cause f o r l o c a l d i s t r i b u t i o n p a t t e r n s , e s p e c i a l l y f o r ephemeral s p e c i e s . The dynamic s t r u c t u r e of the communities s t u d i e d i s a t t r i b u t e d t o s p e c i e s i n t e r a c t i o n i n v o l v i n g three i n t e r r e l a t e d f a c t o r s :  (1) the morphology of the organisms; (2) the phenolog i c a l nature of g e r m i n a t i o n , growth, r e p r o d u c t i o n , and of spore or gamete release;, and (3) the c o m p e t i t i o n f o r space.  GRADUATE STUDIES Field  of Study; Advanced Phycology  R.F.  Scagel  Phytoplankton  R. F.  Scagel  R. F.  Scagel  Ecology  Phytoplankton S y n o p t i c Oceanography  G. L. P i c k a r d  Dynamic Oceanography  R. W,  Chemical  Oceanography  P.. M.  Burling Williams  SCHOLARSHIPS  1958-59 - Hawaiian B o t a n i c a l S o c i e t y S e n i o r Botany Award 1963-64 - E d i t h Ashton Memorial S c h o l a r s h i p  PUBLICATIONS  S t e i n e r , L. F. and  R. K.  S. Lee.  1955=  Large-area  of a m a l e - a n n i h i l a t i o n method f o r o r i e n t a l fly control. Lee,  R. K.  S. 1963.  J o u r . Econ. Entom. 48: The  fruit  311-317.  s t r u c t u r e and r e p r o d u c t i o n of  Dudresnaya h a w a i i e n s i s sp. nov. Amer. J o u r . Bot. 50:  tests  315-31.9.  (Rhodophyta).  DEVEL0PI1ENT OF MARINE BENTHIC ALGAL COMMUNITIES -1  ON JUAN D E FUCA STRAIT, BRITISH COLUMBIA  by  ROBERT EUI SUNG L E E B.A., U n i v e r s i t y o f H a w a i i , 1959 M . S c , U n i v e r s i t y of H a w a i i , 1962  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY  i n t h e Department of B i o l o g y and Botany  We a c c e p t t h i s t h e s i s as conforming t o t h e required standard  THE UNIVERSITY OF BRITISH COLUMBIA August,  1965  In p r e s e n t i n g the  r e q u i r e m e n t s f o r an  British  Columbia,  available for mission  cation  of  w i t h o u t my  this  g r a n t e d by  Department o f  It  thesis  written  the  this  October 1 2 ,  1965  University  of  make i t  for  copying or  shall  not  freely per-  scholarly  Department o r  that  gain  Botany  Columbia  of  shall  thesis  Head o f my  i s understood  and  fulfilment  I f u r t h e r agree that  permission.  Biology  the  Library  study.  for financial  The U n i v e r s i t y o f B r i t i s h V a n c o u v e r 8, C a n a d a Date  the  copying of  representatives*  in p a r t i a l  advanced degree at  r e f e r e n c e and  be  thesis  I agree that  for extensive  p u r p o s e s may his  this  be  by publi-  allowed  ABSTRACT Developmental s t u d i e s were made on c e r t a i n a l g a l communities a t t h r e e s i t e s on Juan de Fuca  intertidal S t r a i t , Bo Go  The o b j e c t was t o d e s c r i b e the form and s t r u c t u r e o f these communities and t o p r o v i d e an i n t e r p r e t a t i o n t h a t would for  t h e manner i n which t h e y  occur  account  0  P e r i o d i c o b s e r v a t i o n s were made on communities d e v e l oping on denuded r o c k s u r f a c e s and on i n s i t u  communities»  By u s i n g t h e denuded-quadrat method, a method f a m i l i a r t o t e r r e s t r i a l p l a n t e c o l o g i s t s , s p e c i e s - d i s t r i b u t i o n i n d i c e s of frequency  and abundance were taken t o q u a n t i t a t i v e l y d e s c r i b e  the s t a g e s o f re c o l o n i z a t i o n . , mental p r o c e s s , such as l i f e  Data r e l a t i v e t o t h e d e v e l o p span and p e r i o d o f r e p r o d u c t i o n o f  the s p e c i e s i n v o l v e d , were a l s o gatheredo The e x p e r i m e n t a l  d a t a r e v e a l a p a t t e r n o f development  t h a t i s c o n s i s t e n t and predictable»  D e s p i t e t h e presence o f  an o r d e r l y sequence o f e v e n t s , t h e r e i s no evidence t h a t t h i s i s an e x p r e s s i o n o f e c o l o g i c a l succession,-, tial  to indicate The p a r -  o r even t o t a l e l i m i n a t i o n o f a p o p u l a t i o n i s concluded  n o t t o be due t o any changes i n h a b i t a t o r i g i n a t e d b y t h a t populationo  Instead i t s e l i m i n a t i o n , p a r t i a l o r otherwise, i s  c o n s i d e r e d t o be a consequence o f t h e degree o f e s t a b l i s h m e n t of  the proceeding  population„  The s u c c e s s i o n a l phenomenon, which can be a l t e r e d b y seasonal populants, i s r e l a t e d t o the morphological nature of the c o l o n i z i n g specieso  U n i c e l l u l a r forms appear b e f o r e  iio  f i l a m e n t o u s ones, and f i l a m e n t o u s forms appear b e f o r e p a r e n chymatous ones.  Such a s u c c e s s i o n i s i n t e r p r e t e d as b e i n g  i n d i c a t i v e of t h e r e l a t i v e growth r a t e s and l i f e growth formso  spans of t h e  The l e n g t h of time i n which a p o p u l a t i o n  o c c u p i e s an a r e a i s determined b y t h e s e factors..  The p r e s e n c e  o r absence of growth space can he a main cause f o r l o c a l d i s t r i b u t i o n a l p a t t e r n s , e s p e c i a l l y f o r ephemeral species<> The dynamic  s t r u c t u r e of t h e communities s t u d i e d i s a t t r i b u t e d  to species i n t e r a c t i o n i n v o l v i n g three i n t e r r e l a t e d (1)  factors:  t h e morphology of t h e organisms; ( 2 ) t h e p h e n o l o g i c a l  n a t u r e of g e r m i n a t i o n , growth, r e p r o d u c t i o n j and o f spore o r gamete r e l e a s e ; and (3) the c o m p e t i t i o n f o r space.  Hi TABLE OF CONTENTS jtYBS^KJLOT  O  O  O  O  O  ACKNOWLEDGMENTS LIST OF TABLES  O  O  O  O  O  O  O  O  O  O  O  O  O  O  O  O  O  X  O  . . . . . . . . . . . . . . . . . . . V'.ii.. . . . . . . . . . . . . . . . . . . . . .  LIST OF FIGURES  i v  . . . . . . . . . . . . . . . . . . . vi,  INTRODUCTION . . . . . . . . . . . . . . . . . . . . .  1  GENERAL CLIMATIC AND OCEANOGRAPHIC FEATURES  3  Pn^-DSOX^tE)  o  o  o  Til© P X O t S  o  o  o  o  o  o  o  . . . . .  o  o  o  o  o  o  o  o  e  a  e  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  ^  5  D e nud i n g * « * • . o * « <» o * • o • • « « o * 8 O b s e r v a t i o n P e r i o d s . . . <> * o * • « * o • . . . * 9 333.tst OlDtcixiied « * o « « » o » o o « 0 e o o * o « „ 9 Taxonomy . . . . . . . . . . . . . . . . . . . . . . 12 0  e  o  SYNOPSIS OF RESULTS AND INTERPRETATION . . . . . . . . STJI^JT^A.E.IL * 7  O  O  LITERATURE  O  O n  O  O  O  O  O  O  O  O  O  O  O  O  O  O  O  O  O  O  3^  ©  CITED . . . . . . . . . . . . . . . . . . .  APPENDIX I . "Vl O t  O  13  3.  DETAILED OBSERVATIONS ON DEVELOPMENT P i  O t  X  o  o  o  O  O  O  O  O  O  O  O  O  O  O  O  34  . . 41  O  C  O  XX o e o o o o o o o o o o o o o o o Victoria Plot I I I . . . . . . . . . . . . . . . .  .  If X G t O r  o  V X O t O r X c l Pl0"b Xcl  PX  O t  X V  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  ^1"2  5^ 59 ^7  Vx cfcor x SL PX o t V o V i c t o r i a P l o t VI G l a c i e r IPOXIlt. o o  o o« o o o o © o o o o « o © < > o 73 . . . . . . . . . . . . . . . . . 78 o o o o o o o o o o o o o o o o o 3X  P o r t Renfrew  o  APPENDIX I I .  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  o  LIST OF SPECIES AND COLLECTION NUMBERS .  93 99  Iv. LISO? OF TABLES Table  Page  l o  Observation periods  2o  Developmental events a t V i c t o r i a P l o t I i n terms  o  o  o  o  o  o  o  o  o  o  of f r e q u e n c y p e r c e n t a g e . . . . o « „ . 3o 4. 5o  o  o  .  o  o  » .  o  .  o  .  10  .  .  .  1 4  Developmental events a t V i c t o r i a P l o t I I i n terms of f r e q u e n c y p e r c e n t a g e . 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Developmental events a t V i c t o r i a P l o t I I I i n terms of f r e q u e n c y p e r c e n t a g e o » » o . o » . . o . » . .  15 » 1 6  Developmental events a t V i c t o r i a P l o t IV i n terms of f r e q u e n c y p e r c e n t a g e . . . . . . . . . . . . . . .  60  Developmental events a t V i c t o r i a P l o t V i n terms of f r e q u e n c y p e r c e n t a g e 0 0 . 0 0 0 0 0 0 0 0 . 0 0 0  7»  Developmental events a t V i c t o r i a P l o t VI i n terms of f r e q u e n c y p e r c e n t a g e . . . . . . . . . . . . . . .  17 1 8 19  80  Developmental events a t G l a c i e r P o i n t i n terms of f r e q u e n c y p e r c e n t a g e 0 0 0 0 0 0 0 0 0 . 0 0 0 0 . 2 0 ,  9»  Developmental events a t P o r t Renfrew i n terms of f r e q u e n c y p e r c e n t a g e 0 0 0 . 0 0 0 0 . 0 0 0 0 . 0  2 1  10o  T h a l l u s h e i g h t and s t a g e o f m a t u r i t y as r e l a t e d t o growth p e r i o d 0 0 0 0 0 0 . 0 0 0 0 0 0 0 0 0 0 0  2 5  11o  Enumeration o f t h e community p r e s e n t b e f o r e denuding at V i c t o r i a H?l0"fc X o o o o o o o o o o o o o o o o o  ^ 3  12o 13o  Enumeration o f the r e c o l o n i z i n g communities a t V i c t o r i a PXO"fcf X o o o o o o o o o o o o u o o  o  o  o  o  Enumeration of t h e community p r e s e n t b e f o r e denuding  53  9."t Vx cb 0I*JL3. PXo"t XX 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 14o 15° 16o  Enumeration o f t h e r e c o l o n i z i n g communities a t VlCtjOriR PXO"t XX o o — o o o o o o o o o o o o  o  o  o  o  Enumeration of t h e community p r e s e n t b e f o r e denuding si"fc V i c b oi*xsi PX o*fc XXX • o o o o o 0 0 0 0 0 0 0 0 0 0 Enumeration o f t h e r e c o l o n i z i n g communities a t V i c t o r i a -P X O i j r X X X o o o o o o o o o o o o o o  o  o  o  60 o  6X  Table 17» 18»  Page Enumeration o f t h e community p r e s e n t b e f o r e denuding at V i c t o r i a P l o t IV . . . < > < > . . . . . . . . . c o o  68  Enumeration o f t h e r e c o l o n i z i n g communities a t VlC"b OX*lSL PX 0"b XV 0 0 0 0 0 0 0 0 0 0 0 0 0 * 0 0 0 0  6^  19°  Enumeration o f t h e community p r e s e n t b e f o r e denuding Sl"fc VlC"fc03?13L ?XO"fc V 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  20o  Enumeration o f t h e r e c o l o n i z i n g "Vl C "\j O X* X 9. I?XO"fc V  21o  o  o 0 0 0 0 0 0 0 0  23o  O  0  O  O  O  O  Enumeration o f the r e c o l o n i z i n g V i c t o r i a PXo"b VX O 0 0 o o o 0  O  0  0  O  9  O  -  O  0  O  ©  O  0  0  O  O  O  6  o  o  o  o  »  o  0  o  o  c  -  O  O  O  O  0  O  O  O  O  O  25.  Enumeration o f t h e community p r e s e n t b e f o r e denuding Poi**fc jR.G33.fr ©ToT 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  26»  Enumeration o f t h e r e c o l o n i z i n g 3?OX*"fc BlGHfl^QW O  O  O  0  O  0  0  O  80 83  communities a t  G l a c i e r POlXlt' 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  O  ^  communities a t  O  Enumeration o f t h e r e c o l o n i z i n g  75  ^  Enumeration o f t h e community p r e s e n t b e f o r e denuding a t G l a c i e r POIII^ O  24o  0 0 0 0 0 0 0 0 0  Enumeration o f t h e community p r e s e n t b e f o r e denuding at V i c t o r i a !PXO"t VX O  22o  communities a t  8^1"  communities a t Q  0  O  0  0  O  0  O  O  O  0  95  LIST OP FIGURES Figure  Page  l o ' Southwest p o r t i o n o f B r i t i s h Columbia showing t h e three experimental s i t e s  o o o o o o o o o o o o » o o <> « o <, o o „ <, « o o  38 40  2c  Denuded p l o t  a t P o r t Renfrew  3=  Denuded p l o t  at Glacier  4o  P o r t i o n of t h e V i c t o r i a Harbor breakwater  5°  The U r o s p o r a w o r m s k i o l d i i and Enteromorpha l i n z a stage on V i c t o r i a P l o t I T V o o o o o o o o - o o o o o P o r t i o n o f t h e V i c t o r i a P l o t I I I c o l o n i z i n g commun i t y composed m a i n l y of Monostroma fuscum and Sp pngjamorph a c o a l i t a » o o o o o ° o » o o o o o <> o  40  6o  Point  o »  0  <, o o  0  0  o « « °  40  o » » »  40 40  7°  Victoria Plot  days a f t e r denuding „ » <, » „ »  40  8o  C l o s e up of a s e c t i o n o f F i g o 7 showing a dense p a t c h o f U l v a l o b a t a and Enteromorpha l i n z a „ o o o  40  I , 367  vii.  ACKNOWLEDGMENTS  The a u t h o r wishes t o thank t h e graduate members,  D r s o  G .  L o  Pickard,  Ro  P o  committee  S c a g e l , W. B. S c h o f i e l d ,  and T o M o C o T a y l o r , f o r t h e i r a d v i c e and a s s i s t a n c e .  Special  acknowledgment i s made t o Dr. S c a g e l f o r t h e encouragement and c r i t i c i s m g i v e n d u r i n g t h e course o f the s t u d y and i n t h e preparation of the manuscript. McTaggart  I am g r a t e f u l t o Dr. I a n  Cowan f o r h i s i d e n t i f i c a t i o n of animal specimens.  F i n a l l y , I wish t o acknowledge  f i n a n c i a l assistance provided  by t h e N a t i o n a l Research C o u n c i l o f Canada through t h e I n s t i t u t e o f Oceanography,  U n i v e r s i t y of B r i t i s h  Columbia,  and t h e Defense Research Board o f Canada (DRB 9520-14).  INTRODUCTION The n a t u r e o f t h e form and s t r u c t u r e o f i n t e r t i d a l communities i s an a s p e c t o f s y n e c o l o g y little o  But j u s t as l i t t l e  algal  o f which we know very-  a t t e n t i o n has been f o c u s s e d and  j u s t as l i t t l e  i n f o r m a t i o n i s a v a i l a b l e on two r e l a t e d  of  one d e a l i n g w i t h d e s c r i p t i o n and c l a s s i f i c a t i o n  synecology:  ( e . g . , Huenscher, 1 9 1 5 ;  Dexter,  and Chapman, 1 9 5 0 ; H a r t o g ,  194-7; I s a a c , .194-9; B e v e r i d g e  1955; M o l i n i e r , I 9 6 0 ) , the other  d e a l i n g w i t h t r o p h i c , o r energy, 194-2; Sargent  aspects  relationships  (e.go,  Lindeman,  and A u s t i n , 194-9; Odum and Odum, 1 9 5 5 ; Kohn and  H e l f r i c h , 1 9 5 7 ; Gordon and K e l l y , 1 9 6 2 ) „  By way o f d e f i n i t i o n ,  the t h r e e a s p e c t s may be c l a s s i f i e d i n t o t h e c a t e g o r i e s o f community morphology, community taxonomy, and community metabolism. Prom t h e s t a n d p o i n t o f t h e p r e s e n t r e s e a r c h , community morphology i s l a r g e l y concerned  w i t h the i n t e r p r e t a t i o n o f t h e  form and s t r u c t u r e o f communities„  As i s t r u e w i t h any complex  m o r p h o l o g i c a l problem, t h e m o r p h o l o g i c a l n a t u r e o f a l g a l  com-  m u n i t i e s can be i n t e r p r e t e d b e s t from evidence d e r i v e d and s y n t h e s i z e d from o b s e r v a t i o n s made on t h e i r developmental a s pects o  T h i s approach i s w e l l e x p r e s s e d ,  ent purpose,  although f o r a d i f f e r -  b y Weaver and Clements ( 1 9 3 8 ,  p. 1 0 4 ) :  "The major  d i f f i c u l t y i n t h e a n a l y s i s of v e g e t a t i o n i s i t s g r e a t complexity,  b u t i t d i s c l o s e s a d e f i n i t e p a t t e r n when a n a l y z e d  t h e developmental  p o i n t o f view."  from  2o A c c o r d i n g l y , t h i s s t u d y i s concerned w i t h d e t e r m i n i n g how  c e r t a i n a l g a l communities d e v e l o p and attempts  to provide  an e x p l a n a t i o n f o r the manner i n which t h e y o c c u r . Three t y p e s of i n t e r t i d a l communities were i n v e s t i g a t e d between May  1962 and January 1964c  Each was  i n a different  a r e a on the s o u t h e a s t p a r t of Vancouver I s l a n d on Juan de Strait  ( F i g * 1)°  The  community t y p e s s t u d i e d and t h e i r  t i o n s a r e : a Balanus-Fucus a p p r o x i m a t e l y 48°  33' No,  59'  Wo;  breakwater  loca-  type n e a r the P o r t Renfrew wharf, 124°  25'  W»; a H e d o p h y l l u m - C o r a l l i n a -  B o s s i e l l a type a t G l a c i e r P o i n t , a p p r o x i m a t e l y 48° 123°  Fuca  24'  I.,  and an A l a r i a - C o r a l l i n a - B o s s i e l l a type on the a t V i c t o r i a Harbor,  a p p r o x i m a t e l y 48°  25' N.,  123°  23' Wo Developmental  s t u d i e s have been made on marine commu-  n i t i e s i n o t h e r p a r t s of the w o r l d . descriptive Coe,  Some r e p o r t s are  ( e . g . , W i l s o n , 1925; P i e r r o n and Huang,  1932; H a t t o n , 1932; Moore, 1939; Katada  merely  1926;  and M a t s u i ,  1954;  Varma, 1 9 5 9 ) , w h i l e o t h e r s p r o v i d e some i n t e r p r e t a t i o n of the events o c c u r r i n g ( e . g . , S h e l f o r d , 1930; Scheer, 1945; c r a f t , 1948;  Fahey and Doty, 1949;  Aleem, 1957;  C i r i n o , 1958)»  The  R e d f i e l d and Deevy, l a s t mentioned paper,  North1952; Cirino  (nee Fahey) (1958), g i v e s a v e r y e x t e n s i v e review of the l i t e r a t u r e d e a l i n g w i t h t h e development of i n t e r t i d a l nities o  commu-  GENERAL CLIMATIC AND OCEANOGRAPHIC FEATURES Data on c l i m a t e i n Canada a r e p u b l i s h e d y e a r l y by t h e M e t e o r o l o g i c a l Branch o f t h e Canada Department  of Transport.  1962 a t V i c t o r i a , t h e mean annual temperature was 50°F  For  (10°C), J a n u a r y had t h e l o w e s t mean monthly temperature a t 40°F  ( 4 ° C ) , and August had t h e h i g h e s t mean temperature a t  59°F  (15°C).  F o r t h e same y e a r a t J o r d a n R i v e r , which  between G l a c i e r P o i n t and P o r t Renfrew, a t u r e was 49°F at  40°F  lies  t h e mean annual  temper-  (9°C), J a n u a r y had t h e l o w e s t mean temperature  ( 4 ° C ) , and b o t h J u l y and August had t h e h i g h e s t mean  temperature a t 58°F  (14°C).  Total precipitation  ( r a i n f a l l and  s n o w f a l l ) f o r 1962 was 27°9 i n c h e s a t V i c t o r i a , and 80.4 i n c h e s at  Jordan R i v e r . Many o f t h e o c e a n o g r a p h i c f e a t u r e s o f Juan de F u c a  Strait  have been d i s c u s s e d by H e r l i n v e a u x and T u l l y  (1961).  These a u t h o r s show t h a t f o r t h e month of June 1952 t h e s u r f a c e water i n t h e v i c i n i t y  o f V i c t o r i a had a d i s s o l v e d  c o n c e n t r a t i o n o f about 7°0 mg/1, a s a l i n i t y and a temperature o f about 9 ° C . s u r f a c e water i n t h e v i c i n i t y  oxygen  o f about 30.5 o/oo,  D u r i n g t h e same p e r i o d , f o r  of G l a c i e r Point the dissolved  oxygen c o n c e n t r a t i o n was between 7°5 and 8.0 mg/1, t h e s a l i n i t y between 31»0 and 31»5 o/oo, and the temperature about 9«5°Co The June 1952 s u r f a c e water a t t h e mouth o f P o r t San Juan, t h e inlet  i n which P o r t Renfrew  i s s i t u a t e d , had a d i s s o l v e d  c o n t e n t o f about 8.5 mg/1, a s a l i n i t y a temperature o f about 9°5°C°  After  oxygen  o f about 31o5 o/oo, and compiling a l l the  4. a v a i l a b l e d a t a , t h e a u t h o r s found s e a s o n a l v a r i a t i o n s i n t h e s u r f a c e water o f t h e S t r a i t  i n g e n e r a l t o be as f o l l o w s : f o r  d i s s o l v e d oxygen, a F e b r u a r y maximum a t about 9 mg/1 and a September minimum a t about 6.5 mg/1; f o r s a l i n i t y , a March and October maximum a t about 31° 5 o/oo and January and J u l y minima at about 30.2 and 31°0 o/oo r e s p e c t i v e l y ; and f o r temperature, an August maximum a t about 10.5°C and F e b r u a r y minimum a t about 6o8°Co The t i d e , which i s o f t h e mixed t y p e , i . e . , t h e r e are two unequal h i g h t i d e s and two unequal low t i d e s o c c u r r i n g i n a l u n a r day, a t V i c t o r i a ranges from a mean lower low water h e i g h t o f 0o8 m t o a mean h i g h e r h i g h water h e i g h t o f 2.5 m. A t P o r t Renfrew  i t ranges from a mean l o w e r low water h e i g h t  of 0.9 m t o a mean h i g h e r h i g h water h e i g h t o f 3°1 m.  Respec-  t i v e h e i g h t s f o r G l a c i e r P o i n t l i e somewhere between t h o s e o f V i c t o r i a and P o r t Renfrew.  These t i d e l e v e l s a r e t h o s e g i v e n  i n t h e Canadian H y d r o g r a p h i c S e r v i c e ' s annual p u b l i c a t i o n , P a c i f i c Coast T i d e and C u r r e n t T a b l e s , i n which t h e l o w e s t normal low water i s c o n s i d e r e d as the r e f e r e n c e p o i n t , o r , i n o t h e r words, t h e zero t i d e l e v e l .  A l l tide levels  i n t h i s paper a r e r e f e r a b l e t o t h e same datum.  mentioned  METHODS The Periodic  ( u s u a l l y monthly) o b s e r v a t i o n s were made  denuded p l o t s , on p l o t s , and  on  c o n t i g u o u s i n s i t u - or  i n s i t u communities i n the  experimental s i t e s o the  denuded and  At "both P o r t  western h a l f the  denuded p l o t o  where more t h a n one  ( P i g o  4,  " b l o c k " was The  5)<,  Port  p l o t was  the  At  Glacier  a l l or p a r t s 3 ) °  t o west o r i e n t a t i o n of the  e a s t e r n h a l f of a b o u l d e r made up  of a g r a n i t e  g e n e r a l a r e a of  of a l a r g e b o u l d e r ( P i g . 2 ,  g e n e r a l east  Relative  e i t h e r a denuded o r a c o n t r o l  V x c t o r x a P l o t XX  o  o  o  Victoria Plot III  o  .  o  o  the the  face  plot  denuded p l o t s were:  o  o  m  0 » 5 6  0 0 0 0 0 0 0 0 0 0 0 0 0 0 o  to  entire horizontal  (top f a c e ) 0 Victoria Plot I  the  shore l i n e ,  Renfrew <» „ . . » . . ( v e r t i c a l f a c e )  G l a c x e r Poxnt^  of  V i c t o r i a breakwater,  denuded, the  a r e a s of the  the  Point,  c o n t r o l p l o t and  the  on  control-community  Renfrew and  c o n t r o l p l o t s took up  exposed s u r f a c e the  Plots  %  o  3 ° 4 7  o  o  o  o  o  o  o  o  l  .  o  o  o  o  o  o  o  o  l  o  0 0 0 0 0 0 0 0 0 0 0 0  3  3 31  l o 3 8  Victoria Victoria Plot V V i c t o r i a P l o t VI The  Port  O  .  0 .  .  o  0  o  o  o  Renfrew b o u l d e r was  exposed p o r t i o n  of the b o u l d e r was  I*2. X l „ 4 m ,  a rather  and  flat  o  o  o  1 . 3 8  0  of p h y l l i t e  2 o l m tide levelo  at about the  I t had  o  . . •. . . . . 0 » . 1 . 5 7  the b o u l d e r was  levelo  .  top  c l o s e t o the  0  The The  top  of  lowermost  1 . 2 1  tide  t h a t measured a p p r o x i m a t e l y  four v e r t i c a l faces  t h a t were 0 „ 8 t o 1 „ 0 m  6c h i g h and  r o s e at an angle o f about 90°  Opposing h a l f  p o r t i o n s of the  from the sandy f l o o r .  seaward v e r t i c a l f a c e , which  more or l e s s p a r a l l e l t o the shore l i n e , and half  corresponding  p o r t i o n s of the top f a c e formed the c o n t r o l and  plots.  The  o t h e r t h r e e v e r t i c a l f a c e s , two  shoreward, were not populated; no  the  shoreward f a c e supported  one  sparsely  practically  growth. The  G l a c i e r Point boulder,  which had  probably  right  t o the shore l i n e ( o r n o r t h t o s o u t h ) ,  angles  of a n d e s i t e .  a very  s u r f a c e , was  g r e a t e s t w i d t h were 4 m and boulder end,  was  0.8  m high;  end had  no  2.5  The  about 0.5  m from the  g r a d u a l l y s l o p e d t o the  s i g n i f i c a n t growth and The  t i d e l e v e l from the  south-end p o r t i o n of the b o u l d e r most n o r t h - e n d p o r t i o n was  not  considered  lowermost  w i t h i n t h e range of 0.6 was  sur-  shoreward  t o the s l i g h t l y h i g h e r ,  uppermost p a r t of the b o u l d e r  the  north  sand  steeper,  t h e r e f o r e was  at  and  h i g h e s t p o i n t of  As a t P o r t Renfrew, the  as p a r t of the p l o t s .  smooth  I t s l e n g t h , which was  m.  t h i s was  from where the b o u l d e r  r o u n d i n g the base.  The  denuded  l a t e r a l s and  i n c l u d e d because t h e y were o n l y  i n f a c t , the  was  lower-  and 0.9  a t about the 1.5  m  m. tide  level. According  t<s> l o c a l r e s i d e n t s , c o n s t r u c t i o n of  breakwater a t V i c t o r i a  ( P i g . 4) was  the  completed i n 1916.  Elongated  g r a n i t e b l o c k s , w i t h f o u r s i d e s each a p p r o x i m a t e l y 1 m wide, were a r r a n g e d i n t i e r s . were s e p a r a t e d  from each o t h e r by a 0 t o 30  with t h e i r length running breakwater.  Each t i e r c o n s i s t e d of b l o c k s  at r i g h t  angles  cm  that  space and  aligned  t o the l e n g t h o f  Each s u c c e s s i v e upper t i e r was  p l a c e d one  the  meter  7o  short  of the  surfaces,  one  i m m e d i a t e l y below.  These exposed  horizontal  a p p r o x i m a t e l y a meter square, comprised the  C o u n t i n g from the uppermost t i e r s i t u a t e d on the  of b l o c k s ,  s i x t h t i e r , which was  the  plots.  p l o t s were  a t about the  0.5  m  tide  level. This  a r t i f i c i a l l y p l a c e d breakwater f u r n i s h e d  t i o n t h a t was  especially well  s u i t e d t o the  were f a i r l y u n i f o r m i n s i z e and t a l placement was Habitat conditions certain portions the  sixth tier,  could  of the  therefore length  s i t u a t e d 120  be  t o the  of a t i e r .  t o 140  y e a r t o determine the The  section.  and  U s i n g as a r e f e r e n c e p o i n t  on the  eighth,  P l o t VI the  no  sea.  At  such a p o r t i o n  m from where the  of  breakwater  a t d i f f e r e n t times  the  P l o t I I I , which  20  m  was  s i x t h b l o c k from i t , P l o t  P l o t I I the n i n t h , P l o t I the  thirteenth,  fourteenth.  and  denuded p l o t s was  f i r s t s t a g e s of the  experiment, t h e r e  c o n t r o l p l o t s , as was  done at  P o r t Renfrew.  I n s t e a d , as the number of  increased,  in situ  denuded b l o c k s between and was  on the  " p a i r i n g " of denuded and  G l a c i e r Point  horizon-  l e v e l of the  p l o t s were s t a g g e r e d i n p o s i t i o n w i t h i n  Except d u r i n g the was  their  blocks  s e a s o n a l a s p e c t s of development.  c l o s e s t t o shore, P l o t IV was V was  The  c o n s i d e r e d u n i f o r m at  b e g i n s , s i x denuded p l o t s were e s t a b l i s h e d of the  study.  c o m p o s i t i o n , and  more or l e s s a l i g n e d  a situa-  the  one  flora  on the  non-  b l o c k beyond P l o t s I I I and  c o n s i d e r e d as a s i n g l e r e p r e s e n t a t i v e  control  IV  community.  8= Denuding The  d a t e s on which the p l o t s were denuded were: P o r t Renfrew . . „ . . . . June 3 ? Glacier Point  . . . . „  Victoria Plot I  0  21,  1962  V i c t o r i a P l o t I I . . . „ . Aug  14,  1962  Victoria Plot III  22,  1963  . June 8,  1963  . . . . Feb  Victoria Plot V  . . . . .  Aug  5,  1963  V i c t o r i a P l o t VI  . . = . „ Dec  1,  1963  r o c k s u r f a c e s were denuded by f i r s t  l a r g e r plants with a penknife, brushing burning  a weed-burner.  removing  f o l l o w e d by s c r a p i n g  w i t h a p a i n t s c r a p e r and with  1962  . . « . . May  Victoria Plot I f . . . .  The  June 4,  1962  the  and  a w i r e b r u s h , and  finally  A f t e r s c r a p i n g and b r u s h i n g  only v i s i b l e organic materials s t i l l  attached  t o the  the  surface  were (when t h e y were p a r t of t h e f l o r a b e i n g denuded) the e n c r u s t i n g t h a l l i o f P e t r o c e l i s f r a n c i s c a n a , the b a s a l p o r t i o n s of C o r a l l i n a v a n c o u v e r i e n s i s mosa, and  p o r t i o n s of k e l p h o l d f a s t s .  e l i m i n a t e d the p o s s i b i l i t y of any the s u r f a c e and brushing but  alone.  The  The  h o l d f a s t s of k e l p s  case,  and  a f t e r about  four  a comparison of " d i s t r i b u t i o n c h a r t s " made  a f t e r denuding d i d not  show any  s p a t i a l p o s i t i o n of the dead c r u s t s and  populants.  scraping  on  e n c r u s t i n g r e d a l g a e remained even  weeks.  the  treatment  c o u l d be burned o f f ,  these e v e n t u a l l y disappeared  and  burning  l i v i n g m a t e r i a l remaining  a f t e r burning;  before  and B o s s i e l l a p l u -  gave a " c l e a n e r " s u r f a c e t h a n w i t h  r e s i s t a n t p o r t i o n s o f the  I n any  encrusting  r e l a t i o n s h i p between t h a t of the  re-  Observation  Periods  As i n d i c a t e d i n f a b l e 1, an e f f o r t was made t o make observations  on a l l t h e p l o t s a t i n t e r v a l s o f a month o r l e s s .  Observations  were made o n l y d u r i n g low t i d e p e r i o d s when t h e  p l o t s were emergent.  The t a b l e excludes  observation  periods  <xuring which q u a n t i t a t i v e s p e c i e s - d i s t r i b u t i o n d a t a on f r e quency and abundance were n o t t a k e n .  Data The  Obtained  r e c o l o n i z i n g communities were c h a r t e d w i t h t h e a i d  of a g r i d d e d a p p a r a t u s .  T h i s c h a r t i n g d e v i c e had a 1 X 1 m  wooden frame e n c l o s i n g an a r e a t h a t was d i v i d e d b y w i r e s 20 X 20 cm g r i d s .  into  By c o u n t i n g t h e number o f g r i d s , o r s u b p l o t s ,  i n which a g i v e n s p e c i e s o c c u r r e d and then c o n v e r t i n g number t o p e r c e n t a g e o f o c c u r r e n c e , t h e g i v e n s p e c i e s was o b t a i n e d .  the frequency  Although  this  percentage of  none o f t h e s i x  V i c t o r i a p l o t s had p r e c i s e l y t h e same dimensions, t h e d i f f e r ences were n o t so g r e a t t h a t a r e l i a b l e comparison of f r e q u e n c y percentages  c o u l d n o t be made among them.  quency p e r c e n t a g e s w i t h those  all  o f one s i t e are n o t d i r e c t l y  o f another  the p e r c e n t a g e s  However, the f r e -  site.  comparable  F o r each o f t h e p l o t s a t V i c t o r i a ,  were based on a t o t a l o f 35 s u b p l o t s , n e a r l y  o f which were 20 X 20 cm; f o r the p l o t a t G l a c i e r P o i n t ,  the p e r c e n t a g e was based on a t o t a l o f 15 s u b p l o t s , o f which t e n c e n t r a l l y l o c a t e d ones were 50 X 50 cm and f i v e  marginal  ones ranged from h a l f t o s l i g h t l y l e s s than t h a t s i z e ; and f o r t h e P o r t Renfrew p l o t , t h e p e r c e n t a g e was based on 15 s u b p l o t s (on t h e v e r t i c a l f a c e , as d i s c u s s e d on p. 6 ) , 12 o f which were  10, TABLE 1. O b s e r v a t i o n p e r i o d s — e x c l u d i n g those p e r i o d s when o n l y q u a l i t a t i v e o b s e r v a t i o n s were m a d e — o n t h e p l o t s expressed as number of days a f t e r denuding  Observation date* Jun  Port Eenf,  Glac, Pt,  Vic, I  Vic, II  Vic, III  Vic. IV  Vic, V  15  5, 1962  Jun 16  13  13-  26  J u l 20  47  47  60  Aug 14  —  71  85  Sep  —  100  114  29  Oct 20  138  138  152  67  Dec 12  191  191  205  120  —  206  —  Jan 11, 1963  221  221  235  150  Feb  4  245  Feb  22  263  262  192  Apr  26  328  327  277 340  May 23  355  354  367  255 282  —  —  106  398  —  —  134  28  12  Dec 27  370  —  63 90  Jun  8  Jul  6  Aug  5  —  426  —  —  164  58  Aug 18  —  439  —  —  177  71  13  Sep  1  —  455  —  —  191  27  Oct  7  —  489  —  85 121  63  Nov  4  517  —  — •  Dec  1  545  —  —  —  399  .  —  —  Dec 28 Jan 15, 1964 Jan 26  Vic, VI  -—  —  227 255 282  149  91  176  118  309  203  145  27  338  232  174  56  590  * The d a t e s a r e a c t u a l ones f o r t h e V i c t o r i a p l o t s ; on t h e few o c c a s i o n s when t h e o b s e r v a t i o n p e r i o d a t t h i s s i t e l a s t e d f o r two days the date o f the f i r s t day i s g i v e n . F o r P o r t Renfrew and G l a c i e r P o i n t , t h e date o f o b s e r v a t i o n may be the same as V i c t o r i a , o r p l u s o r minus one day.  11. 20 X 20 cm and t h e r e m a i n i n g  t h r e e were 10 X 20 cm, 13 X 20 cm,  and 1 8 X 20 cm. A n o t h e r d i s t r i b u t i o n i n d e x , abundance, was f o r a l l t h e denuded p l o t s .  determined  I t i s p r e s e n t e d e i t h e r i n terms o f  s p e c i f i c d e n s i t y ( u s u a l l y f o r g r e g a r i o u s p o p u l a t i o n s ) o r as t o t a l number o f p l a n t s ( u s u a l l y f o r n o n - g r e g a r i o u s p o p u l a t i o n s ) . The  d e n s i t y , which i s s p e c i f i c r a t h e r than r e l a t i v e because i t  r e f e r s t o t h e a r e a o c c u p i e d b y t h e p o p u l a t i o n r a t h e r than t o a f i x e d a r e a such as t h a t o f t h e p l o t , was u s u a l l y o b t a i n e d  from  l a b o r a t o r y counts made on s c r a p i n g s . Growth r a t e s f o r d i s p e r s e d and l o n g - l i v e d forms were determined  as t h e s e forms appeared  v a t i o n p e r i o d to the next. forms,  on the p l o t s from one o b s e r -  For gregarious, short- or l o n g - l i v e d  t h e growth r a t e s were d e r i v e d from measurements of i n -  d i v i d u a l t h a l l i whose p o s i t i o n s were c h a r t e d b y " m i c r o t r a n s e c t s " . Two h o l e s , spaced surface. was  about 60 cm a p a r t , were d r i l l e d i n t h e r o c k  The h o l e s were then plugged w i t h wood and a screw  d r i v e n i n t o t h e wood.  W i t h a c o r d o r rubber band s t r e t c h e d  from screw t o screw, a m i c r o t r a n s e c t , about 2 cm wide, was obtained.  The p o s i t i o n o f t h e t h a l l i t o be measured was then  p l o t t e d on a c h a r t . F e r t i l i t y o b s e r v a t i o n s were made c o n c e r n i n g over 1,000 specimens c o l l e c t e d d u r i n g t h e course o f t h e s t u d y .  Most o f  t h e s e specimens were from t h e t h r e e e x p e r i m e n t a l s i t e s a t which c o l l e c t i o n s were made from denuded p l o t s , from i n s i t u p l o t s , and from areas i n t h e v i c i n i t y o f t h e p l o t s .  12.  Taxonomy The  f o l l o w i n g r e f e r e n c e s , which i n t h e i r e n t i r e t y  c o n s i s t of keys, d e s c r i p t i o n s , and  check l i s t s t o the  f l o r a of a l l or p a r t s o f the temperate r e g i o n of the Coast of N o r t h America, have served i d e n t i f i c a t i o n of the Smith  (1944),  Doty  1947b)  Pacific  as u s e f u l g u i d e s i n the  s p e c i e s : S e t c h e l l and  (1947a,  algal  and  Scagel  Gardner (1957).  (1920,  1925),  SYNOPSIS OP RESULTS AND A d e t a i l e d account  INTERPRETATION  of the r e s u l t s o b t a i n e d from the  d i f f e r e n t p l o t s i s g i v e n i n Appendix I ( T a b l e s 11-26).  This  d i s c u s s i o n c o n t a i n s o n l y a s y n o p s i s of the d a t a which are presented  i n accordance  w i t h one  of the o b j e c t i v e s of the  study, namely, to determine the p a t t e r n of development.  This  d i s c u s s i o n a l s o c o n t a i n s an a n a l y s i s of the d a t a as approached from the s t a n d p o i n t of the second o b j e c t i v e , which i s an to  attempt  p r o v i d e an e x p l a n a t i o n f o r the cause of the p a t t e r n . The  p a t t e r n of c o l o n i z a t i o n can be determined  i n i n g the f r e q u e n c y percentage convenience,  f i g u r e s ( T a b l e s 2-9),  by examwhich, f o r  have been t a b u l a t e d a p a r t from the o t h e r d a t a .  In  o r d e r t o a v o i d m i s i n t e r p r e t a t i o n , i t s h o u l d be noted t h a t the v a l u e of these f i g u r e s i s i n d e p i c t i n g r e l a t i v e t r e n d s i n development. throughout  The  final  e v a l u a t i o n of comments  expressed  t h i s d i s c u s s i o n r e s t s on the d e t a i l e d r e s u l t s  given  i n Appendix I . Examination  of the f r e q u e n c y percentage  figures  together  w i t h o b s e r v a t i o n s made on i n s i t u p o p u l a t i o n s i n d i c a t e s t h a t two  g e n e r a l t y p e s of r e p o p u l a n t s must be c o n s i d e r e d : those t h a t  produce new  thalli  through most of the y e a r and those t h a t  produce new  thalli  o n l y d u r i n g a s m a l l p o r t i o n of the  The  s e a s o n a l aspect of development can be  seen by  year.  comparing  p l o t s t h a t were denuded a t about the same time of a y e a r . example, V i c t o r i a P l o t s I and May  1962  and  June 1963,  For  IV, which were denuded d u r i n g  r e s p e c t i v e l y , are much more s i m i l a r t o  14.  62) Developmental e v e n t s , i n c l u d i n g c o n d i t i o n oust p r i o r t o denuding (Hay 21 TABLE 2, each w i t h i n i n terms of f r e q u e n c y p e r c e n t a g e . The r e c o l o n i z i n g s p e c i e s V i c t o r i a Plot phylum are l i s t e d f i r s t , i n the g e n e r a l o r d e r o f t h e i r appearance  3ays  Year: Day: Month: a f t e r denuding:  Ohrysophyta Amphipleura r u t i l a n s Navicula g r e v i l l e i Chlorophyta Ulothrix flacca >ora m i r a b i l i s Jrospora v a n c o u v e r i a n a Urospora w o r m s k i o l d i i Enteromorpha i i n z a Monostroma fuscum Ulva lobata Spongomorpha s p i n e s c e n s  1962 21 May  5  Jun  -  100  - 100 14 e 3 11 e  16 Jun  26  100  100  20 Jul  60  14 Aug  85  12 Sep 114  20  Oct  11 100 +  100 9  Fucus  evanescens  Rhodophyta Iridaea cordata Polysip'honia h e n d r y i Pterosiphonia bipinnata Odonthaiia f l o c c o s a Prionitls"lyallii B o s s i e l l a plumosa and C o r a l l i n a Vancouver!ensis Ant i t h a m n i o n subulatum Microcladia borealis Microciadia coulterT Petrocelis franciscana Hymenena f l a b e l l i g e r a Porphyra p e r f o r a t a Polypprolithon reclinatum llata  11  6  _  -  22 Feb  26 Apr  23 May  277  340  367  -  -  _  100 +  Phaeophyta Costaria costata A l a r i a marginata Heterochordaria abietina  Sedophyllum s e s s i l e  1963 11 Jan  152 205 235  14  91 100  12 Dec  14 —  —  69  77  97  100  6 71 60  11 9  9 6  11  3 3  3 14  17  20  20 + 83  23  37  31 86 6  11  97 9  51  69  17  11  —  6  9  —  -  6  11  14 6  11 26 89  11 17  + 40 20 14 3 Ir +  9 43 3 89 6  e  —  —  11 54 9 +  —  —  91  6 +  3  —  e  3 — e  - = absent, + = p r e s e n t , e = e p i p h y t i c .  —  15-  •TABLE 5o Developmental e v e n t s , i n c l u d i n g c o n d i t i o n j u s t p r i o r t o denuding (August 14, 1962), a t V i c t o r i a P l o t I I i n terms o f f r e q u e n c y p e r c e n t a g e . The r e c o l o n i z i n g s p e c i e s w i t h i n each phylum a r e l i s t e d f i r s t , i n t h e g e n e r a l order- o f t h e i r appearance  Year: 1962 Day: 14 Konth: Aug Days a f t e r denuding;  20  12 Sep 29  Oct 67  37  Chrysophyta Amphipleur rutiIan3 Javxcula g r e v i l l e i  -  100  Chiorophyta Urospora m i r a b i l i s Enteromorpha l i n z a Eonostroma fascum (and) Ulva lobata  3  100 26  100  12 Dec 120  1963  11 Jan  150  23  54 -  22 leb 192  26 Apr 255  60  (49) (43)  6  26 17 ~  11' Phaeophyta A l a r i a marginata Costaria costata Petalonia debilis Scytosiphon lomentaria Colpomenia s i n u o s a Hedophyllum s e s s i l e H a l f s i a fungiformis  11  -  43 —  —  —  46  +  29 —  9  —  49 3 11 29  34  +  37 29  60 29 17  -  20  11  6 3 3  e  — —  es 6 e  3  29 11  -  3  71 37 1 7  (74) 6  26  -  71  34  37 9  6e 6 +  Ehodophyta Pterosiphonia bipinnata P o T y ^ i p J i p j i l ^ h e ndrya. I r i d a e a cordata donthalia floccosa B o s s i e l l a plumosa and Corallina vancouveriensis O a l l o p h y l l i s sp<= Polyporolithon reciinatum P e t r o c e l i s franciscana. Prionitis l y a l l i i Microcladia borealis Microcladia coulter! Hymenena f l a b e l l i g e r a Laurencia s p e c t a b i l i s  - = absent, + = p r e s e n t ,  20  23 May 282  _ -  —  —  —  -  -  -  -  -  _  e = e p i p h y t i c , es = e p i p h y t i c and  saxicolouso  16 TABLE 40 Developmental events, at V i c t o r i a P l o t I I I i n terms phylum are l i s t e d  .Days  after  Year: Day: Month: denuding:  22, 1963),  i n c l u d i n g c o n d i t i o n gust p r i o r to denuding (February of frequency percentage. The r e c o l o n i z i n g s p e c i e s w i t h i n first, i n the general o r d e r of t h e i r appearance  1963  22  26  23  May  8 Jun  37 £5 97  -  -  80 69  91  83  37 14  97  54  97 60  -  -  -  Feb  Apr  63  6 »  60f 3 e  Phaeophyta Petalonia debilis Alaria marginata D e s m a r e s t i a munda  -  = absent,  + = present,  23  -  14 20 6 54  9  3  Ehodophyta Pterosiphonia bipinnata Iridaea cordata Prionitis l y a l l i i B o s s i e l l a plumosa and Corallina Vancouver!ensis Odonthalia floccosa Polyporoiithon reclinatum petrocelis franciscana licrocladia borealis  e  54 23  20 =  s  —  18  Aug  Sep  -  -  -  227  4 Nov  255  Dec  282  1964 26  509  338  Dec  Jan  11  97 23  74 17  74  54  9 6 3  9  -  (80) (86)(100) (94) (94)  23  -  -  —  -  -  3  —  -  —  es  =  epiphytic  and  43  94  49  6  9 9  +  3  e  epiphytic,  7  Oct  28  aw  29 3  -  Aug  each  3  43 6  —  6  Jul  90 106 134 164 177 191  6  Chlorophyta Urospora vrormskioldii Monostroma fuscum .and) Ulva lobata Spongomorpha coalita Enteromorpha l i n z a Spongomorpha spinescens Monostroma a r c t i c u m  o  saxicolous,  17TABLE 5Developmental e v e n t s , i n c l u d i n g c o n d i t i o n j u s t p r i o r t o denuding (June 8, 1963), a t V i c t o r i a P l o t IV i n terms of f r e q u e n c y percentageThe r e c o l o n i z i n g s p e c i e s w i t h i n each phylum are l i s t e d f i r s t , i n the g e n e r a l o r d e r of t h e i r appearance  Year: Day: Month: Days a f t e r denuding: Chr-ysophyta Amphipleura r u t i l a n s Navicula g r e v i l l e i  -  Chlorophyta Urospora wormskioldii Enteromorpha l i n z a Spongomorpha c o a l i t a Monostroma fuscum (and) Ulva lobata  6 Jul 28  Aug 58  100  69  26  -  34 es  100  18 Aug  100 6  bep 85  100 -  Phaeophyta Alar-ia m a r g i n a t a Petalonia debilis Costaria costata  7 Oct 121  100 (43)  14  14  74 34  6 6  1 Dec 176  28 Dec  -  100  100  97  100  100  97  11 6 3  11 9  11 3  100 100  11  37 11 3  26 74 23 es 6  e = e p i p h y t i c , es = e p i p h y t i c and  1964 26 Jan 203 232  4 Nov 149  34 es  Hhodophyta I r i d a e a cordata B o s s i e l l a plumosa and O o r a l l i n a vancouveriensis Petrocelis franciscana A n t i t h a m n i o n subulatum Odonthalia f l o c c o s a Prionitis l y a l l i i Pterosiphonia bipinnata Polyporolitho'n reclinatum Microcladia borealis  - = absent, + = present,  1963 8 Jun  saxicolous-  14  3 11  1 8 c  •TABLE 60 Developmental e v e n t s , i n c l u d i n g c o n d i t i o n j u s t p r i o r t o denuding (August 5 , 1 9 6 3 ) , a t V i c t o r i a P l o t V i n terms o f f r e q u e n c y percentage<> The r e c o l o n i z i n g s p e c i e s w i t h i n each phylum are l i s t e d f i r s t , i n t h e g e n e r a l o r d e r of t h e i r appearance Years Day: Month: Days a f t e r denuding: Jhrysophyta Amphipleura r u t i l a n s Navicula g r e v i l l e i Chlorophyta Enteromorpha l i n z a Monostroma fuscum (and) Ulva lobata Phaeophyta Petalonia debilis l i a n a marginata fedophyllum s e s s i l e Bhodophyta Iridaea cordata Prionitis l y a l l i i Tol o r o l i t h o n r e c l i n a t u m B o s s i e l l a plumosa and C o r a l l i n a vaneouveriensis Odonthalia f l o c c o s a Hymenena f l a b e l l i g e r a Cryptonemia obovata Rhodomela l a r i x  1963  1 9 6 4  18 Aug 1 3  5  Aug  -  1 0 0  1  Sep 2 7  7  Oct 6 3  3  4 0  8 6  9 4  e  s  )  Nov 91  1  2 8  2 6  Dec  Dec  Jan  1 1 8  1 4 5  1 7 4  8 6  1 0 0  6 6  9 4  5 4  1 0 0  4 6  ( 2 0  4  8 0  5 1  -  3 7  3 9  3 1 6  es  2 0  2 0 3  7 4  e  7 4 3 1 9 3 3  - = a b s e n t , e - e p i p h y t i c , es = e p i p h y t i c and  saxieolouso  1 1  19. TABLE 7° Developmental e v e n t s , i n c l u d i n g c o n d i t i o n j u s t p r i o r t o denuding (November 4, 1963), a t V i c t o r i a P l o t VI i n terms of f r e q u e n c y percentage» The c o l o n i z i n g s p e c i e s w i t h i n each phylum a r e l i s t e d i n t h e order of t h e i r appearance Note: The community a n a l y s e d b e f o r e denuding i s d a t e d November 4, however, the a c t u a l c o m p l e t i o n of the denuding procedure d i d not take p l a c e u n t i l December 1, T h e r e f o r e , the days a f t e r denuding b e g i n s from the l a t t e r d a t e .  Days a f t e r  Tear: Day: Month: denuding:  Chlorophyta Monostroma fuscum Phaeophyta R a l f s i a fungiformis Alaria~margxnata Ehodophyta Ant i t h a m n i o n subulatum Prionitis l y a l l i i PolyporoTithon reclinatum B o s s i e l l a plumosa and ~ C o r a l l i n a vancouveriensis P r i o n i t i s lanceolata Petrocelis franciscana Microcladia"*^*oulteri Iridaea cordata Laurencia spectabi1is  1963 4 Nov  4  63  28 Dec 27  1964 26 Jan 56  es  es  86*  80  14 3  86 6  !« 3 3  = absent, e = e p i p h y t i c , es = e p i p h y t i c and s a x i c o l o u s .  20, 'TABLE 80 Developmental events, i n c l u d i n g c o n d i t i o n j u s t p r i o r t o denuding (June 4, 1 9 6 2 ) , a t G l a c i e r P o i n t i n terms o f f r e q u e n c y percentageo The r e c o l o n i z i n g s p e c i e s w i t h i n each phylum a r e l i s t e d f i r s t , i n the g e n e r a l o r d e r of t h e i r appearance  Days a f t e r  Year: Day: Month: denuding:  1962 4 Jun  17 Jun  -  100  -  100  Chrysophyta Amphipleura r u t i l a n s Navicula g r e v i l l e i  Urospora m i r a b i l i s U l v a l o b a t a and; _Xva stenophylla Spongomorpha c o a l i t a Monostroma a r c t i c u m " Phaeophyta Halfsia fungiformis Petalorlia debilxs A l a r i a marginata Laminaria c u n e i f o l i a Haplogloia andersonii Hedophyllum s e s s i l e mcus evanescens C.ystos'eira geminata ° menzxesii Goi~ ornxca  13 1 5  e  7  e s  21 Jul  47  14 Aug  71  12 Sep 100  20 Oct 138  12 Dec  191  27 Dec 206  1963 11 Jan  221  27  80 53  93 40  93  27  Feb 262  Apr  Jun  370  80  87  73  47  87 73  327  87  87  87  40  47  40  80  53 27  60  7  80  7 33  27 7 27 27 7 7  .354  7 398  4 Aug 426  17 Aug 439  2 Sep 455  6 Oct 489  73  80  60  67  13  40 53  (67)  80  80  Jul  3 Nov  1  1964  15  517  Dec 545  Jan  590  53  13  7  53 53  80  13  7  9  24 May  (40) (53) 67 67  53  27  27  e  33  n (  33 7  20  20  20  13 7  7  e e  60  33°^  40  7  13 20 20  Ptilota filicina 7 Porphyra 13 es Plocamium oregonum B o s s i e l l a plumosa and C o r a l l i n a vancouveriensis Plocamium"  - = absent, + = present,  21  e = e p i p h y t i c , es = e p i p h y t i c and s a x i c o l o u s .  7 33  13  13  20  20  20  20  7  13 13  7 13  13 +  13  20  20  27  7  7  20  20  27  27  33  27  7  13  20 13  e  7  20 7  27 7 +  21. T A B L E 9° Developmental e ( J u n e 3, 1962), a t P o r t recolonizing species gene  Days  Chlorophyta Ent eromorpha Rhizocionium Ulva lactuca Spongomorpha Spongomorpha  a f t e r  Year: Day: Month: denuding:  +  =  present,  1963  3  16  20  19  11  Jun  Jun 13  J u l 4?  Oct 138  Dec 191  Jan 221  7 +  27  100  100  73  100 20  73  27 27  40  spinescens c o a l i t a  Rhodophyta Bangia fuscopurpurea Petrocelis franciscana Pterosiphonia bipinnata Polysiphonia. hendryi Microcladia borealis Iridaea cordata Halosaccion glandiforme Gigartina p a p i l l a t a  absent,  1962  l i n z a riparium  10  3 Feb 245  21  2?  Feb 263  Apr 328  53  7  Phaeophyta Petalonia d e b i l i s iPucus evanescens Ectocarpus sp. Scytosiphon lomentaria Leathesia difformis  =  vents, including condition just p r i o r to denuding Renfrew i n terms of frequency percentage. The w i t h i n each phylum are l i s t e d f i r s t , i n the ral order of t h e i r appearance  93  20  + +  47 13  a  e s  24May 355  7 Jul 399  7 7  13  53 7  100  100  53  73  87 +  7  (and)  (73) 60 7 20  20  7  e  =  epiphytic,  es  =  epiphytic  and  saxicolous,  13  22. each o t h e r i n development than t h e y are t o p l o t s t h a t were denuded a t a d i f f e r e n t time of a y e a r .  The  same i s t r u e f o r  V i c t o r i a P l o t I I , denuded d u r i n g August 1962, V, denuded d u r i n g August 1963° seasonal those  and V i c t o r i a P l o t  T h i s can he a t t r i b u t e d t o  appearance of c e r t a i n a l g a e and  then,  the  of c o u r s e ,  t h a t make appearances t h r o u g h most of the y e a r one  for must  c o n s i d e r the p r e s e n c e of optimum growth p e r i o d s . A l g a e t h a t produced new  t h a l l i most a b u n d a n t l y (sometimes  e x c l u s i v e l y ) d u r i n g the c o l d e r months of the year  included  Navicula g r e v i l l e i , H a l f s i a fungiformis, Gostaria costata, A l a r i a m a r g i n a t a , A n t i t h a m n i o n subulatum, and O d o n t h a l i a e x i s t e n c e of such p o p u l a n t s  i n d i c a t i o n t h e n was  o c c u r r i n g was  t h a t the g e n e r a l  "winter"  w i t h more r e l i a b l e e x p e r i m e n t a l established.  from the 1962  p r e d i c t a b l e , but t h a t the  by what appeared t o be  T h i s was  denuded p l o t s .  sequence of events sequence c o u l d be a l t e r e d  populants. evidence,  To demonstrate t h i s a "winter" p l o t  P l o t VI a t V i c t o r i a .  The  I t was  R a l f s i a f u n g i f o r m i s was  "non-win-  the f i r s t populant  f o l l o w e d by A l a r i a m a r g i n a t a , P r i o n i t i s l y a l l i i ,  A n t i t h a m n i o n subulatum.  distinctive;  populant  was  noticed. and  They appeared d u r i n g December and  u a r y , w i t h i n 56 days a f t e r denuding. ment was  was  results  ( T a b l e 7 ) were d r a s t i c a l l y d i f f e r e n t from t h a t of the ter" plots.  at the  The  became n o t i c e a b l e a f t e r a p r e l i m i n a r y  e x a m i n a t i o n of the d a t a g a t h e r e d The  floccosa.  T h i s p a t t e r n of  other p l o t s the e a r l i e s t  Jan-  developbenthic  a diatom, a f t e r which came c e r t a i n green a l g a l  species. Amphipleura r u t i l a n a , a s e s s i l e , c o l o n i a l diatom, the green a l g a l s p e c i e s U r o s p o r a m i r a b i l i s , U.  and  wormskioldii.  23. Enteromorpha l i n z a , Honostroma fliscum, and U l v a l o b a t a (see F i g . 5-8)  were c o n s i s t e n t i n a p p e a r i n g  on the o t h e r p l o t s a t  V i c t o r i a and, w i t h the e x c e p t i o n of H. fuscum, on the p l o t at G l a c i e r Point.  single  Indeed, among these s i x p l o t s the s p e c i e s  d i s p l a y e d a p a t t e r n of development t h a t had a h i g h degree of unanimity. A°  The  o r d e r and time  of appearance were as f o l l o w s :  m u t i l a n s , w i t h i n 13 days a f t e r denuding; Urospora  w i t h i n 15 days; E. l i n z a , w i t h i n 27 days; M. days; U. l o b a t a , w i t h i n 118  days.  spp.,  fuscum, w i t h i n 63  A n o t a b l e f e a t u r e of  s e r i e s o f c o l o n i z e r s i s t h a t the f i r s t  these  i s represented by  a  c o l o n i a l , u n i c e l l u l a r organism, the second by f i l a m e n t o u s v i d u a l s , and t h e t h i r d by parenchymatous t y p e s . during these f i r s t  Moreover,  appearances, the s p e c i e s were u s u a l l y r e p r e -  sented by p o p u l a t i o n s t h a t e v e n t u a l l y had and h i g h f r e q u e n c y percentage pure s t a n d s .  indi-  such a h i g h d e n s i t y  t h a t t h e y gave the appearance of  As the t a b l e s i n Appendix I w i l l  show, t h e s e  g r e g a r i o u s p o p u l a t i o n s were u s u a l l y composed of i n d i v i d u a l s r e p r e s e n t i n g a wide range of growth s t a g e s , from t i n y to large, f e r t i l e t h a l l i .  Because of the presence  of growth s t a g e s , and because of t h e i r s h o r t l i f e appear t h a t the s t a n d i t s e l f was  not due  group of i n d i v i d u a l s but r a t h e r i t was continuous  s e r i e s of maturing  That the t h a l l i was  t o any  germlings  o f an a r r a y span, i t would  one  "persisting"  b e i n g p e r p e t u a t e d by  individuals.  of t h e s e e a r l y p o p u l a n t s  are  brought out b y the m i c r o t r a n s e c t experiments.  short-lived As  an  example, of a t o t a l of 18 i n d i v i d u a l s of U l v a l o b a t a p l o t t e d two  a  on  of t h e t r a n s e c t s a t the V i c t o r i a breakwater, o n l y seven  remained a f t e r 11 t o 14 days.  Of the seven, t h r e e showed growth  24. ( l e n g t h ) i n c r e a s e s , , from 2.0 cm t o 7 ° 5 cm, and t h e r e m a i n i n g f o u r had d e c r e a s e d The  measurements, a p p a r e n t l y because o f e r o s i o n .  ephemeral c h a r a c t e r of t h e green a l g a e can be c o r r e l a t e d  w i t h t h e r e l a t i v e l y s h o r t p e r i o d o f time i t t a k e s f o r them t o become mature ( i . e . , f e r t i l e ) .  T a b l e 10 p r o v i d e s a g e n e r a l  r e p r e s e n t a t i o n o f t h e growth and m a t u r a t i o n  p e r i o d s f o r most  of t h e s p e c i e s i n v o l v e d i n t h e study. Members of t h e Phaeophyta and Rhodophyta made f i r s t appearances d u r i n g o r a f t e r the green a l g a l s t a g e . most c o n s i s t e n t e a r l y a r r i v a l s were I r i d a e a c o r d a t a , phonia b i p i n n a t a , and P o l y s i p h o n i a h e n d r y i .  Among t h e Pterosi-  These s p e c i e s  sometimes appeared b e f o r e t h e presence o f Monostroma fuscum and U l v a l o b a t a was n o t e d .  I n c o n t r a s t t o t h e diatom and green  a l g a l p o p u l a t i o n s t h e browns and r e d s tended t o have p o p u l a t i o n s t h a t had r e l a t i v e l y low d e n s i t i e s and f r e q u e n c y The  percentages.  low d e n s i t y ( T a b l e s 11-26) can be r e a d i l y a t t r i b u t e d t o  t h e i r growth h a b i t . besides having  Species  such as P i . b i p i n n a t a and Po. h e n d r y i ,  an e r e c t shoot  extensive p r o s t r a t e branching  p o r t i o n , a l s o have a r a t h e r system.  I n Bfc. b i p i n n a t a t h i s  system was found t o be up t o 10 cm i n d i a m e t e r (see T a b l e 16) at V i c t o r i a P l o t I I I .  Other s p e c i e s , l i k e lo c o r d a t a , Odon-  t h a l l i a f l o c c o s a , A l a r i a m a r g i n a t a , and C o s t a r i a c o s t a t a , have spreading h o l d f a s t s , e i t h e r d i s c - l i k e or branching, c l u d e t h e h i g h degree o f g r e g a r i o u s growth found mentioned green a l g a e .  that pre-  i n t h e above  However, a s p e c i a l type of g r e g a r i o u s -  ness might be noted here i n t h a t t h e d i s c - l i k e h o l d f a s t o f lo  c o r d a t a o r 0. f l o c c o s a n e a r l y always had s e v e r a l e r e c t  shoots,  each a t a d i f f e r e n t  stage o f development.  25* TABLE 10c T h a l l u s growth and stage o f m a t u r i t y from the time o f g e r m i n a t i o n as r e l a t e d t o days w i t h i n which t h e y o c c u r r e d Note: A s p e c i e s w i t h an a s t e r i s k i n d i c a t e s t h a t t h e d a t a f o r t h a t s p e c i e s were o b t a i n e d from i n d i v i d u a l p l a n t s . F o r other s p e c i e s the d a t a were d e r i v e d from a p o p u l a t i o n ; hence, t h a l l u s h e i g h t i s the maximum h e i g h t found w i t h i n a p o p u l a t i o n , and t h e time o f r e p r o d u c t i o n i s when t h e p o p u l a t i o n had r e p r o d u c i n g i n d i v i d u a l s .  Species  Growth P e r i o d (days w i t h i n )  Chrysophyta Amphipleura r u t i l a n s Navicula g r e v l l l e i Chlorophyta Ulothrix flacca Jrospora m i r a b i l i s Jrospora v a n c o u y e r i a n a Jrospora w o r m s k i o l d i i ;eromorpha l i n z a Monostroma fuscum Ulva i o b a t a " ~~ Spongomorpha c o a l i t a Phaeophyta Haplogloia andersonii Petalonia debilis *Costaria costaTa~ *Hedoph^rium s e s s i l e * A l a r i a marginata Rhodophyta Bangia f u s copurpurea P o r p h y ra p e r f o r a t a * B o s s i e l l a plumosa: >asal c r u s t e r e c t shoots •Pr-ionitis l y a l l i i *Iridaea c o r a a t a "  lenena flab*eTligera  T h a l l u s Height (cm)  15 27  11.0 9.0  15 15  0,15 2..2 5.0 10.0 37oO 9.0 27*0 4.0  11  26 30 29 30 13  R = Reproductive V = Vegetative  R R R R  27 34 30 28 65  24.0 10.0 21.0 33o0 135c0  R R V V V  16 16  6.0 34.0  R R  119 112  30 15  27  Lntithamnion subuiatum 27 29 poiysipnonia Pterosiphonia S n a t a 28 >Odon-fcnaiia f l occosa 13  (1. 1  width)  0.7 11. 0 15 <0 11. 0 2,0 3<0 7. 0 3<0  V V R V R R R V  26. A d e f i n i t e o r d e r o f events i n the brown and r e d a l g a e c o u l d not be d e s c r i b e d because  o f t h e i r s p a r s e growth.  In  c o n t r a s t , the p r e s e n c e o f each of the e a r l y a p p e a r i n g diatom and green a l g a l s p e c i e s was of  made e v i d e n t by a g r e a t abundance  i n d i v i d u a l s , which i n e f f e c t masked the e x i s t e n c e of o t h e r  species.  The i n d i c a t i o n i s t h a t the p a t t e r n of  development  d i s p l a y e d by these e a r l y c o l o n i z e r s i s , i n p a r t , a measure o f the  r e l a t i v e c o n s p i c u o u s n e s s o f the s p e c i e s w i t h r e s p e c t t o  time.  With diatom and green a l g a l s p e c i e s , c o n s p i c u o u s n e s s i s  due t o the combined e f f e c t of h i g h d e n s i t y and wide d i s t r i b u tion. With t h e subsequent and r e d a l g a l t h a l l i , of  growth and m a t u r a t i o n o f t h e brown  the p l o t g r a d u a l l y took on the  a d j a c e n t i n s i t u communities  ( F i g , 7)«  appearance  The time o f d e v e l o p -  ment, from d e n u d a t i o n t o the i n s i t u c o n d i t i o n , was  340 days a t  V i c t o r i a P l o t I ( s e e T a b l e 12) and 282 days a t V i c t o r i a P l o t I I (see  Table 14).  I t i s s i g n i f i c a n t t o note t h a t the time of  y e a r a t which b o t h p l o t s appeared l i k e t h e i n s i t u i s the same—May 1963«  communities  T h i s can be a t t r i b u t e d t o the f a v o r a b l e  growth p e r i o d a t t h i s time of y e a r f o r the s p e c i e s i n v o l v e d . The i n s i t u c o n d i t i o n , c h a r a c t e r i z e d by A l a r i a m a r g i n a t a , C o r a l l i n a v a n c o u v e r i e n s i s , B o s s i e l l a plumosa, and t o a s m a l l e r degree by I r i d a e a c o r d a t a , O d o n t h a l i a f l o c c o s a , and  Petrocelis  f r a n c i s c a n a , i s a l s o c o n s i d e r e d t o be, i n p a r t , a m a t t e r of r e l a t i v e conspicuousness.  I n t h i s c a s e , however, c o n s p i c u o u s -  ness i s r e l a t e d more t o s i z e than t o abundance. The o t h e r p l o t s a t V i c t o r i a were s t i l l s t a t e when the f i e l d  i n a pre-in  o b s e r v a t i o n s were t e r m i n a t e d .  situ  At G l a c i e r  27. P o i n t the s i t u a t i o n was  days from denuding, the p l o t 8,  24)o  supported  But note t h a t d u r i n g May  n u d i n g , 11 physical  s p e c i e s were p r e s e n t .  factors,  only s i x species  1963,  o r 354  such as the d e c l i v i t y and  The  days a f t e r  de-  smooth t e x t u r e  surf action,  attachment of the t h a l l i .  s i t u a t i o n , anchorage can be  (Tables  Perhaps a combination of  the r o c k s u r f a c e t o g e t h e r w i t h v i g o r o u s any p r o l o n g e d  590  somewhat d i f f e r e n t where, a f t e r  Apparently  of  prevented i n such a  a major problem.  P o r t Renfrew p l o t ,  situated  h i g h i n the  intertidal  zone, d i s p l a y e d a d i f f e r e n t type of development, a t l e a s t i n terms of s p e c i e s i n v o l v e d ( T a b l e s 9, were Enteromorpha l i n z a , R h i z o c l o n i u m p l o t , 328  copurpurea.  The  in  of community t h a t was  s i t u type  evanescens and  26).  The  first  colonizers  r i p a r i u m , and B a n g i a f u s -  days a f t e r denuding, supported  Balanus c a r i o s u s .  an  composed l a r g e l y o f Fucus As shown i n T a b l e s 9 and  26,  f o u r s p e c i e s t h a t were removed i n denuding d i d not r e a p p e a r as c o l o n i z e r s — e v e n a f t e r 499  days.  I t i s perhaps s i g n i f i c a n t t h a t  at the time of removal each of the f o u r s p e c i e s was by o n l y one, An  stages  individuals.  developmental a s p e c t  between the e x t e n s i v e  the a l g a l community.  n i t y was  was  or three  interesting  relationship and  two,  epizoic  of the p l o t .  on the s h e l l s of the b a r n a c l e .  By 263  saxicolous.  population  Young  attached  days a f t e r the  plot  days a f t e r denuding t h e y grew over most  Most, i f not a l l , of the a l g a l growth was  p o p u l a t i o n was  the  P r i o r t o denuding, the a l g a l commu-  t o the s h e l l s of the b a r n a c l e . cle  of t h i s p l o t was  Balanus c a r i o s u s  of the animal were f i r s t n o t i c e d 47  denuded.  represented  attached  P r i o r t o t h i s , when the b a r n a -  s p a r s e l y d i s t r i b u t e d , most of the a l g a e were  28. An  o r d e r l y appearance o f c o l o n i z i n g forms on a r t i f i c i a l l y  p l a c e d s u b s t r a t e s o r on denuded r o c k s u r f a c e s has been by o t h e r workers i n v a r i o u s p a r t s o f the w o r l d 1925;  (e.g.,  observed Wilson,  Bokenham, 1938; Eees, 1940; N o r t h c r a f t , 1948; M o l i n i e r  and P i c a r d ,  1953;  C i r i n o , 1958; H a r t o g ,  1959).  The s p e c i e s  i n v o l v e d depended f o r the most p a r t on the l o c a l i t y , b o t h e r a l ( g e o g r a p h i c a l ) and s p e c i f i c  (intertidal position).  gen-  But  a l t h o u g h t h e s p e c i e s may d i f f e r , these o b s e r v a t i o n s and those of  the p r e s e n t s t u d y p o i n t out an i n t e r e s t i n g  relationship  among the s u c c e e d i n g p o p u l a t i o n s o r communities.  This  ship: i s a m o r p h o l o g i c a l  fast-growing  one,  whereby s h o r t - l i v e d ,  forms are succeeded b y l o n g - l i v e d , slow-growing forms.  relation-  This  type o f s u c c e s s i o n was r e c o g n i z e d p a r t i c u l a r l y f i r s t b y Bokenham  (1938) and l a t e r b y N o r t h c r a f t (1948), and Fahey and Doty  (1949).  I t appears,  t h e r e f o r e , t h a t from the s t a n d p o i n t o f t h e  morphology o f the c o l o n i z e r s , t h e p a t t e r n o f development p r e sented b y d i f f e r e n t workers shows c o n f o r m i t y .  Differences l i e  i n attempts t o e x p l a i n why the p a t t e r n o c c u r s as i t does. A review  o f the l i t e r a t u r e g i v e s the i m p r e s s i o n t h a t two  s c h o o l s o f thought  prevail:  one contends the  developmental  p r o c e s s t o be an e x p r e s s i o n o f e c o l o g i c a l s u c c e s s i o n ; t h e o t h e r argues a g a i n s t e c o l o g i c a l s u c c e s s i o n . may  be omly a r b i t r a r y .  The d i s t i n c t i o n , however,  T h i s i s due t o the f a c t t h a t i t i s n o t  always c l e a r how the word s u c c e s s i o n i s b e i n g used.  Succession  i n the o r d i n a r y use o f the term i m p l i e s o r d e r l y sequence.  As  an e c o l o g i c a l term, s u c c e s s i o n must mean a p r o c e s s o f community development i n which f o r m a t i o n o f a g i v e n stage i s dependent on environmental  changes brought on b y a p r e v i o u s s t a g e .  Obviously,  29. the term must he used w i t h d e f i n i t i o n t o a v o i d ambiguity., the problem i n v o l v e s more t h a n mere d e f i n i t i o n .  But  I t also i n -  volves, with greater s i g n i f i c a n c e , i n t e r p r e t a t i o n , f o r accord i n g t o some workers o r d e r l y sequence i s i n d i c a t i v e of ical  ecolog-  succession.. To  i l l u s t r a t e t h i s a p r i o r i approach t o i n t e r p r e t i n g  observed d a t a , the work of C i r i n o most o t h e r a u t h o r s ,  (1958)  she l e a v e s l i t t l e  the term s u c c e s s i o n .  The  i s cited»  Fnlike  doubt as t o how  she  uses  f o l l o w i n g i s a q u o t a t i o n from page  31  of h e r paper: B i o t i c s u c c e s s i o n i s employed synonymously w i t h s e r a i progression, t r u e succession, succession proper, or s e r a i succession. I t i s i n t e r p r e t e d as i n d i c a t i v e of a s e r i e s of changes i n the b i o t a of any community c o n s i d e r e d as a whole, e x c l u s i v e of s e a s o n a l v a r i a t i o n s . . . . P h y s i c a l and c h e m i c a l changes, which may or may not be i n d u c e d by the b i o t a t h e m s e l v e s , change the environment p e r m i t t i n g the i n v a s i o n of the community by other organisms w i t h the subsequent displacement or e l i m i n a t i o n of the former occupants. Such continuous changes i n the community as a whole made obvious by a sequence of forms i s , h e r e , a c c e p t e d as s u c c e s s i o n . T h e r e f o r e , upon f i n d i n g a sequence of development t h a t independent of the seasons, C i r i n o concluded succession did My  that e c o l o g i c a l  occur.  interpretation differs.  I n s p i t e of the p r e s e n c e of  succession, I conclude that establishment ment i s not dependent on any e a r l i e r phase.  was  of a phase i n d e v e l o p  e n v i r o n m e n t a l change caused by  As mentioned above, the r e s u l t s of t h i s  are g e n e r a l l y c o n s i s t e n t w i t h those  r e p o r t e d by o t h e r s .  an  study This  c o n s i s t e n c y i s e v i d e n t when the p o p u l a t i n g s p e c i e s are viewed as m o r p h o l o g i c a l  entities.  30. L e s s complex t h a l l u s types appear b e f o r e more complex t y p e s : u n i c e l l u l a r forms appear b e f o r e f i l a m e n t o u s ones, mentous forms appear b e f o r e parenchymatous ones. lar in  forms, by v i r t u e of r e p r o d u c t i v e c e l l  The  unicellu-  d i v i s i o n , increase  such numbers t h a t t h e y become the most abundant  v e r y e a r l y a f t e r denuding.  fila-  colonizers  They become w e l l - d i s t r i b u t e d  over  the space a v a i l a b l e and form dense stands w h i l e the o t h e r growth forms a r e s t i l l  i n j u v e n i l e s t a g e s of development.  Presumably are  the s p o r e s , gametes, or zygotes of the m u l t i c e l l u l a r forms b e i n g c o n s t a n t l y t r a n s p o r t e d t o the r o c k s u r f a c e j u s t as u n i c e l l u l a r forms a r e .  T h i s i s where o t h e r a s p e c t s of  the  time  come i n t o p l a y . First t h e water.  of a l l t h e r e p r o d u c t i v e c e l l s must be p r e s e n t i n Furthermore,  t h e s e c e l l s may  but a c t u a l g e r m i n a t i o n may adverse  environmental  be d e l a y e d or even p r o h i b i t e d due  conditions.  t e r p r e t a t i o n l e t us assume (1)  But f o r purposes  (2)  of  t h a t the p h y s i c a l e n v i r o n -  f o r growth of these p o p u l a n t s , and  g e r m i n a t i o n o c c u r s immediately  to  of t h i s i n -  t h a t the r e p r o d u c t i v e c e l l s  c e r t a i n p o p u l a n t s are a v a i l a b l e , ment i s compatible  a t t a c h t o the s u b s t r a t e  (3)  that  o r soon a f t e r attachment.  Because of the n a t u r e of t h e i r growth form, f i l a m e n t o u s t y p e s such as U r o s p o r a  and U l o t h r i x would take l o n g e r t o  and mature than diatoms,  and parenchymatous t y p e s such  Monostroma and U l v a would take even l o n g e r .  as  These forms a r e ,  i n t u r n , ephemeral i n comparison t o the l o n g - l i v e d t h a l l i A l a r i a , Hedophyllum. Fucus, a longer l i f e  and the c o r a l l i n e s .  span seems t o be  develop  of  I n o t h e r words,  c o r r e l a t e d w i t h i n c r e a s e d spe-  c i a l i z a t i o n i n thallus structure.  I n terms of community  31. development t h i s means t h a t a l o n g - l i v e d i n d i v i d u a l w i l l  occupy  a space f o r a g r e a t e r l e n g t h o f time t h a n a s h o r t - l i v e d one. As t h e l o n g - l i v e d , u s u a l l y slow-growing, a l g a i n c r e a s e s i n s i z e its  space requirement a l s o i n c r e a s e s .  Ultimately i t w i l l  up a c e r t a i n growth a r e a w i t h i n which t h e e s t a b l i s h m e n t other algae  i s inhibited.  of  As t h e growth space d e c r e a s e s t h e  p r e v i o u s l y dominant f a s t e r - g r o w i n g  population gradually d i -  m i n i s h e s i n number ( s e e F i g . 8 ) and may d i s a p p e a r o r may o c c u r o n l y as e p i p h y t e s . crease  take  i s due t o a s h o r t l i f e  completely  I n any case, t h e a c t u a l de-  span of t h e a t t a c h e d i n d i v i d u a l s  as w e l l as due t o the l a c k o f growth space f o r the e s t a b l i s h ment o f new i n d i v i d u a l s o f t h e same p o p u l a t i o n . By t h i s i n t e r p r e t a t i o n the communities a r e c o n s i d e r e d not t o be the r e s u l t o f any i n t r i n s i c process The  o f development.  p a t t e r n of development, e s p e c i a l l y s u c c e s s i o n , i s i n t e r -  p r e t e d t o be a p r o c e s s  contingent  upon t h e morphology o f t h e  s p e c i e s and t h e phenology o f the v a r i o u s phases i n t h e l i f e h i s t o r y of the species.  The i n t e r p l a y o f these  two f a c t o r s  w i t h t h e a l l - i m p o r t a n t f a c t o r of space a v a i l a b i l i t y governs the abundance and d i s t r i b u t i o n o f t h e p o p u l a n t s .  Heretofore,  emphasis on a s c r i b i n g the i n t e r t i d a l d i s t r i b u t i o n of a l g a l s p e c i e s has been on p h y s i c a l f a c t o r s such as exposure, and  temperature.  salinity,  T h i s s t u d y has shown the b i o l o g i c a l f a c t o r  of space c o m p e t i t i o n  t o be no l e s s s i g n i f i c a n t .  Indeed, i t may  be t h e f a c t o r f o r t h e e x c l u s i o n o f some s p e c i e s from c e r t a i n types  o f communities.  SUMMARY P e r i o d i c o b s e r v a t i o n s were made on communities on denuded r o c k s u r f a c e s and  developing  on i n s i t u communities.  the denuded-quadrat method, a method f a m i l i a r t o  By u s i n g  terrestrial  p l a n t e c o l o g i s t s , s p e c i e s - d i s t r i b u t i o n i n d i c e s of f r e q u e n c y  and  abundance were t a k e n t o q u a n t i t a t i v e l y d e s c r i b e the s t a g e s of recolonization.  Data r e l a t i v e t o the developmental  process,  such as l i f e span and p e r i o d of r e p r o d u c t i o n o f t h e s p e c i e s i n v o l v e d , were a l s o  gathered.  S e a s o n a l v a r i a t i o n s i n development do o c c u r . a t t r i b u t e d t o t h e presence  o f optimum growth p e r i o d s and  the more o r l e s s r e s t r i c t e d p e r i o d s d u r i n g which new c e r t a i n s p e c i e s appear. time  (This i s  The  thalli  of  degree of v a r i a t i o n depends on  of y e a r a t which denuding took p l a c e .  d u r i n g the w i n t e r season had  to  the  A p l o t denuded  the g r e a t e s t v a r i a t i o n i n  development. D e s p i t e s e a s o n a l v a r i a t i o n s , the p a t t e r n of development i s p r e d i c t a b l e and  c o n s i s t e n t e s p e c i a l l y when viewed from  s t a n d p o i n t of m o r p h o l o g i c a l f i l a m e n t o u s forms, and chymatous t y p e s .  and brown a l g a e .  e n t i t i e s : u n i c e l l u l a r forms precede  t h e s e , i n t u r n , are fc-il-otoed by  paren-  I n g e n e r a l , the sequence of development  as f o l l o w s : f i r s t diatoms, The  the  was  t h e n green a l g a e , and f i n a l l y r e d  diatom  and green a l g a l s t a g e s were marked  b y p o p u l a t i o n s t h a t had h i g h d e n s i t i e s and f r e q u e n c y  percent-  ages, w h i l e the brown and r e d a l g a l s t a g e s were r e p r e s e n t e d "by p o p u l a t i o n s t h a t had  low d e n s i t i e s and f r e q u e n c y  percentages.  These d i f f e r e n c e s i n abundance  and d i s t r i b u t i o n a r e r e l a t e d  t o t h e growth h a b i t of the s p e c i e s . A l t h o u g h t h e p a t t e r n o f development i s c o n s i s t e n t and p r e d i c t a b l e , t h e r e i s no evidence  t o i n d i c a t e t h a t t h i s i s an  e x p r e s s i o n of e c o l o g i c a l s u c c e s s i o n .  The p a r t i a l o r even  t o t a l e l i m i n a t i o n o f a p o p u l a t i o n i s concluded t o any changes i n h a b i t a t o r i g i n a t e d by t h a t Instead  i t s elimination, partial  n o t t o be due  population.  or o t h e r w i s e ,  i s considered  t o be a consequence of the degree o f e s t a b l i s h m e n t proceeding  of the  population.  The s u c c e s s i o n a l phenomenon i s r e l a t e d t o t h e morphol o g i c a l nature  of the c o l o n i z i n g s p e c i e s , whereby simple  are f o l l o w e d by more complex ones. p r e t e d as b e i n g life  forms  Such a s u c c e s s i o n i s i n t e r -  i n d i c a t i v e of t h e r e l a t i v e growth r a t e s and  spans of the growth forms.  population occupies  The l e n g t h o f time i n which a  an a r e a i s determined b y t h e s e f a c t o r s .  The p r e s e n c e o r absence of growth space can be a main cause f o r l o c a l d i s t r i b u t i o n a l p a t t e r n s , e s p e c i a l l y f o r ephemeral species.  The dynamic s t r u c t u r e of the communities i s a t t r i -  buted t o species i n t e r a c t i o n i n v o l v i n g three factors:  interrelated  (1) t h e morphology of the organisms; (2) the phono-  l o g i c a l nature  of g e r m i n a t i o n ,  growth, r e p r o d u c t i o n , and of  spore o r gamete r e l e a s e ; and (3) the c o m p e t i t i o n  f o r space.  LITERATURE CITED Aleem, A. A. 1957 • S u c c e s s i o n o f marine f o u l i n g organisms on t e s t p a n e l s immersed i n deep-water a t L a J o l l a , C a l i f o r n i a . H y d r o b i o l o g i a 11(1): 40-58. B e v e r i d g e , W. A., and V. J . Chapman. 1950. The z o n a t i o n o f marine a l g a e a t P i h a , Hew Z e a l a n d , i n r e l a t i o n t o t h e t i d a l f a c t o r ( s t u d i e s i n i n t e r - t i d a l zonation 2). Pac. S c i .  4(3): 188-201.  Bokenham, N. A. H. 1938. The c o l o n i z a t i o n o f denuded r o c k s u r f a c e s i n t h e i n t e r t i d a l r e g i o n o f t h e Cape P e n i n s u l a . Ann. N a t a l Mus. 9(1): 47-81. C i r i n o , E . F. 1958. E v i d e n c e o f t r u e s u c c e s s i o n i n marine l i t t o r a l associations. Ph.D. T h e s i s . Boston U n i v . U n i v . M i c r o f i l m s , Ann A r b o r , M i c h . ( L . C. Card No. M i c 58-3095)» 251 PP. Coe,to".R. 1932. Season of attachment and r a t e o f growth o f s e d e n t a r y marine organisms a t t h e p i e r o f t h e S c r i p p s I n s t i t u t i o n o f Oceanography, L a J o l l a , C a l i f o r n i a . Bull. S c r i p p s I n s t . Oceanogr. Tech. S e r i e s 3(3): 37-86. D e x t e r , R. W. 1947. The marine communities o f a t i d a l i n l e t a t Cape Ann, M a s s a c h u s e t t s : a s t u d y i n b i o - e c o l o g y . Ecol. Monogr. 17(3): 261-294. Doty, M. S. 1947a. The marine a l g a e o f Oregon. P a r t I . C h l o r o p h y t a and Phaeophyta. F a r l o w i a 3(1): l-65« . 1947b. The marine a l g a e o f Oregon. p E y t a . F a r l o w i a 3(2): 159-215.  Part I I .  Rhodo-  Fahey, E . M., and M. S. Doty. 1949. P i o n e e r c o l o n i z a t i o n on i n t e r t i d a l transects. B i o l . B u l l . 97(2): 238-239. Gordon, M. S.,. and H. M. K e l l y . 1962. P r i m a r y p r o d u c t i v i t y o f an H a w a i i a n c o r a l r e e f : a c r i t i q u e o f f l o w r e s p i r o m e t r y i n t u r b u l e n t w a t e r s . E c o l o g y 43(3;: 473-480. H a r t o g , C. den. 1959* The e p i l i t h i c a l g a l communities o c c u r r i n g a l o n g t h e c o a s t o f t h e N e t h e r l a n d s . Wentia 1: 1-241. H a t t o n , H. 1932. Quelques o b s e r v a t i o n s s u r l e repeuplement en Fucus v e s i c u l o s u s des s u r f a c e s r o c h e u s e s denude'es. Bull. Lab. Mar. S t . - S e r v a n 9: 1-6.  35 e Herlinveaux, R. H . , and J . P. T u l l y . features of Juan de Puca S t r a i t . Canada 18(6): 1027-1071.  1961. Some oceanographic Jour. P i s h . Res. Bd.  Isaac, W. E. 1949. Studies of South A f r i c a n seaweed vegetation. II. Trans. Roy. Soc. South A f r i c a 32(2): 125-160^ Katada, M., and T. Matsui. 1954. Studies on the repopulation of the t i d a l vegetation (2). B u l l . Soc. Plant E c o l .  3(4): 153-157.  Kohn, A b J . , and P. H e l f r i c h . 1957. t i v i t y of a Hawaiian coral r e e f . 2(3): 241-251.  Primary organic producLimnol. and Oceanogr.  Lindeman, R. L. 1942. The trophic-dynamic aspect of ecology. Ecology 23(4): 399-417. M o l i n i e r , R. I960. Etude des biocenoses marines du Cap Corse. Vegetatio 9(3): 121-192.. M o l i n i e r , R., and J . P i c a r d . 1953. Recherches analytiques sur l e s peuplements l i t t o r a u x me'diterraneens se developpant sur substrat s o l i d e . Rec. Trav. S t a t . Mar. d'Endoume 9^4): 1-18. Moore, H. B. 1939. The c o l o n i z a t i o n of a new rocky shore at Plymouth. Jour. Animal E c o l . 8(1): 29-38. Muenscher, V. L. C. 1915• A study of the a l g a l associations of San Juan I s l a n d . P u b l . Puget Sound B i o l . S t a . 1: 59-84. Northcraft, R. D. 1948. Marine a l g a l c o l o n i z a t i o n on the Monterey Peninsula, C a l i f o r n i a . Amer. Jour. Bot. 35(7): 396-404. Odum, H. T . , and E . P. Odum. 1955° Trophic structure and p r o d u c t i v i t y of a windward c o r a l reef community on Eniwetok Atoll. E c o l . Mpnogr. 25(3): 291-320. P i e r r o n , R. P . , and Y. C. Huang. 1926. Animal succession of denuded rocks. P u b l . Puget Sound B i o l . S t a . 5: 149-157° R e d f i e l d , A . C . , and E. S. Deevy, J r . 1952. Temporal sequences and b i o t i c successions, pp. 4 2 - 4 7 ° In Marine f o u l i n g and i t s prevention, United States Naval I n s t i t u t e , Annapolis, Maryland. Rees, T. K. 1940. A l g a l c o l o n i z a t i o n at Mumbles Head. E c o l . 28(2): 403-437°  Jour.  Sargent, M. C . , and T. S. A u s t i n . 194-9° Organic p r o d u c t i v i t y of an a t o l l . Trans. Amer. Geophys. Union 30(2): 245-249°  36. Scagel, R. P. 1957 • An annotated l i s t of the marine algae of B r i t i s h Columbia and Northern Washington. N a t l . Mus. Canada, B u l l . 150. 289 pp« Scheer, B. T. 1945. The development of marine f o u l i n g commun i t i e s . B i o l . B u l l . 89(1): 103-121. S e t c h e l l , W. A., and N. L. Gardner. 1920. The marine algae of the P a c i f i c Coast of North America. Part I I . Chlorophyceae. Univ. C a l i f o r n i a Publ. Bot. 8(2): 139-375« . 1925» The marine algae of the P a c i f i c Coast of North America. Part I I I . Melanophyceae. Univ. C a l i f o r n i a Publ. Bot. 8(3): 383-898. Shelford, Y. E. 1930. Geographic extent and succession i n P a c i f i c North American i n t e r t i d a l (Balanus) communities. Publ. Puget Sound B i o l a. Sta. 7: 217-223. Smith, G. M. 1944. Marine algae of the Monterey Peninsula, C a l i f o r n i a . Stanford Univ. Press, i x + 622 pp. Varma, R. P. 1959* Studies on the succession of marine algae on a f r e s h substratum i n Palk Bay. Proc. Indian Acad. S c i . 49B(4): 245-263. Weaver, J . E., and P. E. Clements. 1938. Plant ecology. Ed. McGraw-Hill Book Co., New York, x x i i + 601 pp.  2nd  Wilson, 0. T. 1925Some experimental observations of marine a l g a l successions. Ecology 6(3): 303-311°  37  o  Pig,  1» Southwest p o r t i o n o f B r i t i s h Columbia, showing t h e t h r e e e x p e r i m e n t a l s i t e s : P o r t Renfrew, G l a c i e r P o i n t , and V i c t o r i a Breakwatero  39  o  Pigo 2 o Denuded p l o t a t P o r t Renfrew photographed on 1 6 June 1 9 6 2 , 1 3 days a f t e r denuding. The r i g h t h a l f of t h e b o u l d e r s u p p o r t s the c o n t r o l community. Pig.  3 ° Denuded p l o t a t G l a c i e r P o i n t photographed on 1 7 June 1 9 6 2 , 1 3 days a f t e r denuding. The meter s t i c k l i e s on the non-denuded h a l f of the b o u l d e r . The i n s i t u communities on t h e b o u l d e r and a d j a c e n t t o t h e b o u l d e r s e r v e d as c o n t r o l s .  Pig.  4 . P o r t i o n of the V i c t o r i a Harbor breakwater p h o t o graphed on 5 August 1 9 6 3 a t low t i d e . The s i x denuded p l o t s were on t h e lowermost ( 6 t h ) t i e r . The a l g a l growth t o t h e l e f t of the breakwater i s H e r e o c y s t i s luetkeana.  Fig.  5 » The U r o s p o r a w o r m s k i o l d i i and Enteromorpha l i n z a stage on V i c t o r i a P l o t I on 2 0 J u l y 1 9 6 2 , 6 0 days a f t e r denuding. Some of t h e a l g a e on the non-denuded b l o c k to t h e l e f t a r e I r i d a e a c o r d a t a , O d o n t h a l i a f l o c c o s a , M i c r o c l a d i a b o r e a l i s , and B o s s i e l l a plumosao  Fig.  6 o On the r i g h t i s a p o r t i o n of the V i c t o r i a P l o t I I I c o l o n i z i n g community composed m a i n l y of Monostroma fuscum and Spongomorpha c o a l i t a . On the l e f t i s p a r t of a c o n t r o l community w i t h A l a r i a m a r g i n a t a , C o r a l l i n a y a n c o u v e r i e n s i s , and B o s s i e l l a plumosa d o m i n a t i n g . ™~ Photographed on 5 August 1 9 6 3 , 1 6 4 days a f t e r denuding.  Figo 7 = The b l o c k w i t h p a r t o f i t i n the c e n t e r of t h e phot o g r a p h i s V i c t o r i a P l o t I on 23 May 1 9 6 3 , 3 6 7 days a f t e r denuding. I t can h a r d l y be d i s t i n g u i s h e d from the non-denuded b l o c k s above and below i t . Fig.  8. C l o s e - u p of boxed s e c t i o n i n F i g . 7 t o show a dense p a t c h of U l v a l o b a t a and Enteromorpha l i n z a occupying an a r e a on t h e denuded p l o t (.bottom h a l f of t h e p h o t o graph) t h a t , a t the t i m e , had o n l y s m a l l , young t h a l l i of I r i d a e a c o r d a t a , O d o n t h a l i a f l o c c o s a , C o r a l l i n a yanc o u v e r i e n s i s , and B o s s i e l l a plumosa.  APPENDIX I DETAILED OBSERVATIONS  ON DEVELOPMENT  Each denuded p l o t , s i x a t the V i c t o r i a breakwater, one at G l a c i e r P o i n t , and one a t P o r t Renfrew, i s d i s c u s s e d byd e s c r i b i n g f i r s t t h e community removed the  i n denuding and second  communities a p p e a r i n g i n r e c o l o n i z a t i o n .  clude  The t a b l e s i n -  t h e f o l l o w i n g terms and symbols:  F r e q u e n c y = number o f s u b p l o t s the s p e c i e s o c c u r r e d i n mult i p l i e d b y 100, t h e n d i v i d e d b y t h e t o t a l number of s u b p l o t s ( s e e s e c t i o n on methods). Abundance = i n terms o f t h e t o t a l number o f t h a l l i o r as t h e s p e c i f i c d e n s i t y (see s e c t i o n on methods). When t h e r e was a c l u s t e r o f b l a d e s a t t a c h e d t o a s i n g l e h o l d f a s t , as i n I r i d a e a , t h e e n t i r e s t r u c t u r e was c o n s i d e r e d t o be one t h a l l u s . Repr. o r E =  reproductive.  Vege. o r V = v e g e t a t i v e . _e = e p i p h y t i c . P a t c h = an aggregate o f t h a l l i  o f t h e same  species.  42. Development a t V i c t o r i a P l o t I ( T a b l e 12) B e f o r e denuding on May 21, 1962, t h i s p l o t community composed m a i n l y o f t h e a r t i c u l a t e d  supported a  corallines  B o s s i e l l a plumosa and C o r a l l i n a v a n c o u v e r i e n s i s ( T a b l e 1 1 ) . These c o r a l l i n e s , and t o a l e s s e r e x t e n t P e t r o c e l i s f r a n c i s c a n a , formed a conspicuous  c r u s t a l layer that c o l l e c t i v e l y  n e a r l y 50 p e r cent o f t h e p l o t ' s s u r f a c e .  covered  The l a r g e s t  coralline  p a t c h (formed by t h e g e n e r a l l y c o n f l u e n t c r u s t s o f many t h a l l i ) p  measured r o u g h l y 1,040 cm . 2 was 141 cm .  The l a r g e s t P. f r a n c i s c a n a p a t c h  E p i p h y t i c c r u s t s of P o l y p o r o l i t h o n r e c l i n a t u m  were on a l l t h e c o r a l l i n e specimens examined.  Besides  this  common a r t i c u l a t e d - c o r a l l i n e e p i p h y t e , a t t a c h e d t o t h e c o r a l l i n e s were a few t h a l l i  of each o f t h e f o l l o w i n g :  Spongomorpha  s p i n e s c e n s and Monostroma fuscum, which were on "both  coralline  s p e c i e s ; U l v a l o b a t a , which was on B. plumosa; and H e t e r o c h o r d a r i a a b i e t i n a , whose h o s t ( s ) , as r e g a r d s t o s p e c i e s , was n o t recorded. thalli  Spongomorpha s p i n e s c e n s was a l s o on t h e o n l y two  o f Fucus evanescens.  t i e r o f t h e breakwater. of Porphyra  Fucus was n o t seen a g a i n a t t h i s  As w i t h F. evanescens,  t h e two t h a l l i  p e r f o r a t a were t h e o n l y specimens o f t h e genus seen  on t h i s t i e r .  However, b o t h genera were commonly p r e s e n t and  o c c u r r e d abundantly Prionitis l y a l l i i ,  on t h e upper t i e r s .  Of t h e 11 t h a l l i o f  f o u r had t h e e p i p h y t e M i c r o c l a d i a c o u l t e r i .  Animal p o p u l a t i o n s were s p a r s e ; o f t h e more conspicuous  ones,  t h e r e were e i g h t c h i t i n specimens of t h e s p e c i e s T o n i c e l l a l i n e a t a and K a t h a r i n a t u n i c a t a , and f i v e l i m p e t specimens a l l of which were of Acmaea t e s t u d i n a l i s  scutum.  43. TABLE 11o Enumeration o f t h e community p r e s e n t b e f o r e denuding a t V i c t o r i a P l o t I on May 21, 1962  Species  Abundance (total)  Thallus height (cm)  14® 3  5 8 2  2 t o 11 - to 6 9, 12  R R V  9 9 6 6  4 3 2 2  - t o 12  R  10, 10  V  2  7, 8  R R  Frequency (%)  K  Chlorophyta Spongomorpha s p i n e s c e n s Monostroma fuscum Ulva l o b a t a  e  Phaeophyta Heterochordaria abietina Hedophyllum s e s s i l e A l a r i a marginata Fucus"evanescens Rhodophyta Porphyra p e r f o r a t a Polypo'rolithon reclinatum B o s s i e l l a plumosa and —H  1  -i  1  *  1.  j  Prionitis l y a l l i i Petrocelis franciscana Gigartina papillata Iridaea cordata Microcfadia coulteri Odonthalia f l o c c o s a  e  -  89 .  (17 p a t c h e s ) 11 (10 p a t c h e s ) 2 7  89 26 43 6 p 9 11 n  e  —  8  e = e p i p h y t i c , see p r e v i o u s page f o r d e t a i l s .  —  _  - t o 20 —  6, 10 - t o 35 - t o 10 - t o 16  Repr,=R Vege,=V  — —  R R V R R R R  44 o TABLE 12o  Enumeration o f r e c o l o n i z i n g communities a t Victoria Plot I  Species  Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  June 5, 1962 (15 days a f t e r  Repr.=R Vege =V 0  denuding)  Chrysophyta Amphipleura r u t i l a n s  100  P 12.6/cm  Chlorophyta Ulothrix flacca Urospora m i r a b i l i s  100  P 63.7/cmp 9.6/cm  - t o 11 0.02 t o 0.15 0.4 t o 2.2  Remarks: Except f o r some m a r g i n a l a r e a s , t h e a t t a c h e d and c o l o n i a l diatom, Amphipleura r u t i l a n s , covered t h e e n t i r e p l o t . I t s c o l o n i a l h a b i t , which s i m u l a t e s a branched c y l i n d r i c a l t h a l l u s , and i t s dense growth combined t o form a c a r p e t - l i k e a l g a l mass t h a t appeared as a pure s t a n d . However, beneath t h i s dense c o v e r were s h o r t f i l a m e n t s o f U r o s p o r a m i r a b i l i s . A n o t h e r f i l a m e n t o u s green a l g a , U l o t h r i x flacca,~"and a l s o o t h e r c o l o n i a l diatoms ( B i d d u l p h i a l a e v i s , M e l o s i r a s p . , P r a g i l a r i a sp. and Licmophora sp.T were found t o be p r e s e n t through microscopic, examination o f a s c r a p i n g t a k e n from a 6 X 6 cm a r e a near t h e p l o t ' s c e n t e r . The s p e c i f i c d e n s i t i e s were o b t a i n e d from t h i s s c r a p i n g . June 16, 1962 (26 days a f t e r  denuding)  Chrysophyta Amphipleura r u t i l a n s  100  -  - to 8  Chlorophyta Urospora vancouveriana 100 - to 6 Remarks: Amphipleura r u t i l a n s s t i l l formed a dense, e x t e n s i v e cover and t h e g e n e r a l appearance o f t h e p l o t was l i k e t h a t o f the p r e v i o u s o b s e r v a t i o n . E x a m i n a t i o n o f s c r a p i n g s , which were s c a n t y due t o stormy wave a c t i o n , i n d i c a t e d o n l y o t h e r diatoms (as t h o s e mentioned f o r t h e June 5 s c r a p i n g ) and Urospora vane ouve r i an a t o be p r e s e n t . The U r o s p o r a t h a l l i were more abundant i n t h e o u t e r , o r seaward, h a l f o f t h e p l o t than i n t h e inner h a l f . J u l y 20, 1962 (60 days a f t e r  denuding)  Chrysophyta Amphipleura r u t i l a n s Chlorophyta Urospora wormskioldii Enteromorpha l i n z a  14  13 t o t a l  91 100  - p 22/cm  - to 3 - to 4 - t o 35  R  45. TABLE 12.  Continued Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Species  J u l y 20,  1962  (60 days a f t e r  Rhodophyta Iridaea cordata  Repr.=R Vege. = v"  denuding)—Continued 6  5 total  - to 4  V  Remarks: The community was now dominated by a dense Enteromorpha l i n z a p o p u l a t i o n t h a t , except f o r two s m a l l areas a l o n g the edge, c o m p l e t e l y c o v e r e d the p l o t . The p o p u l a t i o n was composed of m i c r o s c o p i c g e r m l i n g t o l a r g e , f e r t i l e s t a g e s . Urospora w o r m s k i o l d i i was n e a r l y as e x t e n s i v e as E., l i n z a i n d i s t r i b u - .... t i o n ; i t was absent o n l y from a a p p r o x i m a t e l y 17-X 100 cm a r e a , which was a d j a c e n t t o the v e r t i c a l w a l l of the next upper tier. The I r i d a e a c o r d a t a t h a l l i , each as u s u a l w i t h a c l u s t e r , of b l a d e s a r i s i n g from a s i n g l e h o l d f a s t , were growing w i t h i n t h i s i n n e r p o r t i o n of t h e p l o t . They were young t h a l l i . . The 13 c o l o n i a l t h a l l i of the p r e v i o u s l y dominating Amphipleura r u t i l a n s p o p u l a t i o n were w i d e l y s c a t t e r e d and appeared o l d because of t h e i r b a t t e r e d appearance and the heavy c o a t i n g of diatoms on t h e i r "branches". Two specimens of the l i m p e t Acmaea t e s t u d i n a l i s scutum had m i g r a t e d t o the p l o t . Each had w e l l - d e v e l o p e d a l g a e growing on t h e i r s h e l l s : one had Spongomorpha s p i n e s c e n s ; the o t h e r , B o s s i e l l a plumosa. The d e n s i t y f o r E. l i n z a was based on an i n s i t u count made on a 5 X 5 cm area. August 14,  1962  (85 days a f t e r denuding)  Chlorophyta Urospora wormskioldii Enteromorpha l i n z a Monostroma fuscum Rhodophyta Iridaea cordata  11 100 v 9a  (4 p a t c h e s ) 35/cm -  - t o 41 - t o 0.5  R R V  6 total  - t o 12  Y  Remarks: Enteromorpha l i n z a , whose d e n s i t y was o b t a i n e d from a count made i n s i t u , now o v e r l a i d t h e e n t i r e p l o t . As p r e v i o u s l y , a l l a F a g e s of development were p r e s e n t . The U r o s p o r a w o r m s k i o l d i i p a t c h e s ranged from 27 t o 41 cm2. Of the s i x c l u s t e r s of I r i d a e a c o r d a t a b l a d e s , two were the same ones noted d u r i n g the p r e v i o u s o b s e r v a t i o n . The o t h e r s made t h e i r appearance some time between t h i s o b s e r v a t i o n p e r i o d and the one p r e c e d i n g . The t a l l e s t of the two o l d e r c l u s t e r s measured 12 cm. Young, h e m i s p h e r i c a l t h a l l i of Monostroma fuscum were p r e s e n t but were o v e r l o o k e d i n the f i e l c l ^ They were found w i t h the E. l i n z a specimens brought t o the l a b o r a t o r y .  46 TABLE 12*  o  Continued  Species  Thallus Frequency Abundance height (%) (den or t o t ) (cm) 0  Repr.=R Vege.=V  0  September 12, 1962 (114 days a f t e r denuding) Chlorophyta Enteromorpha l i n z a Monostroma fuscum Rhodophyta Iridaea cordata Polysiphonia hendryi  100 9 14 6  (3  patches)  12 t o t a l 4 total  2 t o 18 - to 9  R R  - t o 16 2 to 3  R R  Remarks: The g e n e r a l appearance o f t h e p l o t was s i m i l a r t o what i t was d u r i n g t h e l a s t two o b s e r v a t i o n p e r i o d s , which were made 29 and 54 days e a r l i e r . The Enteromorpha l i n z a p o p u l a t i o n was s t i l l dense and e x t e n s i v e ; t h a l l i l e s s t h a n 1 . 7 cm t a l l were not e v i d e n t . The l a r g e s t o f t h e t h r e e Monostroma fuscum p a t c h e s was 26 cm^. T h i s a l g a was a l s o on the s i n g l e . Acmaea ..... specimen p r e s e n t . T h i s p a r t o f t h e M. fuscum p o p u l a t i o n i s n o t i n c l u d e d i n t h e f r e q u e n c y p e r c e n t a g e because o f t h e m i g r a t o r y nature o f t h e l i m p e t . The 12 I r i d a e a c o r d a t a c l u s t e r s appeared a f t e r August 14; hence, none o f those t h a t were p r e s e n t on August 14 had s u r v i v e d . October 20, 1962 (152 days a f t e r denuding) Chlorophyta Monostroma fuscum Ulva lobata Rhodophyta Iridaea cordata Polysiphonia hendryi  100  11 17  0.4/cm  £  3 to 9 - to 4  V V  4 total 8 total  Remarks: A green a l g a l c o v e r was s t i l l p r e s e n t b u t i t was now formed b y Monostroma fuscum. I t s d e n s i t y was determined from a count made i n s i t u on two 20 X 20 cm a r e a s . Ulva lobata, whose p r e s e n c e was n o t a n t i c i p a t e d , was found w i t h t h e M« f u s cum specimens c o l l e c t e d . The o n l y i n f o r m a t i o n a v a i l a b l e on Il rr ii d a e a c o r d a t a and P o l y s i p a a e a c o r d a t a ana r o i y s i p hn oo nniiaa h e n d r y i i s from t h e d i s t r i b u t i o n c h a r t s ; t h e s e show t h a t f o r b o t h s p e c i e s t h e t h a l l i now p r e s e n t were new growths, because none o f t h e those r e c o r d e d f o r September 12 s u r v i v e d December 12, 1962 (205 days a f t e r denuding) Ghrysophyta Navicula g r e v i l l e l  11  4 total  - to 6  TABLE 12.  Continued  Species  Frequency (%)  Abundance (den.  or  Thallus height  t o t o )  Repr.=R Vege.=V  (cm)  December 12, 1962 (205 days a f t e r d e n u d i n g ) — C o n t i n u e d Chlorophyta Ulva lobata  69  0<»8/cm  Phaeophyta Costaria costata A l a r i a "marginata  11 9  4 total 4 total  3 14 17  2  Rhodophyta B o s s i e l l a plumosa and C o r a l l l n a vancouveriensis Prionitis""lyallii ~ " Iridaea"Tordata Ajotithamnion supulatum Microcladia borealis Polysiphonia~hendryi ^teroslphonia bipinnata Odonthalia f l o c c o s a  2  total 5 total 8 total  -  to  2 3  to 4 to 9  V Y  2  to 3 to 14 to 2 to 2 to 4 t o 11 to 3  Y Y R V V R R Y  —  —  40 20  23 22  —  —  —  —  total total  —  -  14  V  Remarks: Of t h e 13 s p e c i e s now p r e s e n t , o n l y t h r e e , U l v a l o b a t a , I r i d a e a c o r d a t a and P o l y s i p h o n i a h e n d r y i , had made p r e v i o u s appearances. U l v a l o b a t a dominated i n a r a d i u s o f 30 t o 45 cm from t h e c e n t e r o f the p l o t . I t s d e n s i t y was o b t a i n e d i n s i t u from t h i s a r e a , which c o n s t i t u t e d about 40 p e r cent of "EKe p l o t ' s s u r f a c e . There were 11 l a r g e U. l o b a t a t h a l l i beyond t h i s area. Growing w i t h i n t h e U l v a dominated a r e a were a l l t h e N a v i c u l a g r e v i l l e i and C o s t a r i a c o s t a t a t h a l l i , most (20) of the O d o n t h a l i a f l o c c o s a , h a l f (4) o f t h e I_. c o r d a t a , a few (4) of t h e P t e r o s i p h o n i a b i p i n n a t a , and o n l y one of t h e P r i o n i t i s lyallii" A l l o f t h e I . c o r d a t a t h a l l i were new a r r i v a l s . The t h a l l i o f _0. f l o c c o s a were i n an e a r l y stage o f development where the shoot p o r t i o n , which e v e n t u a l l y becomes u p r i g h t , was prostrate. T h i s young growth-habit c o n d i t i o n i n 0. f l o c c o s a was observed throughout t h e course o f t h e study. The c o r a l l i n e t h a l l i , c o n s i s t i n g o f two c r u s t a l b a s e s , 1.5 and 2 cm wide, w i t h e r e c t , unbranched s h o o t s , were s i t u a t e d n e a r t h e edge o f one of t h e l a t e r a l s i d e s o f the p l o t . Young A l a r i a m a r g i n a t a b l a d e s , w i t h o u t s p o r o p h y l l s , were n e a r the o u t e r , o r seaward, edge. The d i s t r i b u t i o n p a t t e r n of M i c r o c l a d i a b o r e a l i s , A n t i t h a m n i o n subulatum and P. h e n d r y i was not r e c o r d e d .  48< TABLE 12.  Continued  Species  Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Repr.=R 7ege.=7  J a n u a r y 11, 1965 (255 days a f t e r denuding) Chrysophyta Navicula g r e v i l l e i Chlorophyta Ulva lobata Phaeophyta Costaria costata A l a r i a marginata  6 77  4 total  -  - to 5 - t o 15  9 6  6 total 3 total  Rhodophyta B o s s i e l l a plumosa and C o r a l l i n a Vancouver!ensis Prionitis lyallTT 9 Iridaea cordata 20 Pterosiphonia bipinnata 11 Odonthalia f l o c c o s a 54  4 total 34 t o t a l 14 t o t a l 0. 2/cm  2  2 t o 21 29, 32, 33  2 3 -  to to to to  8 14 13 2  7 7 7  7 R R 7  Remarks: I n g e n e r a l appearance, t h e community was s i m i l a r t o the one p r e c e d i n g . U l v a l o b a t a dominated t h e p l o t ' s c e n t r a l a r e a as b e f o r e b u t over a s l i g h t l y i n c r e a s e d r a d i u s . T h i s dense U l v a p a t c h now cohered about 48 p e r cent o f t h e p l o t ' s s u r f a c e . I n c l u d e d i n t h i s a r e a ^ e r e a l l t h e N a v i c u l a g r e v i l l e i and C o s t a r i a c o s t a t a p r e s e n t , most o f t h e P r i o n i t i s l y a i i i i (3) ^ a n ^ O d o n t h a l i a f l o c c o s a , about a t h i r d o f t h e P t e r o s i p h o n i a b i p i n n a t a , and o n l y two o f the I r i d a e a c o r d a t a " The f r e q u e n c y p e r c e n t a g e o f jO. f l o c c o s a i n c r e a s e d more t h a n 2.5 t i m e s , b u t i t s d e n s i t y , which was determined i n s i t u , remained about t h e same. I r i d a e a c o r d a t a had o n l y a s l i g h t i n c r e a s e i n f r e q u e n c y p e r c e n t a g e b u t the number o f t h a l l i i n c r e a s e d by 26. O n l y one of i t s t h a l l i was p a r t o f t h e December 12 p o p u l a t i o n . This " s u r v i v o r " had, among o t h e r s , a b l a d e measuring 14 cm l o n g , w h i l e t h e o t h e r c l u s t e r s had b l a d e s l e s s t h a n 3 cm l o n g . I t a l s o had t h e o n l y o b v i o u s l y f e r t i l e b l a d e . A l l 14 t h a l l i o f P. b i p i n n a t a were new a r r i v a l s . There i s some doubt as t o whether o r not a t l e a s t two of the P. l y a l l i i t h a l l i were a l r e a d y p r e s e n t on December 12. OnTy one o f t h e JC. c o s t a t a t h a l l i was from t h e December p o p u l a t i o n . I t grew 17 cm i n 30 days. A l l t h r e e A l a r i a m a r g i n a t a t h a l l i were new a r r i v a l s ; t h e i r s p o r o p h y l l - l e s s s t i p e s had a u n i f o r m l e n g t h o f 3«5 cm. C o r a l l i n e c r u s t s were m e r e l y r e c o r d e d as b e i n g p r e s e n t .  49. TABLE 12.  Continued  Species  Frequency (%)  Abundance  Thallus height  (den. o r t o t o )  Repr.=R Vege.=V  (cm)  F e b r u a r y 22, 1963 (277 days a f t e r denuding) Chlorophyta Ulva lobata  97  Phaeophyta Costaria costata  11  Rhodophyta B o s s i e l l a plumosa and C o r a l l i n a vancouveriensis Prionitis"~lyallii 6 Iridaea cordata 20 MicrocTadia c o u l t e r i 3 P o l y s i p h o n i a hendryi" Pterosiphonia bipinnata 83 O d o n t h a l i a T T occosa 91  - t o 18 4 t o t a l 19,  e  30,  4 total 26 t o t a l 1 total  to to 2 to to to  OoVcmp 0.8/cm  30,  10 19 3 6 3  R 38  V R V R R V  Remarks: The most conspicuous change was the e n l a r g e d a r e a o f dense U l v a l o b a t a growth and t h e i n c r e a s e d number o f P t e r o s i p h o n i a b i p i n n a t a and O d o n t h a l i a f U o c c o s a t h a l l i . The U l v a dominated a r e a now took up 70 p e r cent o f the p l o t ' s s u r f a c e . The r e m a i n i n g a r e a i n c l u d e d o n l y e i g h t w i d e l y s c a t t e r e d U. lobata t h a l l i . P t e r o s i p h o n i a b i p i n n a t a had a s i m i l a r d i s t r i b u t i o n p a t t e r n : i t was more c o n c e n t r a t e d (0.4/cm ) w i t h i n t h e U l v a p a t c h than o u t s i d e i t , where the t o t a l number o f t h a l l i was t e n . At l e a s t " t h r e e t h a l l i o f P r i o n i t i s l y a l l i i and two °f C o s t a r i a c o s t a t a were n o t p r e s e n t on January 11. The t h a l l i of t h e l a t t e r s p e c i e s had h e i g h t i n c r e a s e s o f 26 and 28 cm, r e s p e c t i v e l y , from January 11 t o t h i s p e r i o d . M i c r o c l a d i a c o u l t e r i was e p i p h y t i c on P. l y a l l i i . The d e n s i t i e s were determined from i n s i t u counts made on two 20 X 20 cm a r e a s . 2  A p r i l 26, 1963 (340 days a f t e r denuding) Chlorophyta Enteromorpha l i n z a Ulva l o b a t a Phaeophyta Costaria costata AlariaTmarginata  14 100 3 3  0.02/cm 1 total 1 total  to to 90 33  1  22  V V  R  50 < TABLE 12.  Continued  Thallus Frequency Abundance height C%) (den. o r t o t . ) (cm)  Species  April  26, 1963  Repr.=R Yege.=V  (340 days a f t e r d e n u d i n g ) — C o n t i n u e d  Rhodophyta B o s s i e l l a plumosa and C o r a l l i n a Vancouver!ensis Prionitis l y a l l i i I r i d a e a cordata HicrocTadia b o r e a l i s Pterosiphonia bipinnata Odonthalia f f o c c o s a  51 6 23 17 31 86  2 total 15 t o t a l 12 t o t a l 19 t o t a l  -  —  to to to to to  17 20 7 6 14  V R R R R  Remarks: E x c e p t f o r t h e dominance o f U l v a l o b a t a which, a l t h o u g h w e l l d i s t r i b u t e d , , was not dense, t h e community appeared t o be l i k e t h o s e on t h e a d j a c e n t c o n t r o l p l o t s . T h i s was due m a i n l y t o the t h r i v i n g p o p u l a t i o n s of O d o n t h a l i a f l o c c o s a and I r i d a e a cordata. The C o s t a r i a c o s t a t a t h a l l u s , which measured 38 cm 63 days e a r l i e r , was b a d l y eroded a t the upper p o r t i o n so t h a t i t was a c t u a l l y t a l l e r t h a n t h e 90 cm g i v e n . The reappearance of Enteromorpha l i n z a i s noteworthy. The d e n s i t y of U. l o b a t a was d e t e r m i n e d i n sTtu. May  25, 1963  (367 days a f t e r denuding)  Chlorophyta Enteromorpha l i n z a Monostroma fuscum Ulva lobata  6 71 60  Phaeophyta Costaria costata A l a r i a marginata  3 14  (2 patches) 0.4 & 0.9/cnr 1.3/cm P  2  - t o 14 - to 8 - to 2 7  V R R  1 8  total total  —  R  3  total  - t o 13  V  Rhodophyta B o s s i e l l a plumosa and Prionitis l y a l l i i Petrocelis franciscana Iridaea cordata Microcfadia borealis  Hymenena f l a E e l l i g e r a  Pterosiphonia bipinnata Odonthalia f l o c c o s a  69 9 6 37 11 3 11 97  —  34 t o t a l 8 total 3 total 5 total 0.3 & 2.6/cm  —  p  -  to to to to to  —  56 8 11 11 16  R R V V R  51. TABLE 12.  Species  May  25,  1963  (367  Continued Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm) days a f t e r  Repr.=R Vege^V  denuding)—Continued  Remarks: The d e n s i t i e s were determined from counts made on two 10 X 10 cm s c r a p i n g s , of which one was taken from the c e n t r a l a r e a , the o t h e r about midway between the c e n t e r and margin of the p l o t . The green a l g a l c o v e r , now formed by U l v a l o b a t a and Monostroma fuscum, was most dense i n the c e n t r a l a r e a of the plot. The o t h e r p o p u l a n t s were more abundant o u t s i d e t h i s a r e a . The e n t i r e community may be d e s c r i b e d from t h r e e a s p e c t s : 1. An U. l o b a t a dominated p o r t i o n t h a t r a d i a t e d 31 t o 50 cm from the p l o t ' s c e n t e r . A l s o p r e s e n t were many young O d o n t h a l i a f l o c c o s a t h a l l i p t h a t were up t o 3.5 cm h i g h and were i n c o n c e n t r a t i o n s of 26/cm^, a few M. fuscum w i t h a d e n s i t y of 4/10 cm , f o u r I r i d a e a c o r d a t a , two P r i o n i t i s l y a l l i i , and one Costaria costata. "cY* 3n~0. f l o c c o s a dominated a r e a , which formed a r i n g 6 t o 25 cm wide around t h e dense U l v a c e n t e r . A l t h o u g h i n a low c o n c e n t r a t i o n of 3/10 cm^, most of the t h a l l i were l a r g e and mature. T h i s a r e a c o n t a i n e d n e a r l y a l l the s p e c i e s i n the community. The e x c e p t i o n s were the t h r e e green a l g a l s p e c i e s "and, of c o u r s e , the s i n g l e t h a l l u s of (J. c o s t a t a . 3. The remaining a r e a , composed of the innermost p a r t of the p l o t ( i . e . , next t o the v e r t i c a l w a l l of the upper t i e r ) and c o n t i n u o u s m a r g i n a l p o r t i o n s a l o n g the two l a t e r a l s i d e s , was s p a r s e l y p o p u l a t e d w i t h two 3 X 5 cm p a t c h e s . o f Enteromorpha l i n z a , 9/10 crn^ c o n c e n t r a t e d M. fuscum, some _I. c o r d a t a , and at l e a s t two M i c r o c l a d i a b o r e a l i s t h a l l i .  52 o Development at V i c t o r i a P l o t I I ( T a b l e T h i s p l o t was P l o t I , the  denuded on August 14,  community t h a t was  1962.  14) As  with  removed ( T a b l e 13) had  a  c h a r a c t e r i s t i c c r u s t a l l a y e r formed by P e t r o c e l i s f r a n c i s c a n a and  the  c o r a l l i n e s , B o s s i e l l a plumosa and  iensis .  But  the i n d i v i d u a l p a t c h e s were c o m p a r a t i v e l y  (the l a r g e s t , which was measured 279  cm  ) and  l e s s t h a n 20 p e r and  C o r a l l i n a vancouver-  cent  composed of the two  scattered.  coralline  of the p l o t ' s s u r f a c e .  Prionitis s i z e of  t h a l l i , were the most conspicuous f o l i o s e forms.  l o b a t a was was  o n l y Enteromorpha l i n z a was  growing on P.  growing on B. plumosa, on P.  specimen.  c o u l t e r i and h o s t s , P.  and  lyallii  Among  the  Ulva  Spongomorpha s p i n e s c e n s  lyallii,  and  on an Acmaea  were the two  some M i c r o c l a d i a b o r e a l i s .  Polyporolithon reclinatum  were on t h e i r  thalli  Microcladia usual  and b o t h c o r a l l i n e s p e c i e s , r e s p e c t i v e l y .  t a b l e excludes a f e r t i l e  growing i n t u f t s on the The  and  lyallii their  saxicolous.  E p i p h y t i c on Co v a n c o u v e r i e n s i s  of Oolpomenia s i n u o s a  The  lyallii,  species,  T h e i r coverage amounted t o  I r i d a e a c o r d a t a , because of the number and  green a l g a e ,  small  population  of Monostroma fuscum  s h e l l s of each of 11 Acmaea specimens.  i n d i v i d u a l t h a l l i were 2 t o 9 cm h i g h .  p e r c e n t a g e of the 11 Acmaea specimens was  The 14.  frequency  TABLE 13* Enumeration o f the community p r e s e n t b e f o r e denuding a t V i c t o r i a P l o t I I on August 14, 1962  Species  Frequency (%)  Chlorophyta Spongomorpha s p i n e s c e n s Enteromorpha l i n z a Ulva lobata Phaeophyta R a l f s i a fungiformis Colpomenia s m u o s a Hedophyllum s e s s i l e A l a r i a marginata Rhodophyta Polyporolithon reclinatum B o s s i e l l a plumosa and CorallTna vancouveriensis Prionitis l y a l l i i petrocelis franciscana I r i d a e a cordata Microcladia borealis Microcladia coulteri Hymenena f l a b " e l l i g e r " a LaurencTa s p e c t a b i l i s  11 3  Abundance (total)  6 e  6 6 6  6  2 2 2  Thallus height (cm)  Repr»=R Vege.=V  3 to 4 4 to 9 3 to 4  V V R  10, 10 33, 38  R R V R  71 71 31 37 43 17 es 6' 3 3  20  - t o 16  31 7  - to - to to to to  8 6  e = e p i p h y t i c , see p r e v i o u s page f o r d e t a i l s , es = e p i p h y t i c and s a x i c o l o u s .  25 11 4 6 3  R R V R R V V V  54, TABLE 14.  Enumeration of r e c o l o n i z i n g communities Victoria Plot II Thallus Frequency Abundance height (cm) (%) (den. o r t o t . )  Species  September 12, 1962 Cbrysophyta Amphipleura  at  (29 days a f t e r  Repr.=R Vege.=V  denuding) 2  rutilans  Chlorophyta Urospora m i r a b i l i s Enteromorpha l i n z a  100  6/cm  100 26  (15 p a t c h e s )  - t o 16 - to 4 - to 4  V  Remarks: The d e n s i t y f o r Amphipleura r u t i l a n s was determined from an i n s i t u count. The c o l o n i a l t h a l l i of t h i s diatom e f f e c t e d a brownish c o v e r , except i n a r e a s a p p r o a c h i n g the edge of t h e p l o t . These r e l a t i v e l y bare a r e a s , which v a r i e d i n widths of 2 t o 20 cm from the edge of the dense diatom growth to the p l o t ' s edge, c o n t a i n e d 17 specimens of an Acmaea s p e c i e s ( f r e q u e n c y 34 p e r c e n t ) and p a t c h e s of young t h a l l i of E n t e r o morpha l i n z a . Each of the l i m p e t s c a r r i e d on t h e i r s h e l l s growths of E. l i n z a and Monostroma fuscum; t h e s e are e x c l u d e d from the t a b u l a t i o n . Of the 15 E. T i n z a p a t c h e s , one c o v e r e d an a r e a of 107 cm , the o t h e r s v a r i e d between 1 and 3 cm . A few of the E. l i n z a grew s l i g h t l y w i t h i n the dense A. r u t i l a n s area. I n c o n t r a s t , U r o s p o r a m i r a b i l i s was p r e s e n t o n l y where the diatom was dense. 2  October 20, 1962  2  (67 days a f t e r  denuding)  Chrysophyta Amphipleura Chlorophyta Enteromorpha  rutilans linza  37 100  41 t o t a l -  - to 6 - to 9  R  Remarks: The p l o t now had a green c o v e r caused by a v e r y dense p o p u l a t i o n of Enteromorpha l i n z a . Only a few, s m a l l , m a r g i n a l a r e a s were bare"! C o l o n i a l t h a l l i of Amphipleura r u t i l a n s , which were f o r m e r l y dominant, were now few and s c a t t e r e d . December 12, 1962  (120 days a f t e r  denuding)  Chrysophyta Navicula g r e v i l l e i  23  17 t o t a l  - to 4  Chlorophyta Enteromorpha l i n z a Monostroma fuscum  29 54  (13 p a t c h e s ) 47 t o t a l  - to 4 - to 6  V V  55. TABLE 14.  Continued Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Species  Repr.=R v"ege. = v"  December 12, 1962 (120 days a f t e r denuding)-—-Continued Phaeophyta A l a r i a marginata  11  5 total  — t o 28  V  Rhodophyta Polysiphonia hendryi - to 4 R Pterosiphonia"Tlplnnata 46 21 t o t a l 5 to 8 R Remarks: The community was more complex i n s p e c i e s c o m p o s i t i o n . But t h e t o t a l number o f t h a l l i p r e s e n t was n o t v e r y l a r g e , so t h a t t h e p l o t was n o t d e n s e l y covered. Except f o r Enteromorpha l i n z a which grew i n clumps, o r p a t c h e s , t h a l l i of the d i f f e r e n t p o p u l a t i o n s were mingled and w e l l d i s p e r s e d (0-10 t h a l l i p e r 20 X 20 cm). The E. l i n z a p a t c h e s , the l a r g e r ones o f which were 87 and 130 cm ', were composed of scrubby t h a l l i . The l a r g e s t (28 cm) t h a l l u s o f A l a r i a marginata had two s p o r o p h y l l s . 2  Chrysophyta Navicula g r e v i l l e i  9  4 total  Chlorophyta Monostroma fuscum (and) Ulva lobata  49  33 t o t a l  - to 8 - t o 11  V 7  Phaeophyta A l a r i a marginata  20  9 total  3 t o 52  V  Rhodophyta Iridaea cordata PterosTphonia'HS'ipinnata  9 29  6 total 13 t o t a l  - to 4 - to 4  R  4 to 5  Remarks: The p l o t was s t i l l s p a r s e l y populated. Indeed, i t now had l e s s t h a l l i , t h e g r e a t e s t number of t h a l l i w i t h i n a 20 X 20 cm a r e a b e i n g s i x . The l e a s t p o p u l a t e d p o r t i o n o f t h e p l o t was from the i n n e r edge ( i . e . , from t h e v e r t i c a l f a c e of t h e upper t i e r ) outward t o about 40 cm, where o n l y two U l v a l o b a t a t h a l l i and one P t e r o s i p h o n i a b i p i n n a t a t h a l l u s were p r e s e n t . Of t h e s i x I r i d a e a c o r d a t a t h a l l i , f i v e were growing w i t h i n a 12 X 20 cm a r e a o f one o f t h e seaward c o r n e r s . Among those t h a t were p r e s e n t on December 12, o n l y A l a r i a m a r g i n a t a i n c r e a s e d i n number. Of t h e n i n e t h a l l i o f I'nis" s p e c i e s , o n l y one was from the p r e v i o u s p o p u l a t i o n . I t was the t a l l e s t a t 52 cm; of t h e o t h e r s , one was 33 cm, another was 29 cm, and s i x were 3 t o 8 cm t a l l . The 52 and 29 cm t a l l t h a l l i had s p o r o p h y l l s . Monostroma fuscum and U l v a l o b a t a were n o t d i s t i n g u i s h e d from each other i n d e t e r m i n i n g f r e q u e n c y and abundance.  56« TABLE 14.  Continued  Species  Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  F e b r u a r y 22, 1963 (192 days  Repro=R Vege.=V  after  Chrysophyta Navicula g r e v i l l e i  60  Chlorophyta Monostroma fuscum (and) Ulva lobata  43  41 t o t a l  - t o 10 - t o 22  V R  Phaeophyta Costaria costata A l a r i a marginata  9 37  3 total 29 t o t a l  1, 2, 7 2 t o 32  V V  Rhodophyta Iridaea cordata Polysiphonia hendryi Pterosiphonia bipinnata Odonthalia f l o c c o s a  11 3 49 29  8 2 26 24  total total total total  - t o 16 3, 7 - t o 17 - to 3  R R R V  - to 5  Remarks: The t o t a l number of t h a l l i i n c r e a s e d , n o t o n l y because of the g r e a t e r number of s p e c i e s p r e s e n t , but a l s o because each o f t h e January 11 p o p u l a t i o n s were now made up b y more thalli. There was a c o i n c i d e n t i n c r e a s e b o t h i n c o n c e n t r a t i o n , which was now up t o 10 p e r 20 X 20 cm, and i n d i s t r i b u t i o n , which l e f t o n l y a i n n e r - c o r n e r l o c a t e d 20 X 20 cm a r e a t a r e . Monostroma fuscum and U l v a l o b a t a were c o n s i d e r e d as one p o p u l a t i o n i n d e t e r m i n i n g f r e q u e n c y and abundance. Of the 29 A l a r i a m a r g i n a t a t h a l l i , o n l y the 32 cm t h a l l u s had s p o r o p h y l l s . I t had two, b o t h immature, and were 0.4 and 1 cm i n l e n g t h . Most, i f n o t a l l , of the t h a l l i of t h i s k e l p appeared a f t e r January 11. T h i s was a l s o t r u e f o r I r i d a e a c o r d a t a . Costaria c o s t a t a d i d n o t appear a g a i n on t h i s p i o l A p r i l 26, 1965 (255 days a f t e r Chrysophyta Navicula g r e v i l l e i Chlorophyta Enteromorpha l i n z a Monostroma fuscum Phaeophyta Scytosiphon lomentaria Petalonia delpilia Colpomenla s i n u o s a A l a r i a marginata  3  denuding) 3 total  17  (20 p a t c h e s ) 18 t o t a l  3 6 3 26  1 total 7 total 1 total 18 t o t a l  26  —  —  to 6  —  t o 24 t o 15  V V  23 4 to 9 —  —  to  102  R R V R  57.  TABLE 14o  Continued  Species  Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Repr.=R Vege = v' 0  A p r i l 26, 1965 (255 days a f t e r d e n u d i n g ) — C o n t i n u e d Rhodophyta B o s s i e l l a plumosa%and C o r a l l T n a vancoutoeriensis I r i d a e a cord"ata Folysiphonia hendryi Pterosiphonia. b i p i n n a t a Odonthalia f l o c c o s a  20 37  (13 p a t c h e s ) 21 t o t a l  34 29  24 t o t a l 38 t o t a l  1 -  to to to to  24 4 20 5  Y Y  R R V  Remarks: There was an o v e r a l l i n c r e a s e i n t h e number o f s p e c i e s and i n t h e s i z e and number o f t h a l l i p r e s e n t . But t h e concent r a t i o n , i n terms o f t h a l l i p e r 20 X 20 cm, d i d n o t change from t h e l a s t o b s e r v a t i o n . A c t u a l l y the g e n e r a l appearance o f the p l o t was s i m i l a r t o t h a t on F e b r u a r y 22, f o r t h e newly a r r i v e d populations of Scytosiphon lomentaria, P e t a l o n i a d e b i l i s , Colpomenia s i n u o s a , B o s s i e l l a plumosa, and C o r a l l i n a v a n c o u v e r i e n s i s were, as a whole, r e p r e s e n t e d b y few, s m a l l thalli. May 23. 1963 (282 days a f t e r denuding) Chrysophyta Navicula g r e v i l l e i Chlorophyta Spongomorpha c o a l i t a Enteromorpha l i n z a Monostroma fuscum (and) Ulva lobata Phaeophyta Petalonia debilis A l a r i a marginata Rhodophyta Bossiella C a l l o p h y l l i s sp. Iridaea" cordata Polysiphonia hendryi Odonthalia f l o c c o s a  6  3 total  6 34  2 total 10.7/cm  74-  1.5/cm2  11  29  11  3 29  60 17  2  1.2/cm2 8 total 23 t o t a l  1 total 32 t o t a l 0.7/cm 29 t o t a l 2  - to 5  —  3, 4 - t o 18 - to 7 - t o 15  R R V  mm  am*  R  5  V V  - to 5 - to 8  R V  —  —  TABLE 14o  Species  May  23, 1963  Continued Thallus Frequency Abundance height {%) (den. o r t o t . ) (cm)  Repr.=R Vege.=V  (282 days a f t e r d e n u d i n g ) — C o n t i n u e d  Remarks: The d e n s i t i e s were determined from a 6 X 6 cm s c r a p i n g t a k e n from an a r e a h a v i n g a dense growth o f Enteromorpha l i n z a , Monostroma fuscum, and U l v a l o b a t a . T h i s growth, which was s i t u a t e d t o one s i d e and c o v e r e d n e a r l y a t h i r d of t h e p l o t ' s s u r f a c e , was the f i r s t expansive c o v e r of greens s i n c e October 20, when t h e p l o t was almost c o m p l e t e l y covered by a growth o f E. l i n z a . Most of the P o l y s i p h o n i a h e n d r y i and P e t a l o n i a c T e b i l i s t h a l l i were growing w i t h i n t h e dense g r e e n a l g a l p a t c h . But o n l y one o f the A l a r i a m a r g i n a t a t h a l l i was i n the p a t c h . The o t h e r s p e c i e s were mdre o r l e s s d i s t r i b u t e d throughout t h e s u r f a c e o f the p l o t . Of the greens f o r m i n g the dense growth, b o t h U. l o b a t a and M. fuscum o c c u r r e d elsewhere on the p l o t . These two s p e c i e s were n o t d i s t i n g u i s h e d from each o t h e r i n the f r e q u e n c y p e r c e n t a g e d e t e r m i n a t i o n / Of the 23 t h a l l i o f A. m a r g i n a t a , 18 were f e r t i l e .  59* Development a t V i c t o r i a P l o t I I I ( T a b l e The  community t h a t was  22,  1963  ( T a b l e 15),  did  P l o t s I and I I .  16)  removed from t h i s p l o t  on  February  d i d not have a d i s t i n c t c r u s t a l l a y e r as There were o n l y t e n c o r a l l i n e p a t c h e s  p r a n g i n g from 21  t o 157  cm  , and f o u r P e t r o c e l i s f r a n c i s c a n a  p p a t c h e s r a n g i n g from 7 t o 54- cm  .  While some of t h e  g r e v i l l e i and Spongomorpha s p i n e s c e n s  t h a l l i were e p i p h y t i c on  .the c o r a l l i n e s , C o r a l l i n a v a n c o u v e r i e n s i s most of t h e i r t h a l l i were s a x i c o l o u s .  and B o s s i e l l a plumosa,  These s a x i c o l o u s ones  were s c a t t e r e d i n d i s t r i b u t i o n except covered by a dense growth of S.  f o r a 16 X 43  spinescens  cm  area  and another  a r e a covered by dense growths of b o t h S. s p i n e s c e n s grevillei.  Navicula  16 X 49  and  cm  N.  A l l seven Monostroma a r c t i c u m b l a d e s , whose s m a l l e r  ones were g o b l e t - l i k e , were on a shoot  of B. plumosa.  The  P o l y p o r o l i t h o n r e c l i n a t u m c r u s t s were, as u s u a l , e p i p h y t i c on both  coralline species.  r a t h e r l a r g e and was  The A l a r i a m a r g i n a t a p o p u l a t i o n  composed of young t h a l l i without  Besides  t h e s e , however, t h e r e were at l e a s t 11,  thalli,  of which o n l y the s t i p e and  remained.  The  e n t i r e p o p u l a t i o n was  was  sporophylls.  apparently old  lowermost m i d r i b p o r t i o n s s i t u a t e d w i t h i n 30  cm  from  the o u t e r , o r seaward, edge o f t h e p l o t , where t h e y formed a r a t h e r dense  stand.  60, TABLE 15. Enumeration o f t h e community p r e s e n t b e f o r e denuding a t V i c t o r i a P l o t I I I on F e b r u a r y 22, 1963  Species  Frequency (%)  Abundance (total)  37  -  Chrysophyta Navicula g r e v i l l e i Chlorophyta Spongomorpha s p i n e s c e n s Monostroma a r c t i c u m Monostroma fuscum Phaeophyta Desmarestia  munda  IIarI"ma?gi'na^r  Rhodophyta Polyporolithon reclinatum B o s s i e l l a plumosa and C o r a l l l n a vancouveriensis Prionitis l y a l l i i *"""" Petrocelis franciscana Iridaea cordata *"""* MicrocTadia borealis Pterosiphonia bipinnata  es  60®  3  e  6  3 23 54 54 6  e  2 3 20  20  14  s  7 5  Thallus height (cm)  —  to 4  to 4 0.2 t o 4 — to 6  1 —  _  -  2  16 18 8  e = e p i p h y t i c , see p r e v i o u s page f o r d e t a i l s , es = e p i p h y t i c and s a x i c o l o u s .  7  Repr.=R Yege.=Y  —  Y Y Y  2 t o 26  Y Y  -  R  — to  -7  1 to 5 — to 3 — to 9  R  -  Y Y Y  R  61. TABLE 16.  Enumeration o f r e c o l o n i z i n g communities a t Victoria Plot I I I  Species  Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  A p r i l 26, 1965 (65 days a f t e r  denuding)  Chrysophyta Amphipleura r u t i l a n s  97  Chlorophyta Urospora wormskioldii Spongomorjgha c o a l i t a Enteromorpha l i n z a Monostroma fuscum  80 37 14 69  Rhodophyta Pterosiphonia bipinnata  Repr.=R Vege.=V  9  to - to 4-5 t o t a l 1 to (8 p a t c h e s ) 0.2 t o 64 t o t a l 0.2 t o 10  total  3 8 7 6 4  V  Y Y  - to 3  Remarks: Amphipleura r u t i l a n s was the most d e n s e l y o c c u r r i n g and the most w i d e l y d i s t r i b u t e d s p e c i e s , b u t t h e " t h a l l i " o f t h i s c o l o n i a l diatom were s h o r t , t h i n and s o f t e r t h a n u s u a l . The most c o n s p i c u o u s s p e c i e s was Monostroma fuscum. The Enteromorpha l i n z a p a t c h e s were s m a l l , r a n g i n g from 1 t o 8 cm^. A l t h o u g h the U r o s p o r a w o r m s k i o l d i i p o p u l a t i o n had a wide d i s t r i b u t i o n , i t was made up o f o n l y a few f i l a m e n t s . The t h a l l i o f P t e r o s i p h o n i a b i p i n n a t a , which were a l o n g and n e a r a l a t e r a l margin of t h e p l o t , were s m a l l b u t t h o s e c o l l e c t e d had immature s t a g e s of c y s t o c a r p s and spermatangia. May 23, 1963 (90 days a f t e r  denuding)  Chlorophyta Spongomorpha c o a l i t a JUnteromorpha l i n z a Monostroma fuscum  97 54 91  0.3/cm| 0.6/cm 3.5/cm  3  1 total  6  4 total  Phaeophyta Petalonia  debilis  Rltodophyta Iridaea cordata PTerosiphonia Fipinnata  43  o 2  0.1/cm2  2 0.2 0.1  to to to  19 20 7  R R V  3  V R  8  0.7  to to  8  62. (TABLE 16.  Continued Thailus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Species  May 25, 1965  Repr.=R Vege.=V  (90 days a f t e r d e n u d i n g ) — C o n t i n u e d  Remarks: Except a t m a r g i n a l a r e a s , the p l o t had a dense g r e e n a l g a l c o v e r p r o v i d e d by Spongomorpha c o a l i t a , Enteromorpha l i n z a , and Monostroma fuscum. A 25 cm wide s t r i p a l o n g t h e i n n e r edge (next t o t h e v e r t i c a l w a l l of the upper t i e r ) o f the p l o t was the b a r e s t a r e a w i t h o n l y 13 S. c o a l i t a and f i v e M. fuscum t h a l l i p r e s e n t . The M. fuscum p o p u l a t i o n was composed m a i n l y of t i n y , hemisphericaT t h a l l i . Pterosiphonia bipinnata was more c o n c e n t r a t e d toward t h e o u t e r , o r seaward, edge o f the p l o t . A l l of the I r i d a e a c o r d a t a c l u s t e r s were w i t h i n 10 cm from t h i s edge. The d e n s i t i e s were determined from a count made on a 6 X 6 cm s c r a p e t a k e n n e a r the p l o t ' s c e n t e r . June 8. 1963  (106 days a f t e r  denuding)  Chlorophyta Spongomorpha c o a l i t a Enteromorpha l i n z a lonostroma fuscum  97 60 83  Rhodophyta Iridaea cordata Pterosiphonia bipinnata  3 29  3 total 25 t o t a l  - to 6 - to 4  Remarks: There was l i t t l e change from t h a t observed on May 25° Both Spongomorpha c o a l i t a and Monostroma fuscum were dominating, T o g e t h e r w i t h Enteromorpha l i n z a t h e y "formed a dense green cover that l e f t only a narrow, m a r g i n a l p a r t s o f t h e p l o t b a r e . None of the I r i d a e a c o r d a t a t h a l l i were p a r t o f t h e May 23 p o p u l a t i o n . J u l y 6, 1963  (154 days a f t e r  Chlorophyta Spongomorpha c o a l i t a Enteromorpha l i n z a Monostroma fuscum  denudini  ..  97 23 100  Rhodophyta Prionitis l y a l l i i Pterosiphonia bipinnata  3 54  - t o 16 - t o 14 - t o 10 1 total 32 t o t a l  1.3 t o 4  R R V  63. TABLE -16.  Continued  Species  Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  J u l y 6, 1963 (134 days a f t e r  Repr.=R Vege.=V  denuding)—Continued  Remarks: The g e n e r a l appearance of t h e p l o t was s i m i l a r t o t h a t on June 8. But Monostroma fuscum had spread and almost comp l e t e l y covered t h e p l o t . I t a l s o appeared t o have i n c r e a s e d i n d e n s i t y ( a t l e a s t there were more l a r g e b l a d e s p r e s e n t ) . The Enteromorpha l i n z a p o p u l a t i o n was much s m a l l e r and t h e t h a l l i were v e r y eroded. The P t e r o s i p h o n i a b i p i n n a t a t h a l l i were w e l l s c a t t e r e d , a l t h o u g h more o r l e s s r e s t r i c t e d t o areas w i t h i n 20 cm o f the seaward and l a t e r a l edges of the p l o t . August 5, 1963 (164 days a f t e r denuding) Chlorophyta Spongomorpha c o a l i t a Enteromorpha l i n z a Monostroma fuscum Rhodophyta Prionitis l y a l l i i I r i d a e a coraalfa" PterosTphonia b i p i n n a t a  74 17 100 3  6 9  0.04/cm (12 p a t c h e s ) 2  0.5/cm2  1 total 3 total 11 t o t a l  - t o 17 - to 8 - t o 12  13  - to 1.3 t o  R —  R  4 2  —  R  Remarks: Monostroma fuscum was absent o n l y from c e r t a i n m a r g i n a l p o r t i o n s of the p l o t . Absent from a g r e a t e r p a r t o f t h e marg i n a l areas was Spongomorpha c o a l i t a , whose p a t t e r n o f d i s t r i b u t i o n was a h e m i - c i r c l e t h a t arched from one of the l a t e r a l edges o f t h e p l o t and r a d i a t e d 75 cm inward. The p a t c h e s o f Enteromorpha l i n z a were s m a l l , b e i n g n o t more t h a n 6 cm2 T h i s s p e c i e s and t h e s i n g l e t h a l l u s o f P r i o n i t i s l y a l l i i , whose b l a d e was u n d i v i d e d and which was t h e same one recorded, p r e v i o u s l y , were growing w i t h i n t h e M. fuscum c o v e r . Both I r i d a e a c o r d a t a and the scrubby, coarse t h a l l i of P t e r o s i p h o n i a b i p i n n a t a grew o u t s i d e the M. fuscum cover, c l o s e t o t h e s e a ward edge of the p l o t . The d e n s i t i e s were o b t a i n e d from an i n s i t u count made on a 10 X 10 cm a r e a n e a r t h e p l o t ' s c e n t e r . c  August 18, 1963 (177 days a f t e r denuding) Chlorophyta Spongomorpha c o a l i t a Enteromorpha l i n z a Monostroma fuscum Rhodophyta Prionitis l y a l l i i PterosipEonia bipinnata  7423 100 3 9  -  - to 7 - to 5 - t o 18  V R R  1 total 5 total  16 - t o 0.5  V  64. TABLE 16=  Continued Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Species  August 18, 1963  Repr.=R Vege»=V  (177 days a f t e r d e n u d i n g ) — C o n t i n u e d  Remarks: There was h a r d l y any change i n t h e d i s t r i b u t i o n p a t t e r n of t h e p o p u l a t i o n s . The b l a d e s o f Enteromorpha l i n z a were d i s t i n c t l y eroded. No young t h a l l i o f t h i s s p e c i e s were seen. I t was the same w i t h P t e r o s i p h o n i a b i p i n n a t a , which was r e p r e s e n t e d by t h a l l i t h a t were c o a r s e and stubby. The p r e v i o u s l y u n d i v i d e d b l a d e of P r i o n i t i s l y a l l i i mow had f o u r dichotomies. September  1, 1963  (191 days a f t e r  denuding)  Chlorophyta Monostroma fuscum  100  Rhodophyta Prionitis l y a l l i i  6  -  - t o 16  1 total  13  R V  Remarks: There was s e v e r e wave a c t i o n a t t h i s time d u r i n g which o n l y Monostroma fuscum and t h e same P r i o n i t i s l y a l l i i t h a l l u s of J u l y 6 and August 5 and 18 were n o t e d t o be p r e s e n t . The f e r t i l i t y d e t e r m i n a t i o n f o r P. l y a l l i i was based on e x a m i n a t i o n of a fragment o f t h e s i n g l e T S h a l l u s p r e s e n t . October 7, 1965  (227 days a f t e r  Chlorophyta Monostroma fuscum (and) U l v a lob"ata  80  denuding) - t o 21 - t o 15  -  R R  Remarks: O n l y t h e f o l i o s e t h a l l i o f Monostroma fuscum and U l v a l o b a t a were p r e s e n t . They were n o t d i s t i n g u i s h e d from each o t h e r i n p l o t t i n g , which i s the r e a s o n f o r t h e s i n g l e f r e q u e n c y figure. Both s p e c i e s formed a dense c o v e r i n the c e n t r a l r e g i o n of the p l o t . They were absent from an a r e a t h a t was anywhere from 8 t o 30 cm from t h e edges of t h e p l o t * November 4. 1965  (255 days a f t e r  Chlorophyta Monostroma fuscum (and) U l v a lob"ata  86  denuding)  0.08/cm  o  - t o 14 - t o 16  V R  Remarks: As i n t h e l a s t o b s e r v a t i o n p e r i o d , the two f o l i o s e s p e c i e s were p l o t t e d as a s i n g l e p o p u l a t i o n . A l t h o u g h s l i g h t l y " expanded, t h e growth a r e a had a b a r e f r i n g e s i m i l a r t o t h a t of October 7« The d e n s i t y was based on i n s i t u counts made on f o u r 20 X 20 cm a r e a s .  65. TABLE 16.  Continued Thallus Frequency Abundance height (%) (den. or t o t . ) (cm)  Species  December 1, 1965  (282  Eepr.=E Yege.=Y  days a f t e r denuding)  Chlorophyta Monostroma fuscum (and) Ulva lobata 100 Rhodophyta B o s s i e l l a plumosa and C o r a l l l n a vancouveriensis 6 Pterosiphonia bipinnata 45  - to 8 - t o 12  -  (5 p a t c h e s ) 17 t o t a l (basal parts only)  R V  V  Remarks: The c e n t r a l expanse of green a l g a l c o v e r formed by Monostroma fuscum and U l v a l o b a t a had e n l a r g e d s i g n i f i c a n t l y so t h a t the bare- a r e a now measured 2 t o 17 cm wide from edges of the p l o t t o the edge of the cover. A l t h o u g h the two s p e c i e s were not d i s t i n g u i s h e d from each o t h e r i n p l o t t i n g , i t was n o t e d t h a t M. fuscum o c c u r r e d more a b u n d a n t l y t h a n U. l o b a t a . The c o r a l l i n e p a t c h e s were a t one of the i n n e r c o r n e r s of the plot. The p r o s t r a t e , r a d i a t i n g b a s a l p a r t of P t e r o s i p h o n i a b i p i n n a t a , which was a c o n s i s t e n t and p r e v a l e n t (up t o 10 cm i n d i a m e t e r ) f e a t u r e of the s p e c i e s noted throughout the course of the study, was a l l t h a t remained of a p o p u l a t i o n t h a t f i r s t appeared some time a f t e r the l a s t o b s e r v a t i o n p e r i o d . December 28,  1963  (509  days a f t e r denuding)  Chlorophyta Monostroma fuscum (and) Ulva lobata Rhodophyta B o s s i e l l a plumosa and C o r a l l l n a vancouveriensis Pterosiphonia bipinnata Odonthalia f l o c c o s a  94-  9 3^ 9  0  0.05/cnT  (4 p a t c h e s ) 13 t o t a l  - to 9 - to 8  - t o 1.7 to 8 - to 2  V V  E E V  Remarks: The g r e e n a l g a l c o v e r was s m a l l e r and l e s s dense (the l a t t e r c o n d i t i o n a t l e a s t from t h a t of the November 4 o b s e r v a tion). The young, p r o s t r a t e t h a l l i of O d o n t h a l i a f l o c c o s a were growing w e l l w i t h i n the Monostroma fuscum and U l y a lobata"" growth a r e a . The c o r a l l i n e s were r e s t r i c t e d t o the same i n n e r c o r n e r of the p l o t as p r e v i o u s l y . One c r u s t of B o s s i e l l a plumosa had e r e c t , w e l l - b r a n c h e d shoots w i t h many t e t r a s p o r i c conceptacles. The d e n s i t y was hased on i n s i t u counts made on two 20 X 20 cm a r e a s .  66,  TABLE 16.  Continued  Species  Frequency Abundance (%) (den. or t o t . )  Thallus height (cm)  Repr.=R Vege.=V  January 26, 1964 (338 days a f t e r denuding) Chrysophyta Navicula g r e v i l l e i Chlorophyta Honostroma fuscum (and) Ulva lobata  11  7 total  94  0.03/cm'.2  - to 9 - to 10  H V  Rhodophyta B o s s i e l l a plumosa and C o r a l l i n a vancouveriensis Pterosiphonia bipinnata 49  35 t o t a l .  - to 7  R  1  Remarks: The most noticeable change i n the green a l g a l cover was i t s l e s s dense appearance. Although the frequency percentage f o r t h i s period was the same as that of December 28, there was a c t u a l l y l e s s area covered. The density was determined from i n s i t u counts made on three 20 X 20 cm areas.  67  o  Development a t V i c t o r i a P l o t IV ( T a b l e 1 8 ) The  community removed on June 8 , 1 9 6 3 ( T a b l e 1 7 ) had  r e l a t i v e l y l a r g e A l a r i a m a r g i n a t a p o p u l a t i o n t h a t was for  the most p a r t of f u l l - g r o w n t h a l l i o  t i p s so t h a t t h e y must have had i n d i c a t e d i n t h e enumeration. had  a l e n g t h of 3 2 cm,  sporangia.  The  Most had d e f o l i a t e d  S p o r o p h y l l s , the l a r g e s t of which  were p r e s e n t  Two  made up  a g r e a t e r height than that  on a l l , but  e n t i r e p o p u l a t i o n was  ward h a l f of the p l o t .  a  thalli  o n l y a few  s i t u a t e d w i t h i n the  were growing on  had sea-  coralline p  crusts.  The  O n l y a few  l a r g e s t of the c o r a l l i n e p a t c h e s was  of the  c r u s t s were of C o r a l l i n a  2 9 2 cm  .  vancouveriensis.  B e s i d e s A. m a r g i n a t a , e p i p h y t i c on the c o r a l l i n e s were some of the Monostroma fuscum and M i c r o c l a d i a b o r e a l i s t h a l l i , t h a l l u s of H a l o s a c c i o n reclinatum t h a l l i .  glandiforme.  T h i s was  the  forme w i t h i n the e x p e r i m e n t a l  and  the s i n g l e  a l l of the P o l y p o r o l i t h o n  only occurrence  of H,  glandi-  s i t e of the breakwater.  The 2  P e t r o c e l i s f r a n c i s c a n a patches,  the l a r g e s t of which was  were d i s t r i b u t e d c l o s e r t o t h e edges of the p l o t .  4-7 cm  ,  Hymenena  f l a b e l l i g e r a were p r e s e n t w i t h i n a 8 X 2 5 cm a r e a n e a r  one  seaward c o r n e r of the p l o t where they grew between the h o l d f a s t branches of A. marginata,. present  Two  of the l a r g e r animal  were K a t h e r i n a t u n i c a t a and Acmaea m i t r a .  two  specimens of the l a t t e r had  its  shell.  species One  of  B o s s i e l l a plumosa growing  the on  68. TABLE 17. Enumeration o f t h e community p r e s e n t b e f o r e denuding a t V i c t o r i a P l o t IV on June 8, 1963  Species  Frequency (%)  Chlorophyta Spongomorpha c o a l i t a HonostromaTuscum  6 34  Abundance (total)  Thallus height (cm)  Repr.=R Vege.=V  4 21  2 to 3 - to 8  V V  22  48 t o 65  R  Phaeophyta A l a r i a marginata Rhodophyta Polyporolithon reclinatum B o s s i e l l a plumosa and C o r a l l i n a vancouveriensis Petrocelis franciacana Iridaea cordata Halosaccion glandiforme Hicrocladla borealis Hymenena f l a b e l l i g e r a Odonthalia f l o c c o s a  34  e  74 74 34 14 3® 25 6 26  (16 p a t c h e s ) (11 p a t c h e s ) 12 1 20 7 25  e = e p i p h y t i c , see p r e v i o u s page f o r d e t a i l s , es = e p i p h y t i c and s a x i c o l o u s .  R  -  to 4 to to to  15 10 6 8  R V R V R V R  69.  TABLE 18.  Enumeration of r e c o l o n i z i n g communities a t V i c t o r i a P l o t IV  Species  Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  J u l y 6. 1965 (28 days a f t e r  Repr.=R Vege.=V  denuding)  Chrysophyta Amphipleura r u t i l a n s Chlorophyta Urospora,wormskioldii  100  -  - to 6  26  -  - t o 10  Remarks: The p l o t was d e n s e l y c o v e r e d b y a p o p u l a t i o n of Amphipleura r u t i l a n s . I t was a pure s t a n d except a t a 45 X 60 cm a r e a o f a seaward c o r n e r of the p l o t where U r o s p o r a wormsk i o l d i i f i l a m e n t s grew a b u n d a n t l y among the c o l o n i a l t h a l l i of t h e diatom. August 5. 1965 (58 days a f t e r Chrysophyta Amphipleura r u t i l a n s Chlorophyta Enteromorpha  denuding) p  69  0.2/cm  100  10.2/cm  - to 1  ?  linza  Rhodophyta Iridaea cordata  9  14 t o t a l  0.5 t o 37 1 to 6  R R  Remarks: The s h o r t Amphipleura r u t i l a n s specimens were u n u s u a l l y s o f t and l i m p . They were w e l l d i s t r i b u t e d but grew o n l y w i t h i n the Enteromorpha l i n z a growth a r e a . T h i s green a l g a was absent from an up t o 25 cm wide s t r i p next t o each o f t h e two l a t e r a l edges o f t h e p l o t . On one o f t h e s e s t r i p s ( b o t h extended t o t w o - t h i r d ' s o f t h e l e n g t h o f t h e edges) were t h e 14 c l u s t e r s o f I r i d a e a c o r d a t a . The d e n s i t i e s were determined from a count made on a 5 X 5 cm s c r a p e t a k e n n e a r t h e p l o t ' s c e n t e r . August 18. 1965 (71 days J f t e r Chlorophyta Spongomorpha c o a l i t a Enteromorpha l i n z a  !  6 100  Rhodophyta B o s s i e l l a plumosa and C o r a l l i n a vancouveriensis 6 Petrocelis franciscana 6 I r i d a e a "cordata 14  denuding) 6 total -  (6 p a t c h e s ) (1 p a t c h ) 13 t o t a l  3 to 4 - to 16  R R  - to 7  V V R  TABLE 18.  Continued  Species  Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Repr.=R Vege.=Y  August 18, 1963 (71 days a f t e r d e n u d i n g ) — C o n t i n u e d Remarks: Enteromorpha l i n z a s t i l l formed a dense c o v e r o v e r n e a r l y the e n t i r e surface of the p l o t . I t was s t i l l absent from t h e I r i d a e a cordata: inhabited, a r e a d e s c r i b e d f o r August 5. T h i s a r e a now had t e n o f t h e 14 I . c o r d a t a c l u s t e r s , of which f i v e , a t most, were from t h e p r e v i o u s l y observed p o p u l a tion. A l s o i n t h i s r e l a t i v e l y bare a r e a were a l l t h e c o r a l l i n e and Spongomorpha c o a l i t a t h a l l i . The c o r a l l i n e p a t c h e s c o n s i s t e d o f c r u s t s t h a t were v e r y t h i n and s m a l l i n d i a m e t e r . A c t u a l l y t h e r e i s some doubt as t o t h e i r i d e n t i f i c a t i o n b e cause t h e s e a p p a r e n t l y e a r l y s t a g e s of c r u s t development were the o n l y c o r a l l i n e r e p o p u l a n t s seen on t h i s p l o t . The p a t c h of P e t r o c e l i s f r a n c i s c a n a was 5 cm wide. September 1, 1965 (85 days a f t e r Chlorophyta Enteromorpha l i n z a  100  denuding) -  - t o 23  R  Remarks: A l t h o u g h a rough s e a p r e v e n t e d a d e t a i l e d e x a m i n a t i o n of the p l o t , Enteromorpha l i n z a appeared t o be, and i n a l l p r o b a b i l i t y was, t h e o n l y s p e c i e s p r e s e n t . October 7. 1963 (121 days a f t e r Chlorophyta Enteromorpha l i n z a Monostroma fuscum (and) Ulva lohata Rhodophyta Iridaea cordata  100 43 6  denuding) _ —  3 total  - t o 21 - to 7 - t o 17  R R R  - to 3  V  Remarks: The Enteromorpha l i n z a p o p u l a t i o n was s t i l l w i d e l y d i s t r i b u t e d , l e a v i n g o n l y m a r g i n a l p o r t i o n s of t h e p l o t b a r e . But. i t was f a r l e s s dense t h a n a t any o f the t h r e e former o c c a s i o n s i n which i t was observed on t h i s p l o t . The o t h e r g r e e n s , Monostroma fuscum and U l v a l o b a t a , which were p l o t t e d as a s i n g l e p o p u l a t i o n , a l s o were s m a l l i n number. November 4, 1965 (149 days a f t e r Chlorophyta Enteromorpha l i n z a Ulva lobata  100 100  denuding) -  3 to 6 - to 4  V V  71. TABLE 18o  Continued  Species  Thallus Frequency Abundance height (%) (den. or t o t . ) (cm)  November 4, 1963 (149 days a f t e r  i£epr.=R Vege» = v"  denuding)—Continued  Remarks: The Ulva lobata and Enteromorpha l i n z a populations formed a green cover except at the two l a t e r a l sides of the p l o t where they were bare anywhere from 6 to 25 cm from the p l o t ' s edge. The E. l i n z a t h a l l i , whose blades showed some i n d i c a t i o n of very~"recent f e r t i l i t y , were o l d . The stipes were coarse and t h i c k , and the blades were small due to erosion. The reduced s i z e of the blades could be a t t r i b u t e d to progressive l o s s of the marginal f e r t i l e area. In contrast to the eroded condition- of these blades, those of U. l o b a t a . which were young, had i n t a c t margins. ~" December 1. 1965 (176 days a f t e r denuding) Chrysophyta Navioula g r e v l l l e i Chlorophyta Enteromorpha l i n z a Ulva lobata Phaeophyta Petalonia d e b i l i s Costaria costata A l a r i a marginata Rhodophyta Prionitis l y a l l i i  I r i d a e a c o r•8 data ?Q6 subulatum Antltha'mnion Odonthalia f l o c c o s a  100 100 6  - to 9  3 total  3  1 total 10 t o t a l  3  1 total 5 total 26 t o t a l  11 11 37  11  -  (stipes only) 0,2 to 14 - to 8 2.5 0.3 to 5  —  - to 2 - to 1  V V V V  -  R V  Remarks: The population of Ulva lobata was most prominent because i t was made up of l a r g e - s T z e c T T h a l l i that grew densely and were absent only from marginal areas. With the exception of Odonthalia f l o c c o s a . which was growing at the c e n t r a l area of the p l o t , the red and brown a l g a l species were present only on the seaward h a l f of the p l o t . Of these the brown algae were the most r e s t r i c t e d , occurring only i n a 28 cm wide area from the seaward edge. The Enteromorpha l i n z a stipes were o l d , and were obviously remnants of a previous population. The A l a r i a marginata t h a l l i were devoid of sporophylls. December 28, 1965 (205 days a f t e r denuding) Chrysophyta Navicula g r e v i l l e i  100  - to 7  72, TABLE 18.  Continued Thallus Frequency Abundance height (%) (den. or t o t . ) (cm)  Species  December 28,  1965  (203 days a f t e r  Chlorophyta ulva lobata  denuding)-—Continued  100  Phaeophyta Petalonia debilis A l a r i a marginata  9 11  Rhodophyta Iridaea cordata  Repr.=R Vege.=V  - to 10 7  total total  5  total  15  - to 9 - to 4  V V  Remarks: The U l v a l o b a t a p o p u l a t i o n was as prominent as d u r i n g the p r e v i o u s o b s e r v a t i o n . The m a r g i n a l a r e a s were s t i l l d e v o i d of t h i s a l g a . A l l of t h e t h a l l i of I r i d a e a c o r d a t a , A l a r i a marg i n a t a , and P e t a l o n i a d e b i l i s appeared s i n c e the l a s t o b s e r v a tion. These t h r e e s p e c i e s were growing i n an a r e a w i t h i n 20 cm from the p l o t ' s seaward edge. The A. marginata were w i t h o u t sporophylls. January 26.  1964-  (252 days a f t e r denuding)  Chrysophyta Navicula g r e v i l l e i  97  —  - to  7  —  Chlorophyta Ulva lobata  97  -  - to  15  V  total 3 total  - to  11  R V  1 total 6 total 8 total  3 - to 5 - to 6  Phaeophyta Petalonia debilis A l a r i a marginata Rhodophyta Prionitis l y a l l i i Iridaea cordata PterosTphonla b i p i n n a t a  3  11 3 14  11  1  11  V  —  R  Remarks: The U l v a l o b a t a c o v e r e n l a r g e d s l i g h t l y , so t h a t o n l y a seaward c o r n e r r e g i o n of the p l o t was l e f t b a r e . Except f o r P t e r o s i p h o n i a b i p i n n a t a , which was p r e s e n t t o one l a t e r a l s i d e of the p l o t i n a 20 X 25 pm a r e a , t h e r e was no s p e c i a l l y rers t r i c t e d p a t t e r n of d i s t r i b u t i o n i n t h e i n d i v i d u a l p o p u l a t i o n s . As a whole, however, the r e d s and browns formed a r i n g e d p a t t e r n of growth because t h e y were absent from the c e n t r a l p l o t a r e a but grew n e a r e r t o the m a r g i n a l a r e a s . The s i n g l e P e t a l o n i a d e b i l i s t h a l l u s was not p a r t of t h e December 28 p o p u l a t i o n nor were two of the A l a r i a marginata and one, perhaps, of the I r i d a e a c o r d a t a . The A. m a r g i n a t a t h a l l i d i d not have s p o r o phylls. ~~  73. Development a t V i c t o r i a P l o t V ( T a b l e 20) Of t h e community removed on August 5, 1963 ( T a b l e c o r a l l i n e s p e c i e s , B o s s i e l l a plumosa and O o r a l l i n a  19) t h e  vancouveri-  e n s i s , formed a d i s t i n c t i v e c r u s t a l l a y e r , which was made up of 2 patches ranging at and  from 1 t o 530 cm .  l e a s t two t h a l l i  Growing on t h e p a t c h e s were  o f Monostroma fuscum, one o f U l v a  one o f I r i d a e a c o r d a t a .  lobata,  They a l s o had t h e e p i p h y t e  commonly a s s o c i a t e d w i t h them, P o l y p o r o l i t h o n r e c l i n a t u m , occurred  on a l l t h e specimens examined.  e p i p h y t e was a l s o on Rhodomela l a r i x . larix,  This  which  corallinaceous  The one t h a l l u s o f R.  as i n t h e case f o r example o f 1, c o r d a t a , was comprised  of s e v e r a l s h o o t s t h a t were a t t a c h e d A l a r i a marginata population  t o a common h o l d f a s t .  The  was growing o n l y i n t h e seaward  h a l f o f t h e p l o t ; most of t h e t h a l l i were c l o s e t o the seaward edge.  The t e n green a l g a l t h a l l i ,  on t h e o t h e r hand, were  growing i n t h e i n n e r h a l f o f t h e p l o t .  74. TABLE 19» Enumeration of t h e community p r e s e n t b e f o r e denuding a t V i c t o r i a P l o t V on August 5, 1963  Species  Chlorophyta Monostroma fuscum Ulva lobata  Frequency (%)  Thallus height (cm)  Abundance (total)  (and)  Phaeophyta Hedophyllum s e s s i l e A l a r i a marginata Rhodophyta Polyporolithon- reclinatum B o s s i e l l a plumosa and OorallTna vancouveriensis Cryptomenia obovata Prionitis l y a l l i i Iridaea cordata Symenen'a f l a b e T l i g e r a Rhodomela l a r i x Odonthalia f l o c c o s a  20  e s  2 to 7 8 t o 13  10  6 51  3 17  74  -  745 11 20 9 5 51  (28 p a t c h e s ) 1 4 11 5 1 25  e s  e = e p i p h y t i c , see p r e v i o u s page f o r d e t a i l s , es = e p i p h y t i c and s a x i c o l o u s .  4-0, 45, 45 45 t o 90  5 -  Repr.=R Vege.=V  R V V R  -  R  18 to to to 15 to  R R R R V R V  16 25 8 25  75. TABLE 20.  Enumeration o f r e c o l o n i z i n g communities a t Victoria Plot V  ;£ Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Species  August 18, 1963  (15 days a f t e r  Chrysophyta Amphipleura r u t i l a n s  Repr.=R Vege =V D  denuding)  100  -  - to 2  Remarks: T h i s d i a t o m p o p u l a t i o n grew d e n s e l y i n some a r e a s o f the p l o t and s p a r s e l y i n o t h e r p a r t s . I t s c o l o n i a l t h a l l i were e x c e p t i o n a l l y slimy. September 1, 1965  (27 days a f t e r  denuding)  Chrysophyta Amphipleura r u t i l a n s Chlorophyta Enteromorpha l i n z a  100 46  -  - t o 13  (9 p a t c h e s )  - to 4  V  Remarks: I t was n o t p o s s i b l e t o examine the p l o t i n any g r e a t d e t a i l because of a rough s e a , but i t appeared c e r t a i n t h a t o n l y two s p e c i e s were p r e s e n t . The Amphipleura r u t i l a n s p o p u l a t i o n grew d e n s e l y The n i n e p a t c h e s of young Enteromorpha l i n g a t h a l l i were w i d e l y s c a t t e r e d and ranged from 16 t o 135 cm^. O c t o b e r 7, 1963  (63 days a f t e r  denuding)  Chrysophyta Navicula g r e v i l l e i  3  Chlorophyta Ent eromorpha l i n z a  86  1 total  5  -  -  - t o 33  R  Remarks: The c e n t r a l a r e a of t h e p l o t was c o v e r e d by a dense growth of Enteromorpha l i n z a , . T h i s p a t c h was o u t l i n e d by a b a r e margin t h a t was i n t e r r u p t e d i n c e r t a i n a r e a s b y t h e p a t c h b u l g i n g out t o t h e p l o t * S ; e d g e s . The N a v i c u l a g r e v i l l e i specimen was growing among t h e t h a l l i o f E. i T n z a . November 4, 1965  (91 days a f t e r  denuding)  Chrysophyta Navicula g r e v i l l e i  40  0.1/cm  2  Chlorophyta Enteromorpha l i n z a Monostroma fuscum  94 51  P 14.4/cm| 0.2/cm  - to 4 0.2 t o 8 - to 4  R V  76c  TABLE 2 0 o  Continued  Species  November 4 - , 1 9 6 5 (91  Thallus Frequency Abundance height (%) (den, o r t o t , ) (cm) days a f t e r  Repr,=R Vege,=V  denuding)—Continued  Remarks: The Enteromorpha l i n z a cover now extended t o a major p o r t i o n of one o f the l a t e r a l edges of t h e p l o t . The o t h e r s i d e of t h e p l o t was bare i n an a r e a 1 4 - t o 6 0 em from the p l o t ' s edge The t h a l l i of N a v i c u l a g r e v i l l e i and Honostroma fuscum d i d not o c c u r o u t s i d e the E, l i n z a p a t c h . The d e n s i t i e s were determined from a count macEe on a 6 X 6 cm scrape t a k e n n e a r the p l o t ' s c e n t e r , 0  December 1 , 1 9 6 5 ( 1 1 8 days a f t e r denuding) Chrysophyta * Navicula g r e v i l l e i Chlorophyta Ent eromorpha l i n z a Ulva lobata Rhodophyta Prionitis l y a l l i i Iridaea cordata  86  80 57  5  20  1 11  total total  - to  6  - to - to  6  R Y  5  Y Y  11  - to  Remarks: Enteromorpha l i n z a was now absent from m a r g i n a l areas a l o n g b o t h l a t e r a l s i d e s and t h e seaward edge. A s s o c i a t e d w i t h £° l i n z a were U l v a l o b a t a and N a v i c u l a g r e v i l l e i . The l a t t e r a l s o o c c u r r e d o u t s i d e t h e E, l i n z a p a t c h , i , e , , a l o n g the m a r g i n a l areas of the plot"7 t o g e t h e r w i t h the s i n g l e P r i o n i t i s l y a l l i i t h a l l u s and a l l except one of the I r i d a e a c o r d a t a thalli, The l o n e I_, c o r d a t a e x c e p t i o n was s i t u a t e d 5 cm w i t h i n the dense E, linza~~stanc" ~ December 2 8 , 1 9 6 5 ( 1 4 - 5 days a f t e r denuding) Chrysophyta Navicula g r e v i l l e i Chlorophyta Ulva lobata Phaeophyta Petalonia  debilis  Rhodophyta I r i d a e a cordata  - to  100  7  - to  94-  5  2  total  5  1  total  5,  12  6  V R  5  Remarks: A l t h o u g h N a v i c u l a g r e v i l l e i had a h i g h e r f r e q u e n c y , U l v a l o b a t a was much more abundant. T h i s green a l g a was absent from c e r t a i n m a r g i n a l a r e a s of the p l o t . The I r i d a e a c o r d a t a t h a l l u s was not p a r t of the December 1 p o p u l a t i o n ,  77*  TABLE 20o  Continued Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Species  Repr.=R Vege.=V  1  J a n u a r y 26,  1964  (174 days a f t e r denuding)  Chrysophyta Navicula g r e v i l l e i  66  _  - to 9  -  Chlorophyta Ulva lobata  54  _  - to 8  R  2 to 6  V  Phaeophyta A l a r i a marginata Rhodophyta Iridaea cordata  9  4  total  11  4  total  Remarks: The U l v a l o b a t a p o p u l a t i o n formed a green cover a t t h e c e n t r a l a r e a of the p l o t . Most of the c o l o n i a l t h a l l i of N a v i c u l a g r e v i l l e i were p r e s e n t w i t h i n t h i s c o v e r . The t h a l l i of I r i d a e a c o r d a t a , none of which was the one p r e s e n t on December 28. and A l a r i a m a r g i n a t a , which were without s p o r o p h y l l s , grew w i t h i n 30 cm of the p l o t ' s seaward edge*  78. Development a t V i c t o r i a P l o t VI ( T a b l e The 1963;  community on t h i s p l o t was removed on November  but burning  o f t h e s u r f a c e , which was t h e f i n a l  the denuding p r o c e d u r e , 1963o of  22)  step i n 1,  c o u l d n o t be done u n t i l December  Thus, t h e denudation  date does not c o r r e s p o n d  4,  t o t h e date  t h e census o f t h e community p r e s e n t b e f o r e denuding.  Itis  noteworthy, however, t h a t t h e r e was no v i s i b l e growth on t h e p l o t on December 1,  j u s t b e f o r e i t was burned.  no s c r a p i n g s f o r m i c r o s c o p i c  examination  were  Unfortunately taken.  No o t h e r p l o t had so l a r g e a p o p u l a t i o n o f A l a r i a n a t a i n the b e f o r e - d e n u d i n g  community ( T a b l e 2 1 ) .  margi-  Most o f the  A l a r i a t h a l l i were i n t h e p l o t ' s seaward h a l f where a few grew i n dense c l u s t e r s . thalli and  The c l u s t e r s were composed o f up t o e i g h t  each, o f which some were l a r g e and mature, o t h e r s  undeveloped, and s t i l l  o t h e r s had o n l y t h e s t i p e s  A t l e a s t f o u r A. m a r g i n a t a t h a l l i lated corallines. of  2 cm  were e p i p h y t i c on the a r t i c u -  The 25 c o r a l l i n e p a t c h e s ,  about 75 p e r cent than  2 t o 4-91 cm .  F o u r o f t h e Monostroma fuscum t h a l l i  and a l l  t h e P o l y p o r o l i t h o n r e c l i n a t u m c r u s t s were growing on t h e  corallines. of  remaining.  which were C o r a l l i n a v a n c o u v e r i e n s i s , ranged from l e s s  2  of  small  M i c r o c l a d i a c o u l t e r i was e p i p h y t i c on b o t h  specimens  P r i o n i t i s l a n c e o l a t a . The P e t r o c e l i s f r a n c i s c a n a p a t c h was p 12 cm . The I r i d a e a c o r d a t a c l u s t e r had o l d , eroded b l a d e s .  79. TABLE 2 1 c Enumeration of t h e community p r e s e n t b e f o r e denuding a t V i c t o r i a P l o t VI on November 4, 1963  Species  Frequency (%)  Abundance (total)  Thallus height (cm)  Chlorophyta Monostroma fuscum  9 es  8  2  Phaeophyta A l a r i a marginata  63 es  67  2 7  Rhodophyta Polyporolithon reclinatum B o s s i e l l a plumosa and " C o r a l i i n a vancouveriensis Prionitis lanceolata Petrocelis franciscana Iridaea cordata jjicrocTadia c o u l t e r i Laurencia s p e c t a b i l i s  Repr.=R Vege.=V  to 6 t o 85  R  86 86 6 6 3, 6 3  R  (25  patches) 2  7, 9  (1 p a t c h ) 1 5 3 0 •2, 0.3, 0.5 6 t o 10 7  e = e p i p h y t i c , see p r e v i o u s page f o r d e t a i l s , es = e p i p h y t i c and s a x i c o l o u s .  R V V V V V  80. TABLE 2 2 o  Enumeration of r e c o l o n i z i n g communities a t V i c t o r i a P l o t VI  Species  Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Repr«=R Vege.=V  December 28, 1963 (27 days a f t e r denuding) Phaeophyta R a l f s i a fungiformis  80  V  Remarks: The w i d t h of the l a r g e s t t h a l l u s of t h i s brown a l g a was 1.5 cm; most were 0.5 cm wide.  crustose  January 26, 1964 (56 days a f t e r denuding) Phaeophyta A l a r i a marginata Rhodophyta Prionitis l y a l l i i A n t i t h a m n i o n subulatum  6  4 total  1.5 t o 8  V  5 14  1 total 10 t o t a l  2 0.5 t o 1  R  Remarks: As on December 28, no green a l g a e were p r e s e n t . Besides the t h r e e s p e c i e s l i s t e d , a l l of which were w i t h i n 45 cm from the seaward edge* of t h e p l o t , t h e r e was a s p e c i e s of Rhabdomeniao T h i s diatom, which i s c o n s i d e r e d here t o be more p l a n k t o n i c than b e n t h i c , was abundant over most o f t h e p l o t . Its colonial h a b i t , u n l i k e Amphipleura r u t i l a n s o r N a v i c u l a g r e v i l l e i , i s f i l a m e n t o u s w i t h each o p p o s i t e v a l v e f a c e of a c e l l j o i n e d t o the v a l v e f a c e of another. The A l a r i a m a r g i n a t a t h a l l i were without s p o r o p h y l l s .  81 o Development a t G l a c i e r P o i n t ( T a b l e 24-) The  community t h a t was removed on June 4-, 1962, had 2?  a l g a l s p e c i e s , of which n e a r l y t w o - t h i r d s were r e d a l g a e 23)o  (Table  T h i s group a l s o was the l a r g e s t i n terms of number of  specimens<,  The more conspicuous  group, however, was t h e brown  a l g a e , e s p e c i a l l y t h e l a r g e kelps«  Of these k e l p s , o n l y  Hedophyllum s e s s i l e grew a t the upper and middle ( w i t h r e s p e c t to an  t i d e l e v e l s ) p a r t s of the p l o t .  The o t h e r s , A l a r i a m a r g i n a t a  < i E g r e g i a m e n z i e s i i , were r e s t r i c t e d t o the lower p a r t of t h e  p l o t , w i t h i n an a r e a 30 cm from the sand s k i r t i n g the b o u l d e r . I n t h i s same a r e a grew a l l the t h a l l i  of Plocamium p a c i f i c u m ,  M i c r o c l a d i a b o r e a l i s , P t i l o t a f i l i c i n a , and Hymenena  flabelli-  g e r a , and most o f those o f Rhodomela l a r i x and O d o n t h a l i a cosa. of  The Fucus evanescens t h a l l i  the p l o t .  grew a t the uppermost  floclevel  The l a r g e s t c r u s t o s e p a t c h was t h a t o f B o s s i e l l a p  plumosa, and i t covered  an a r e a of 4-32 cm .  plumosa, t h e r e were v e r y few t h a l l i E p i p h y t i c on these  R e l a t i v e t o B.  of O o r a l l i n a v a n c o u v e r i e n s i s .  c o r a l l i n e s were some o f the t h a l l i  p o r o l i t h o n reclinatum, Halosaccion glandiforme, Oo  floccosa.  Ro  l a r i x , and H, g l a n d i f o r m e  tis lyallii, some t h a l l i  of P o l y -  R. l a r i x , and  P o l y p o r o l i t h o n r e c l i n a t u m was a l s o growing on was a l s o on F. evanescens, P r i o n i -  R. l a r i x , and 0. f l o c c o s a .  B e s i d e s H.  glandiforme,  of P o r p h y r a p e r f o r a t a and some of U l v a l o b a t a were  e p i p h y t i c on F_. evanescens.  B e s i d e s H. g l a n d i f o r m e  c l i n a t u m , some o f the t h a l l i  o f U. l o b a t a and a l l of t h a t of  Monostroma a r c t i c u m were e p i p h y t i c on E » l a r i x .  and P. r e -  The Coilodesme  c a l i f o m i c a t h a l l i were on the s i n g l e t h a l l u s of C y s t o s e i r a geminata.  At l e a s t two t h a l l i  c o u l t e r i growing on them. included three six  o f P. l y a l l i i had M i c r o c l a d i a  N o n - a l g a l elements i n the community  clumps o f P h y l l o s p a d i x  c h i t o n and e i g h t Acmaea  specimens.  s c o u l e r i , and a t l e a s t  83. TABLE 2 3 o Enumeration o f t h e community p r e s e n t b e f o r e denuding a t G l a c i e r P o i n t on June 4, 1962  Species  Frequency (%)  Chlorophyta Spongomorpha c o a l i t a Monostroma a r c t i c u m Ulva lobata Phaeophyta R a l f s i a fungiformis Haplogloia andersonii Coilodesme c a l i f o r n i e a Hedophyllum s e s s i l e A l a r i a marginata ggregia menziesii Imcus "e'vanescens C y s t o s e i r a geminata Rhodophyta Porphyra p e r f o r a t a Polyporolithon reclinatum B o s s i e l l a plumosa and Corallina vancouveriensis Prionitis l y a l l i i Petrocelis franciscana Plocamium p a c i f i c u m i r i d a e a cordata Halosac'cion g l a n d i f o r m e Microcladia borealis Microcladia coulter! Ptilota filicina Hymenena f l a b e l l i g e r a Pterosiphonia bipinnata Rhodomela l a r i x Odonthalia f l o c c o s a  e 7 13 1 3  e s  13 7  e  27  27 7  27 7  1 3  es  40  e  40 20 40  27 60 1 3  e  ee  13  7 7 2 207  tl  33  e s  e s  Thallus height (cm)  Abundance (total)  2 6 12  7, i3 0,5 t o 4 3 t o 17  (2 patches ) 1 4 13 10 1 6 1  16 1 to 5 t o 40 _ t o 70 240 — t o 17 65  5  8 t o 14  mm  (9 p a t c h e s ) 5 9 (12 p a t c h e s ) 11 3 — 11 0,3  -  —  -  —  10 7  -  e = e p i p h y t i c , see p r e v i o u s page f o r d e t a i l s , es = e p i p h y t i c and s a x i c o l o u s .  —  7 V V w  -_  t o 20 —  to to to — to — to — to 5 to 6 to to — to  Repr.=R Vege,=V  15 16 6 12 4  15  15 14 15 16  R V —  R —  R R R R R R V V R V R V V V R R V  84 „ TABLE 24«  Enumeration of r e c o l o n i z i n g communities a t G l a c i e r Point  Species  Frequency (%)  June 17, 1962  Abundance (den.  or t o t o )  Thallus height  Repr<,=R Vege =Y 0  (cm)  (15 days a f t e r denuding)  Chrysophyta Amphipleura r u t i l a n s  100  190/cm  Chlorophyta Ulothrix flacca  100  425/cnr  p  - t o 0„002  -  0  - to  0.08  Remarks: The c o l o n i a l t h a l l i of Amphipleura r u t i l a n s and t h e f i l a m e n t s of U l o t h r i x f l a c c a , t o g e t h e r w i t h o t h e r diatoms i n c l u d i n g F r a g i l a r i a sp., M e l o s i r a s p , and Licmophora sp,, appeared as a brown scum. The d e n s i t i e s were determined from microscope counts made on s c r a p i n g s . Q  J u l y 21, 1 9 6 2 (47 days a f t e r denuding) Chlorophyta Urospora wormskioldii Enteromorpha l i n z a  53 80  -  - t o 11 - t o 17  V  Remarks: Urospora w o r m s k i o l d i i was p r e v a l e n t o n l y a t the h i g h e r r e g i o n of the p l o t . August 14, 1962  (71 days a f t e r denuding)  Chrysophyta Amphipleura r u t i l a n s Chlorophyta Urospora m i r a b i l i s Enteromorpha l i n z a  -  -  - to 2  -  40 93  -  - to 8 - t o 63  R  Remarks: There w e r e s e v e r a l bare a r e a s , 10-15 cm i n d i a m e t e r , w i t h i n the r a t h e r dense Enteromorpha l i n z a c o v e r . Distributed w i t h i n two of t h e s e bare p o c k e t s were a l l of f o u r Acmaea sp. specimens p r e s e n t . As w i t h t h e U r o s p o r a w o r m s k i o l d T i p o p u l a t i o n of J u l y 21, U r o s p o r a m i r a b i l i s was n o t i c e a b l e o n l y a t t h e upper p a r t of the p l o t . September 12, 1962 Chlorophyta Enteromorpha l i n z a  (100 days a f t e r denuding) 93  2 1.7/cm  - t o 26  Remarks: The d e n s i t y was determined from a 30 X 30 cm t a k e n n e a r the c e n t e r of the plot»  R  scraping  85. TABLE  2 4 c  Continued  Species  Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  October 20, 1962 (138 days a f t e r  Repr.=R v"ege.=V  denuding)  Chlorophyta Enteromorpha l i n z a  -  December 12, 1962 (191 days a f t e r  -  - t o 17  R  denuding)  Chrysophyta Amphipleura r u t i l a n s  27  19 t o t a l  - to 4  Chlorophyta Enteromorpha l i n z a 87 - to 3 V Ulva l o b a t a " 40 t o 14 V Phaeophyta R a l f s i a fungiformis 7 (2 p a t c h e s ) V Remarks: T h a l l i making up t h e Enteromorpha l i n z a p o p u l a t i o n were t w i s t e d and scrubby; a l s o p r e s e n t were d e f o l i a t e d ones w i t h o n l y b a s a l , t u b u l a r p o r t i o n s up t o 0.8 cm l o n g r e m a i n i n g . The Amphipleura r u t i l a n s c o l o n i a l t h a l l i were u n u s u a l l y s o f t and jelly-like. U l v a l o b a t a grew o n l y i n t h e lower p a r t o f t h e plot. December 27, 1962 (206 days a f t e r Chlorophyta Enteromorpha l i n z a Ulva lobata Rhodophyta Iridaea cordata  denuding)  87 47  P 4/cm -  7  1 total  - to 4 - to 7 15  R  Remarks: The d e n s i t y f o r Enteromorpha l i n z a , whose t h a l l i were s c r u b b y as on December 12, was determined from counts made i n situ. The I r i d a e a c o r d a t a t h a l l u s was made up o f one almost 15 cm t a l l b l a d e and s e v e r a l t h a t were l e s s t h a n 2 cm t a l l . U l v a l o b a t a formed a band of growth, 15 t o 20 cm wide, a t t h e lowermost p a r t o f t h e p l o t . Enteromorpha l i n z a was absent from t h i s a r e a . January 11, 1963 (221 days a f t e r Chlorophyta Enteromorpha l i n z a Ulva lobata  87 40  denuding) -  - to 3 - to 9  V V  86, TABLE 24.  Continued  Species  Frequency  0%)  January 11, 1963  Repr.=R 7ege.=7  (221 days a f t e r d e n u d i n g ) — C o n t i n u e d  Rhodophyta Iridaea cordata Odonthalia  Thallus Abundance height (den. o r t o t . ) (cm)  floccosa  13 20 20  2 total  5, 10 - to 1 - to 1  V V  Remarks: The Enteromorpha l i n z a were s t i l l scrubby and were a p p a r e n t l y o l d , f o r t h e i r t u b u l a r , b a s a l p o r t i o n s were f i l l e d w i t h r h i z o i d s . N e i t h e r of the I r i d a e a c o r d a t a t h a l l i was t h a t p r e s e n t on December 27• M i c r o c l a d i a b o r e a l i s and O d o n t h a l i a f l o c c o s a were a s s o c i a t e d w i t h U l v a l o b a t a , which was r e s t r i c t e d t o the lower p a r t o f the p l o t . F e b r u a r y 21, 1963  (262 days a f t e r denuding)  Chrysophyta Amphipleura r u t i l a n s Navicula g r e v i l l e i  53 53  27.0/cm~  Chlorophyta Ulothrix flacca  80 53  38o2/cm| 5ol/cm 17.7/cmJ 163.4/cnT  13  (1 p a t c h )  Ent eromorpha l i n z a Ulva lobata " Rhodophyta Petrocelis  franciscana  27 80  60  12.3/cnT  9  t o 0.2 to 0.2 to  to to to to  O0-O8  R  2?.  7 V R  2 0.6 12  Remarks: The d e n s i t i e s r e p r e s e n t averages of counts made on t h r e e 4 X 4 cm s c r a p i n g s . The f r e q u e n c y p e r c e n t a g e s were i n f e r r e d from t h e s e s c r a p i n g s which were t a k e n from the upper, middle and lower p a r t s o f t h e p l o t . Urospora m i r a b i l i s was p r e s e n t o n l y a t the h i g h e r p a r t of the p l o t , a n T l J l v a l o b a t a was o n l y a t the lower p a r t . A p r i l 27, 1965  (327 days a f t e r denuding)  Chlorophyta Spongomorpha c o a l i t a Ent eromorpha l i n z a Ulva lobata  80 80 47  - t o 21 - t o 24 - t o 53  R V 7  87 TABLE 24c  Continued  Species  A p r i l 27, 1965  Frequency  (%)  Thallus Abundance height (dene o r tote) (cm)  Repr==R 7ege.=V  (327 days a f t e r d e n u d i n g ) — C o n t i n u e d  Phaeophyta Petalonia debilis X l a r i a marginata  7 53  2 total 25 t o t a l  Rhodophyta Porphyra p e r f o r a t a Iridaea cordata Microcladia borealis P t i l o t a FTTicina Odonthalia f l o c c o s a  7 7 55 20 20  2 total 1 total — —  5, 4  R V  15, 14 25 - to 8 - to 6 - to 8  R V R  - t o 120  V V  Remarks: R e s t r i c t e d t o t h e lower p a r t of the p l o t were U l v a l o b a t a , M i c r o c l a d i a b o r e a l i s , P t i l o t a f i l i c i n a , and Odonthalia~flo°ccosac Most of the A l a r i a m a r g i n a t a t h a l l i were a s s o c i a t e d w i t h them. A l l of the t h a l l i of t h i s k e l p were w i t h o u t s p o r o p h y l l s .  Chlorophyta Spongomorpha Enteromorpha Ulva l o b a t a  coalita linza  Phaeophyta Haplogloia andersonii Laminaria c u n e i f o l i a A l a r i a marginata Rhodophyta Porphyra p e r f o r a t a B o s s i e l T a plumosa and C o r a l l i n a vancouveriensis Plocamium oregonum Ptilota filicina Odonthalia f l o c c o s a  p  75 87 87  Oc5/cm2 2.8/cmp  7 7 35  5 total 5 total 20 t o t a l  15  14 t o t a l  7 15 20 20  1.6/cm  1  total — — —  t o 23 O c l t o 13 0.2 t o 25  2 —  -  _  V 7  t o 24 to 5 t o 275  R V R  t o 17  R  „  to 5 _ to 8 — to 11  V R R V  Remarks: The d e n s i t i e s were determined from counts made on a 6 X 6 cm scrape* The c o r a l l i n e t h a l l u s c o n s i s t e d o f o n l y t h e c r u s t o s e b a s a l p o r t i o n , which was 2 cm wide* I t was a t t h e lower p o r t i o n of t h e p l o t , which a l s o i n c l u d e d some of the t h a l l i of Enteromorpha l i n z a and U l v a l o b a t a , most of t h a t of A l a r i a m a r g i n a t a , and a l l o f t h a t of H a p l o g l o i a a n d e r s o n i i , L a m i n a r i a c u n e i f o l i a , Plocamium oregonum, P t i l o t a f i l i c i n a , and O d o n t h a l i a f l o c c o s s u A l l of the Porphyra p e r f o r a t a b l a d e s were a t the upper p a r t of t h e p l o t  88 a TABLE 24.  Continued  Species  Frequency  (%)  June 9, 1963 (570 days a f t e r Chlorophyta Spongomorpha c o a l i t a Enteromorpha TXnza IIva l o b a t a (and.)  ""Ulfra s t e n o p h y l l a  Phaeophyta Laminaria  cuneifolia  Abundance  (dene o r t o t . )  Thallus height  (cm)  Repro=E Vege.=V  denuding)  67 75  -  40  7 55  Rhodophyta Porphyra p e r f o r a t a 15 B o s s i e l l a plumosa)and C o r a l l i n a vancouveriensis 7  4 total 16 t o t a l 8 total  to to to to  18  12 17 20  V R V  ¥  1, 2 , 2 , 25 - t o 150  V R  - t o 17  R V  (5 p a t c h e s )  Remarks: The t h r e e s m a l l e r s i z e d L a m i n a r i a c u n e i f o l i a t h a l l i . were new a r r i v a l s ; t h e r e i s some doubt as t o whether t h e 25 cm t h a l l u s was p a r t o f the May 24 p o p u l a t i o n o r whether i t appeared a f t e r t h a t p e r i o d . Of the 16 A l a r i a m a r g i n a t a t h a l l i , a l l of which were p a r t o f the May 24 p o p u l a t i o n , seven had o n l y s t i p e s and l o w e r - m i d r i b p o r t i o n s r e m a i n i n g . Growing a t the lower r e g i o n of t h e p l o t were a l l t h e t h a l l i of U l v a l o b a t a and L. c u n e i f o l i a , and most of t h a t of A. m a r g i n a t a . P o r p h y r a p e r f o r a t a was o n l y i n the upper a r e a of the p l o t . J u l y 7, 1965 (598 days a f t e r Chlorophyta Spongomorpha c o a l i t a Enteromorpha l i n z a U l v a l o b a t a (and) Ulva stenophylla Phaeophyta A l a r i a marginata Rhodophyta B o s s i e l l a plumosa and CorallTna vancouveriensi Plocamium pacTificum  denuding)  67 75 55 20  20  15  —  _ —  10 t o t a l  4 total  -  to to to to  15  19 27  40  - to 6  R R V Y  R  V Y  Remarks: O n l y one o f the b l a d e - l e s s A l a r i a m a r g i n a t a t h a l l i o f June 9 was s t i l l p r e s e n t . The Spongomorpha c o a l i t a t h a l l i were somewhat coarse and were s p a r s e l y d i s t r i b u t e d .  89° TABLE 2 4 .  Continued  Species  Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Repr.=R ¥ege.=¥  August 4 , 1963 (426 days a f t e r denuding) Chlorophyta Spongomorpha c o a l i t a enteromorpha l i n z a jjlva lobata  53 80 40  0«5/cm| 1 o 3/cnip 0.4/cm  to 9 t o 38 t o 45  'V R V  Phaeophyta Hedophyllum s e s s i l e Laminaria c u n e i f o l i a X l a r i a marginata ~  .7 7 20  1 total 1 total 9 total  33 6  V V R  Rhodophyta Porphyra B o s s i e l l a plumosa and C o r a l l l n a v a n c o u v e r i e n s i s 20 Petrocelis franciscana "" 13 Iridaea cordata 13 Odonthalia f l o c c o s a 7 <  t o 280 1 total 22 t o t a l 34 t o t a l 2 total 3 total  17 3, 18 2 to 3  V V R V  Remarks: The d e n s i t y f o r t h e green a l g a e was o b t a i n e d from i n s i t u counts made on two,6 X 6 cm a r e a s . The Spongomorpha c o a l i t a t h a l l i were c o a r s e and "ropy" i n appearance. There were now t h r e e A l a r i a marginata t h a l l i without b l a d e s ; one o f t h e s e was t h a t p r e s e n t on J u l y 7° The P e t r o c e l i s f r a n c i s c a n a and a r t i c u l a t e d c o r a l l i n e c r u s t s were s m a l l ; none were more than 0 . 4 cm i n diameter. Growing i n t h e lower p a r t o f t h e -plot were a l l t h e t h a l l i o f U l v a l o b a t a , a l l o f those o f t h e r e d a l g a l s p e c i e s except t h a t o f Porphyra p e r f o r a t a and one o f I r i d a e a c o r d a t a , and a l l o f those of t h e brown a l g a l s p e c i e s except two of A. m a r g i n a t a . August 1 7 , 1963 (439 days a f t e r denuding) Chlorophyta Spongomorpha c o a l i t a Ent eromorpha l i n z a U l v a l o b a t a (and) Ulva stenophylla Phaeophyta A l a r i a marginata  53 60 67 7  Rhodophyta B o s s i e l l a plumosa and C o r a l l i n a vancouveriensis P e t r o c e l i s f r a n c i s c a n a "*" — I r i d a e a cordata 7 Odonthalia f l o c c o s a 13  — —  —  -  to to to to  3 total  _  —  —  1 total  -  9 20 22 75  18 - to 6  ¥ R  ¥ ¥  ¥ ¥ R  ¥  90. TABLE 24.  Continued Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Species  August 17,  1965  (459 days a f t e r  Repr.=R Vege.=V  denuding)-—Continued  Remarks: The Spongomorpha c o a l i t a t h a l l i were v e r y c o a r s e and appeared t o be v e r y o l d . The I r i d a e a c o r d a t a t h a l l u s was t h e ' same one r e c o r d e d on August 4." There were no new a d d i t i o n s t o "fc A l a r i a marginata p o p u l a t i o n . The a r t i c u l a t e d c o r a l l i n e c r u s t s Cthose of P e t r o c e l i s f r a n c i s c a n a d i d not appear a g a i n ) were merely r e c o r d e d as b e i n g p r e s e n t from t h i s p e r i o d on; however, d a t a on s e v e r a l i n d i v i d u a l t h a l l i were o b t a i n e d from a m i c r o - t r a n s e c t i n s e r t e d on August 4 , 1965= There were Acmaea specimens i n bare a r e a s . The d i s t r i b u t i o n p a t t e r n was s i m i l a r t o p r e v i o u s o c c a s i o n s w i t h S. c o a l i t a and Enteromorpha l i n z a growing i n the upper and middle areas of t h e p l o t and the o t h e r s more o r l e s s r e s t r i c t e d t o the Lower p a r t . ne  September 2 ,  1965  (455 days a f t e r denuding)  Chlorophyta Spongomorpha c o a l i t a Enteromorpha l i n z a Ulva l o b a t a " Phaeophyta A l a r i a marginata Rhodophyta Bangia f u s c o p u r p u r e a Porphyra p e r f o r a t a B o s s i e l l a plumosa and CorallTna vancouveriensis Iridaea cordata Odonthalia f l o c c o s a  27 67 80  0.05/cnr —  7 7 7 15 7  5  total  1  total  - to 8 - t o 45 - t o 50  V R R  -  -  - to 6  e  54  »  5 5  total total  - t o 15 2 to 4  R R V R V  Remarks: The P o r p h y r a p e r f o r a t a t h a l l u s was e p i p h y t i c on a I r i d a e a c o r d a t a b l a d e , which was the l a r g e s t (15 cm t a l l ) among a c l u s t e r of o t h e r s on t h e same h o l d f a s t . T h i s J.. c o r d a t a t h a l l u s was the same one r e c o r d e d on August 1 7 ° The A l a r i a marginata t h a l l i were those noted p r e v i o u s l y . The t h a l l i of Spongomorpha c o a l i t a , whose d e n s i t y was determined from counts made i n s i t u , s t i l l had a c o a r s e , o l d appearance. The U l v a l o b a t a growth extended t o the middle p a r t of t h e p l o t where i t grew i n w i d e l y spaced clumps. A t t h e lower p a r t of the p l o t o n l y 16 t h a l l i of t h i s s p e c i e s remained. The few f i l a m e n t s of Bangia fuseopurpurea were i n the uppermost p a r t of t h e p l o t .  91 o TABLE 24,  Continued Thallus Frequency Abundance height (%) (den„ o r t o t o ) (cm)  Species  October 6, 1963  (4-89 days a f t e r  27 13  Phaeophyta Petalonia  20  9  7 20  debilis  Rhodophyta Porphyra p e r f o r a t a B o s s i e l l a plumosa and CorallTna vancouveriensis Iridaea~cordata Halosaccion glandiforme Delesseria decipiens Pterosiphonia bipinnata Odonthalia f l o c c o s a Remarks: i n t h e lower p a r t o f the November 5» 1965  (517  Chlorophyta Ulva lobata  Chlorophyta Ulva lobata  R R R  total  1  to  10  R  3  total  12  to  15  R  5  total  (1  patch) —  —  2 12  total total  -  .s and O d o n t h a l i a plot,  days a f t e r  (545  days a f t e r  15  Rhodophyta B o s s i e l l a plumosa and Corallina vancouveriensis Iridaea~cordata ' 27 Pterosiphonia bipinnata 27 Odonthalia f l o c c o s a 27  7 5 3, 5 - to 6 - to 5  - to - to  V V V V R V  f l o c c o s a grew o n l y  denuding)  55  Rhodophyta B o s s i e l l a plumosa and Corallina vancouveriensis Iridaea cordata ' 20 Pterosiphonia'"5ipinnata 55 Odonthalia f l o c c o s a 20 December 1, 1965  - t o 11 - to 7 - t o 28  —  —  7 27 20  0  denuding)  Chlorophyta Spongomorpha c o a l i t a ait eromorpha l i n z a (IIva l o b a t a  80  Repr =R Yege«=V  - t o 18  4- t o t a l  - to - to - to  15 7 5  R  V R V  denuding) 5  total  10  total  V (base o n l y ) - to 6  V  Remarks: The P t e r o s i p h o n i a b i p i n n a t a t h a l l i were e s s e n t i a l l y def o l i a t e d as o n l y t h e i r a t t a c h e d , p r o s t r a t e f i l a m e n t s remained.  TABLE 24.  Continued Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Species  January  15, 1964  (590  Repr.=R Vege.=V  days a f t e r denuding)  Chlorophyta Ulva lobata  7  1 total  Phaeophyta Laminaria c u n e i f o l i a A l a r i a marginata ~  7 15  5 total 4 total  Rhodophyta B o s s i e l l a plumosa and C o r a l l l n a vancouveriensis Iridaea cordata Odonthalia floccosa  7 27  2 total 11 t o t a l  V 4, 4, 9 - t o 42  V V  15, 15  V Y V  - to 3  Remarks: A l l t h e O d o n t h a l i a f l o c c o s a and;: I r i d a e a c o r d a t a t h a l l i were new a r r i v a l s " ! Both brown a l g a l s p e c i e s were r e s t r i c t e d t o t h e lower p a r t of t h e p l o t . The s i n g l e t h a l l u s o f U l v a l o b a t a was n o t part; of t h e December 1 p o p u l a t i o n .  9 5 °  Development a t P o r t Renfrew ( T a b l e 2 6 ) The The  p l o t at P o r t Renfrew was  a l g a l community t h e n removed comprised t e n s p e c i e s , of which  t h e r e were two was  denuded on June 3 , 1 9 6 2 ,  g r e e n s , two  a r e l a t i v e l y simple  browns and  s i x reds  community i n which the t h a l l i  evanescens were the l a r g e s t b o t h i n s i z e and e n t i r e community, however, was  occurred very densely,  4o5  Ro  have been p r e s e n t although  at t h i s t i m e .  p l o t ' s v e r t i c a l f a c e , two zontal face.  of Pucus  i n number.  The  and  the s h e l l s were up  r e c o r d s were kept of o t h e r animals t h a t  Ulva l a c t u c a occurred  It  e p i z o i c on Balanus c a r i o s u s .  This barnacle cm t a l l .  (Table 2 5 ) °  Regarding d i s t r i b u t i o n  may patterns,  o n l y i n the lower h a l f of  the  of i t s t h a l l i were on the t o p ,  Fucus evanescens was  to  hori-  the o n l y o t h e r a l g a growing  on the h o r i z o n t a l f a c e , where i t appeared t o occur l e s s d a n t l y t h a n i t d i d on the v e r t i c a l f a c e .  The  abun-  individual  specimens of Spongomorpha c o a l i t a , L e a t h e s i a d i f f o r m i s , and I r i d a e a c o r d a t a were s i t u a t e d w i t h i n the upper h a l f of vertical  the  face.  Because of the v a s t d i f f e r e n c e i n h a b i t a t and type  of  community between the h o r i z o n t a l and v e r t i c a l f a c e s of the t h e r e was  little  j u s t i f i c a t i o n i n t r e a t i n g b o t h f a c e s as a u n i t .  S i n c e b o t h the community p r e s e n t  before  denuding and  the  r e c o l o n i z i n g communities a t the h o r i z o n t a l f a c e were the complicated  of the two  species being  less  f a c e s , a t l e a s t i n terms of number of  i n v o l v e d , they are excluded  enumerations and  plot,  from the  are t r e a t e d o n l y under "remarks".  tabular  94« TABLE 25o Enumeration of the community p r e s e n t b e f o r e denuding a t P o r t Renfrew on June 3 , 1962  Species  Frequency (%)  Chlorophyta Spongomorpha c o a l i t a Ulva l a c t u c a Phaeophyta Leathesia  difformis  Rhodophyta G-igartina p a p i l l a t a Iridaea cordata Halosaccion glandiforme Microcladia borealis' P o l y s i p h o n i a h e n d r y i (and)  7  40  Abundance (total)  1 14  7 93  1  7 7  2 1  20 60  —  3  24  Thallus height (cm)  3 3 t o 14  - t o 18 1, 5 8  0*5  to 4  3 to 6  - to 2  Repr.=R Vege»=V  ¥ J  R R V  R y V R  95 c  TABLE 26.  Enumeration of r e c o l o n i z i n g communities a t P o r t Renfrew Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Species  June 16, 1962  (15 d a y s . a f t e r  Chlorophyta Rhizoclonium riparium Enteromorpha l i n z a  Repr»=R Vege.=V  denuding) 7  ((1 p a t c h )  Rhodophyta Bangia f u s c o p u r p u r e a  - t o 0*7 - to 5  V  - t o 0.4-  2 Remarks: The Enteromorpha l i n z a p a t c h was no more t h a n 50 cm and i t was s i t u a t e d i n t h e lower p a r t o f the V e r t i c a l f a c e . I t was the o n l y v i s i b l e growth. The other two s p e c i e s were d e t e c t e d t h r o u g h m i c r o s c o p i c e x a m i n a t i o n o f s c r a p i n g s , i n which t h e y were p r e s e n t i n s m a l l numbers. There were s e v e r a l s p e c i mens of L i t t o r i n a s i t k a n a and a t l e a s t seven Acmaea c a s s i s pelto. J u l y 20, 1962  (4-7 days a f t e r  Chlorophyta Enteromorpha l i n z a  denuding) 27  (1 p a t c h )  - t o 17  R  Remarks: No s c r a p i n g s were t a k e n . The Enteromorpha l i n z a growth was quite, dense and was l o c a t e d i n t h e same a r e a as previously. Indeed, i t appeared as though the June 16 p a t c h had m e r e l y become extended, i n a r e a . A v e r y sparse s e t t l e m e n t of a r e c o l o n i z i n g p o p u l a t i o n of Balanus c a r i o s u s was n o t e d a t t h i s time. October 1 9 , 1962  (158 days a f t e r  Chlorophyta Ulva lactuca  100  Phaeophyta Petalonia debilis Fucus evanescens  100 20  denuding) p  2.2/cm p  1.9/cm (1 p a t c h )  - ta 8  V  - to 7 - to 4  R V  Remarks: B e s i d e s t h e l i s t e d Fucus evanescens p a t c h , which was about 14- cm wide and s i t u a t e d o n l y 12 cm from t h e t o p of t h e v e r t i c a l f a c e , a n o t h e r p a t c h , c o v e r i n g an a r e a of 15 X 28 cm was on the t o p , h o r i z o n t a l f a c e . O n l y two of the F. evanescens t h a l l i were 4- cm t a l l ; t h e o t h e r s had h e i g h t s of 2 cm o r l e s s . The d e n s i t i e s were determined from _in s i t u counts made on two 20 X 20 cm a r e a s .  96. TABLE 26.  Continued  Species  Frequency (°/o)  December 11, 1962 (191  Thallus Abundance height (den. o r t o t . ) (cm)  Repr =R Vege.=V 0  days a f t e r denuding)  Chlorophyta Ulva lactuca  100  -  - to 5  V  Phaeophyta Petalonia debilis 73 - to 4 R Fucus evanescens 20 (1 p a t c h ) - to 4 V Remarks: The g e n e r a l appearance of t h e community was t h e same as i t was on October J9. The Fucus evanescens p a t c h was i n the same p o s i t i o n as t h a t o b s e r v e d p r e v i o u s l y . The U l v a l a c t u c a and P e t a l o n i a d e b i l i s p o p u l a t i o n s were made up of b o t h young and o l d , eroded t h a l l i . January 10, 1965 (221 days a f t e r  denuding)  Chlorophyta Ulva lactuca  75  o 2.2/cnT  - to 2  R  Phaeophyta Petalonia debilis Fucus evanescens  27 27  15 t o t a l 54 t o t a l  - to 5 - to 4  H V  Remarks: Most o f the 54 Fucus evanescens t h a l l i were new; o n l y e i g h t t h a l l i grew where the p a t c h of December 11 was l o c a t e d . The t o p , h o r i z o n t a l f a c e now s u p p o r t e d o t h e r p o p u l a t i o n s b e s i d e s F. evanescens, of which t h e r e were about 50 t h a l l i . They were I>pongomorpha s p i n e s c e n s (1 t h a l l u s , 1.2 cm t a l l ) , U l v a l a c t u c a (.about 80 t h a l l i , ) , anoT'Petalonia d e b i l i s ( s p e c i f i c d e n s i t y a t 8/cm2). F e b r u a r y 5, 1965 (245 days a f t e r  denuding)  Chlorophyta Ulva lactuca Phaeophyta Petalonia debilis Fucus evanescens Rhodophyta Petrocelis franciscana  -  -  - to 5  V  -  -  - to 5 - to 4  R V  7  (1 p a t c h )  R  97. TABLE 26.  Continued  Species  F e b r u a r y 5,  Frequency  Abundance  Thallus height  C%) (den. or tote) (cm)  1965  (24-5  days a f t e r  Repr.=R Vege.=V  denuding)—Continued  Remarks: The P e t r o c e l i s f r a n c i s c a n a p a t c h had a diameter of 3 to 4- cm I t was growing on a s l o p i n g , or l e s s v e r t i c a l s e c t i o n , 8 cm below t h e edge of t h e t o p f a c e . A l t h o u g h t h i s c r u s t o s e a l g a had t e t r a s p o r a n g i a , i t was o b v i o u s l y young w i t h r e l a t i v e l y s h o r t , e r e c t f i l a m e n t s t h a t had l i t t l e , i f any, anastomosing c e l l s . The b l a d e s of U l v a l a c t u c a and P e t a l o n i a d e b i l i s were v e r y much eroded. 0  February 21,  1965  (265  days a f t e r denuding)  Chlorophyta Ulva l a c t u c a Phaeophyta E c t o c a r p u s sp. Fucus evanescens  53  29  total  - to 3  V  13 47  3 total 28 t o t a l  - to 2 - to 5  V V  Remarks: U l v a l a c t u c a , which was b o t h e p i p h y t i c and s a x i c o l o u s , was d i s t r i b u t e d from the top t o the lower a r e a o f the p l o t , whereas Fucus evanescens was r e s t r i c t e d t o the upper h a l f of the plot"! f h e s p e c i e s of E c t o c a r p u s , or p o s s i b l y P y l a i e l l a , was e p i p h y t i c on F. evanescens. Some of the U l v a l a c t u c a t h a l l i was a l s o e p i p h y t i c on the Fucus. There were t h a l l i of b o t h U. l a c t u c a and F. evanescens a t t a c h e d t o the s h e l l s of Balanus c a r l o s u s , but no e f f o r t was made t o determine t o what e x t e n t t h i s o c c u r r e d . The B. c a r i o s u s p o p u l a t i o n was dense and i t had a 100 p e r cent f r e q u e n c y . None of the s h e l l s was more than 0.5 cm t a l l . The o n l y o t h e r animal p r e s e n t was L i t t o r i n a sitkana. A p r i l 27,  1963  (328  days a f t e r denuding)  Chlorophyta Spongomorpha s p i n e s c e n s Ulva lactuca  7 7  1 12  total total  4  3 to 7  Phaeophyta Scytosiphon lomentaria Fucus evanescens  7 55  Rhodophyta Microcladia borealis Pterosiphoni'a'bipinnata  20 55  1 59  52  total total  15  total  - to 5 - to 2 - to 8  V  V V  R  98, TABLE 26.  Continued Thallus Frequency Abundance height (%) (den. o r t o t . ) (cm)  Species  A p r i l 27,  1965  (528  days a f t e r  Repr»=R Vegeo=V  denuding)—Continued  Remarks: The e n t i r e community was e p i z o i c on Balanus c a r i o s u s , Fucus evanescens and P t e r o s i p h o n i a b i p i n n a t a were absent o n l y from m a r g i n a l r e g i o n s of the p l o t . The o t h e r s p e c i e s o c c u r r e d o n l y w i t h i n the upper h a l f of the p l o t . On the h o r i z o n t a l f a c e , F. evanescens was the o n l y s p e c i e s p r e s e n t , w i t h l a r g e , up t o 9 cm t a l l t h a l l i . May  24,  1965  (355  days a f t e r denudin  Chlorophyta Ulva .lactuca  13  Phaeophyta Fucus evanescens Rhodophyta Pterosiphonia bipinnata  17  total  - to 5  R  100  - t o 11  V  73  - to 8  R  Remarks: As. p r e v i o u s l y , the a l g a l t h a l l i were a t t a c h e d t o the s h e l l s of Balanus c a r i o s u s . The l a r g e r specimens of t h i s b a r n a c l e were 1»5 cm t a l l . Other animals p r e s e n t were s e v e r a l specimens of L i t t o r i n a s i t k a n a , a few of Acmaea d i g i t a l i s and A° c a s s i s p e l t o , and f o u r specimens of M y t i l u s e d u l i s . The 17 TUva l a c t u c a t h a l l i o c c u r r e d as a p a t c h , o n l y 26 cm from the p l o t ' s lower edge. The t o p - f a c e s e c t i o n had o n l y Fucus evanescens and two animal s p e c i e s , B. c a r i o s u s and L„ s i t k a n a . J u l y 7,  days a f t e r denuding)  196;  Phaeophyta Fucus evanescens Etoodophyta Iridaea cordata IPolysiphonia h e n d r y i Pterosiphonia bipinnata January 26,  1964  (606  15  5  total  87  days a f t e r  14  R  9, 10 - to 3 - to 8  R R R  - to  100  7,  denuding)  Remarks: The e n t i r e b o u l d e r , b o t h denuded and c o n t r o l h a l v e s , was b a r e except f o r a v e r y few s c a t t e r e d 13 t o 14 cm t a l l Balanus c a r i o s u s specimens. These came l o o s e when s l i g h t p r e s s u r e was applied against t h e i r s h e l l s .  APPENDIX I I LISO? OF SPECIES AND  COLLECTION NUMBERS  Only t h o s e s p e c i e s found on the denuded p l o t s ,  either  as o r i g i n a l p o p u l a n t s ( i . e . , those removed i n denuding) o r as r e p o p u l a n t s , a r e l i s t e d .  The arrangement o f the a l g a l  s p e c i e s i s as t h a t used b y S c a g e l (1957)° phanerogam  The a l g a l and  specimens, which were c o l l e c t e d from denuded  plots,  i n s i t u p l o t s , and the g e n e r a l a r e a o f t h e e x p e r i m e n t a l  sites,  a r e d e p o s i t e d i n the P h y c o l o g i c a l Herbarium o f the U n i v e r s i t y of B r i t i s h Columbia.  The i n v e r t e b r a t e specimens, which were  c o l l e c t e d o n l y from the denuded p l o t s , a r e r e t a i n e d b y t h e author.  The c o l l e c t i o n numbers a r e my own.  Those w i t h t h e  l e t t e r s a., b, _c, o r d., r e f e r t o e p i p h y t e s , the h o s t o f which have the same c o l l e c t i o n number.  specimens  A number w i t h one  o r more o f t h e l e t t e r x i n d i c a t e s t h a t t h e number has been a p p l i e d more t h a n once.  100 o V i c t o r i a Breakwater S p e c i e s CHRYSOPHYTA Amphipleura r u t i l a n s  (Trentepohl) Cleve  852, 854, 899, 906, 950, 978, 1021, 1196c, 1227, 1228, 1515, 1621, 1679, 1727= Navicula g r e v i l l e i 1007,  ( C . Agardh) C l e v e  1016x, 1054,  1056, 1119,  1155, 1217,  1295, 1554,  1421, 1497, 1847, 1916, 1952, 1956, 1948, 1952, 1975, 1977* CHLOROPHYTA Ulothrix  flacca  ( D i l l w y n ) Thuret  852xo  U r o s p o r a m i r a b i l i s Areschoug 852xx, 948,  950x, 1279,  1512, 1662, 1824, 1876.  U r o s p o r a w o r m s k i o l d i i ( M e r t e n s ) Rosenvinge 907, 1181, 1226, 1298, 1485, 1680, 1695° Urospora  vancouveriana  (Tilden) Setchell  and Gardner  899x  0  Spongomorpha s p i n e s c e n s K u t z i n g 855a, 855, 905, 905, 910, 955, 1155, 1188, 1196b, 1505a, 1422x, 1495a, 1494, 1500, 1829°  1287b,  Spongomorpha c o a l i t a (Ruprecht) C o l l i n s 1180, 1198a, 1229, 1282, 1299, 1619, 1666, 1675, 1677 ° Enteromorpha l i n z a ( L i n n a e u s )  1559,  1542, 1426, 1441, 1509,  Agardh  904, 908, 909, 915, 956, 949, 951, 955, 957, 980, 981, 1015, 1017, 1081, 1098, 1166, 1177, 1200, 1222, 1248, 1281, 1290, 1297, 1528, 1551, 1558, 1540, 1415, 1425, 1484, 1510, 1611, 1622, 1642, 1675, 1678, 1682, 1685, 1688, 1695, 1702, 1726, 1825a, 1827, 1845, 1846, 1848, 1914, 1917, 1922, 1957, 1955° Monostroma fuscum ( P o s t e l s and R u p r e c h t ) W i t t r o c k 842, 912, 929, 947, 952, 977, 1012, 1151, 1197, 1221, 1247, 1291, 1505b, 1556, 1541, 1425x, 1457, 1511, 1618, 1724, 1854x, 1858, 1859, 1840, 1845, 1918, 1929, 1946, 1970o Monostroma a r c t i c u m W i t t r o c k  1154  1052x, 1099x, 1124x, 1507a, 1523, 1550, 1651x, 1674, 1705, 1895, 1910, 1915x,  101. CHLOROPHYTA ( C o n t i n u e d ) U l v a l o b a t a ( K u t z i n g ) S e t c h e l l and Gardner 84-3, 9 3 7 , 1010, 1046, 104-7, 1 0 5 2 , 1 0 7 1 , 1 0 9 9 , 1114, 1124, 1167, 1176, 1212, 1215, 1289, 1522, 1525*, 1529, 1414, 1416, 1426x, 1495, 1504, 1 5 0 5 , 1 5 0 7 a , 1615, 1651, 1644, 16653, 1685, 1689, 1696, 1704, 1717, 1718, 1 7 2 2 , 1 7 2 5 , 1850, 1855a, 1854, 1855, 1856, 1841, 1844, 1880, 1904, 1 9 1 1 , 1915, 1915, 1951, 1 9 5 8 , 1 9 5 9 , 1945, 1 9 5 0 , 1 9 5 5 , 1 9 6 9 , 1974,  1979.  PHAEOPHYTA R a l f s i a f u n g i f o r m i s (Gunnerus) S e t c h e l l and Gardner.  9 5 4 , 1501, 1 8 7 9 , 1886, 1 9 5 4 . H e t e r o c h o r d a r i a a b i e t i n a (Ruprecht) S e t c h e l l and Gardner 859, 1175, 1285. D e s m a r e s t i a munda S e t c h e l l and Gardner  1157. S c y t o s i p h o n l o m e n t a r i a (Lyngbye) J . Agardh 1168, 1220. Petalonia debilis  ( C . Agardh) Derbes and S o l i e r  1 0 8 5 , 1 0 9 7 , 1174, 1 2 2 5 , 1284, 1852, 1 9 5 5 , 1949, 1951, 1956, 1975. Colpomenia s i n u o s a (Roth) Derbes and S o l i e r 9 5 1 b , 952a, 1224. C o s t a r i a c o s t a t a ( T u r n e r ) Saunders  1 0 5 0 , 1 1 0 5 , 1126, 1 1 7 2 ,  1950x.  Hedophyllum s e s s i l e (C. Agardh) S e t c h e l l 1205, 1285, 1506, 1656, 1706, 1710, 1892. A l a r i a m a r g i n a t a P o s t e l s and Ruprecht 1051, 1100, 1104, 1122, 1150, 1178, 1189, 1201, 1 5 0 5 , 1427, 1434, 1455, 1657, 1 7 0 1 , 1857, 1898, 1899, 1 9 0 9 , 1950, 1976, 1978, 1980. Fucus evanescens C. Agardh  8 5 5 , 1169, 1171,  1287, 1418, 1495, 1610, 1 6 9 9 .  RHODOPHYTA Porphyra p e r f o r a t a J . Agardh 844, 1 1 7 1 a , 1175,  1287a, 1288, 1419, 1496.  102. RHODOPHYTA ( C o n t i n u e d ) P o l y p o r o l i t h o n r e c l i n a t u m ( F o s l i e ) Mason 840a, 841a, 944a, 945a, 1045a, 1147a, 1148a, 1149a, 1281xa, 1282xa, 1586a, 1422a, 1425a, 1458b, 1507b, 1625a, 1626a, 1652a, 1711a, 1712a, 1895a, 1894a. B o s s i e l l a plumosa (Manza) S i l v a 841, 944, 1149, 1282x, 1507, 1425, 1458, 1614, 1625, 1712,  1720, 1894, 1908, 1944.  C o r a l l i n a v a n c o u v e r i e n s i s Yendo 840, 951, 952,  945,  1045, 1147, 1148, 1281x, 1586, 1422,  1615, 1626, 1711, 1719, 1895, 1907° Crypt onemia obovata Jo Agardb 1655° P r i o n i t i s l a n c e o l a t a Harvey  1881, 1897, 1945o P r i o n i t i s l y a l l i i Harvey 857, 890, 895, 916, 950, 956, 1001, 1041, 1045, 1101, 1107, 1118, 1159, 1170, 1186, 1204, 1209, 1286, 1502, 1510, 1511, 1526, 1428, 1650, 1667, 1715, 1901x, 1925° C a l l o p h y l l i s sp»  1552o P e t r o c e l i s f r a n c i s c a n a S e t c h e l l and Gardner 852, 946, 959, 1105, 1164, 1500, 1420, 1499, 1645, 1700, 1878, 1885. Gigartina. p a p i l l a t a  (C. Agardh) J° Agardh  858, 1040, 1080, 1163, 1415, 1417, 1488, 1491, 1492, 1609, 1616, 1669, 1692, 1697, 1828, 1884, I r i d a e a c o r d a t a ( T u r n e r ) Bory 855, 854, 845, 891, 892, 902, 915, 914, 921, 922, 925, 924, 925, 926, 954, 1005, 1011, 1058, 1048, 1069, 1108, 1111, 1115, 1116, 1125, 1125, 1158, 1195, 1194, 1195, 1199, 1210, 1211, 1214, 1218, 1219, 1512, 1515, 1517, 1518, 1320, 1321, 1429, 1436, 1502, 1506, 1624, 1654, 1655, 1638, 1645, 1672, 1676, 1707, 1714, 1721, 1842, 1891, 1900, 1902, 1905° H a l o s a c c i o n g l a n d i f o r m e (Gmelin) Ruprecht 1458a. A n t i t h a m n i o n subulatum (Harvey) Jo Agardh 1018, 1955,  1982o  103 o RHODOPHYTA (Continued) M i c r o c l a d i a b o r e a l i s Ruprecht 911, 927, 931a, 1008, 1136, 1187, 1207, 1308, 1310a, 1325, 1430, 1440, 1501, 1687 M i c r o c l a d i a c o u l t e r i Harvey  857a, 890a, 895a, 950a, 956a, 1107a, 1118a, 1170a, 1186a, 1204a, 1502a, 1511a, 1428a, 1881a, 1897a, 1945a.  Hymenena f l a b e l l i g e r a  ( J . Agardh) K y l i n  895, 955, 1004, 1042, 1109, 1190, 1191, 1514, 1515, 1516, 1519, 1424, 1627, 1670, 1705, 1888, 1905, 1927, 1941. P o l y s i p h o n i a h e n d r y i Gardner  955,  1016, 1019, 1106, 1115, 1120, 1215a, 1555°  P t e r o s i p h o n i a b i p i n n a t a ( P o s t e l s and Ruprecht) P a l k e n b e r g 1006, 1015, 1044, 1055, 1055, 1102, 1112, 1121, 1132, 1182, 1183, 1205, 1206, 1215, 1216, 1249, 1295, 1296, 1527, 1557, 1412, 1486, 1490, 1498, 1508, 1620, 1686, 1851, 1882, 1947, 1971, 1972. L a u r e n c i a s p e c t a b i l i s P o s t e l s and Ruprecht 894, 928, 1005, 1192, 1196, 1198, 1503, 1509, 1671, 1887, 1896, 1928, 1940. Rhodomela l a r i x 1507,  ( T u r n e r ) C. Agardh  1652o  Odonthalia f l o c c o s a (Esper) Palkenberg 856, 1002, 1009, 1059, 1049, 1110, 1117, 1127, 1179, 1202, 1208, 1225, 1504, 1524, 1555, 1451, 1459, 1505, 1628, 1629, 1640, 1641, 1665, 1664, 1708, 1709, 1715, 1716, 1855, 1889, 1890, 1901, 1906, 1912, 1926, 1954, 1942. MOLLUSCA K a t h e r i n a t u n i c a t a (Wood) 849, 1452. Tonicella lineata  (Wood)  849x. Acmaea m i t r a E s c h s c h o l t z 1455° Acmaea t e s t u d i n a l i s scutum E s c h s c h o l t z 849xx.  104. G l a c i e r Point  Species  CHRYSOPHYTA Amphipleura r u t i l a n s  ( T r e n t e p o h l ) CIeve  8.96x, 939, 1000, 1141xx. Navicula g r e v i l l e i  (Co Agardh) C l e v e  1141 o CHLOROPHYTA Ulothrix flacca  ( D i l l w y n ) Thuret  896, 1142xx. U r o s p o r a m i r a b i l i s Areschoug  882, 1141x, 1254, 1263, 1275, 1546, 1565, 1577, 1446, 1455, 1475, 1479, 1523, 1545, 1554, 1595, 1602, 1656, 1759, 1770, 1775, 1807, 1817o Enteromorpha l i n z a  ( L i n n a e u s ) J , Agardh  918, 958, 959x, 960, 976, 999x, 1066, 1142, 1256, 1266,  1278, 1544, 1349, 1564, 1581, 1448, 1461, 1476, 1482, 1524, 1525a, 1552, 1580, 1585, 1605, 1646, 1658, 1755, 1757, 1758, 1746, 1764, 1780, 1781, 1785, 1813.  Monostroma a r c t i c u m W i t t r o c k 886b. U l v a l o b a t a ( K u t z i n g ) S e t c h e l l and Gardner 872b, 885, 886c, 941, 974a, 975b, 998, 1025, 1025a, 1064, 1140, 1157, 1255, 1259, 1260, 1275, 1545, 1554, 1565, 1582, 1585, 1584, 1585, 1445, 1460, 1462, 1475, 1481, 1520, 1554, 1547, 1548, 1551, 1581, 1582, 1585x, 1597, 1600a, 1606, 1607, 1650a, 1651, 1657, 1756, 1744b, 1751, 1765, 1778, 1779, 1782a, 1785, 1784b, 1786a, 1789, 1790, 1796, 1802a, 1805, 1821, 1822, 1855a, 1855b, 1859, 1867,  1875, 1958.  U l v a s t e n o p h y l l a S e t c h e l l and Gardner 1485,  1555, 1659, 1747.  PHAEOPHYTA R a l f s i a f u n g i f o r m i s (Gunnerus) S e t c h e l l and Gardner 999, 1144, 1592,  1766x,  1851.  105. PHAEOPHYTA ( C o n t i n u e d ) H a p l o g l o i a a n d e r s o n i i (Farlow) L e v r i n g  875, 1579. P e t a l o n i a d e b i l i s (C. Agardh) Derbes and S o l i e r  1277,  1444, 1818.  Coilodesme c a l i f o r n i c a (Ruprecht) K j e l l m a n 884a. Laminaria c u n e i f o l i a Specimens not  collected.  Hedophyllum s e s s i l e 1150,  1559,  JV Agardh (C. Agardh) S e t c h e l l  1469, 1748, 1760,  1797,  1800, 1852, 1865-  A l a r i a m a r g i n a t a P o s t e l s and Ruprecht 1154, 1262, 1861, 1862.  1274, 1575,  1749,  1470, 1558,  1761, 1798,  1799,  E g r e g i a m e n z i e s i i ( T u r n e r ) Areschoug Specimens not  collected.  Fucus evanescens C. Agardh 871, 872, 1516, 1745. C y s t o s e i r a geminata C. Agardh 884. RHODOPHYTA Bangia f u s c o p u r p u r e a ( D i l l w y n ) Lyngbye  1729,  1751,  1745.  P o r p h y r a p e r f o r a t a J . Agardh 871a, 889, 1276, 1556, 1480, 1517, 1774a, 1788, 1815, I860.  1555,  1545, 1742,  1755,  P o l y p o r o l i t h o n r e c l i n a t u m ( F o s l i e ) Mason 886d, 901a, 1061xa, 1145a, 1146a, 1258a, 1280xa, 1588a, 1589a, 1590a, 1457b, 1467-a, 1468a, 1558a, 1559a, 1605a, 1604a, 1776a, 1777a, 1802b, 1810a, 1869a, 1871a. B o s s i e l l a plumosa (Manza) S i l v a 878, 901, 1061x, 1146, 1252, 1280x, 1588, 1590, 1468, 1558, 1604, 1777, 1810. Corallina  901x, 1603,  1457,  v a n c o u v e r i e n s i s Yendo  1060x, 1145, 1255, 1776, 1811, 1871.  1279x,  1587, 1589, 1467,  1559,  106 o RHODOPHYTA ( C o n t i n u e d ) Prionitis  l y a l l i i Harvey  875, 879, 990,  1558,  1268, 1865, I960, 1965.  1561, 1458, 1474,  1792,  1806,  P e t r o c e l i s f r a n c i s c a n a S e t c h e l l and Gardner 900, 1022, 1028, 1145, 1466, 1526, 1556, 1766, 1808, 1850, 1870, 1919°  1591,  1660, 1750,  Plocamium oregonum Doty 986, 1160, 1578, 1596, 1754, Plocamium p a c i f i c u m 874,  876,  1062,  I r i d a e a cordata  1795-  Kyiin  1159,  1452,  1550, 1791.  ( T u r n e r ) Bory  848, 887, 992, 994, 995, 996, 1029, 1058, 1Q6?, 1151, 1152, 1250, 1269, 1552, 1382, 1575, 1445, 1|55, 1477, 1552, 1559, 1601, 1649, 1654, 1752, 1762, 1774, 1775, 1816, 1856, 1864, 1964. Halosaccion  g l a n d i f o r m e (Gmelin) Ruprecht  872a, 878a, 879b, 885a, 961b, 975a, 997a, 1025b, 1155, 1252a, 1255a, 1348, 1357, 1370a, 1571, 1450a, 1457a, 1478, 1516a, 1527a, 1531a, 1540a, 1544, 1599, 1650, 1744a, 1755a, 1759a, 1769, 1784a, 1804, 1820, 1855a, 1959a,  1251a,  M i c r o c l a d i a b o r e a l i s Ruprecht 881, 1067, 1270, 1555, 1362, 1472, 1522, 1528, 1546, 1655, 1771, 1809, 1868. Microcladia  c o u l t e r i Harvey  879a, 1268a, 1855c, Ptilota filicina  (Parlow) J . Agardh  985, 1158, 1264, 1555, 1587, 1758, 880,  Delesseria decipiens  1272, 1551, 1576, 1454, 1464, 1551,  J . Agardh  1814, Hymenena f l a b e l l i g e r a  ( J . Agardh) K y l i n  846, 850, 877, 988, 989, 1057, 1060, 1257, 1267, 1555, 1566, 1456, 1459, 1515, 1542, 1589, 1590, 1594, 1750, 1768,  1795 °  Pterosiphonia  bipinnata  ( P o s t e l s and Ruprecht) P a l k e n b e r g  847, 888, 1245, 1545, 1560, 1465, 1812, 1872,  1537, 1595,  1652, 1740,  107° RHODOPHYTA  (Continued)  Rhodomela l a r i x ( T u r n e r ) C. Agardh  886, 961, 974, 975, 1026, 1156, 1251, 1258, 1570, 1450, 1527, 1541, 1600, 1648, 1744, 1759, 1767, 1784, 1786, 1802, 1855, 1855, 1869, 1957, 1959° Odonthalia floccosa  (Esper) Falkenberg  885, 987,- 1027, 1061, 1065, 1155, 1246, 1265, 1271, 1550, 1568, 1569, 1580, 1451, 1465, 1518, 1539, 1540, 1598, 1647, 1655, 1755, 1765, 1772, 1782, 1794, 1805, 1819, 1854, 1866, 1961, 1962° SPERMATOPHYTA Phyllospadix scouleri  Hooker  1525, 1550, 1586, 1756° MOLLUSCA (The c h i t o n and Acmaea specimens p r e s e n t were n o t c o l l e c t e d and a more s p e c i f i c i d e n t i f i c a t i o n i s n o t a v a i l a b l e . )  108 o  P o r t Renfrew S p e c i e s CHLOROPHYTA R h i z o c l o n i u m r i p a r i u m (Roth) Harvey 897xo  Spongomorpha s p i n e s c e n s K u t z i n g  8660 Enteromorpha l i n z a 8 9 8 ,  917,  1 2 5 3 ,  Ulva l a c t u c a 8 6 1 ,  8 6 2 ,  1 5 9 5 ,  ( L i n n a e u s ) J . Agardh 1 4 0 4 ,  1 4 0 9 ,  1576o  Linnaeus  971,  1 4 0 6 ,  9 8 5 ,  1 0 5 5 ,  1 0 7 4 ,  1 0 8 8 ,  1095,  1 2 5 2 ,  1 2 4 1 ,  1 5 7 7 .  PHAEOPHYTA Ectocarpus sp. 1 0 9 6 .  L e a t h e s i a d i f f o r m i s ( L i n n a e u s ) Areschoug 869 o  S c y t o s i p h o n l o m e n t a r i a (Lyngbye) J . Agardh Specimens n o t c o l l e c t e d . Petalonia debilis 9 7 2 ,  9 8 2 ,  ( C . Agardh) Derbes and S o l i e r  1057, 1075.  Fucus evanescens C. Agardh 8 6 0 ,  9 6 6 ,  1 0 9 5 ,  1 0 5 0 ,  1 0 9 4 ,  1 5 6 1 ,  1 0 5 1 ,  1 2 5 4 ,  1 0 5 2 ,  1 2 4 0 ,  1 0 5 6 ,  1 5 9 1 ,  1 0 7 2 ,  1 5 9 2 ,  1075, 1090, 1091,  1 5 9 6 ,  1 5 9 9 ,  1 5 5 6 ,  1575-  RHODOPHYTA Bangia f u s c o p u r p u r e a  ( D i l l w y n ) Lyngbye  8 9 7 .  P e t r o c e l i s f r a n c i s c a n a S e t c h e l l and Gardner 1070,  1 0 8 9 ,  1258o  Gigartina papillata 8 6 8 ,  9 6 8 ,  1 0 5 4 ,  ( C . Agardh) J . Agardh  1 0 7 6 ,  1 0 9 2 ,  1 2 5 5 ,  1 4 0 1 ,  I r i d a e a c o r d a t a ( T u r n e r ) Bory 8 7 0 ,  9 6 7 ,  1 4 0 7 ,  1557,  1 5 6 5 ,  1 5 6 8 .  H a l o s a c c i o n g l a n d i f o r m e (Gmelin) Ruprecht 8 6 4 ,  9 6 5 ,  1 0 8 6 ,  1 2 5 7 ,  1 4 0 0 ,  1 5 6 0 ,  1 5 6 7 .  1 5 6 2 ,  1 5 7 0 .  109. RHODOPHYTA (Continued) M i c r o c l a d i a "borealis Ruprecht 863, 1242. Polysiphonia hendryi  Gardner  865, 1 5 7 9 . P t e r o s i p h o n i a b i p i n n a t a ( P o s t e l s and Ruprecht)  Falkenberg  867, 1239, 1244, 1393, 1397, 1398, 1408, 1555, 1578. MOLLUSCA Acmaea c a s s i s p e l t a  Eschscholtz  898xx, 1394x. Acmaea d i g i t a l i s  Eschscholtz  1394xx. L i t t o r i n a sitkana  Philippi  898xxx, 1096xx. Mytilus  e d u l i s Linnaeus  1394xxx. ARTHROPODA Balanus c a r i o s u s ( P a l l a s ) 898x, 1096x, 1394.  

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