Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Growth and distribution of the vegetation of a southern Fraser delta marsh Moody, Anne Irene 1978

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Notice for Google Chrome users:
If you are having trouble viewing or searching the PDF with Google Chrome, please download it here instead.

Item Metadata

Download

Media
831-UBC_1978_A6_7 M65.pdf [ 11.48MB ]
Metadata
JSON: 831-1.0094285.json
JSON-LD: 831-1.0094285-ld.json
RDF/XML (Pretty): 831-1.0094285-rdf.xml
RDF/JSON: 831-1.0094285-rdf.json
Turtle: 831-1.0094285-turtle.txt
N-Triples: 831-1.0094285-rdf-ntriples.txt
Original Record: 831-1.0094285-source.json
Full Text
831-1.0094285-fulltext.txt
Citation
831-1.0094285.ris

Full Text

GROWTH.AND DISTRIBUTION OF THE VEGETATION OF A .SOUTHERN "FRASER .DELTA" MARSH by ANNE IRENE MOODY B.A., Un ivers i ty of B r i t i s h Columbia, 197*4 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n THE FACULTY OF GRADUATE STUDIES (Department of Plant Science) We accept th i s thes i s as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA May, 1978 (C) Anne I. Moody, 1978 In presenting th i s thesis in pa r t i a l fu l f i lment of the requirements for an advanced degree at the Un ivers i ty of B r i t i s h Columbia, I agree that the L ibrary shal l make it f ree ly ava i lab le for reference and study. I fur ther agree that permission for extensive copying of th i s thesis for scho lar ly purposes may be granted by the Head of my Department or by his representat ives. It is understood that copying or pub l i ca t ion of th is thesis for f inanc ia l gain sha l l not be allowed without my writ ten permission. Department The Univers i ty of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 ABSTRACT •. - The foreshore marshes of the Fraser River estuary are of great importance to migrating and resident waterfowl and shorebirds, t rans ient j uven i l e salmonids, and to the many other components of the i n t r i c a t e estuar ine food web. Urban r e s i d e n t i a l , a g r i c u l t u r a l and ' i ndus t r i a l developments have encroached, and continue to encroach, upon these va lu -able foreshore marshes. This study was i n i t i a t e d to obtain information on the factors c o n t r o l l i n g , and c h a r a c t e r i s t i c s o f , the primary product-i v i t y , decomposition and spa t i a l and temporal d i s t r i b u t i o n s of the emergent vegetation of Brunswick Point marsh. Sampling locat ions were se lected to cover e levat iona l and s a l i n i t y gradients in th i s brackish t i d a l marsh. Per iod ic harvest ing of the ae r i a l vegetation components was undertaken to estimate net primary p roduc t i v i t y . In add i t i on , shoot dens i ty , reproductive shoot numbers, and nitrogen content, among other vegetation c h a r a c t e r i s t i c s were re lated to such environmental var iab les as s a l i n i t y , temperature and e l eva t i on . Standing crops for Scirpus mavitirms and Carecc lyngbyei showed a pos i t i ve as soc ia t ion with e l eva t i on ; peak standing crops were 565 g/m2 and g09 g/m2 re spec t i ve ly . Shoot d e n s i t i e s , reproduction shoot numbers and nitrogen content a l l showed re la t ionsh ips with e leva t i on . The growth rate of Carex lyngbyei,, the most productive spec ies, was very high, on the order of 20 g/m 2/day in-May and June. During l i t t e r bag f i e l d t r i a l s , Triglochin mavitima and Salicovnia vivginiaa decomposed much more r a p i d l y than did S. mavitimus and C. lyngbyei. In v i t r o decomposition studies r e f l e c t e d a s i m i l a r pattern f o r these species. Transplant studies of the species used in the decomposition i n v e s t i g a t i o n s showed that S. mavitimus t o l e r a t e d the v a r i e d c o n d i t i o n s at the four t r a n s p l a n t s i t e s best of a l l . The r o l e of S. mavitimus as .a. pioneer species in marsh succession at Brunswick Point was f u r t h e r supported by f i e l d observations and h i s t o r i c a l information. A simple succession pattern occurs in the Brunswick Point marsh where S. mavitimus and S. ameviaanus c o l o n i z e the barren mud and sand f l a t s and are succeeded by C. lyngbyei. The emergent marshes of the Fraser River estuary have experienced major m o d i f i c a t i o n s during the past century and these may continue. Extensive dyking of high marsh areas has reduced the areal extent of foreshore marshes: Thevremaining marsh areas are an important source of d e t r i t a l material which forms the basis of extensive e s t u a r i n e food webs. TABLE OF CONTENTS Page 1 . Introduction 1 2. L i t e r a t u r e Review 4 2.1 Marsh Habitat 2.1.1 Development 4 2 . 1 . 2 Plant Relations to T i d a l Regime 6 2 .2 Marsh Vegetation of the P a c i f i c Coast 8 2 .3 P r o d u c t i v i t y 9 2.4 D e t r i t u s 12 3. Study Area 3-1 General D e s c r i p t i o n 15 3.2 Geological S e t t i n g 18 3.3 The Local Aquatic Environment 19 3.A Marsh Vegetation of the Fraser River Estuary 21 3.4.1 Vegetation D e s c r i p t i o n 23 3.5 Sampling S i t e s 26 4. Environmental Factors Deemed Important in Marsh Habitat 27 4.1 Tides 4.1.1 Methods 28 4.1.2 Results and Discussion 29 4.2 S a l i n i t y 4.2.1 Methods 40 4.2^,2 Results and Discussion 40 4.3 Temperature 4.3-1 Methods 41 4.3.2 Results and Discussion 41 4.4 Substrate and Underground Biomass 44 5. P r o d u c t i v i t y 55 5.1 Methods 55 5.2 Results 56 5-2.1 .Standing Crop 56 5-2.2 Shoot Counts .... 59 5.2.3 Shoot Measurements 59 5.2.4 R e l a t i o n s h i p s with Environmental Factors 67 5 . 2 . 5 Nitrogen 76 5 .2 .6 Summary of Y i e l d V a r i a b l e s 76 - i V Page 5-3 Discussion 82 6. Detri tus • • • 88 6.1 F i e l d Cond i t ions 6.1.1 Methods 88 6.1 .2 Results 89 6 . 1 . 3 Discussion jcj 6.2 Laboratory Conditions 6.2.1 M e t h o d s 96 6 . 2 . 2 Results 99 6 . 2 . 3 Discussion 100 7. Transp lantat ion 101 7.1 Methods 1 0 2 -1.2 Resul ts 1 0 7 7.3 Discussion U 3 8. H i s t o r i c a l Changes of the Brunswick Point Marsh 116 9. Succession 128 10. Summary and Conclusions 11. Bibl iography I2*7. LIST OF TABLES Table Page 1 Percentage Exposures During the 1976 Growing Season for Selected Elevations 30 2 Continuous Inundation Time for Selected Elevations. Means for 1976 30 3 Newman - Keuls Multiple Range Test for Significant Differences between Means for Carex lyngbyei Shoot Lenths and Diameters 66 Mean Yields of C. lyngbyei, S. mavitimus and S. amevicanus 81 5 Percent of Initial Dry Weight of Plant Material Remaining After 103 Days (Species Means) 90 6 Newman-Keuls Multiple Range Test for Significant Differences Among Mean Weights of Detrital Material Remaining After 103 Days in Mesh Bags 91 7 Percent NitrogenContent of Detritus at Transplant Sites 93 8 Number of Amphipods (X of detritus bags for each species at each station) Sk 9 Ranked Mean Vigour of Transplant Sites, 1976 £ 1977 110 - v i -LIST OF FIGURES Figure Page 1. A e r i a l photo mosaic of the Fraser River Delta foreshore showing l o c a t i o n of the study area. Major marsh areas are o u t l ined 16,17 2. Vegetation map of the Brunswick Point Marsh showing transect and sampling s t a t i o n l o c a t i o n s 24,25 3. Mean d a i l y exposure at se l e c t e d e l e v a t i o n s '. . 3 1 , 3 2 4. Seasonal d i s t r i b u t i o n of mean d a i l y exposure f o r s e l e c t e d e l e v a t i o n s 33,34 5. Seasonal d i s t r i b u t i o n o f mean d a y l i g h t exposure f o r selec t e d e l e v a t i o n s 33,34 6. Seasonal changes in i n t e r s t i t i a l s a l i n i t y . Brunswick Point Marsh 36,37 7. Seasonal changes in s a l i n i t y at 1 m and 20 m depths. Sandheads 1976. 38,39 8. Seasonal changes in s a l i n i t y at Tsawwassen, surface and 1.5 m 38,39 9. Seasonal f l u c t u a t i o n s in substrate temperature. Brunswick Point marsh at 8 cm and 16 cm depths 42,43 10. Seasonal changes in subs t r a t e temperatures (8 cm and 16 cm depths) . .Brunswick Point Marsh 45,46 11. Seasonal v a r i a t i o n s in temperature; mean and imaximum.monthly temperatures f o r Vancouver I n t e r n a t i o n a l A i r p o r t , tempera-tures o f seawater at 1 m depth 45,46 12. Sediment p r o f i l e of a Sairpus americanus community 48,49 13. Sediment p r o f i l e of a Sairpus maritimus community 48,49 14. Sediment p r o f i l e of a Sairpus maritimus community which i s being invaded by Triglochin maritima roots 50,51 15- Sediment p r o f i l e of a Triglochin maritima community. A varving of sediments i s apparent 50,51 16. Sediment p r o f i l e of a Carex lyngbyei community 52,53 17. Comparison of seasonal d i s t r i b u t i o n of standing crop ; weights f o r three species 57,58 18. Comparisons of seasonal d i s t r i b u t i o n of standing crop weights: a) Carex lyngbyei at Sta t i o n s A1 , A2, B1, 2, 3 57,58 - v i i — Figures Page b) Carex lyngbyei at Stations A3, B4 c) Sairpus paludosus at a l l stations d) Sairpus amerioanus at a l l stations 5 7 , 5 8 19- Seasonal changes in vegetative and reproductive shoot numbers per square meter of Carex lyngbyei . 60,61 20. Frequency distribution of Carex lyngbyei shoot lengths, a) Reproductive b) Vegetative 6 2 , 6 3 2 1 . Frequency distributions of Carex lyngbyei shoot dia-meters . a) Reproductive b) Vegetative 64 , 6 5 22. Regression of standing crop on elevation for Carex lyngbyei and Sairpus maritimus 6 8 , 6 9 23 . Regression of shoot length on elevation for Carex lyngbyei in May and August 6 8 , 69 2k. Regression of standing crop on stem length for Carex lyngbyei 70,71 25. Regression of stem number on elevation for Carex lyngbyei 70,7.1 26 . Mean number of shoots of Carex lyngbyei at different elevations above chart datum 7 2 , 73 27 . Seasonal changes in growth rates for Carex lyngbyei at different stations 7^ ,75 28. Seasonal changes in nitrogen content of Carex lyngbyei. Means of a l l stations 7 7 , 7 8 29 . Regression of nitrogen yield on elevation for three species at a l l stations 7 7 , 7 8 30. Changes in nitrogen content of three species (com-bined) with elevation 7 9 , 8 0 31 . Seasonal changes in nitrogen yield for Carex lyngbyei at various stations 7 9 , 8 0 32. Tall form of Carex- lyngbyei as sampled in*Brunswick Point 84 , 85 33- Color infrared photograph of early Carex lyngbyei growth along channel banks. Red indicates actively growing vegetation - .... 8^ ,85 - v i i i -F i g u r e s Page 34. I n ' v i t r o d e c o m p o s i t i o n o f t h r e e s p e c i e s , changes i n the p e r c e n t r e m a i n i n g o v e r time 97,98 35« L o c a t i o n o f t r a n s p l a n t s i t e s a t R o b e r t s Bank 103,104 36. T r a n s p l a n t p l u g s i n s i t u a t s i t e "1 OS'-1. (Photo) 105,106 37- M o n i t o r i n g o f t r a n s p l a n t e d v e g e t a t i o n : stem c o u n t s and measurements. (Photo) 105,106 38. T r a n s p l a n t Scheme 108,109 39- H y d r o g r a p h i c c h a r t d a t e d 1827, showing t h e main arm o f t h e F r a s e r R i v e r 117,118 40. H y d r o g r a p h i c c h a r t d a t e d i 8 6 0 , showing t h e main arm of t h e F r a s e r R i v e r 119,120 41. Photo number A4527 (29) da t e d September, 1932. Bru n s w i c k Cannery i s i n d i c a t e d by a w h i t e dot 121,122 42. Photo number A5984 (21 ) d a t e d June, 1938. B r u n s w i c k Cannery i s i n d i c a t e d by a w h i t e dot 121,122 43- Photo number A37170 dated June, 1975. B r u n s w i c k Cannery i s i n d i c a t e d by a b l a c k dot 121,122 44. Photo number X156C (19) d a t e d June 5, 1948 , . 124,125.. 45. Photo number 39422B ( P a c i f i c Survey C o r p o r a t i o n ) d a t e d 26 J u l y , 1969 124,125 46. Photo number BC 822 (29) da t e d June 20, 1949 126,127 47. Photo t a k e n August 26, 1976 126,127 48. S p e c i e s s u c c e s s i o n i n Oregon c o a s t a l s a l t marshes (from J e f f e r s o n 1975: p. 85) 130,131 49. B l u e green a l g a e c o l o n i z e t h e t i d e f l a t s , o f t e n f o r m i n g a s o l i d c a r p e t o f v e g e t a t i o n w h i c h e f f e c t -i v e l y b i n d s t h e s u r f a c e s e d i m e n t s t o g e t h e r 133,134 50. Sairpus maritimus^ a p i o n e e r v a s c u l a r p l a n t , i s a b l e t o c o l o n i z e t h e s t a b l i z e d mud f l a t , e i t h e r by seed o r by v e g e t a t i v e e x p a n s i o n . F o l l o w i n g e s t a b l i s h m e n t i s a p e r i o d o f f a i r l y r a p i d v e g e t a t i v e growth w h i c h r e -s u l t s i n a pa t c h y d i s t r i b u t i o n o f t h e c o l o n i z e r s . 133,134 51. Sairpus ameriaanus a l s o o c c u r s as a c o l o n i z e r but i s more o f t e n found on sandy s u b s t r a t e s , _, - i x -Fi gure Page 5 2 . Colonization can also occur as the result of " r a f t i n g " of established material which has broken away from the edge of a drainage channel or the front of the marsh . 1 3 5 , 1 3 6 5 3 . A c h a r a c t e r i s t i c pattern of t i d a l f l a t colonization is a contagious series of clumps which eventually ' coalesce 1 3 7 , 1 3 8 5 4 . The clumped pattern is apparent in the Triglochin maritima community in which T. maritima occurs as elevated clumps while Sairpus maritimus f i l l s in the hollows between. The T. maritima hummocks eventually form a higher marsh surface, up to 1 5 cm above the pioneer community. The photograph depicts this com-munity prior to spring growth 1 3 7 , 1 3 8 5 5 - The raising of the marsh surface serves to decrease the period of inundation. The vegetation draws water from the substrate and t h i s , combined with evapora-tion , results in a drying of the substrate ] 5 6 . Marshes are dynamic systems. The photograph depicts a C. lyngbyei community which had i t s habitat altered by dyking prior to 1 9 4 8 (see Section 8 ) . Only remnant clumps of C. lyngbyei remain and erosion is gradually eliminating those. 1^ 2 5 7 - A healthy CV lyngbyei community, in contrast to the de-grading one described above, has a uniform marsh sur-face, drained by deeply incised t i d a l channels, l j i o - x -ACKNOWLEDGMENTS The study was funded, in i t s e n t i r e t y , by the B r i t i s h Columbia Hydro and Power Author i ty . Special apprec iat ion is expressed towards Dr. R. Ferguson and Mr. R. Dundas of the Environmental group of th i s agency for the i r ass i s tance and cons iderat ions . Margaret North provided in sp i ra t ion and encouragement throughout the f i e l d work and f i n a l wr i t ing of the thes i s . The ass i s tance given by Dr. P. G. Harrison with the decomposition aspects of the work is g r a t e f u l l y acknowledged. Dr. C. D. Levings o f fered valuable advice and c r i t i c i s m from my f i r s t ventures onto the marshes to the f i na l stages of thes i s pre-parat ion. My other committee members, Dr. V. Runeckles, Dr. L. Lavku l i t ch , Dr. P. Murtha and Mr. W. Munro a lso provided ass i s tance and helpfu l d i scuss ion . The help of the fo l lowing i nd i v idua l s , Dr. J . Luternauer, Dr. A. Tamburi, Dr. G. Eaton, Ed Medley, B i l l Tupper, and W. J . Rapatz is acknowledged and s incere l y appreciated. My research superv i sor , Dr. V. C. Brink rea l i zed the importance of the foreshore marshes and gave f r ee l y of his time, energy and resources in seeing the study to i t s completion. ( am indebted;to.my parents for the i r in terest and wi l l ingness to help in many ways. Above a l l 1 would l i k e to express my deepest grat i tude to my husband Bob; he has been a f r i e n d , an adv i sor , and an in sp i ra t ion but a l so much, much more. - 1 -1. INTRODUCTION Each year the t i d a l marshes of the Fraser River delta foreshore undergo a cycle of l i f e and death which forms the basis of an i n t r i c a t e food web which on the one hand supports waterfowl along the P a c i f i c flyway, and on the other supports the v i t a l l y important salmon fishing industry. Each spring the marshes emerge from what appears to be bare mud in the winter months. Waterfowl on their northward migration stop in these marshes to rest and feed on the stored materials within the rootstocks of the plants and on the inverte-brates in the marsh area; snowgeese in particular use the rhizomes of the -marsh vegetation (Burgess 1970; Burton 1 977 ) . The vegetation grows rapidly during the months of May and June and by mid July a dense, waist-high f i e l d of green stretches seaward from the dykes. The average production of the Fraser River foreshore marshes has been calculated as ^ . 9 tons of dry matter per hectare (Yamanaka 1 9 75 ) ; this can be contrasted to the average hay crop in the lower Fraser Valley which yields approximately 3.8 tons per hectare. Marsh-hawks, bitterns and ducks co-habit and nest in these areas; smaller birds such as marsh-wrens, blackbirds, and shorebirds such as dunlins and snipe are p l e n t i f u l ; their songs and chatterings bring a new aspect to the l i f e of the marsh. Insects are numerous and offer some support to the bird l i f e but as grazers their effect on the vegetation is very limited (Smalley, 1 959 ) . Of large animals only the occasional muskrat or racoon can be seen. By late summer the vegetation takes on a golden tone and, as i t scenesces is easily pushed down by wind and wave action. Bacteria,fungi and possibly other micro-organisms colonize the dead leaves and the decay accelerates. Numerous inver-tebrates feed on i.the decaying vegetation and i t s associated microorganisms. Tidal cycles cause the decaying vegetation and the associated microorganisms (in combination known as detritus) to be shifted around in the marsh and often out to sea; winds and waves break the material allowing for more rapid decay. - 2 -In the f a l l months the waterfowl again stop in the marshes on their way south. During f a l l and winter the summer's accumulation of vegetation is broken apart, fed on by microorganisms and invertebrates and shifted to the estuary where i t eventually feeds f i s h such as the herring and salmon. By the end of the winter the marsh areas has largely been swept clean of surface organic material. It is d i f f i c u l t to estimate how much of the Fraser t i d a l marshes have been lost due to human a c t i v i t y . Dyking has been the prime reason for loss of marsh land; this was done in the last century and early in this century so few re-cords of previous marsh areas are available. Impending alienations to the Fraser river foreshore marshes include airport expansion, land f i l l , marinas, more dyking, river training (with a possible reduction of sediment and nutrient flow to marsh areas) and nearby port expansion (Roberts Bank). It is the objective of this study to explain some of the features important in the cycle of the emergent vegetation. The major part of this study is con-cerned with the Brunswick Point marsh, near Ladner, B. C. Some of the habitat factors are discussed; the productivity of the marshes is considered; as i s the fate of the aerial vegetation as detritus. The question of plant establish-ment, the importance of certain environmental variables, and possible succes-sional roles are discussed in relation to transplant experiments.. Some his-t o r i c a l changes of the marsh are documented by means of aerial photographs, and in a f i n a l discussion, the ecological role of the marsh is developed as a combination of the factors considered in the study. The objectives of the study can be recapitulated as follows: a) to describe the emergent marsh communities from Brunswick Point to the Roberts Bank Superport j e t t y ; b) to assess the net primary production of the dominant marsh species and to relate this to various environmental factors; to study the decomposition rate of four prime species under quasi-natural conditions and under laboratory conditions, with regard to environmental variables; and to discern successional patterns within the marsh and relate these to the success of transplanting various species into different en-vironmental conditions. - 4 -2. LITERATURE REVIEW The l i t e r a t u r e on wetlands of the world is rapidly growing, especially for wetlands associated with river deltas since these are among the most densely populated and intensively exploited areas in the world. The l i t e r a -ture reviewed below is restricted to those a r t i c l e s which appear to be rele-vant to the P a c i f i c Coast situation-. 2.1 MARSH HABITAT The marshes on the P a c i f i c Coast of North America are d i s t i n c t from marshes found elsewhere (Chapman, 1974). Salt marshes occur throughout the world on gently sloping or protected coastlines. On the eastern coast of North America, where the continental shelf slopes gently, there are large expanses of sa l t marsh. The rugged, exposed nature of much of the P a c i f i c coast has limited the development of marshes to protected bays or river estu-aries (MacDonald and Barbour, 1974). Chapman (i960) observes, "...they (Pacific coast marshes) appear to be b u i l t on a sand substratum; and they are interesting because the succession of the different communities developed on them with increasing height above sea level appears to be very simple, as compared with the complex development found on other s a l t marshes." 2.1.1. DEVELOPMENT Marsh expansion in a very general way depends on sediment accretion and/or i s o s t a t i c u p l i f t , as the topset beds of sand and mud reach a level where plants can grow (Redfield, 1972). Motion of sand in some areas may in-h i b i t plant growth though s u f f i c i e n t elevation exists (Redfield, 1371)- Once pioneer species become established the roots and shoots serve as baf f l e s , - 5 -which may bring about increased d e p o s i t i o n of f i n e sediments c a r r i e d by t i d a l and other currents (Pestrong, 1965). Once f i n e sediment i s trapped by a root mat i t is seldom freed by water movements (Ginsburg and Lowenstam, 1958). The influence of vegetation on sediment was p a r t i c u l a r l y evident in a case where the presence of seagrass (presumably Thalassia testudinum) r e s u l t e d in the formation of elongate mud banks 1.2 to 2 .4 meters deep over a rock seabed, where, without plant i n t e r v e n t i o n , uniform s t r a t a of sediments could be ex-pected (Ginsburg and Lowenstam, 1958). ' Seagrasses are on occasion considered to be precursors to marsh development. A grading of sediments occurs in the marshes with the coarsest s e d i -ments near the lower reaches of channels and f i n e sediments at the higher e l e v a t i o n s , a r e s u l t of decreased flow v e l o c i t i e s (Pestrong, 1 9 72 ) . Pestrong (1972) demonstrated that considerably more sediment i s moved i n t o the marsh sys-tem by the f l o o d t i d e than i s removed by the ebb t i d e . Greatest accumulation occurs at the leading edge of the marsh, thus accounting f o r the gradual spread of the marsh onto adjacent sand f l a t s (Pestrong, 1 972 ) . E i l e r s (1975) at Nehalem Bay, Oregon observed a great increase in the rate of a c c r e t i o n once the marsh reached an e l e v a t i o n near MHHW (Mean Higher High Water); MHHW occurs at approximately 4.1 m above chart datum at Roberts Bank. At t h i s point the f r e -quency and duration o f t i d a l inundation was considerably reduced and as a re-s u l t , l i t t l e d e t r i t a l vegetation was removed from the marsh. The inundation period was s t i l l long enough to create predominantly anaerobic s o i l c o n d i t i o n s and thus decompostion w a s " i n h i b i t e d . E i l e r s recognized another major step in marsh development which he e s t a b l i s h e d at the 2.8 m above MLLW (Mean Lower Low Water) mark. At t h i s p o i n t , t i d a l inundation becomes n e g l i g i b l e . As a r e s u l t , t e r r e s t r i a l i n v e r t e b r a t e s invade the s u b s t r a t e , l i t t e r decomposition increases and the s o i l develops t e r r e s t r i a l c h a r a c t e r i s t i c s . The marsh even-t u a l l y ceases v e r t i c a l growth and becomes a sera i climax (Chapman, 1 97 * 0 -R e d f i e l d (1972) observed s t r a t i f i c a t i o n of i n t e r - t i d a l marsh sub-s t r a t e s and a t t r i b u t e d i t to annual v a r i a t i o n in sedimentation. Fibrous layers were formed by a l g a l mats and Spavtina fragments during the growing season. During w i n t e r , storms and a lack of vegetative cover r e s u l t e d in increased sand d e p o s i t i o n . The presence of vegetation s t i m u l a t e s the d e p o s i t i o n of f i n e sediments. K e l l e r h a l s and Murray (1969) observed a s i m i l a r phenomenon in Boundary Bay, B r i t i s h Columbia, where a l t e r n a t i o n of blue-green a l g a l mats in summer and sand i n winter produced "a v a r v e - l i k e s t r a t i f i c a t i o n " . The accumu l a t i o n of sediment by the a l g a l mats was s u f f i c i e n t to raise' the e l e v a t i o n of the area to a point where vascular plants could c o l o n i z e . 2 . 1 . 2 PLANT RELATIONS TO TIDAL REGIME Tid a l f a c t o r s have received considerable a t t e n t i o n in the l i t e r a t u r e because they are the most obvious environmental v a r i a b l e s i n f l u e n c i n g the coast-a l marshes. W. F. Gagnong's (1903) i n v e s t i g a t i o n of the marshes in the Bay of Fundy concluded that the observed zonation r e f l e c t e d the i n d i v i d u a l species' a b i l i t i e s to withstand inundation. Johnson and York (1915) were the f i r s t to measure t i d a l l i m i t s and r e l a t e them to pla n t d i s t r i b u t i o n . They concluded that t i d a l a c t i o n was most s i g n i f i c a n t in a f f e c t i n g t r a n s p i r a t i o n a b i l i t i e s , gas ex-change, and photosynthesis. Emergence-submergence 1 r a t i o s were c a l c u l a t e d and a d e t a i l e d l i s t of p l a n t s and t h e i r h a b i t i t a t s (type of s u b s t r a t e , upper and lower t i d a l l i m i t s and average t o l e r a b l e submergence periods) were included. The presence of a i r "storage" t i s s u e in some species was considered important in t h e i r a b i l i t y to t o l e r a t e long periods of submergence. A number of other studies have d e a l t w i t h species d i s t r i b u t i o n s as determined by t i d a l regime: Nichols ( 1 9 2 0 ) , Conrad ( 1 9 3 5 ) , Penfound and Hathaway (1938) and Reed (19^7) • The general concensus is that t i d a l movement, with i t s associated submergence and emergence of marsh vegetation, i s responsible - 7 -f o r c o n t r o l l i n g the v e r t i c a l d i s t r i b u t i o n of species. Associated f a c t o r s are s o i l a e r a t i o n , s o i l s a l i n i t y , and type of substrate. Chapman (193*0 concluded, a f t e r c a l c u l a t i n g submergence and emergence times f o r various marsh areas and conducting l e v e l l i n g surveys, that the period of submergence was v i t a l in c o n t r o l l i n g upper marsh species, w h i l e emergence c o n t r o l l e d the lower vegetation. Most of the research r e l a t i n g vegetation to t i d e l e v e l s i s not d i r e c t l y a p p l i c a b l e to the P a c i f i c Northwest since the l o c a l vegetation composition i s d i f f e r e n t from other North American marshes. Recent works by E i l e r s (1975) and Jef f e r s o n (1975) have d e a l t w i t h vegetation comparable to that of the B r i t i s h Columbia marshes; included are some references to t i d a l r e l a t i o n s h i p s . E i l e r s (1975) computed inundation periods and discovered two d i s c o n t i n u i t i e s in the r e l a t i o n s h i p of decreased submergence with increased e l e v a t i o n at Nehalem Bay, Oregon. He considered the region between .91 to 1.21 m above MLLW to be c r i t i -cal f o r marsh development and c o l o n i z a t i o n . Carex lyngbyei Hornem. occurred the lowest in the i n t e r t i d a l zone extending down to .97 m above: MLLW, whi1e Sairpus maritimus L. was found immediately below 1.21 m and Triglochin maritima L., immediately above. The second e l e v a t i o n break occurred between 2.59 and 2.7k m and was considered the l e v e l of an "upper t r a n s i t i o n a l marsh". J e f f e r s o n (1975) d i d not record e l e v a t i o n s of plant communities, but did make note of a number of i n d i v i d u a l species ranges i n c l u d i n g Carex lyngbyei and Sairpus americanus Pers. which extended from 1.5 m above MLLW to 2.7 and 3-0 m above MLLW r e s p e c t i v e l y . The lack of uniform t i d a l base l i n e s as w e l l as varying t i d a l regimes between study areas make i n t e r p r e t a t i o n of t i d e l e v e l s and t h e i r e f f e c t s on vegetation extremely d i f f i c u l t . In Canada, Chart Datum i s the plane below which the t i d e seldom f a l l s ; i t i s p e r i o d i c a l l y modified as t i d a l f l u c t u a t i o n s d i c t a t e . In the United States, Chart Datum i s represented by MLW (mean low water) and MLLW (mean lower low water) on the P a c i f i c Coast (Chapman, i960). - 8 -2.2 MARSH VEGETATION OF THE PACIFIC COAST The f l o r i s t i c s of west coast marshes have been poorly documented and those in their northern extremes have been especially neglected. The most comprehensive overview of P a c i f i c coast marshes to date was produced by MacDonald and Barbour ( 1 9 7 4 ) . Working from f l o r l s t i c l i s t s as well as detailed ecological studies where available, they formed a l i s t of species distributions from 53 locations, ranging from Alaska to Baja, C a l i f o r n i a . They recognized three groups of vegetation which changed with latitude; Alaska to northern C a l i f o r n i a , central and southern C a l i f o r n i a , and Baja, C a l i f o r n i a . Diversity of marsh vegetation seemed to increase in a southerly direction and species which spanned a wide geographical range tended to occupy different marsh levels as they changed groups. For example, Triglochin maritima occurs in the mid - l i t t o r a l zone in southern C a l i f o r n i a , but colonizes the lower l i t t o r a l further north. The area from Alaska to Point Conception in Northern C a l i f o r n i a contains a f a i r l y uniform f l o r a . Carex lyngbyei, Salicornia virginica, Triglochin maritima, Scirpus americanus, Sc,irpus maritimus, and Distichlis striata occur as common elements throughout this region. South of this area are the marshes of central and southern C a l i f o r n i a , dominated by Spartina foliosa in the lower l i t t o r a l and a diverse f l o r a in the upper zones. Furthest south is the Baja Ca l i f o r n i a region where salt-marshes grade into mangrove swamps. The e a r l i e s t work on P a c i f i c coast marshes was concentrated in the Calif o r n i a region. As these were c l a s s i c papers and considered environmental features of interest to the P a c i f i c Coast they are reviewed despite species differences. Purer (19^2) studied the marshes of San Diego County, C a l i f o r n i a . The results of the study are not d i r e c t l y applicable as only one of the species considered {Distichlis spioata) occurs in B r i t i s h Columbia. - 9 -Hinde (1954) i n v e s t i g a t e d t i d a l r e l a t i o n s h i p s and species d i s t r i b u -t i o n s in San Francisco Bay, and found that three main a s s o c i a t i o n s dominated by Salicornia ambigua, Spartina leiantha, and Distichlis spicata were c o n t r o l l e d by t i d a l emergence and submergence. Vogl (1966) discovered that Spartina foliosa dominated the lowest l e v e l s of the marshes at Upper Newport Bay i n C a l i f o r n i a . Salicornia virginica occurred interspersed w i t h Spartina foliosa in the lowest reaches.but a l s o spread throughout the marsh zones being most prevalent in the m i d - 1 i t t o r a l . Triglochin maritima reached i t s lowest extent in the m i d - l i t t o r a l but was a l s o most abundant there, tapering o f f as e l e v a t i o n increased. Salicornia virginica played a very important r o l e in marsh development as i t was the prime c o l o n i z e r of mudflats, yet t o l e r a t e d extremely v a r i a b l e environmental c o n d i t i o n s and so occurred in even the uppermost marsh regions. E l e v a t i o n was a prime determin-ant of vegetation d i s t r i b u t i o n , e s p e c i a l l y in the m i d - l i t t o r a l zone, where small e l e v a t i o n changes r e f l e c t e d species preferences. In the P a c i f i c Northwest, marsh research was conducted by J e f f e r s o n (1975) and E i l e r s ( 1 9 7 5 ) . They were concerned w i t h marshes in Oregon which contained many of the same species as B r i t i s h Columbia marshes, among which were Carex lyngbyei, Salicornia virginica, Triglochin maritima, Sairpus maritimus, Sairpus ameriaanus,, and Sairpus validus. E i l e r s observed that Triglochin maritima, Carex lyngbyei and Juncus balticus had wide e l e v a t i o n ranges while others such as Salicornia virginica were more l i m i t e d in t h e i r d i s t r i b u t i o n . Species o c c u r r i n g at upper e l e v a t i o n s were g e n e r a l l y more r e s t r i c t e d in range than those o c c u r r i n g lower in the i n t e r - t i d a l zone. 2.3 PRODUCTIVITY A large l i t e r a t u r e e x i s t s concerning both s a l t marsh and freshwater marsh p r o d u c t i v i t y estimates. It i s now common knowledge that e s t u a r i e s and - 10 -t h e i r a s s o ciated marshes are extremely productive f o r a v a r i e t y of reasons. Odum (1961) s t r e s s e s two main f a c t o r s responsible f o r the high p r o d u c t i v i t y ; the estuary acts as a " n u t r i e n t t r a p " , and the t i d a l a c t i o n s u p p l i e s n u t r i e n t s and oxygen while removing waste products. In a d d i t i o n the e f f e c t of freshwater c o n t r i b u t i o n s in terms of n u t r i e n t s and aeration cannot be ignored in the estuary. Keefe (1972) provided a comprehensive treatment of marsh production l i t e r a t u r e . High p r o d u c t i v i t y was a t t r i b u t e d to unique environmental f a c t o r s to which the marsh species were adapted. Turner (1976) a l s o summarized pro-duction l i t e r a t u r e w i t h the aim of demonstrating that a north-south gradient e x i s t e d in the production l e v e l s of Spartina dlterniflora. Although a consider-able amount of v a r i a t i o n occurred w i t h i n , as w e l l as between marshes, he found p r o d u c t i v i t y l e v e l s increased from north to south. An exhaustive summary of the production l i t e r a t u r e i s beyond the scope of t h i s study; the reader i s re f e r r e d to Keefe (1972) and Turner (1976) f o r t h e i r e x c e l l e n t summations. Sedge wetlands occur commonly throughout the world, but they have re-ceived r e l a t i v e l y l i t t l e study. In so f a r as the p r o d u c t i v i t y of the Fraser d e l t a emergent marshes is concerned, the information obtained from other sedge wetlands is more d i r e c t l y a p p l i c a b l e than that from s a l t marsh areas. The re-cent papers r e l a t i n g to Carex production w i l l be b r i e f l y summarized. Carex wetlands have been examined to determine t h e i r p r o d u c t i v i t y and to r e l a t e the growth v a r i a b l e s to c e r t a i n environmental f e a t u r e s . Bernard (1973) compared Carex wetlands f o r various l a t i t u d e s and a l t i t u d e s ; those at high l a t i t u d e s and high e l e v a t i o n s had standing crops of less than 300 g/m2 while in more favorable s i t e s , standing crops ranged up to 1,000 g/m2. Bernard (1973) a l s o s t r e s s e s the importance of overwintering shoots in the Carex wet-lands. Shoots are i n i t i a t e d twice during the year, in spring and f a l l ; those i n i t i a t e d in the f a l l overwinter as shoots and t h e i r c o n t r i b u t i o n to the b i o -mass should be taken i n t o account in p r o d u c t i v i t y estimates. In the same study, - 11 -Bernard discussed the translocation of l a b i l e chemical constituents into under-ground organs; the rate was approximately 1 g/m2 per day beginning in July. During August the underground biomass represented only 18 percent of the total biomass while in winter i t rose to ~]k percent. In a subsequent study (Bernard, 197*0, the above and below ground standing crops were investigated in more de-t a i l . The below ground "standing crop" was the highest during winter and de-clined at a rate of 11 g/m2 per day.until mid-July whereupon i t increased at a rate of 1 g/m2 per day. An investigation of a Carex laaustris wetland (Bernard and MacDonald, 197*0 indicated that shoots in his area lived for one year or less; shoots were i n i t i a t e d ; ei ther i;h'the f al 1" or (i n" the f o l 1 bwi hg'* - '. spring and died in late summer. The number of shoots declined steadily over the summer from an i n i t i a l count of 253 shoots per m2 in May to 97 shoots per m2 in October. The maximum above ground biomass in this area was 1,037 g/m2; the maximum daily production was estimated as 15 g/m2 per day. The growth rates of Carex wetlands are considerably lower than those of reed swamps (eg. Typha and Phragmites stands) which in general have a net production of over 1,000 g/m2 per year (Bernard, 1973), and growth rates ex-ceeding 15 g/m2 per day during the most rapid period of growth. These d i f f e r -ences have been attributed to the increased amount of s i l t a t i o n these sites receive when compared to the Carex wetlands (Bernard, 1973 and papers quoted therein); the increased s i l t a t i o n presumably increasing the nutrient input. In New Jersey, Jervis (1969) recorded a production rate of 12 g/m2 per day for Carex striata; in a montane area, Carex rostrata had production rates of 6g/m2 per day (Gorham and Somers, 1973). In the Squamish River delta, B. C, Levings and Moody (1976) reported production of Carex lyngbyei as 1,323 g dry weight/m 2; the greatest increase in standing crop occurred at the end of June with a growth rate of 22.9 g/m2 per day. (The Squamish River carries a high suspended sedi-ment load, 550 mg/1 in 197*», the year of the study.) - 12 -Gorham (197*0 reported a strong correlation between mean summer temperature and above ground biomass; the highest biomass yields came from low latitude, low elevation s i t e s , which consequently had high summer temperatures. 2.4 DETRITUS The pathway of energy flow from net primary production has been separ-ated into the grazing food chain and the detritus food chain (Odum, 1963), the term detritus being widely accepted as meaning non-living plant or animal remains and the associated microflora. Macrophytes of coastal marine environments are not grazed to any extent; the large amounts of structural tissues ( l i g n i n and cellulose) in many of these species make them unpalatable to grazers (Odum, et al., 1972) Smalley (1959) found direct grazing in a marsh system to be less than 5 percent. Harrison and Mann (1975) observed that the high C:N rati o of eelgrass, greater than 2 0 : 1 , made i t a very poor direct food source (17:1 being the maximum for an adequate di e t , Russel1-Hunter, 1970); eelgrass detritus had C:N ratios of between 11:1 and 1 7 - 5 : 1 , considerably improving i t s n u t r i t i v e value. Similar studies for marsh vegetation have not been found in the l i t e r a -ture. The importance of detritus in shallow coastal waters has been exten-sively documented (a summary is provided by de la Cruz, 1965) and in the past two decades the processes involved have been explored in depth. Decomposition includes both mechanical and chemical action. In the high energy i n t e r t i d a l zone, physical forces play important roles in the breakdown and contribution of detritus to the sea. Harrison and Mann (1975) observed that microbial a c t i -v i t y and leaching rates were increased as mechanical action reduced the size of Zosteva (eelgrass) leaves. They also found that bacterial a c t i v i t y was propor-tional to the surface area of the pa r t i c l e s . Upon death of the plant, there are rapid chemical changes in which autolysis may be of some importance. Odum - 13 -et al. (1972) have summarized these degradation processes f o r marsh vegetation. Soluble organic compounds, such as sugars, starches and organic acids may be l o s t by leaching as soon as the pla n t d i e s ; losses of up to 25 percent (of i n i t i a l dry weight) may occur in the f i r s t few days. Once the organic compounds enter i n t o s o l u t i o n , there i s a rapid increase in the as s o c i a t e d b a c t e r i a and f u n g i , and a succession of these organisms as the various plant components become a v a i l a b l e f o r degradation. Mechanical fragmentation occurs c o n t i n u a l l y due to phys i c a l f a c t o r s and consumer a c t i o n . Smaller p a r t i c l e s u s u a l l y have higher surface to volume r a t i o s ( D a r n e l l , 1967), which allow a l a r g e r surface f o r c o l o n i z a t i o n by micro-organisms (Odum and de l a Cruz, 1967, Harrison and Mann, 1975). A number of studies have explored the r e l a t i o n s h i p s between d e t r i t u s and the as s o c i a t e d m i c r o b i a l populations w i t h the conclusions t h a t m i c r o b i a l decomposition i s the main agent f o r plant degradation (Burkholder and Bornside, 1957; T e a l , 1962; de l a Cruz, 1965; D a r n e l l , 196?; Odum and de l a Cruz, 1967; Fenchel , 1970, Gosselink and Kirby , 197*0 • Increases i n p r o t e i n are f r e q u e n t l y recorded in a s s o c i a t i o n with the aforementioned m i c r o b i a l s t u d i e s ; these i n -creases can be a t t r i b u t e d to the loss of carbohydrates and the increase in the mi c r o b i a l biomass. In one study (Odum and de l a Cruz, 1967), Spartina d e t r i t u s had a p r o t e i n content of up to 2k percent, compared w i t h 6 and 10 percent in the dead and l i v i n g grass r e s p e c t i v e l y . The decomposition of p r o t e i n s and s o l u b l e carbohydrates occurs more r a p i d l y than that of crude f i b r e (Burkholder and Bornside, 1957). Leaching was determined to be the major agent i n decomposition of e e l g r a s s , accounting f o r up to 92 percent of the loss (Harrison and Mann, 1975). The e f f e c t of leaching does not seem to have been explored in marsh degradation. Estimates from laboratory and f i e l d s t u d i e s (Burkholder and Bornside, 1957) conclude that (on a dry weight basis) about 11 percent of the ye a r l y production of Spartina could be converted to b a c t e r i a . - ]k - ! While i t was known f o r many years that b a c t e r i a and fungi played v i t a l r o l e s in the decomposition of d e t r i t u s , and that d e t H t i v o r e s fed upon ;these ;par-t i d e s , the e c o l o g i c a l s i g n i f i c a n c e of the i n t e r r e l a t i o n s h i p s was not appreciated. Newell (1965) made a s i g n i f i c a n t discovery to t h i s end when he observed that the f e c a l p e l l e t s of Eydvobia, a d e t r i t u s feeding s n a i l , r a p i d l y developed bac-t e r i a l c o l o n i e s r e s u l t i n g in an increase in the nitrogen of the system. He con-cluded that b a c t e r i a l p r o t e i n had been produced using atmospheric n i t r o g e n . Fenchel (1970) supported t h i s information when he observed amphipods feeding on d e t r i t u s and found undigested d e t r i t u s i n t h e i r f e c a l p e l l e t s ; the f e c a l p e l l e t s were devoid of microorganisms but were r a p i d l y r e c o l o n i z e d . The rapid recolon-i z a t i o n was a t t r i b u t e d to the presence o f mucus on the p e l l e t surfaces. He con-cluded the amphipods were important to the system in breaking apart d e t r i t u s p a r t i c l e s thus i n c r e a s i n g surface area; and by using the microorganisms they a c t u a l l y stimulated regrowth of the microorganisms. Odum et al. (1972) s i m i l a r l y a t t r i b u t e d the rapid breakdown of mangrove leaves in seawater to the a c t i v i t y of amph i pods. The f a t e of the d e t r i t u s w i t h i n the es t u a r i n e system i s an i n t e r e s t i n g problem. Marsh grass c o n t r i b u t i o n s to the estuary vary with the amount of t i d a l f l u s h i n g they experience. T e a l , (1962) estimated that only kS percent of a Spartina marsh in Georgia a c t u a l l y c o n t r i b u t e d to the estuary. Pomeroy (1977) concluded that 90 percent of vascular plant production in the Squamish River estuary entered the d e t r i t a l food chain, and kS percent of the p a r t i c u l a t e organ-i c matter ( l a r g e l y from v a s c u l a r plants) was exported to the estuary. D i f f e r e n t s i z e f r a c t i o n s of d e t r i t u s may c o n t r i b u t e in various ways. Large d e t r i t u s par-t i c l e s may be broken down by d e t r i t i v o r e s and thus added i n t o suspension; f i l t e r feeders may c y c l e suspended d e t r i t u s i n t o feces; suspended ma t e r i a l may combine with other l i v e or dead organic matter i n t o l a r g e r clumps and then become de-pos i t e d on the bottom. Odum et al. (1972) discuss the various f a c e t s o f suspended or deposited d e t r i t u s . - 15 -3. THE STUDY AREA 3.1 GENERAL DESCRIPTION The study area located approximately 20 km south of Vancouver, B r i t i s h Columbia (Figure 1) is bounded by Canoe Pass, a part of the Main Arm of the Fraser River, to the north, the Roberts Bank Superport j e t t y to the south, the dyke to the east and the lowest lower low water t i d e l e v e l to (the west. This area was chosen because i t was r e l a t i v e l y f r e e from man-made disturbance. Im-pending a l i e n a t i o n s such as the h y d r a u l i c d i t c h i n g of a sec t i o n of the study area made the choice of l o c a t i o n p a r t i c u l a r l y important. The remainder of the Fraser River foreshore marshes have been subject to major a l t e r a t i o n s . lona Island i s now the s i t e of a major sewage treatment p l a n t . Sea Island i s the s i t e of Vancouver; I n t e r n a t i o n a l A i r p o r t and foreshore areas are subject to expansion of a i r p o r t f a c i l i t i e s . The Richmond foreshore has had r i v e r flow d i v e r t e d from i t by the Steveston j e t t y and recent suburban development has probably r e s u l t e d in increased ground water discharge. The Westham-Reifel Island foreshore has experienced m o d i f i c a t i o n s such as dyking f o r a g r i c u l t u r a l land, the e r e c t i o n of r i v e r t r a i n i n g w a l l s and the use of marsh land to extend R e i f e l Refuge f o r waterfowl nesting h a b i t a t . These marshes are now considered secure from f u r t h e r m o d i f i c a t i o n s by v i r t u e of t h e i r reserve s t a t u s . Brunswick Point marsh i s the southernmost of the Fraser foreshore brackish marshes. West of the Tsawwassen Indian Reserve i s a true s a l t marsh o c c u r r i n g in what was probably a bay f i l l e d w i t h long-shore d r i f t m a terial o r g i n a t i n g from Point Roberts, t h i s source was cut of by the Ferry causeway in 1960 (Medley and Luternauer, 1976). This marsh has been the t o p i c of much controversy between the Tsawwassen Indian Band who wish to dyke and f i l l i t and the Federal Depart-ment of Environment, who maintain i t i s an important l i n k in the e s t u a r i n e food web. ( H i l l a b y and Barrett,. 1976). - 16 -Figure 1: A e r i a l photo mosaic of the Fraser River Delta foreshore showing l o c a t i o n of the study area. Major marsh areas are o u t l i n e d . \ - 1 8 -The Brunswick Point marsh is presently a public hunting ground and is part of the 8,000 acre (Roberts Bank) Provincial Order-in-Counci1 reserve Number 2374 for waterfowl management (Gates, 1967; Harris and Taylor, 1972), however, the reserve status is very tenuous as is indicated by the establishment of the Westshore Terminal f a c i l i t y on reserve land. The present port f a c i l i t y occupies some 150 acres (causeway and port) and has j u r i s d i c t i o n over a further 3,600 acres of in t e r t i d a l f l a t s (Pearson, 1972). , 3-2 GEOLOGICAL SETTING. ' ' Current information suggests the development of the present Fraser River delta began approximately 8,000 years ago near New Westminster, at which time Pleistocene ice had disappeared and "post-glacial rebound was v i r t u a l l y com-plete" in the Fraser Delta (Luternauer, 1974). Surveys of the s u r f i c i a l deposits of dyked lands indicate the occur-rence of t i d a l f l a t deposits up to 30 m thick on the southern half of Sea Island and the western third of Lulu Island, the eastern two-thirds of Lulu Island be-ing marsh accumulated sediments now overlain by peat bogs (Blunden, 1973). The Municipality of Delta is also underlain by thin floodplain or t i d a l f l a t , depos-it s from .15 to 3-5 m thick. Recent palynological research indicates that Burns Bog in Delta Municipality may have at one time been a coastal marsh which subse-quently developed into a sphagnum bog (R. Hebda pers. comm.). Kellerhals and Murray (1969) discuss the development of ti d a l f l a t to marsh community in an adjacent area (Boundary Bay). The present delta has been greatly altered by extensive dyking and urban and industrial development. The dyked lands are com-prised largely of floodplain, channel and i n t e r t i d a l deposits. At the seaward side of the dykes l i e s a 6.5 km wide expanse of mainly unvegetated t i d a l f l a t which slopes seaward at 0.08° (Luternauer, 1974). The t i d a l marsh clings to the dykes in approximately a 1 km wide s t r i p along 42 km of foreshore. The 1 9 -growth of the Fraser Delta has occurred s t e a d i l y over the past 8,000 years and few changes have occurred in the r i v e r passes because the d e l t a i s b u i l d i n g into deep water (Blunden, 1973)- Mathews and Shepard (1962) report that growth of the d e l t a has progressed at a rate of about 9 meters per year. "Sturgeon Bank is covered almost e n t i r e l y by sand-size sediment...", as i s Robert's Bank which has, in a d d i t i o n , f i n e r inshore sediments. "This seems to i n d i c a t e that there is ample discharge of at l e a s t suspended sediment from the main channel of the Fraser River to Robert's Bank." (Luternauer and Murray, 1975)- It has a l s o been observed that due to p r e v a i l i n g currents there is a general northward trend f o r sediments discharged, from the main channel (Luternauer, 1976). Luternauer (197*0 observed an anomalous occurrence in the sand-sized sediment to the north of the Westshore Terminal cuaseway in the form of a lobe of very f i n e sand and s i l t l y i n g adjacent to the causeway. He suspects t h i s may be due to f i n e s s e t t l i n g out of water impounded by the causeway during an ebbing t i d e . Sediment discharge past Port Mann located approximately 30 km from the mouth of the Fraser R i v e r , averages about 18,000,000 T an n u a l l y , w i t h about 80 percent of t h i s o c c u r r i n g between mid-May and mid-July. Local d e p o s i t i o n may be s u b s t a n t i a l in some areas of the foreshore as in the case of Brunswick Point where an average d e p o s i t i o n rate of 3-5 cm per annum has been noted (K. F l e t c h e r pers. comm.). Mathews et al. (1970) have re-ported that e i t h e r sediment compaction or t e c t o n i c down-warping r e s u l t in a sub-sidence of approximately 1 cm per decade on the Fraser Delta. 3.3 THE LOCAL AQUATIC ENVIRONMENT An estuary i s a unique blend of f r e s h and s a l t waters, ,both i n f l u e n c -ing the b i o t a in various ways. The f o l l o w i n g i s a summary of the s a l i e n t f eatures of the r i v e r and ocean environments. - 20 -FLUVIAL ENVIRONMENT The most c h a r a c t e r i s t i c feature of the Fraser River i s the murky brown c o l o r of i t s downstream reaches. Draining an area of approximately 233,000 square km, the Fraser River has a high suspended sediment load (maximum of about 800 ppm) and a normal flow rate of 3 to k knots, reaching 5 i knots at fres h e t (Tabata, 1972). Studies done by the B. C. Research Council in the f a l l of 1971, reported by Benedict et al. (1973), i n d i c a t e d that d i s s o l v e d oxygen l e v e l s were very high (at or near s a t u r a t i o n ) in the lower reaches of the Fraser River. During the period of f r e s h e t , mid-May to mid-July, the mean monthly discharge of the Fraser River i s in the order of 7,000 cu m/sec. Low discharges occur in l a t e winter w i t h minimum l e v e l s in the order of 800 cu,m/sec (March). MARINE ENVIRONMENT The Fraser River has a s a l t wedge estuary which c h a r a c t e r i s t i c a l l y has a large f r e s h water runoff. The fre s h water flows out over more dense s a l i n e water which, in t u r n , i s forced upstream in contact with the r i v e r bed forming a t h i n s a l t wedge, e s p e c i a l l y prominent during f l o o d i n g t i d e s ( P i c k a r d , 1970). The t u r b i d f r e s h water spreads over s a l t water in a t h i n l a y e r , very evident dur-ing periods of f r e s h e t ; the s a l t wedge i t s e l f moves up and downstream in response to the amount of discharge and the t i d a l c y c l e . Mixing and f l o c c u l a t i o n occur in s a l i n i t i e s between 0 and 15 0/60 (Waldichuk, 1967). Upwelling may occur in re-sponse to the seaward flow of f r e s h and mixed seawater (Waldichuck, 1952, 1957). Although many f a c t o r s are involved in c r e a t i n g the current patterns of the Fraser River estuary, wind seems to pl'ay a major r o l e . Wind-generated waves cause v e r t i c a l and h o r i z o n t a l mixing of f r e s h and s a l t water. The p r e v a i l -ing winds of the estuary are wes t e r l y w i t h the strongest winds being north-w e s t e r l y and s o u t h e a s t e r l y , although considerable v a r i a t i o n occurs seasonally. During the summer a land-sea breeze pattern takes e f f e c t w i t h the sea-breeze beginning in the mornings, reaching peak strength by .the afternoon withv.wind - 21 -speeds of 15 to 25 km/hr and d i s s i p a t i n g by sunset. Land breezes at night are weaker, being in the range of 5 to 13 km/hr (Hoos and Packman, 197*0 . Wave a c t i o n i s minimized on the wide, gently s l o p i n g foreshore, as the greatest wave impact occurs at the d e l t a f r o n t where large waves break. Smaller waves f u r t h e r inshore r e s u l t in r i p p l i n g e f f e c t s on the sand f l a t s . The mixing of s a l t and fres h water by winds may serve to moderate s a l i n i t y extremes during f l o o d i n g t i d e s (Hoos et al. , 197*0. 3.*f MARSH VEGETATION OF THE FRASER RIVER ESTUARY B r i t i s h Columbia marshes are among the most poorly documented in North America. The Fraser R i v e r , because of i t s proximity to a large urban centre and two u n i v e r s i t i e s , " has the best understood t i d a l marshes in B r i t i s h Columbia, yet Mac Donald and Barbour (197*0 s t a t e , " D e s c r i p t i o n s of the Fraser River Delta marshes (*t9°N) have not been found i n the l i t e r a t u r e . " The information which does e x i s t has not appeared in r e a d i l y a v a i l a b l e p u b l i c a t i o n s . Gates (1967) described some o f the important marsh areas o f the Lower Mainland in his d i s c u s s i o n of wetland reserves. Burgess (1970) used a e r i a l photographs to map and determine the extent of the Fraser River foreshore marshes. The areal extent was c a l c u l a t e d as 1,512 ha, of which Brunswick Point comprised approximately 10 percent. He stated that plant species d i s t r i b u t i o n was a f f e c t e d by t i d a l f l o o d i n g , degree of drainage, and p o s s i b l y s a l i n i t y ; upper arid lower marsh l e v e l s were d i s t i n g u i s h e d , they were separated u s u a l l y by a rapid change in slope at approximately the 3-05 m t i d e l e v e l . Carex lyngbyei was the most dominant species in the upper zone (3-96 m to 3-05 m) wh i l e Sairpus ameriaanus was dominant in the lower zone (3.05 m to 2.13 m). Burgess (1970) a l s o e s t i -mated seed production of these species and concluded that Carex lyngbyei, Sairpus validus and Sairpus ameriaanus were the most important food sources f o r ducks. - 22 -A summary of e c o l o g i c a l r e l a t i o n s h i p s was produced by Becker (1971), w i t h emphasis on the vegetation information from Burgess (1970)- McLaren (1972) and Forbes (1972) described and produced genera l i z e d maps of the Fraser River estuary marshes. Wade (1972) discussed plant d i s t r i b u t i o n along Sturgeon Bank and included a f l o r a l l i s t . H a r r i s and Taylor (1972) discussed human im-pact on e s t u a r i e s and mentioned marsh vegetation as r e l a t e d to migratory water-fowl and Halladay (1968) considered marsh vegetation as r e l a t e d to b i r d hazards at Vancouver I n t e r n a t i o n a l A i r p o r t . In d i s c u s s i o n of "Biology of the Lower Fraser" Northcote (1972) em-phasized f i s h d i s t r i b u t i o n s but r e l i e d on Forbes (1972) and McLaren's maps f o r vegetation information. He stated t h a t , "Probably they (marsh areas) form an . important h a b i t a t f o r various i n v e r t e b r a t e s and young f i s h e s , i n c l u d i n g salmonid Hoos and Packman (1974), summarized environmental information a v a i l a b l f o r the Fraser Estuary. Vegetation d e s c r i p t i o n s of marsh areas were derived from McLaren (1972) and Forbes (1972). Upland and bog vegetation of the d e l t a i s a l s o discussed. Taylor (1974) included in h i s report a s p e c i a l study by Entech Consultants (Sverre) commissioned by the Canadian W i l d l i f e S ervice to evaluate the vegetation o f Sea and lona Islands. Sverre ( i n T a y l o r , 1974) d i s t i n g u i s h e d three zones along the foreshore. Sairpus ameriaanus y i e l d s from the most sea-ward zone were reported as being approximately 1.1 tons per hectare. (Other values were not given.) Seed production of Sairpus amevioanus was estimated and the values were considered low (5.1 percent of stems were reproductive) due to s t r e s s c o n d i t i o n s caused by l i g h t a t tenuation during f l o o d i n g by t i d e s and i n t o l e r a n c e of sewage e f f l u e n t (Sverre in T a y l o r , 1974). Burgess (1970) reported the average percentage of reproductive stems {Sairpus amerioana) as 3.1 percent over the e n t i r e Fraser foreshore. It i s d i f f i c u l t to assess the r o l of s t r e s s in seed production without f u r t h e r s t u d i e s . - 23 -Yamanaka (1975) studied p r o d u c t i v i t y changes across the Fraser River d e l t a marshes. Carex lyngbyei, Sairpus ameriaanus and Sairpus paludosus {maritimus) accounted f o r over 80 percent of the standing crop. An average dry matter y i e l d was 4 .9 tons per hectare (490 g per sq m) per year. In gene r a l , dry matter y i e l d and d i v e r s i t y decreased w i t h distance from the dyke. The highest dry matter y i e l d was found in the marshes adjacent to the North Arm of the Fraser River w i t h average values of approximately 1,700 g per sq m. Yamanaka a t t r i b u t e s these.high values to p o s s i b l e enrichment by sewage e f f l u e n t . Parsons (1975) analyzed a s a l t marsh at Boundary Bay. Distichlis spicata and S a l i c o r n i a v i r g i n i c a were i n h a b i t a n t s of a low marsh which he c l a s -s i f i e d as ranging between 4 .3 m and 4 .9 m above mean sea l e v e l (these values are probably above chart datum (o) rather than mean sea l e v e l {2.96 m}); the low marsh di s p l a y e d high s o i l c o n d u c t i v i t y values. Upper marsh i n h a b i t a n t s c o n s i s t e d of Distichlis spicata, A c h i l l e a millefolium, Junaus sp., and Grindelia integrifolia. H i l l a b y and Ba r r e t t (1976) i n v e s t i g a t e d the Tsawwassen s a l t marsh and described plant communities s i m i l a r to those of Boundary Bay. Burton (1977) i n v e s t i g a t e d rhizome use by snow geese in the Fraser foreshore area. 3.4.1 VEGETATION DESCRIPTION The vegetation of Brunswick Point i s repr e s e n t a t i v e of a brackish marsh. The area i s s i t u a t e d on the i n t e r f a c e of fre s h water and marine e n v i -ronments and hence the vegetation not only e x h i b i t s a h o r i z o n t a l zonation, which i s mainly influenced by t i d a l exposure, but a l s o a gradation from brack-ish to marine species. The number of species o c c u r r i n g in t h i s marsh i s r e l a t i v e l y smal1 , with the three major ones being Sairpus ameriaanus Pers., Sairpus maritimus L., and Carex lyngbyei Hornem,(Figure 2 ) . Other species common to the area but which u s u a l l y occur in i s o l a t e d patches are: T r i g l o c h i n maritima L., - 2k -Figure 2: Vegetation map of the Brunswick Point Marsh showing transect and sampling station locations. O Dittichlis / Solicornia - 26 -Typha latifolia L. , Juncus balticus W i l l d . , Sairpus validus Vahl., Sagittaria latifolia W i l l d . , Lythrum salicaria L., Cotula coronopifolia L. , Distichlis striots (Torr.) Rydb., and Salicornia virginica L. S c i e n t i f i c names w i l l be used throughout. 3.5 SELECTION OF SAMPLING SITES Three transects (A, B, C) were s e l e c t e d in order to cover maximum marsh area. S t a t i o n s along these transects were e s t a b l i s h e d 150 m apart. The o b j e c t i v e was to sample both a s a l i n i t y and an e l e v a t i o n a l g r a d i e n t . Lines were e s t a b l i s h e d by choosing compass bearings p r i o r to f i e l d work. In a d d i t i o n to these t r a n s e c t s , three s h o r t e r ones (M, D, E) were e s t a b l i s h e d f u r t h e r south in a narrow band of Triglochin/Scirpus marsh adjacent to the dyke (Figure 2). S t a t i o n s D and E were on e i t h e r side of an area d i s -turbed by trenching and cable b u r i a l . Because of the l i m i t e d vegetated area, sampling s t a t i o n s were e s t a b l i s h e d 50 m apart. - 27 -k. ENVIRONMENTAL FACTORS DEEMED IMPORTANT IN MARSH HABITAT Introduct ion An understanding of the h a b i t a t i s of paramount importance in assessing the succession, p r o d u c t i v i t y or even decomposition in a t i d a l marsh area. The t i d e i s the most apparent phenomen in t h i s h a b i t a t ; i t c o n t r o l s not only the moisture, oxygen, temperature and s a l i n i t y contents of marsh s o i l s but i t a l s o determines the p o t e n t i a l f o r photosynthesis because f l o o d i n g reduces gas ex-change and t u r b i d waters reduce a v a i l a b l e l i g h t . The period that a plant i s con-t i n u o u s l y flooded i s of as great an i n t e r e s t as the cumulative d a y l i g h t exposure, since both are l i m i t i n g measures in t h e i r own r i g h t . Continuous f l o o d i n g l i m i t s plant growth by waterlogging roots, imposing s a l i n i t y s t r e s s in s a l i n e waters, and by reducing l i g h t a v a i l a b i l i t y . A s a l i n e environment imposes p h y s i o l o g i c a l s t r e s s e s on the veget a t i o n . Osmotic s t r e s s i s induced when the external water p o t e n t i a l i s lowered below that of the c e l l , thus causing " p h y s i o l o g i c a l drought". N u t r i e n t d e f i c i e n c y s t r e s s i s caused by the p r e f e r e n t i a l uptake of sodium ions (which are in great abundance) over potassium ions. Hormonal s t r e s s i s induced by s a l t s t r e s s e d roots being i n -h i b i t e d in transport of hormone to leaves, e v e n t u a l l y causing hormonal imbalance and r e s u l t i n g in the increased r i g i d i t y of c e l l w a l l s which prevents t h e i r ex-pansion. ( L e v i t t , 1972; Waisel, 1 9 7 2 ) . In the brackish environment the s a l i n i t y l e v e l s are u s u a l l y q u i t e low, but they f l u c t u a t e in response to other environmental v a r i a b l e s , t h i s may impose stresses on plants which are not normally subject to extremes. In the Brunswick Point marsh, the substrate s a l i n i t i e s vary on a d a i l y basis according to t i d e heights, the duration of f l o o d i n g and the amount of r a i n f a l l or evaporation. Over a longer term, the s a l i n i t i e s are a f f e c t e d by the volume o f r i v e r discharge. - 28 -Temperature may determine the rate of evaporation from the marsh sur-face, thus a f f e c t i n g s a l i n i t y . The dark "mud f l a t s " of the Fraser foreshore have low albedos; the mud absorbs a great deal of the in c i d e n t r a d i a t i o n , and as a r e s u l t there are high surface temperatures. Vegetation both absorbs r a d i a t i o n and increases the albedo thus c o n t r o l l i n g surface temperatures, reducing evapor-a t i o n and thereby not a f f e c t i n g s a l i n i t y . Vegetation both influences and i s influenced by the substrate in which i t e x i s t s . An examination of depth p r o f i l e s can lead to an understanding of these r e l a t i o n s h i p s . 4.1 TIDES 4.1.1 METHODS Tides are a dominant feature of the marsh environment; vegetation zonation o f t e n r e f l e c t s the r e l a t i v e a b i l i t i e s of the d i f f e r e n t species to t o l e r -ate inundation and emergence. A l e v e l l i n g survey was undertaken i n February, 1977 in order to determine marsh e l e v a t i o n s ; a t o t a l of 62 spot e l e v a t i o n s along the e s t a b l i s h e d transects were determined by using standard l e v e l l i n g techniques and equipment. D e t a i l s of vegetation and notable surface features were relayed to the t r a n s i t operator by means of portable two-way radios. The f i n a l c o r r e c t e d v e r t i c a l and h o r i z o n t a l distances and other d e t a i l e d inforamtion were l a t e r t r a n s f e r r e d onto a base map of the area. In order to r e l a t e the marsh e l e v a t i o n s to t i d a l o s c i l l a t i o n s , the observed t i d a l data from the recording s t a t i o n at Tsawwassen were obtained f o r the year 1976" from the Regional Tide Superintendent, V i c t o r i a , B r i t i s h Columbia. These hourly observations were i n t e r p o l a t e d to provide information regarding exposure and submergence periods f o r s e l e c t e d t i d a l e l e v a t i o n s . - 29 -4 . 1 . 2 RESULTS AND DISCUSSION L e v e l l i n g enabled d e l i m i t a t i o n o f contours which seemed to be c r i t i c a l f o r plant d i s t r i b u t i o n . The lowest l i m i t of plant growth w i t h i n the surveyed p o r t i o n of Brunswick Point marsh appeared to be 2.82 m; the Carex lyngbyei com-munity appeared to reach dominance at the 3-05 m l e v e l and at the 3-35 TI l e v e l . Other species such as Potentilla pacifica and Argrostis semiverticillata were found in a s s o c i a t i o n . The greatest exposure in the growing season occurred during the months of A p r i l and May, when the 3-35 m l e v e l was exposed 6 4 percent and the 2 . 4 4 l e v e l was exposed 29 percent of the time. Table 1 shows the percentage exposure at the above mentioned e l e v a t i o n s plus that of 2 . 4 4 m, representing unvegetated areas. The greatest d i f f e r e n c e s between the seasonal means and the maximum exposure periods were not constant with e l e v a t i o n ; the 3-35 and 3-05 m l e v e l s had the greatest d i f f e r e n c e s w i t h 5 and 4 percent d i f f e r e n c e s r e s p e c t i v e l y , while the 2.82 m and the 2 . 4 4 m l e v e l s had only 2 and 1 percent d i f f e r e n c e s . The mean d a y l i g h t exposure f o r the growing season ranged between 4 6 and 6 6 per-cent f o r the vegetated areas. Figure 3 d i s p l a y s the r e l a t i o n s h i p between expo-sure and e l e v a t i o n both o v e r a l l and in d a y l i g h t hours; a s l i g h t l y curved r e l a t i o n -ship i s apparent, more so f o r "day 1ight" than f o r t o t a l exposure. The mean ex-posure ( t o t a l ) ranges from 6 . 5 {27%) to 1 4 . 1 {53%) hours per day (Figure 4 ) . The l e v e l which l i m i t e d most pla n t growth (2.82 m) was an exposure of 9 . 1 hours per day or approximately 38 percent. Exposure to d a y l i g h t ranges from 3-5 0 5 % ) to 7.7 hours (32%) (Figure 5 ) . The actual number of hours exposed in d a y l i g h t i s greatest in June, a r e s u l t of a f o r t u i t o u s combination of the summer s o l s t i c e w i t h low t i d e s o c c u r r i n g during the day. The 2.82 l e v e l i s exposed 4 . 9 hours (20 percent of d a y l i g h t hours). It i s to be noted that these values are the y e a r l y means; i f the d a y l i g h t exposure means are c a l c u l a t e d f o r the growing season, A p r i l to September, the mean exposure would be - 30 -Table 1: Percentage, Exposures During the 1976 Growing Season f o r 'Selected E l e v a t i o n s . Meters Above Chart Datum 2.kk 2 . 8 2 3-05 3.35 Apri 1 28.9 39.2 49.3 64.0 May 28.4 38.3 47.3 62.8 June 2 8 . 6 37.5 46.0 58.6 J u l y 26.6 35.9 43.0 54.7 August 21.k 35-5 kk.k 55.8 September 26.9 36.7 43.4 58.3 2k Hour x 27.9 37.6 45.4 59.2 Daylight x 34.0 45.6 53.1 66.0 Table 2: Continuous Inundation Time f o r Selected E l e v a t i o n s . Means'for 1976. 2.44 Meters Above Chart Datum 2.82 3.05 3-35 Mean maximum continuous in-undation per day Hours 9 'a 2 0 832 17.8 lk% 16.3 68% 12.4 52% Mean maximum continuous in-undation in d a y l i ght Hours 11.8 '0 11.2 81% 10.0 72% 8.2 59% - 31 -gure 3: Mean d a i l y exposure at s e l e c t e d e l e v a t i o n s . - 33 -Figure k: Seasonal distribution of mean daily exposure for selected elevations. "Figure 5: Seasonal distribution of mean daylight exposure for selected elevations. - 3k -MONTH - 35 -as f o l l o w s : f o r 2.44 m, 5-5 hours or 34 percent; f o r 2.82 m, 7.3 hours or 46 percent; f o r 3.05 m, 8.5 hours or 53 percent; and f o r 3-35 rn, 10.6 hours or 66 percent of 16 hours (the average number of d a y l i g h t hours f o r the growing :-season). The period of continuous submergence was deemed to be important as i t r e f l e c t s the amount of waterlogging to which the substrate and plant roots are subjected. There was a four hour, o r 16 percent d i f f e r e n c e in the maximum sub-merged period between the 3.35 m and 3.05 m t i d e l e v e l s ; between the 3.05 and 2.82 m t i d e l e v e l s , the d i f f e r e n c e was only 1.5 hours or 5 percent ( T a b l e ' 2 ) . Comparison of marsh zonation and species vigour in d i f f e r e n t geographi-cal areas would be very u s e f u l , such comparisons are very d i f f i c u l t to make, not only are there d i f f e r e n t base l i n e s but there are a l s o d i f f e r e n t t i d a l ranges be-tween various l o c a t i o n s . Tides do not r i s e and f a l l e q u a l l y along a s h o r e l i n e , even over r e l a t i v e l y short d i s t a n c e s ; c u r r e n t s , winds and bottom c o n f i g u r a t i o n s a f f e c t both t i d a l range and extremes. Although mean t i d e l i n e s are e s t a b l i s h e d f o r areas, they are e x t r a p o l a t i o n s from the nearest t i d e recording s t a t i o n s and do not f u l l y r e f l e c t the on s i t e s i t u a t i o n . In marsh areas where even a 30 cm v a r i a t i o n in e l e v a t i o n can produce d i s t i n c t vegetation changes (Purer, 19**2; Hinde, 1954; Chapman, I960; Adams, 1963) the lack of p r e c i s e t i d a l information can r e s t r i c t the understanding of vegetation d i s t r i b u t i o n . - 36 -Figure 6: Seasonal changes in i n t e r s t i t i a l s a l i n i t y . Brunswick Point Marsh - 38 -Figure 1: Seasonal changes in s a l i n i t y at 1 m and 20 m depths. Sandheads 1976. Figure 8: Seasonal changes in s a l i n i t y at Tsawwassen, surface and 1 .5 rn. - 39 -- 40 -4.2 SALINITY 4.2.1 METHODS Water samples were obtained from each of the sampling stations by re-moving a core of sediment (approximately 10 cm deep) and c o l l e c t i n g the water which percolated into the core hole. Conductivity determinations were undertaken in the laboratory using a Guild Line Autosal; readings were converted to s a l i n i t y values based on a computer-prepared conversion table. Water with values lower than 2.83 0/00 was considered to be fresh as the machine could not accurately detect differences below that l e v e l . 4.2.2 RESULTS AND DISCUSSION S a l i n i t i e s , in general, increased as the distance from the riv e r in-:' creased (Figure 6). The effect of the Fraser River freshet can be seen on tran-sects A and B; after the onset of the freshet, the s a l i n i t y values declined from approximately 5 percent to fresh values ( i . e . less that 2.83°/oo) where they, re-mained for the rest of the growing season. This decline in s a l i n i t y during the period of freshet can also be seen at depths off Sandheads and Tsawwassen (Figure 7 and 8)(see Figure 1 for locations). S a l i n i t i e s on transect C were s l i g h t l y higher than on A or B with values fluctuating around 5 °/oo a l l summer but with considerably greater variation at the outer stations (C4 and C5) than at the inner ones. Transect M values were considerably higher than the preceding o ones with values in the 10 /oo range; highest values occurred in unvegetated areas. A paired-sample test between stations M1 (vegetated) and M3 (unvegetated) indicated that s a l i n i t i e s at M3 were s i g n i f i c a n t l y higher than those at M1. The highest s a l i n i t i e s were observed at transects D and E with values of between 10 o . and 20 /oo Again the highest values occurred in unvegetated areas. - 41 -S a l i n i t y v a r i a t i o n s can be a t t r i b u t e d in general to the i n f l u e n c e of environmental v a r i a b l e s such as r a i n f a l l , evaporation, proximity, to creeks and channels and the height of the previous t i d e . The r e s u l t s should be considered r e l a t i v e between sampling s t a t i o n s . A pattern of higher s a l i n i t i e s in unvegetated areas was observed; those areas with sparse vegetation a l s o had higher s a l i n i t i e s than areas with dense vegetation. High s a l i n i t i e s were observed at s t a t i o n s C4 and C5 before the shoots and canopy developed when values became comparable w i t h those of the inner s t a -t i o n s . The high s a l i n i t i e s in areas of sparse of no vegetation can probably be a t t r i b u t e d to the higher temperatures and greater evaporation as a r e s u l t of low albedos in unvegetated areas. S a l i n i t y i n t e r a c t i o n s w i t h vegetation w i l l be considered in more d e t a i l in Sections 5.3 and 7-3. 4.3 TEMPERATURE 4.3-1 METHODS During each sampling pe r i o d , thermometers were in s e r t e d to depths of 8 cm.and 15 cm,at each sampling s t a t i o n . Temperatures, time of measurement, substrate and vegetation c o n d i t i o n s (e.g. wet or dry, dense or sparse) were re-corded. 4.3.2 RESULTS AND DISCUSSION Unvegetated areas showed greater v a r i a t i o n s than vegetated sur f a c e s , as can be seen by the great discrepancies between 8 cm and 16 cm temperatures e a r l y in the growing season when l i t t l e . o r no vegetation cover had yet developed, e.g. transects A and B (Figure 9)• In areas of sparse cover the temperature d i f f e r e n c e s between surface - kl -Figure 9: Seasonal fluctuations in substrate temperature. Brunswick Point marsh at 8 cm and 16 cm depths. \ \ ) TEMPERATURE C - kh -and depth was considerable throughout the season. The temperature of unvegetated or sparsely vegetated areas v a r i e d more c l o s e l y w i t h d a i l y maxima while densely vegetated areas were more c l o s e l y a s s ociated with d a i l y mean temperatures. The e f f e c t of temperature on vegetation i s probably most dramatic in the temperature d i f f e r e n c e s between the a i r , substrate and seawater (Figure 10 and 11). As an example, in June there was a d i f f e r e n c e of 8°C between seawater and marsh substrate means, and a 7°C d i f f e r e n c e between the mean maximum a i r temperature and the seawater temperature. The rapi d change in temperatures be-tween the exposed and the inundated marsh environments must impose considerable s t r e s s on the vegetation. This s t r e s s i s p o s s i b l y r e f l e c t e d in the lowered pro-d u c t i v i t y of marsh vegetation at higher l a t i t u d e s (see Section 2.3). The d i f -ferences between seawater and ambient a i r temperatures may not be as great in southern regions but di s c u s s i o n s of t h i s f a c t o r have not been found in the l i t e r a -ture. It would be useful to know i f the c a r d i n a l and threshold temperatures f o r wetland s i t e s are s i m i l a r to those used in studies of the d i s t r i b u t i o n of t e r r e s -t r i a l vegetation. k.k SUBSTRATE AND UNDERGROUND BIOMASS In order to assess substrate c h a r a c t e r i s t i c s , p i t s were excavated in each of the major plant communities. This proved to be a very d i f f i c u l t opera-t i o n because of the high water t a b l e in the marsh; the p i t s began f i l l i n g w i t h water while digging progressed. Three layers of root density could be discerned in each p r o f i l e ; the top 30 cm (approximately) were densely rooted with v a r i a b l e amounts of a e r i a l m a t e r i a l s mixed i n ; (values ranged from 10 to 50 percent organic m a t e r i a l ) ; the middle 30 cm were sparsely rooted (2 to 20 percent) but with a l o t of decaying organic material present; the lowest layer reached (0 to 10 percent) showed l i v e roots only in the case of Triglochin maritima, decaying remnants of other species were v i s i b l e under T. maritima in the p r o f i l e . - k5-Figure 10: Seasonal changes in substrate temperatures (8 cm and 16 cm depths). Brunswick Point marsh. Figure 11: Seasonal v a r i a t i o n s in temperature; a) monthly mean a i r temperature b) ' monthly mean a i r temperature c) seawater temperatures at lm depth. - 46 -- kl -V i s u a l l y Estimated Rooting Density with Depth of Several Marsh Communities °/ °/ °/ °/ 'o 'o 'o 'O S. americanus S. maritimus C. lyngbyei T. maritimus 0 to 30 cm 20 10 35 50 31 to 60 cm 10 2 20 10 61 to 90 cm 3 0 10 2 Photographs i l l u s t r a t e the p r o f i l e s of four communities from Brunswick Point marsh (Figures 12 to 16). Moody and Luternauer ( i n preparation) undertook a more d e t a i l e d study of plant-sediment r e l a t i o n s along the Fraser River foreshore and examined rhizome fragments in order to d i s c e r n successional patterns as evidenced in the l a y e r i n g of the sediments. A very successful but labor i n t e n s i v e techinque was used in which p l e x i g l a s s tubes (7 cm in diameter) were forced to a depth of 1 meter i n t o the marsh su b s t r a t e . (See a l s o Section 9-1). During regular biomass sampling, a hand auger was used to remove short cores (10 cm x 15 cm) from each sampling s t a t i o n at the beginning of the growing season. In order to separate root and sediment components washing was attempted with a r o t a t i n g screened drum in t o which two sprays of water were d i r e c t e d . This proved unsuccessful in removing any sediment beyond the surface l a y e r . Next, the cores were manually washed and broken apart to expose the i n t e r i o r p o r t ions to water spray. This method was more successful than the previous one but the re-s u l t s were extremely v a r i a b l e . Even though the roots had been washed u n t i l they appeared " c l e a n " , ash content v a r i e d from 38 to 82 percent and the r e s u l t s were not considered valuable enough to merit such a labor i n t e n s i v e , time consuming operat ion. Figure 12: Sediment p r o f i l e of a Sairpus ameriaanus commun i t y . Figure 13: Sediment p r o f i l e of a Sairpus maritimus community 1 -E-oo i o Figure 14: Sediment p r o f i l e of a Sairpus mavitimus community which i s be-i ng i nvaded by Triglochin maritima roots Figure 15: Sediment p r o f i l e of a Tvigloohin maritima community. A varving of sediments i s appar-ent. - 51 -- 52 -gure 16: Sediment p r o f i l e of a Cavex lyngbyei communi - 53 -- Sk -Textural " r a t i n g s " f o r each sampling s t a t i o n (see s e c t i o n 3.5) are in progress by research personnel at A g r i c u l t u r e Canada and may be obtained on request. - 55 -5. PRODUCTIVITY Salt marshes have been claimed among the most productive habitats in the world (Odum, 1961). Detailed investigations of marsh productivity have been carried on for decades on the eastern North American seaboard,,but very l i t t l e productivity assessment has been undertaken on the west coast u n t i l recently. Brackish marsh systems have been especially neglected. Yamanka (1975); the f i r s t major study of marsh productivity on the Fraser foreshore, contributed y i e l d estimated for the Fraser marshes but did not attempt to follow temporal changes. The.present study in part was intended to examine the productivity of one particular marsh over the course of one growing season. 5.1 METHODS A 50 cm by 20 cm (0.1 m2) rectangular quadrat was used for vegetation sampling. This size has been established as the most appropriate size for simi-lar vegetation types ( E i l e r s , 1975). The quadrat location was randomly (by means of a "shut eye, over the shoulder" randomization) chosen in the v i c i n i t y of each sampling station. A l l of the vegetation rooted within the quadrat was clipped at the s o i l surface with a battery powered, grass clipper. Three replicates were obtained from each sampling station (15 stations in t o t a l ) , during each sampling period (9 in t o t a l ) , for a total of hOS samples during the growing season. Samples were placed in p l a s t i c bags, tagged and transported to a refrigerator upon completion of f i e l d sampling. In the laboratory, samples were separated into component species, and the number of reproductive and vegetative stems enumerated. Ten stems were chosen at random and measured for total length and stem diameter twice during the study period, (May and August). In order to remove sediment from leaves, (see Levings and Moody, 1976) the plant material was placed in fine mesh bags and - 56 -washed in a Hoover washer (Model 0610) f o r k minutes, rinsed and spun dry. Samples were then t r a n s f e r r e d to paper bags, l a b e l l e d and d r i e d in a forced a i r oven at 105°C f o r 4 8 hours. The samples were cooled, weighed, and ground in a Wiley M i l l , the statiomsamp 1 es (3) were pooled f o r each date and subsampled. P o r t i o n s were ashed using standard ash determination procedures (A.O.A.C) in a muffle furnace at 550°C. Nitrogen analyses (micro-Kjeldahl) were performed on the aforementioned subsamples. 5.2 RESULTS 5.2.1 STANDING CROP Of the dominant species in the Brunswick Point area, Carex lyngbyei was the most productive, peak phytomass (above ground) averaged over a l l s i t e s was 909 g/m2.dry :weight in J u l y . Sairpus maritimus peaked in August with an aver-age weight of 565 g/m2. Sairpus ameriaanus, while occupying the greatest area in the Brunswick Point marsh, was the l e a s t productive w i t h a peak mean of 397 g/m2 o c c u r r i n g in J u l y (Figure 17)- The S. ameriaanus and S. maritimus shoots were i n i t i a t e d approximately two weeks l a t e r than the C. lyngbyei shoots. C. lyngbyei displayed r a p i d , steady growth in the period from mid-May to a peak in mid-J u l y , succeeded by a f a i r l y rapid d e c l i n e . The growth s t r a t e g i e s of C. lyngbyei can be separated i n t o two d i s t i n c t p a t t e r n s . ( F i g u r e 18) . The s t a t i o n s f u r t h e s t from the dyke experienced a rapid growth, reaching a peak in mid-July, then de-c l i n i n g e q u a l l y r a p i d l y . Inner areas were on the average not as productive, but p a r a l l e l e d the growth of the outer s t a t i o n s u n t i l mid-June when the inner growth proceeded in a slower rate to reach a peak in August with a rapid d e c l i n e there-a f t e r . The infrequency of sampling l a t e in the growing season may mean that the peak standing crops a c t u a l l y occurred e a r l i e r or l a t e r than on the sampling dates. - 57 -v Figure 17: Comparison of seasonal distributions of standing crop weights for three species Figure 18: Comparisons of seasonal distribution of standing crop weights: a) Carex lyngbyei at.;Stations Al , A2, Bl , 2, 3 b) Carex lyngbyei at Stations A3, Bh c) Sairpus paludosus at a l l stations d) Sairpus ameriaanus at a l l stations - 58 -- 59 -5.2.2 SHOOT COUNTS The mean number of vegetative.,C. lyngbyei shoots d e c l i n e d s t e a d i l y through the season, beginning with 1,250 shoots per square meter at the beginn-ing of May, and d e c l i n i n g to 770 shoots by the end of September (Figure 19). Reproductive shoot counts peaked at the end of May, with 130 shoots per square meter and showed a steady d e c l i n e t h e r e a f t e r ; since the ve g e t a t i v e p o r t i o n was a l s o d e c l i n i n g , the percentage of reproductive shoots remained at a l e v e l of about 11 percent from May u n t i l J u l y . 5.2.3 SHOOT MEASUREMENTS Shoot lengths and diameters, which were measured in May and August are shown as frequency d i s t r i b u t i o n s in Figures 20 and 21. In May, shoot length frequencies ranged between 10 and 50 centimeters; reproductive shoots were fewer but c l o s e l y approximated the patter n of the vegetative shoots. By August the veg e t a t i v e shoot lengths ranged between 60 and 200 cm, the shoot s i z e s being much more v a r i e d than before; the range of reproductive shoot lengths was be-tween 50 and 110 cm. In other words, in May, there appeared to be no d i f f e r e n c e s in the lengths of reproductive and vegetative shoots; by August the reproductive ones tended to be shorter than the vege t a t i v e . The veget a t i v e shoot diameters d i d not appear to be changed from May to August but w h i l e the May reproductive shoots were comparable in s i z e to the v e g e t a t i v e , the August diameters had experienced a d e c l i n e . A Newman-Keuls t e s t of s i g n i f i c a n c e f o r overal1"shoot lengths and diameters is summarized in Table 3- S t a t i o n B3 had the greatest mean shoot length; S t a t i o n B4 had the shortest mean shoot length. These s t a t i o n s are only 150 meters apart but have an e l e v a t i o n d i f f e r e n c e o f approximately 0.8 meter. S t a t i o n C1 had the great e s t mean stem diameter; i t occurred 0.5 meter above the smallest stem diameter at A3-- 60 -Figure 19: Seasonal changes in vegetative and reproductive shoot numbers per square meter of Carex lyngbyei. 1250 - 62 -Figure 20: Frequency distribution of Carex lyngbyei shoot lengths. a) Reproductive b) Vegetative AUGUST 10-Mr*! ran I am I ftsa ^1 10H reproductive j j vogetative o — o " I s I 03 o Shoot Longth Ccm) I •O •o o I 8 S 8 I o I - ek -Figure 2 1 : Frequency d i s t r i b u t i o n s of Carex lyngbyei shoot diameters. a) Reproductive b) Vegetative - 65 -A U G U S T 50 25 3 I M A Y T JZL 5 OH 25 H o i in O I — j o b-I i t o I n b i Ln "o I 'o I In O In - 66 -Table 3' Newman - Keuls M u l t i p l e Range Test f o r S i g n i f i c a n t D i f f e r e n c e s between Means f o r Carex lyngbyei Shoot lengths and Diameters Shoot Length (cm) Ranks of Species Means 1 2 3 4 5 6 7 8 Ranked Species Means 52.59 56.52 56.94 59-13 60.15 63-58 69-35 76.62 Conclusion (P=0.05) S t a t i o n B4 A3 A1 CI A2 B2 B1 B3 Shoot Diameter (cm) Ranks of Species Means 1 2 3 4 5 6 7 8 Ranked Species Means 3-18 3-45 3-52 3-55 3-63 3-83 3-87 4.22 Conclusion (P=0.05) S t a t i o n A3 A2 B2 A1 B4 B1 B3 C1 - 67 -5.2.4 RELATIONSHIPS WITH ENVIRONMENTAL FACTORS The mean phytomass" for each station (for a l l the sampling dates) showed definite trends when compared to the elevation above chart datum. In both Carex lyngbyei and Sairpus maritimus the standing crop increased as the elevation increased.(Figure 22). In comparing the shoot length of C" lyngbyei with elevation there was a similar trend of longer shoots with higher elevations (Figure 23). The basal diameters of C. lyngbyei stems measured twice during the growing season were also plotted against elevation; no visible trends were observed. An interesting relationship was observed when comparing C. lyngbyei mean stem length. In essence, the areas of greater biomass had longer stems. Although this relationship deserves further investigation, it could prove to be a rapid method of estimating the standing crop of an area (eg. i f the mean stem length was 115 cm, the standing crop would be approximately 1,000 grams per v. square meter) (Figure 24). The number of reproductive C. lyngbyei shoots showed a strong rela-tionship to elevation; the number of shoots declined as the elevation increased (Figure 25). An examination of the percentage of reproductive shoots indicated the shoots followed a normal distribution.. The mean number of C. lyngbyei shoots seemed to be a correlation be-tween the distance from the river and the number of stems; A3, the closest sta-tion to the river had the largest number of stems; B4 was next with the second largest number while A2 and B3 were about equal; B1 , the station furthest'from the river had the lowest stem count (Figure 26). The mean rate of growth (g/m2/day) is shown of individual stations over time (Figure 27). In general, transect B had the greatest rate of growth, reaching a mean of 21 g'/m2/day by the beginning of June; transect A followed a similar pattern but reached a maximum of 17.5 g/m2/day. Transect C exhibited - 68 -Figure 22: Regression of standing crop on e l e v a t i o n f o r Carex lyngbyei and Sairpus maritimus Figure 23: Regression of shoot length on e l e v a t i o n f o r Carex lyngbyei in May and August. - 69 --7 0-Figure 2k: Regression of standing crop on stem length f o r Carex lyngbyei. Figure 25: Regression of stem number on e l e v a t i o n f o r Carex lyngbyei. - 7 1 -- 7 2 -Figure 26: Mean number of shoots of Carex lyngbyei at d i f f e r e n t e l e v a t i o n s above chart datum. - 73 -- Ik -Figure 27: Seasonal changes in growth rates f o r Carex lyngbyei at d i f f e r e n t s t a t i o n s . - 7 6 -an e n t i r e l y d i f f e r e n t p a t t e r n ; C1 which had a mixture of Carex lyngbyei and Sairpus maritimus showed a peak in growth at the beginning of June, as d i d tr a n -sects A and B; a f t e r June the growth dropped to zero and then showed a second, but lower peak in J u l y . This drop in growth cannot be a t t r i b u t e d to sampling v a r i a b i l i t y as i t i s uniformly evident in a l l of the s t a t i o n s of tran s e c t C with the exception of C5. The s t a t i o n s w i t h the most rapid growth rates were A2, B1 and C1, wi t h maximum rates at l e a s t 5 g/m2/day above the other s t a t i o n s at each t r a n s e c t . 5.2.5 NITROGEN Nitrogen analyses revealed a general trend of decrease with time (Figure 28 ) . Peak nitrogen l e v e l s were reached at the beginning of May ( a mean of 2.75%) and then de c l i n e d r a p i d l y u n t i l J u l y (mean of approximately 1%); a slow d e c l i n e a f t e r t h i s r e s u l t e d i n a f i n a l mean nit r o g e n of 0.67 percent. . A Newman Keuls t e s t of s i g n i f i c a n c e i n d i c a t e d that a l l C. lyngbyei s t a t i o n means were s i g n i f i c a n t l y d i f f e r e n t (Table 3). Upon converting the nitrogen percentage to y i e l d values (Figure 29) the d e c l i n e in nitrogen y i e l d (g/m2) with e l e v a t i o n became apparent. The percentage ni t r o g e n a l s o showed a decrease w i t h e l e v a t i o n (Figure 30) though not as pronounced as the y i e l d decrease. During the period of peak biomass nitrogen y i e l d s were in the order of 5 to 10 g/m2; the only notable exception was S t a t i o n C1 where high biomass and high nitrogen combined to produce a y i e l d of 19 g/m2 (Figure 31)-5.2.6 SUMMARY OF YIELD VARIABLES Table k summarizes the Newman Keul m u l t i p l e range t e s t r e s u l t s f o r each of the dominant sp e c i e s , C. lyngbyei, S. maritimus, and S. ameriaanus, f o r each fo the main y i e l d v a r i a b l e s . S t a t i o n B1, nearest the dyke, had the greatest mean biomass, s i g n i f i c a n t l y d i f f e r e n t from the other s t a t i o n s , as was A1 w i t h the - 7 7 -Figure 28: Seasonal changes in nitrogen content of Carex lyngbyei. Means of a l l s t a t i o n s . I Figure 29: Regression of nitrogen y i e l d on e l e v a t i o n f o r three species at a l l s t a t i o n s . - 78 -- 7 9-Figure 30: Changes in nitrogen content of three species (combined) with e l e v a t i o n . F i g u r e 31: Seasonal changes in nitrogen y i e l d f o r Carex lyngbyei at various s t a t i o n s . - 80 -% 2H M o n t h Table 4: Mean Y i e l d s of C. lyngbyei, S. maritimus and S. ameriaanus Carex lyngbyei S t a t i o n n Weight #Stems #Repr, A1 21 401.9 d 951.4 c 136.7 a A2 21 528 .5 be 1025.0 c 79.1 b A3 21 533.6 be 1560.0 a 90 .0 b B1 21 660.8 a 849.0 c 55.2 b B2 21 525.3 be 905.7 c 60.5 b B3 21 595.1 ab 1030.0 c 63 .3 b B4 21 464.9 cd 1223.0 b 138.1 a L.S.D. 81.1 144.9 34.8 Sairpus maritimus CI 6 556.7 a 423 .3 a 13-3 b C2 9 626.9 a 392.2 a 71.1 a C3 9 188.7 b 226 .7 b 27.8 b M1 9 507.3 a 356 .7 a 24.4 b L.S.D. Sairpus ameriaanus C4 18 265.7 a 803.9 a 387.8 a C5 18 173.6 b 423.9 b 201 .7 b L.S.D. 52 .3 172.0 98.7 #Veg %Repr. w Wt/Stem 814.8 c 14.9 1 .62 c 0.53 be 945.7 be 8.9 be 1 .43 e 0.59 be 1470.0 a 6.2 c 1.42 f 0.35 c 779.0 c 6.8 c 1.69 b 0.90 a 845.2 c 6.6 c 1.79 a 0.66 b 966.2 be 7.1 c 1.62 d 0.60 be 1085.0 b 11.3 b 1.39 g 0.43 be 140.2 3.14 0.002 0.18 410.0 a 2.77 c 1.14 1 ,04 b 322.2 a 17.6 a 0.97 1.64 a 198.9 b 9-30 b 1.22 0.82 b 322.2 a 6.1 be 0.71 1.48 a n; s. 416.1 a 43.9 1.93 0.46 222.2 b 42.4 1.84 0.50 87.4 n. s. n. s. n .s. lowest yield. Station A3 had the largest number of stems, significantly dif-ferent from the next largest, Bk, which was significantly different from the other C. lyngbyei stations. Station A3 also had the largest number of vegetative stems; A1 and Bk had the largest numbers of reproductive stems. Station B1 had the "heaviest" individual stems. For S. maritimus, Station C3 had significantly lower values than other stations for mean biomass, mean number of stems and mean number of vegeta-tive stems; C 2 had the highest percentage of reproductive stems. No significant differences were found in the nitrogen contents. Station Ck in a l l cases had higher yield variables than C5 when significant differences were found; the species at these stations was S. ameriaanus. 5.3 DISCUSSION A variety of measurements were taken to assess-) productivity; attempts were made to relate these values to environmental variables which may influence plant production. Phytomass increased with elevation for both Carex lyngbyei and Sairpus maritimus, with the difference being more dramatic fon.iS';. maritimus. S. ameriaanus was not included in the assessment due to a lack of elevation data for its zone of occurrence. Associated with these differences were changes in stem densities and sizes; the C. lyngbyei vegetative and reproductive stem numbers decreased as the elevation increased but stem lengths and diameters in-creased with elevation. For S. maritimus, the number of vegetative stems increased with increasing elevation but the number of reproductive stems de-creased. The smallest percentage of reproductive stems occurred at the highest elevations. The task of interpreting these variations in growth is a very d i f f i -cult one as the results may be due to any combination of environmental variables which cannot be measured in unison to give a stress or benefit factor. - 83 -The increased production w i t h increased e l e v a t i o n p o s s i b l y r e f l e c t s the i n h i b i t i o n of photosynthesis due to s i l t y waters. The f a c t that transect A, in g e n e r a l , had a lower p r o d u c t i v i t y may r e f l e c t r i v e r i n f l u e n c e ; i n essence tra n s e c t A may be considered as o c c u r r i n g lower in the i n t e r t i d a l zone than i t a c t u a l l y does, and i s more subject to r i v e r flow and s i l t l o ading. In Oregon ( E i l e r s , 1975), C. lyngbyei has been found to be a primary c o l o n i z e r in the t i d a l marsh, extending lower than e i t h e r S. ameriaanus or Triglochin maritima; i t extended down to 0.97 m above MLLW which i s roughly equivalent to 2.27 ni above chart datum in the Fraser foreshore area. Other species grew to 1.21 m (lower l i m i t ) which i s equivalent to 2.51 m in the Fraser area. Biomass in Oregon was a l s o found to be higher than in the Fraser River marsh areas; f o r S. ameriaanus the net primary production was c a l c u l a t e d as 609 g/m 2/year; C. lyngbyei was separated i n t o two forms, the t a l l y i e l d i n g a mean of 1,746 g/m2/ year and the s h o r t , a mean of 875 g/m 2/year. The C. lyngbyei studied at the Brunswick Point marsh would probably f i t i n t o the t a l l category. The d i s t i n c -t i o n of t a l l and short forms was a l s o observed by Levings and Moody (1976) in the Squamish River estuary. The outer marsh areas seem to d i s p l a y a d i f f e r e n t pattern of growth to that of inner areas. During e a r l y s p r i n g a " f l u s h " of vegetation is apparent near creeks and c l o s e to the r i v e r (Figure 33). It i s p o s s i b l e that t h i s rapid growth i s due to n u t r i e n t enrichment in these areas as wel l as warmer tempera-tures from the f l o o d i n g water. V a l i e l a and Teal (1974) noted that marsh s e d i -ments were very e f f i c i e n t at removing n u t r i e n t s from water; hence, "...creek bank sediments would be supplied with more n u t r i e n t s than high marsh sediments." In a d d i t i o n they found that enrichment experiments w i t h urea in upper marsh areas r e s u l t e d in vegetation resembling that of low marsh areas, again suggest-ing the rapid absorption of nitrogen by sediments. Growth was rapid in the outermost areas of Brunswick Point marsh, reaching a peak before other areas and a l s o d e c l i n i n g r a p i d l y . The more frequent t i d e and wave a c t i o n in the - && -Figure 32: T a l l form of Carex lyngbyei as sampled in Brunswick Point 'Figure 33: Color i n f r a r e d photograph of e a r l y Carex lyngbyei growth along channel banks. Red in d i c a t e s a c t i v e l y growing veg e t a t i o n . - 86; -lower marsh areas may be important in the rapid removal of scenescent vegetation. Growth rates i n May were very high, and were comparable to those of the Squamish marshes (Section 2.3)- These high values were p r e v i o u s l y a t t r i b u -ted to high s i l t a t i o n rates and n u t r i e n t input. The decrease in reproductive material w i t h e l e v a t i o n i s an unusual pat t e r n . J e f f r i e s (1971) noted that under c o n d i t i o n s of high i n t r a s p e c i f i c den-s i t y s t r e s s or under c o n d i t i o n s of high s a l i n i t y , f l o w e r i n g d i d not occur in Plantago maritima or Tvigloohin mavitima; he concluded that under s t r e s s f u l con-d i t i o n s the p l a n t s tend to reproduce v e g e t a t i v e l y and l i v e longer. He a l s o ob-served that many plants in s a l t marshes d i d not flower f r e q u e n t l y . Vogl (1966) found that constant innundation i n h i b i t e d flower s t a l k production in Spavtina. The observations of C. lyngbyei f l o w e r i n g f r e q u e n t l y in lower marsh e l e v a t i o n s (more s t r e s s f u l s i t u a t i o n s ) seem to disagree w i t h previous patterns. S. mavitimus on the other hand f o l l o w s the e s t a b l i s h e d pattern and i s s e x u a l l y more reproductive at higher e l e v a t i o n s . The pattern e x h i b i t e d by C. lyngbyei could r e f l e c t n itrogen enrichment at lower l e v e l s as discussed e a r l i e r , which tends to st i m u l a t e i n f l o r e s c e n c e production, or i t may r e f l e c t increased competition at the higher marsh l e v e l s . Reproductive shoots showed e a r l i e r scenescence ( i n "C. ".lyngbyei) 'than did v e g e t a t i v e shoots; l e a f t i p s began to yellow a f t e r seed s e t , i n d i c a t i n g a m o b i l i z a t i o n and t r a n s l o c a t i o n of c e l l c o n s t i t u e n t s (Langer, 1972); reproductive stems were sho r t e r and slimmer than vegetative stems in August. ' The " v e g e t a t i v e frequency" d i s t r i b u t i o n s i n d i c a t e there may be a d i f -ference in the shoot lengths of those i n i t i a t e d in the f a l l and those i n i t i a t e d in the s p r i n g . This r e l a t i o n s h i p bears f u r t h e r i n v e s t i g a t i o n . Since the number of shoots d e c l i n e d through the growing season, the p o s s i b l i t y e x i s t s that shoots i n i t i a t e d in the f a l l may reach scenescence e a r l i e r and d i e . No records were kept of dead stems or leaves found on the marsh surface s i n c e w i t h the heavy sedimentation in the area, they were q u i t e r a p i d l y buried and d i f f i c u l t to spot. - 87 -increased e l e v a t i o n seemed to e l i c i t a response c h a r a c t e r i z e d by t a l l e r , t h i c k e r and fewer stems in C. lyngbyei. The s h o r t e r , slimmer, and denser stems at lower e l e v a t i o n s and at s i t e s c l o s e to the r i v e r could be a t t r i b u t e d to stresses |/n these l o c a t i o n s a t t r i b u t a b l e to increased inundation and higher s i l t loads. C. lyngbyei may a l s o be l i m i t e d by the presence of t o t a l l y f r e s h water. - 88 -6. DETRITUS It has long been recognized that marshes c o n t r i b u t e very l i t t l e to the est u a r i n e ecosystem by way of the grazing food chain (Smalley, 1954); most of the abundant vegetation produced in these areas i s decomposed and washed i n t o the marine environment (Pomeroy, 1977). The r o l e of d e t r i t u s has been-:extensively explored in s a l t marsh systems in other areas of the world but l i t t l e a t t e n t i o n has been paid to the brackish marsh communities and the f a t e of t h e i r production. The examination of l i t t e r bag loss and in v i t r o decomposition i s a p r e l i m i n a r y step to understanding the d e t r i t a l p a r t of the marsh system. 6.1 DETRITUS - FIELD CONDITIONS 6.1.1 METHODS The r e l a t i v e decomposition rates of four species of marsh plants {Carex lyngbyei, Salioornia vivginiaa, Triglochin maritima and Sairpus maritimus) were determined by en c l o s i n g 25 g plant samples in nylon mesh bags (25 cm x 25 cm). Two mesh s i z e s (1 mm and 0.5 rnm) were used to determine the e f f e c t of the aper-' tures on l i t t e r l o s s . Dried plant material was placed in the mesh bags and bag openings were c l o s e d by heat s e a l i n g . The mesh bags were s t a p l e d t o 8 f o o t (244 cm) lengths of wooden studs ("two by f o u r s " ) : these were attached by poly-ethylene ropes to wooden stakes driven i n t o the sediment at 8 foot (244 cm) and 10 foot (305 cm) t i d e l e v e l s on e i t h e r side of the Westshore Terminal j e t t y . The binding ropes were allowed enough s l a c k (approximately 15 cm) to all o w the bags to r i s e o f f the mud at high t i d e s . This was to simulate natural c o n d i t i o n s of d e t r i t u s s h i f t i n g in the marsh and to keep the bags from clogging w i t h mud. / The bags were set out in October, 1976 and recouped in January, 1977). A f t e r removal from the f i e l d the bags were washed, then d r i e d in a forced a i r oven at - 89 -60°C f o r 2k hours. The contents were weighed; inv e r t e b r a t e s were separated from the v e g e t a t i o n , counted and weighed; and the net weight of vegetation was deter-mined. Nitrogen analyses, (micro-Kjeldahl) were performed on subsamples of the dr i e d vegetation from which the amphipods had been removed. 6 .1 .2 RESULTS The nylon mesh bags became q u i t e b r i t t l e during the course of the study, and as a : r e s u l t , s p l i t along the edges ( e s p e c i a l l y where heat sealed) which r e s u l t e d in the complete loss of 37 percent of the bags. Another 21 per-cent of the bags y i e l d e d u n r e l i a b l e r e s u l t s due to small breaks i n the bags. The l i t t e r bags were returned to the f i e l d a f t e r the f i r s t set of ob-servat i o n s were recorded. Plans f o r f u r t h e r monitoring were halted when a heavy i winter storm r e s u l t e d in the loss of a l l the l i t t e r bags. Despite the lack of observations repeated over time and the loss of r e p l i c a t e s , the comparative data between species and s t a t i o n s , and d i f f e r e n t mesh s i z e s reveal trends. Table 5 shows the percentage of d e t r i t u s remaining a f t e r 103 days in the f i e l d . C. lyngbyei and S. mavitimus had'the greatest amounts remaining, w i t h 52 percent each (mean of a l l s t a t i o n s and mesh s i z e s f o r each s p e c i e s ) . S. vivginica had 19 percent of the i n i t i a l material remaining but T. maritima, the most e a s i l y degraded of the four species, had only 12 percent of the i n i t i a l weight present. A model 1 s i n g l e f a c t o r a n a l y s i s of variance (Zar, 1974) was undertaken and a t e s t of s i g n i f i c a n c e (Newman-Keuls) performed to compare the mean weights of species enclosed in mesh bags. The r e s u l t s i n d i c a t e that f o r each mesh s i z e there were four d i s c r e t e populations w i t h no means being equal (Table ^ ) . The means were ranked from 1 - k (smallest to l a r g e s t ) w i t h T. maritima and S. virginica being 1 and 2 r e s p e c t i v e l y f o r both mesh s i z e s . S. maritimus - 9 0 -Table 5- Percent of I n i t i a l Dry Weight of Plant M a t e r i a l Remaining A f t e r 103 Days (Species means) S i tes Carex Scirpus T r i g l o c h i n S a l i c o r n i a Mean ION 1mm 0. 5mm 54 62 kk 53 8 18 12 (20 est;.) 30 38 10S:1mm 0. 5mm 55 55 38 59 8 13 18 30 (20 est.) 37 8N 1 mm 0. 5mm 55 kk 5k 53 8 16 15 21 33 34 8S 1 mm 0. 5mm 51 kk 55 57 10 16 16 23 33 35 Mean 1 mm 0. 5mm 5k 51 48 56 8 16 15 22 - 91 -Table 6: Newman-Keuls M u l t i p l e Range Test f o r S i g n i f i c a n t Differences Among Mean Weights of D e t r i t a l M a t e r i a l Remaining A f t e r 103 Days in Mesh Bags 0.5 mm Mesh Ranks of Species Means 1 2 3 4 Ranked Species Means (g) 3-66 5.21 12.50 13-90 Conclusion (P = 0.05) Species T. maritimus S. V i r g i n i a C. lyngbei S. maritifmus 1.0 mm Mesh Ranks of Species Means 1 2 3 4 Ranked Species Means (g) 1.91 3-56 12.36 13-18 Conclusion (P = 0.05) Species T. maritima S. v i r g i n i c a S. maritimus C. lyngbei - 92: -had the highest weights f o r the 0.5 mm mesh, whi:le C. lyngbyei was highest f o r the 1.0 mm mesh. A paired-sample t t e s t was used to compare the mesh s i z e s w i t h i n each species r e s u l t i n g in no s i g n i f i c a n t d i f f e r e n c e s f o r any species w i t h the exeption of T. maritima which i n d i c a t e d a h i g h l y s i g n i f i c a n t d i f f e r e n c e in weight loss between mesh s i z e s at the 5 percent l e v e l . To t e s t f o r d i f f e r e n c e s between the four l o c a t i o n s , a model 1 two f a c -t o r a n a l y s i s of variance (Zar, 1974) was used. In a l l cases the hypothesis that the weight of d e t r i t u s at each l o c a t i o n was equal was accepted. As expected the species e f f e c t proved to be h i g h l y s i g n i f i c a n t . • •' Table 7 shows the nitrogen content of the d e t r i t u s of various species at the d i f f e r e n t s t a t i o n s . A.paired-sample t t e s t was used to compare i n i t i a l n i t rogen values w i t h those o c c u r r i n g in the d e t r i t u s bags a f t e r 103 days. C. lyngbyei d e t r i t u s in a l l cases (except of 8N, 1 mm mesh) had s i g n i f i c a n t l y greater nitrogen l e v e l s than the o r i g i n a l p l a n t m a t e r i a l . S. virginica and T. maritima both had s i g n i f i c a n t l y lower nitrogen values than the o r i g i n a l m a t e r i a l , however f o r the T. maritima t h i s only a p p l i e d to the 1.0 mm mesh'. Amphipod (probably Anisog.qmmarus pugettensis, pers. comm. C. D. Levings) counts are recorded in Table 8.„ C. lyngbyei appeared to be the most a t t r a c t i v e species f o r amphipods at a l l l o c a t i o n s . "8 S" appeared to be the best l o c a t i o n f o r large amphipod numbers w h i l e "10 N" was the l e a s t favorable. As expected, the smaller s i z e mesh r e s u l t e d in fewer amphipods per bag at a l l l o c a t i o n s and f o r a l l species. The 0.5 mm mesh may have been too small f o r amphipods to enter w i t h ease and the presence of more e a s i l y a c c e s s i b l e d e t r i t u s nearby (1 mm mesh) may have confounded the e f f e c t s . Table 7: Percent Nitrogen Content of Detritus, at Transplant S i t e s S i t e 1 C. "X Jyngbye i SE N S. X" ma r i t i mus SE N T. X" ©a r i t i ma SE N S. vi X r g i n i c a SE N 8N 0.5 mm .93 .06 2 .55 - 1 .64 - 1 .52* .01 2 1 .0 mm .83 .25 2 .48 • 09 2 .75* .08 2 .60* .02 2 8S 0.5 mm 1 .01** .09 2 .64 .04 2 .97 .10 2 • 59 - 1 1 .0 mm .93* - 1 .69 .01 2 .76* .03 2 .62 - 1 ION 0.5 mm .81* .02 2 • 73 .03 2 1 .06 .27 2 - - 0 1 .0 mm .83* .02 2 .57 - 1 .57* .03 2 .48** .03 2 10S 0.5 mm • 95* .08 2 .54 .11 2 - - 0 - - 0. 1 .0 mm .93* .03 2 .52 .14 2 .83* .04 2 .53** .02 2 I n i t i a l . .58 .08 7 .65 .05 3 1.31 .12 3 1.68 .10 2 * Denotes s i g n i f i c a n c e at p <0.05 ** Denotes s i g n i f i c a n c e at p <0.01 Locations are shown in Figure T a b l e 8: Number o f Amphipods (X o f d e t r i t u s bags f o r each s p e c i e s a t each s t a t i o n ) S i t e Carex S c i r p u s T r i g l o c h i n S a l i c o r n i a Mean ION 1mm 21 11 3 4 10 0. 5mm 0 1 0 0 0 10S 1mm 39 41 33 11 31 0.5mm 3 1 0 0 1 8N 1 mm 45 17 19 12 23 0.5mm 8 8 0 3 19 8S 1 mm 62 34 48 45 47 0. 5mm 20 17 5 2 11 Mean 1 mm 42 26 26 18 0. 5mm 8 7 1 1 - 95 -6.1.3 DISCUSSION The d e t r i t u s bags were placed at four d i f f e r e n t l o c a t i o n s w i t h the i n -tent of e x p l o r i n g the e f f e c t of t i d a l inundation and s a l i n i t y on decomposition. At the l.kk m t i d e l e v e l s the d e t r i t u s bags were submerged f o r 17-5 hrs.per:day while at the 3.05 m l e v e l d e t r i t u s bags were submerged f o r an average of 13.1 hours per day. S a l i n i t i e s v a r i e d by 5 ° / 0 0 between the r i v e r i n fluenced north s i d e and the more marine south side of the j e t t y . The h.k hours of increased submergence at the l.kk m t i d e l e v e l were expected to have some e f f e c t on decomposition r a t e s ; however the a n a l y s i s of v a r i -ance f o r Vocation e f f e c t s showed no s i g n i f i c a n t d i f f e r e n c e s . While the amount of d e t r i t u s was not a f f e c t e d by l o c a t i o n the number of amphipods were, w i t h l a r g e r numbers o c c u r r i n g at the lower e l e v a t i o n s . Mesh s i z e s a l s o probably l i m i t e d the number of amphipods by r e s t r i c t i n g e n t r y , as the l a r g e mesh s i z e a l -ways contained more amphipods than the small mesh, regardless of species.or l o c a -t i o n . The mesh s i z e s d i d not play s i g n i f i c a n t r o l e s in degradation of species other than T. maritima. In t h i s species losses from the 1 mm mesh bags were s i g n i f i c a n t l y greater than from the 0.5 mm mesh. This species i s q u i t e f l e s h y and becomes b r i t t l e when dry. It i s probable that mechanical degradation occurs very r a p i d l y in t h i s species and hence,losses due to mesh s i z e are f a r more important than in the other species with more r e s i l i e n t leaves and stems. S. maritimus stems had developed c e n t r a l woody cores by the end of the growing season; surrounding the core was a f l e s h y sheathv The removal of the f l e s h y material probably occurred q u i t e r a p i d l y w i t h a gain, and then a loss in n i trogen content as'the microfauna was removed by amphipods and wave a c t i o n . The d e t r i t u s l e f t in the bags contained very/1 i t t l e - f l e s h y - m a t e r i a l ; p o r t i o n s - o f the woody cores of stems were abundant. Nitrogen content was s i g n i f i c a n t l y d i f -f erent from that of the i n i t i a l p lant m a t e r i a l . - 96 -S. virginiaa d e t r i t u s was s i g n i f i c a n t l y lower in ni t r o g e n than the i n i -t i a l t i s s u e s , as can be expected with only 19 percent of the material remaining, that: remaihing presumably being the most d i f f i c u l t to degrade; m a t e r i a l l e f t in the bags was mainly s t r u c t u r a l t i s s u e . The material which i s more e a s i l y broken down has a higher nitrogen content as t e s t i f i e d a l s o by the loss of t h i s m aterial and a lower nitrogen value in the 1 mm mesh bags f o r T. maritima. .".The material remaining in the bags was mainly the s t r u c t u r a l remnants of flower .stalks. C. lyngbyei d i d not show any d i f f e r e n c e s between mesh s i z e s ; e v i d e n t l y i t s r esi 1iency, e s p e c i a l l y when w e t , r e s i s t s mechanical breakdown. C. lyngbyei, a f t e r 103 days in the d e t r i t u s bag, could barely be d i s t i n g u i s h e d fromjthe: i n i t i a l p lant m a t e r i a l ; s e c t i o n s of leaves and stems were r e a d i l y apparent although considerable fragmentation had occurred. The f a c t that C. lyngbyei had the most material remaining of a l l the species i n d i c a t e s i t s importance as a slow r e l e a s e r of n u t r i e n t s . It i s the only species with nitrogen values s i g n i f i c a n t l y greater than the i n i t i a l ; t herefore we can assume a r i c h b a c t e r i a l population and t h i s appears p a r t i c u l a r l y a t t r a c t i v e to the amphipods which occur in t h e i r greatest numbers w i t h C. lyngbyei. The amphipods which i n h a b i t the d e t r i t u s bags may i n -crease nitrogen content with t h e i r feces as described in Section 2.k. 6 .2 LABORATORY CONDITIONS 6.2.1 METHODS Dead standing C. lyngbyei^ T. maritima and S. maritimus stems and leaves obtained from Brunswick Point marsh in September, 1976 were oven d r i e d (at 1 0 5 ° ) , ground and screened to e l i m i n a t e p a r t i c l e s l a r g e r than 2 mm. Twenty-four r e p l i c a t e s ( l gram each) f o r each of the three species were incubated in 250 ml erlenmeyer f l a s k s with 100 ml of f i l t e r e d seawater (obtained from the Roberts Bank area, having a s a l i n i t y of approximately 18 o/oo).and 1 ml of a - 9.7 " Figure 3k: In v i t r o decomposition of three species; changes in the percent remaining over time. - 99 -marsh mud suspension. Aeration and mixing were maintained by mounting the f l a s k s on a continuously r o t a t i n g shaker (at a slow speed). The f l a s k s were incubated at 12°C in a dark chamber (to prevent photosynthesis) f o r a maximum of 27 days. Three r e p l i c a t e s of each species were removed from the chamber at 3 -4 day i n t e r -v a l s , d r i e d at 60°C, cooled in a d e s i c c a t o r and weighed on an a n a l y t i c a l balance. Dried r e p l i c a t e s were excluded from the remainder of the study. Three c o n t r o l s were prepared without any vegetation to determine the t o t a l s a l t content of the med i urn. 6.2.2 RESULTS The r e s u l t s of the in v i t r o decomposition of marsh vegetation are shown in Figure 34. Residues, minus s a l t s , are p l o t t e d as percent of i n i t i a l dry matter. The graphy d i s p l a y s a rapid loss of vegetation during the f i r s t 6 days; a l o s t of between 50 and 56 percent f o r S. maritimus and T. maritime/,, re-s p e c t i v e l y . V a r i a b i l i t y w i t h i n species r e p l i c a t e s , ( c o e f f i c i e n t of v a r i a t i o n ) was l e s s than 4 percent at a l l times. The r e l a t i v e values of the species were remarkably c o n s i s t e n t , w i t h T. maritima being the most e a s i l y degraded but with S. maritimus and C. lyngbyei f o l l o w i n g p a r a l l e l patterns throughout the e x p e r i -ment. A f t e r day 6 the d e c l i n i n g trend reversed and a gradual build-up in the amount of d e t r i t u s occurred u n t i l day 23, whereupon the d e t r i t u s underwent a 30 percent increase in four days. F i n a l r e s u l t s i n d i c a t e d that C. lyngbyei and S. maritimus f l a s k s had a dry matter content of between 85 and 90 percent of the i n i t i a l dry weight; T. maritima f l a s k s contained 67 percent of the i n i t i a l dry weight (Figure 34). - 1 0 0 -6.2.3 DISCUSSION Previous in v i t r o decomposition studies have e x t e n s i v e l y d e a l t with the m i c r o b i a l populations developed during decomposition. This type of a n a l y s i s was beyond the scope of t h i s study. The purpose of the laboratory study was to complement the d e t r i t u s bag r e s u l t s and assess the r e l a t i v e decomposition rates of three marsh species. The lack of mic r o b i a l population analyses makes any re-s u l t s , other than the r e l a t i v e r a t e s , very d i f f i c u l t i f not impossible, to i n t e r -pret . The r e s u l t s i n d i c a t e d that the r e l a t i v e decomposition rates between f i e l d and laboratory experiments were f a i r l y comparable. T. maritima was the most e a s i l y degraded of the three species; C. lyngbyei and S. maritimus shared very s i m i l a r patterns but w i t h 5 to 7 percent more material remaining at any time than did T. maritima. In the f i e l d , a f t e r 103 days, the d i f f e r e n c e between T. maritima and C. lyngbyei was in the order of kO percent. Decomposition progressed much more r a p i d l y i n the la b o r a t o r y than i n the f i e l d . The l i t t e r bags which contained whole leaves and stems of the various species had l o s t approximately 50 percent of the i n i t i a l m a terial by 103 days in the f i e l d . In the laboratory the same amount of loss occurred in the f i r s t 6 days; a large p o r t i o n of t h i s l o s s can be a t t r i b u t e d to rapid leaching of the f i n e l y fragmented m a t e r i a l s . The unusually high values reached at the end of the experiment may have in part been due to some undetected systematic e r r o r . The comparison of f i e l d and laboratory r e s u l t s demonstrates the importance of mechanical breakdown in the decomposition of these marsh p l a n t s . - 101 -7. TRANSPLANTATION, SPECIES SUCCESS AS RELATED TO ENVIRONMENTAL FACTORS Introduction The t r a n s p l a n t i n g of vegetation was undertaken to answer two prime questions; what are the f a c t o r s l i m i t i n g the vegetation to i t s present boundaries and, i s the establishment of the vegetation in unvegetated areas a f e a s i b l e pro-j e c t ? The use of t r a n s p l a n t s i s a time proven technique of experimentally demonstrating adaptation, as in the i n v e s t i g a t i o n of ecotypes (Clausen, et al, 1940; McNaughton, 1974). A c l a s s i c technique has been to piace-ecotype clones in a standard garden and to observe d i f f e r e n c e s which p e r s i s t d e s p i t e the u n i -form environmental c o n d i t i o n s . A m o d i f i c a t i o n of t h i s technique (Clausen, et a13 1948) involves r e c i p r o c a l t r a n s p l a n t s of species to various environmental condi-t i o n s . The l i m i t a t i o n s of the standard garden technique can be e l i m i n a t e d by the v a r i e d environment t r a n s p l a n t s (Hes^lop-Harrison, 1964). Transplant experiments, u n t i l r e c e n t l y , have been used to a very minor extent in assessing marsh h a b i t a t s . S t a l t e r and Batson (1969) produced the f i r s t published account of attempts to explore h a b i t a t f a c t o r s by means of trans-p l a n t a t i o n in North America; the p l a n t i n g of t i d e lands f o r the purposes of land reclamation and harbor p r o t e c t i o n had been undertaken e a r l i e r in Europe (Ranwel1, 1967)- A tra n s p l a n t study, done by Mooring et al. (1971) explored the e c o l o g i c a l r e l a t i o n s h i p s associated with t a l l and shor't v a r i e t i e s of Spartina a l t e r n i flora. Recent research in marsh t r a n s p l a n t s has been d i r e c t e d to the problem of reestablishment or c o l o n i z a t i o n of dist u r b e d or a l t e r e d t i d a l f l a t s rather than to the problem of determining which environmental f a c t o r s a plant i s adapted to (e.g. Woodhouse, et al., 1974); Seneca, 1974). An example of t h i s approach was undertaken at M i l l e r Sands on the Columbia River estuary where a dredge s p o i l i s l a n d was planted w i t h natural marsh species. Although f i n a l r e s u l t s have not - 1 0 ' 2 -been published, Cavex lyngbyei and Desohampsia aaespitosa proved to be e s p e c i a l l y successful t r a n s p l a n t s (Dredged M a t e r i a l Research, 1 9 7 6 ) . The t r a n p l a n t a t i o n of four l o c a l species of marsh vegetation i n the southern Fraser d e l t a foreshore i s the f i r s t attempt to r e l a t e species to v a r i -ous environmental f a c t o r s in a B r i t i s h ColUmbia t i d a l marsh. 7.1 TRANSPLANTATION METHODS Transplant s i t e s were chosen adjacent to .the Westshore' T e r i f n naK-cause-wasy. The area afforded a v a r i e t y of environmental c o n d i t i o n s w i t h i n easy access. (Figure 3 5 ) . The Z.hk m and 3 -05 m t i d e l e v e l s were chosen to represent normally unvegetated l.kh m and vegetated 3 -05 m t i d e f l a t s . Due to the recent construc-t i o n of the causeway ( i n 1969) vegetation had not c o l o n i z e d the t r a n s p l a n t area at the s t a r t of the study; however, during the period of the study, c o l o n i z a t i o n occurred on both sides of the j e t t y (T. maritima on the north s i d e , S. virginioa on the south side) c l o s e to the 3 -05 m t r a n s p l a n t l o c a t i o n s . The trans-plant l o c a t i o n s included s i t e s on e i t h e r side of the j e t t y to consider probable s a l i n i t y d i f f e r e n c e s which occurred between the r i v e r - i n f 1 u e n c e d water to the north and the more marine water to the south. The t r a n s p l a n t program was i n i t i a t e d in March of 1 9 7 6 . Tide tables were used to determine the s p e c i f i c time each e l e v a t i o n was to be exposed and then at that time, marking the water's edge w i t h a wooden stake. These l o c a t i o n s were l a t e r cross checked using observed t i d e data w i t h the time of exposure. S i x t y -four 2 0 cm 3 centimeter/blocks of marsh ve g e t a t i o n , representing four species {Carex lyngbyei, Sairpus maritimus, Triglochin maritima, and Salioornia virginioa) were removed from Brunswick Point marsh (near S t a t i o n s B 2 and M1) on March 2 0 , 1 9 7 6 . The blocks were placed in p l a s t i c bags and stored in a cool area overnight u n t i l the next low t i d e . Transplant l o c a t i o n s were s e l e c t e d at random from 64 p o s s i b l e s i t e s at each l o c a t i o n . Holes were excavated in 1 . - 10.3 -Figure 35: Location of t r a n s p l a n t s i t e s at Roberts Bank. - 104 -T R A N S P L A N T S C H E M E ( n o t t o sca le ) C S B c T S /ION] B B C S S T T C T B B ' T S C T B j C B S C » C T S B T B S C 18SJ. S T" S T C C B B e T Scirput merit [mus Carex lyngbyei Salicornia virginica Triglochin maritima R o b e r t s Bank S u p e r p o r t - 105 -Figure 36: Transplant plugs in s i t u at s i t e " 1 0 S " . (Photo) Figure 37: Monitoring of transplanted v e g e t a t i o n : stem counts and measurements. (Photo) - i o . f -preparation f o r the cores, and the excavated sediments removed from the immediate area to maintain the e x i s t i n g e l e v a t i o n . The plugs of vegetation were planted and t h e i r p o s i t i o n s recorded. Figure 37 shows the t r a n s p l a n t scheme. ln addi-t i o n to the four t r a n s p l a n t s i t e s , the aforementioned species were transplanted to d i f f e r e n t nearby s i t e s w i t h i n t h e i r own communities (four r e p l i c a t e s of each species) to determine the "shock" e f f e c t of the t r a n s p l a n t i n g techniques. P e r i o d i c monitoring of the tra n s p l a n t s i t e s was undertaken. Stem counts and measurements were taken, and observations made on the p l a n t s ' vigour (Figure 38). Vigour was ranked on a s c a l e of 0 - 5 (Table ?) based p a r t i a l l y on stem numbers and dimensions, as these r e l a t e d to the o r i g i n a l communities on the Brunswick Point marsh; and p a r t i a l l y on s u b j e c t i v e estimates. S a l i n i t i e s were measured p e r i o d i c a l l y by c o l l e c t i n g water samples and an a l y s i n g them on a Gui l d Line Autosal and substrate temperatures were recorded from depths of 8 and 16 cm. 7.2 RESULTS For a l l species, the best growth was observed at the "10N" t r a n s p l a n t s i t e s . In general, growth d e c l i n e d w i t h higher s a l i n i t i e s and lower e l e v a t i o n s . Table 9 i l l u s t r a t e s the ranked mean growth values f o r each species and l o c a t i o n . S. maritimus grew best of a l l the species. S t a t i o n "ION" had the great-est growth rate and expansion; as evidenced by stem counts c l o s e l y approximating those of s i m i l a r e l e v a t i o n s at Brunswick Point . Stems measured up to 60 cm t a l l and 7 mm t h i c k . By 1978, two of the cores had expanded almost four-f o l d and had v i r t u a l l y closed a one meter wide gap between.them. S t a t i o n s "10S" and "8N" were very s i m i l a r in the amount and type of growth in 1976, although one core at " 8 N " was able to expand w h i l e those at "10S" did not. Stem counts in these areas were in the range of 25 - 50 percent of those at Brunswick Point and measured 18 - 50 cm t a l l and 8 mm t h i c k . By the spring of 1978, two cores - 10,8 -gure 38: Transplant Scheme INITIAL 1976 [ION ' O N 1 1 Ta B4 B4 T3 T3 C4 B2 O Tl S4 CA B? C2 Tl S« S3 S' V '• CI S) B3 BI Ct Si BI BI T4 • . o r SJ T4 . o r s » f i o s l 1 TB Til TS BS S6 TS BS S« C7 Bt Ss B4 Ss CS Bs S7 > Bt S/ Ci > T7 C« T6 / os* T« St 67 St w 8 N CH . S» c n S9 CH CIO Til Bll CIO Til Bll S10 SIO B9 B» BIO 813 B/6 A. SI2 SI2 TIO T» Ta Sll C» TIO T? T« Sll C» LH] TI3 BIS p f BIS SIS SM CIS SIS SM o d BI) BIS S3 T IS S3 SU T«« CU SM t * c / J OeBM OBBH BM> CH Tl4 BM * 1977 1978 CA S3 T3 'Ti S< a OT Si T3 Tl S« H2D T» TS BS S« BS SS f i o s l I / B S S< Bt S7 <f <ji T« v St 17 Bt S7 St B* S 9 C / V Til Bll t T/ Bll SIO SIO BIO S13 , TIO y» B» ,* T I J S I I T /b T> B» BI2 c y T/l BIS Hi] T / Bft BI3 SM C«f S6 BIS SM c/& pefBW &M p> T/6 7* *< T/o </j - n o -Table 3: Ranked Mean Vigour of Transplant S i t e s , 1976 & 1977 1 ON 10S 8N 8S Total Sci rpus marit imus /76 /77 5.0 5.0 3.25 3.25 3.0 2.5 1.5 0.75 3.2 2.9 Sa l i co rn i a v i r g i n i c a /76 4.5 111 3.25 4.0 1.5 1.75 0.5 1.0 0.25 2.8 1 .4 Tr i g l o ch in maritima /76 3-75 /77 2.0 3.0 0 0.75 0 0 0 1.8 0.5 Carex lyngbyei /76 111 Total /76 /77 3-75 3.75 4.2 3-5 0 0 2.6 1 .2 0.75 0 1.5 0.75 0 0 0.6 0.25 1 . 1 0.94 Rank 0 1 2 3 4 5 Characteri s t i c Vegetation absent Barely a l i v e or dec l i n ing S t a t i c SIi ght growth Healthy growth Lush expansion - 111 •• at "10S" were eliminated probably due to heavy sediment deposition. The poorest growth in this species occurred at "8S" where most of the stems showed l i t t l e development. Stem counts were approximately 25 percent of those at Brunswick Point; with stem lengths and diameters ranging from 12 - 39 cm and 3.4 - 5 mm respectively. No reproductive shoots were observed at any location. In the transplant s i t u a t i o n , C. lyngbyei thrived best at Station "10N". Two cores planted at this s i t e had expanded by the f a l l of 1976, and continued growth in 1 9 7 7 - One core which had lost several of i t s shoots by July, 1976 had greatly increased the density of shoots by October, and continued growth in 1977- Stems at this location were around 40 cm t a l l , with a density of roughly half that of a comparable elevation at Brunswick Point. A l l of the C. lyngbyei plugs had disappeared by July, 1976 at Stations "10S" and "8S". At "8N", this species survived u n t i l the f a l l of 1976, having experienced declining numbers throughout the season (with about 5% of the expected number of shoots in July as compared with Brunswick Point marsh) and then disappearing completely by 1977. Stem heights in this location reached a maximum of 8 cm in the f i r s t year. C. lyngbyei did not reproduce at any stations. S. virginioa, thrived at the "10N" location and showed some expansion and healthy green growth. "10S" showed similar growth with the exception of a reddish hue on some shoots, indicating possible stress. In both cases, at the 2.44 m tide levels, S. virginioa survived u n t i l the f a l l of 1976, but with red shoots and weak growth. During 1977, three of four cores at each location dis-appeared and the remaining ones appeared very weak in the spring of 1978. •T. maritima also experienced i t s best growth at "10N". Less vigorous growth was apparent at "1 OS", there was one reproductive stem at each of the 3.05 m sites in 1976. Leaf lengths ranged from 22 - 26 cm and 28 - 32 cm at "10S" and "10N" respectively. At "8N", stem density was about half of that at "10N", while at "8S" the species did not survive. By 1977, T. maritima had disappeared at "8N" and had but two remaining units at "10S" both of which - 112 -disappeared by 1978 as did one of the weaker cores at ."ION". C u r i o u s l y one of the T. maritima cores at "8N" contained S. maritimus rhizomes as w e l l . In A p r i l , 1976, one S. maritimus shoot became apparent, and in J u l y , 7 stems had appeared while the o r i g i n a l T. maritima shoots had disappeared. Observations i n d i c a t e d that the p h y s i c a l e f f e c t of t r a n s p l a n t i n g was n e g l i g i b l e as intra-community t r a n s p l a n t s were a l l successful and the transplanted cores were i n d i s t i n g u i s h a b l e from the rest of the community by J u l y , 1976. How-ever, the t r a n s p l a n t s in t h i s case were a l l placed i n t o p r e v i o u s l y vegetated areas and there may have been a s u b s t a n t i a l c o n t r i b u t i o n from the vegetated areas around the plug in " f i l l i n g i n " the disturbed s i t e d . S a l i n i t i e s v a r i e d seasonally but maintained about a 5 0/00 d i f f e r e n c e between the north and south sides of the j e t t y . S a l i n i t i e s were measured from i n t e r s t i t i a l water which was in abundant supply at each s t a t i o n except f o r "10N". The more rapid drainage in t h i s area may have been important in the tr a n s p l a n t success. Changes o c c u r r i n g f o l l o w i n g the summer of 1976 revealed that winter storms a f f e c t e d t r a n s p l a n t success. P a r t i c u l a r l y at "10S", there was a heavy accumulation of s i l t s (up to 15 cm.deep) over top of the transplanted m a t e r i a l , probably i n h i b i t i n g growth in a l l remaining cores. Areas of erosion were a l s o apparent, e s p e c i a l l y at the "10N" s i t e were in some instances, roots and rhizomes were exposed. In a two year period S. maritimus cores at "10N" had expanded to about four times t h e i r o r i g i n a l t r a n s p l a n t s i z e . At 111 OS" h a l f of the cores were buried by s i l t , "8N" s t i l l had 3 i n t a c t cores, the one which disappeared being the one with only 1 stem. S i m i l a r l y , the only s u r v i v i n g S. maritimus core at "8S" was the one with the l a r g e s t number of shoots i n i t i a l l y (4). S. virginioa had appeared to be q u i t e well e s t a b l i s h e d at both "10N" and "1 OS". I t , too, was l o s t from two cores and in the remaining' two was severely impaired by sediment d e p o s i t i o n . Of the "8" s i t e s only one - 1 1 3 -Sdlioovnia virginioa unit remained alive at each location as of April, 1978 and continued growth was doubtful. C. lyngbyei continued healthy growth at " 1 0 N " in those cores which had previously shown good growth and expansion, but was eliminated from a l l the other s i tes. 7.3 DISCUSSION One of the major problems with transplanting rhizomatous material within cores of sediment is the inability to assess the exact amount and nature of materials transferred. For example, i n i t i a l stem counts of C. lyngbyei at "10N' 1 ranged from 11 to 32 shoots. Undoubtedly the amount of material transferred plays an important role in the eventual success of the transplant. In isolated instances where one core out of four;has failed while the others have done well, i t is possible to attribute this failure to insufficient root material in the core (e.g. " B 1 6 " , "T7", " T 1 0 " ) . In other cases, the original transplanted material has disappeared and has been replaced by a different species, presumably because there was root material from more than one species present and not because of fortuitous seedling establishment. It is interest-ing to note the species changes which did occur in two such instances: " C 3 " {Carex lyngbei) had 11 shoots i n i t i a l l y which were taken over by T. maritima stems in July, 1976 at "ION"; at " 8 N " a T. maritima plug which was observed to have one S. maritimus shoot i n i t i a l l y was eventually taken over by S. maritimus with T. maritima disappearing completely. Although these occur as isolated instances it is interesting to speculate about successional relationships as a result. Jeffries (1971) reports growing Plantago maritima and Triglochin maritima both separately and in mixed stands. Triglochin maritima growth was greatly reduced in the presence of Plantage maritima. Jeffries observes that: "Much of the variation which has been observed in salt marsh plants may be _ 114 -more c l o s e l y linked to the adverse e f f e c t s of interference from nearby plants than to the influence of the edaphic factors as such." Apparently in l i g h t of competition the plant most suited for the environment can overtake the one which i n i t i a l l y appeared dominant; therefore in the C. lyngbyei plug "C3", T. maritima was more suited to the environment at "10N" and s i m i l a r l y S. maritimus appeared to be more suited to "8N" than T. maritima. The varying amount of root and shoot material in the plugs, plus the d i f f e r e n t types of growth, made stem counts un r e l i a b l e ; hence a system of rank-ing the growth according to i t s apparent vigour was established. In terms of ove r a l l success, S. maritimus was the most tolerant of a l l environmental condi-tions with a mean growth value of 3-2, then S. virginioa with 2.8, T. maritima with 1.8 and C. lyngbyei showing the least success with a rank of 1.1 (see Table 8 for rank c h a r a c t e r i s t i c s ) . Placing each station in perspective "10N" was most successful with an average rating of 4.2, "10S" with 2.6, "8N" with 1.6 and "8S" with 0.6. Substrate c h a r a c t e r i s t i c s and nutrient l i m i t a t i o n s were not explored, but tide levels and s a l i n i t y values indicate that a high i n t e r t i d a l brackish zone is more e a s i l y colonized than high i n t e r t i d a l high s a l i n i t y or both low t i d a l locations. In this context i t should be noted that "8S" was the least favorable location for plant growth in any species. In summary i t may be stated that: a) "10N" was the most successful transplant location, presumably because of the combined "high" elevation and low s a l i n i t y . The declining order of success by location was "10N", "8N", and "8S"; b) Sairpus maritimus must be deemed the most successful species having undergone a f o u r f o l d expansion in two years of growth (at "10N") while t o l e r a t -ing conditions at a l l s i t e s to varying degrees; c) Salioorniz virginioa was the next again with the greatest success obtained at "10N" but growth occurred at a l l other stations; d) Carex lyngbyei did well at "10N" but did not survive at any other location; and e) Triglochin maritima did well in the f i r s t year - 1 1 5 -at both "10S" and "ION" l o c a t i o n s but had d e c l i n e d considerably by the spring of 1978. - 116 -8. HISTORICAL CHANGES OF THE BRUNSWICK POINT MARSH H i s t o r i c a l charts and a e r i a l photographs were used to assess the changes o c c u r r i n g in the Brunswick P o i n t area from 1827 to date. These changes are im-portant in determining successional patterns and p r e d i c t i n g responses to habi-t a t m o d i f i c a t i o n s . The foreshore environment may seem s t a t i c in terms of a human l i f e span but in terms of g e o l o g i c a l h i s t o r y i s a c t u a l l y a very dynamic system. A hydrographic chart (Figure 39) d e p i c t s the l o c a t i o n of the Main Arm of the Fraser River as i t was in 1827. The South Channel flowed south then east and e v e n t u a l l y emerged f a r south of the present Canoe Pass. The emergence of the South Channel at t h i s l o c a t i o n may have been important to the establishment of the Tsawwassen S a l t marsh. By 1860 (Figure 40) the South Channel had a l t e r e d i t s course and assumed the present l o c a t i o n of Canoe Pass. Marshes are not i n d i -cated in these c h a r t s , however, i f the foreshore of Westham Island as shown in 1827 (Figure 39) did have a marsh bordering i t , then the flow of Canoe Pass would have cut through the foreshore marsh separating i t into the Westham Island and the Brunswick Point marshes. The e a r l i e s t a v a i l a b l e a e r i a l photography f o r the study area (Figure 40 and 41, 1932) i n d i c a t e s that an area of marsh which appeared to 1ie on a l i n e w i t h the former s h o r e l i n e of the large Westham Island had been dyked. Brunswick Cannery (to be used as a reference point) had been e s t a b l i s h e d at the edge of the marsh. The areal extent of Brunswick Point marsh in 1932 was ~Jk ha of which Carex lyngbyei occupied 21 ha (see Figure 43, 1975 f o r comparison). S. maritimus appeared to be c o l o n i z i n g an embayment immediately to the south east of the marsh. By 1938 l i t t l e change had taken place (Figure 42) in the a r e a l ex-tent or d i s t r i b u t i o n of marsh species. By 1948 a sand bar, roughly 90 ha in area had appeared west of the marsh (Figure 42), p o s s i b l y as a r e s u l t of the 1948 f l o o d (Al Tamburi pers. comm.). - 1.17 -Figure 39: Hydrographic chart dated 1827, showing the main arm of the Fraser River. - 118 -8 •r. IT i. v r. v. o u c i A Figure kO: Hydrographic chart dated 1860, showing the main arm of the Fraser River. - 120 -- 121 -41: Photo number A4527 (29) Figure 42: Photo number A5984 (21) dated September, 1932. dated June, 1938. Brunswick Cannery i s i n - Brunswick Cannery i s i n -dicate d by a white dot. dicat e d by a white dot. Figure 43: Photo number A37170 dated June, 1975- Brunswick Cannery i s in d i c a t e d by a black dot. - 123 -Although no vegetation had c o l o n i z e d the area the shape was very s i m i l a r to the vegetated area of the Brunswick Point marsh in 1969 (Figure 45) • By 19^8, f u r t h e r dyking of the high marsh area had occurred, but marsh expansion between 1938 and 1948 had r e s u l t e d in a net increase of 2 ha. Much of t h i s growth had occurred i n the aforementioned embayment as a r e s u l t of S. maritimus expansion. Carex lyngbyei had ret r e a t e d in an area south east , of the new dyke; the dyking probably r e s u l t e d in higher s a l i n i t i e s and lower sediment and n u t r i e n t s u p p l i e s to the area, c r e a t i n g an unfavorable h a b i t a t f o r C. lyngbyrei. An oblique photo (Figure 46) of the sand bar area at the f o r e f r o n t of the Brunswick Point marsh in 1949 shows the area s t i l l unvegetated; a s i m i l a r photo (Figure hi) taken in 1976 shows the sand bar covered w i t h predominantly S. ameriaanus. By 1966 the marsh had assumed i t s present shape (Photos taken between 1949 and 1966 are e i t h e r at too high water or not a v a i l a b l e ) . The S. ameriaanus community formed on the 1948 sand bar appears to have been g r a d u a l l y extending southward; the 1976 extent of the marsh was approximately 170 ha (Figure 2. - 124 -F igure 44: Photo number X156C (19) dated June 5, 1948. F igure 45: Photo number 39422B ( P a c i f i c Survey Corporat ion) dated 26 J u l y , 1969. - 125 -- 1?6; -Figure 46: Photo number BC 822 (29) dated June 20, 1949. \ Figure 47: Photo taken August 26, 1976. - 128 -9. SUCCESSION Although the environmental f a c t o r s c o n t r o l l i n g the marsh are very complex, the basic ones a f f e c t i n g marsh succession are probably the depth of water and the lack of a e r a t i o n ; the successional trend i s towards the accumula-t i o n of sediment, r a i s i n g the s o i l to a higher l e v e l in the t i d a l range, and e v e n t u a l l y lowering the water t a b l e . Competition is one of the key f a c t o r s o f succession. The process of succession begins when a pioneer species i s able to c o l o n i z e a bare substrate. In the t i d a l marsh area, a pioneer must be able to t o l e r a t e a mobile, f r e q u e n t l y innundated h a b i t a t . S a l i n i t y i s q u i t e v a r i a b l e in the b r a c k i s h envionment and along with the type of s u b s t r a t e , whether sand or s i l t , is probably a prime determinant in the establishment of pioneer species. Once the pioneer species has e s t a b l i s h e d , i t a l t e r s the environment; water movements are slowed down r e s u l t i n g in increased s i l t d e p o s i t i o n ; organic matter is added to the " s o i l " ; temperature extremes are attenuated; evaporation is decreased. The modified environment permits the establishment of other species which are probably bet t e r adapted to the environment than the o r i g i n a l c o l o n i z e r . As observed by Chapman (1974), the marshes on the P a c i f i c Coast of North America have very simple successions. This i s p a r t i c u l a r l y true in the case of the Fraser River d e l t a marshes which have been subject to extensive dyking of mature marsh areas and hence only have pioneer and b u i l d i n g stages present w i t h t h e i r rather l i m i t e d f l o r i s t i c components. The pioneer species along the foreshore are u s u a l l y ' Sairpus maritimus and Sairpus ameriaanus; / Sairpus maritimus occurs in sparse monotypic stands on very s i l t y s u b s t r a t e s , w h i l e Sairpus ameriaanus is u s u a l l y found on sandy substrates in f a i r l y dense monotypic stands. An examination of cores obtained from various communities in the Fraser area (Moody and Luternauer, in preparation) revealed that Sairpus - 129 -ameriaanus had in a l l instances c o l o n i z e d on sandy s u b s t r a t e s . Deposited s e d i -ments i n the e s t a b l i s h e d Sairpus ameriaanus community were mainly comprised of s i l t s and oft e n there was a change in species to Sairpus maritimus a f t e r the dep o s i t i o n o f s i l t s . The dynamic nature of these c o l o n i z e r s was revealed in the frequent instances of one species present in one l a y e r , being "overtopped" by the other species only to return to the o r i g i n a l species again. J e f f e r s o n (1975) developed an elaborate scheme of succession f o r Oregon coastal s a l t marshes (Figure 48) while many p a r a l l e l s occur between B r i t i s h Columbia and Oregon marshes, they are d i f f i c u l t to compare p r i m a r i l y be-cause vegetation d i s t r i b u t i o n i s so i n t i m a t e l y t i e d to t i d a l r e l a t i o n s h i p s and no real basis of comparison e x i s t s (Section 4.1) between t i d e s at various l o c a -t i o n s . J e f f e r s o n d i f f e r e n t i a t e d between those communities formed on s i l t s and those formed on sands, although the patterns are s i m i l a r to those of the Fraser marshes, J e f f e r s o n noted that Sairpus validus was a successor to C. lyngbyei. In the Fraser foreshore marshes, S. validus i s very o f t e n found among S. :. r ' ameriaanus communities in s i l t y patches which develop a f t e r the community p i o -neers on sand (Moody and Luternauer, in p e r p a r a t i o n ) . The d i s t r i b u t i o n of S. validus seemed to be r e s t r i c t e d to areas with a heavy i n f l u x of f r e s h water and a low e l e v a t i o n . S i m i l a r l y T. latifolia occurred in large patches along the Fraser River foreshore, in areas with f r e s h water i n f l u x but occurred only in small patches amid other marsh species as remnant patches or p o s s i b l y in re-sponse to ground water discharge in some areas. An important r o l e in the succession of the Fraser foreshore marshes i s played by Triglochin maritima; i t ' o f t e n occurs amid S. maritimus stands forming elevated hummocks which coalesce and e v e n t u a l l y e l i m i n a t e the S. maritimus com-munity. (See 4.4) P i t s dug in a S. maritimus, T. maritima mixture (Figure 14, Section 4.4) i n d i c a t e d that areas which appeared to be S. maritimus at the surface had T. maritima roots in the deeper l a y e r s . These roots o r i g i n a t e d in the T. maritima mounds and had spread to the S. maritimus hollows. T. maritima - 130 -Figure 48: Species succession in Oregon coastal s a l t marshes (from J e f f e r s o n 1975: p. 85). Cl«dophoro fucua ( T N S I M M e f t « S I L T ) Kuppta Cy«nophyta rtnellla Triglochin y-» Sal I C Q mi a >DlstlcMt«  Jaurnea — fuccoid© Spcrgularla nacrotheca Sclrpus cernum  J u n c u s bufonlua Triglochin . — — » pvirltimma Triglochin concinnum Sclrpua aawrlcanoa flantago -y> Claim Orthocarpua Lllaaopsla Carex Trlfpllvm Peachampala \ Grindclia \ Potcntilla \ Juncua * \ ^ . \ , Elmus Poa _____ Car ax obnupta 6WAKP OR fORLST SAHD DUKES Oft DCTI>TZOM PLAIN - 132 -showed a great c a p a c i t y f o r e l e v a t i n g the marsh surface by a large b u i l d up of roots i n the surface sediment l a y e r s . The evidence from the t r a n s p l a n t e x p e r i -ments (Section 7) suggests that S. maritimus i s more t o l e r a n t of inundated con-d i t i o n s than T. maritima; the b u i l d up of sediments by T. maritima roots creates an environment in which T. maritima can s u c c e s s f u l l y compete with S. maritimus. Remnants of T. maritima stands are oft e n found w i t h i n t h e C . lyngbyei community. P i t s dug i n the C. lyngbyei a l s o i n d i c a t e d p o r t i o n s of T. maritima roots below the C. lyngbyei roots. From t h i s evidence i t may be deduced that T. maritima is indeed a forerunner to the C. lyngbyei community. J e f f e r s o n (1975) observed that t h i s p a t t e r n d i d occur in Oregon as a po r t i o n of the much more complex suc-ce s s i o n a l scheme (Figure 48). ; j E i l e r s d i v i d e d the Nehalem marsh (Oregon) i n t o four zones; the edge marsh, which had an a c t i v e l y s h i f t i n g margin (occurred up to approximately the 3.00 l e v e l when co n s i d e r i n g the t i d e regime of the F r a s e r ) , the low marsh, 3-00 to 3-35, the t r a n s i t i o n a l marsh 3-35 to 3.75 m, and the high marsh 3-75 to 4.08 In the study of Brunswick P o i n t , i t was noted that S. ameriaanus and S. maritimus occurred up to approximately the 3-00 m t i d e l e v e l ( i n some cases extending f u r -t h e r ) ; C.lyngbyei became dominant from 3-00 m to 3-35 m in the low marsh and had mixtures of other species in the t r a n s i t i o n a l marsh at 3-35 to 3-75 m (using the d i v i s i o n s of E i l e r s 1975)- The zones determined by Burgess (1970) in general agree with these d i v i s i o n s (Section 3.4). A l l high marsh areas in the Brunswick Point area are now a g r i c u l t u r a l land, located east of the dyke. A summary of successional r e l a t i o n s h i p s i s presented in Figure 49 - 57-m m. - 133 -In the southern Fraser Delta foreshore the succession of marsh vege-t a t i o n can be depicted as f o l l o w s : Figure kj: Blue green algae c o l o n i z e the t i d e f l a t s , o ften forming a s o l i d carpet of vegetation which e f f e c t i v e l y binds the surface sediments together. Figure 50: Sairpus maritimus, a pioneer vascular p l a n t , i s able to c o l o n i z e the s t a b l i z e d mud f l a t , e i t h e r by seed or by v e g e t a t i v e expansion. Following establishment i s a per-iod of f a i r l y rapid v e g e t a t i v e growth which r e s u l t s in a patchy d i s t r i b u t i o n of the c o l o n i z e r s . ( - 135 -Figure 51: Sairpus ameriaanus a l s o occurs as a c o l o n i z e r but i s more ofte n found on sandy substrates. Figure 52: C o l o n i z a t i o n can a l s o occur as the r e s u l t of " r a f t i n g " of e s t a b l i s h e d material which has broken away from the edge of a drainage channel or the f r o n t of the marsh. - 136 - 137 -Figure 53: A c h a r a c t e r i s t i c pattern of t i d a l f l a t c o l o n i z a t i o n i s a contagious'series of clumps which e v e n t u a l l y coalesce. Figure 54: The clumped pattern i s apparent in the Triglochin maritima community i n which T. maritima occurs as elevated c1umps while Scirpus maritimus f i l l s in the hollows between. The T. maritima hummocks eve n t u a l l y coalesce to form a higher marsh sur-face, up to 15 cm above the pioneer community. The photograph d e p i c t s t h i s community p r i o r to spring growth. - 138 -- 139 -Figure 55: The raising of the marsh surface serves to decrease the period of inundation. The vegetation draws water from the substrate and this,°combined with evaporation, results in a drying of the substrate. - 140 -- 141 -Figure 56: Marshes are dynamic systems. The photograph depicts a C. lyngbyei community which had i t s ha b i t a t a l t e r e d by dyking p r i o r to 1948 (see Section 8). Only remnant clumps of C. lyngbyei remain and erosion i s g r a d u a l l y e l i m i n a t i n g those. Figure 57: A healthy C. lyngbyei community, in contrast to the degrading one described above, has a uniform marsh surface, drained by deeply i n c i s e d t i d a l channels. - ]k2 -- 143 -10. SUMMARY AND CONCLUSIONS Spec i f i c features of. the.marsh environment, higher plant pro-duct i on. and hab i t a t have been discussed in each s e c t i o n . It i s d i f f i c u l t to place so many v a r i a b l e s in pe r s p e c t i v e ; however, a general understanding of how such a marsh system func t i o n s and what the pe r t i n e n t v a r i a b l e s are is e s s e n t i a l before proceeding to more d e t a t a i l e d s t u d i e s . A d e t a t i l e d inves-t i g a t i o n - of the ways in which these f a c t o r s , i n t e r a c t with the vegetation was beyond the scope of t h i s study. Brunswick Point marsh i s a brackish.marsh subject to both t i d a l inundation and r i v e r discharge. The d i s t r i b u t i o n of vegetation responds to these i n f l u e n c e s in that each species i s l i m i t e d in i t s lower extent by the amount of inundation i t is able to t o l e r a t e . T i d a l inundation, combined w i t h s i l t laden r i v e r flows may reduce the photosynthetic p o t e n t i a l of plants o c c u r r i n g low in the i n t e r t i d a l zone. The upper extent of the marshes on the Fraser River foreshore is l i m i t e d by the extent of dyking; the high marsh areas which in Oregon E i l e r s (l975)found to be most productive have, in the Fraser Delta been converted to a g r i c u l t u r a l land. The high marsh areas are s i g n i f i c a n t in the development of the marsh into a t e r r e s t r i a l system as organic material i s incorporated into the su b s t r a t e ; in the low marsh areas most of the production is exported into the estuary ( E i l e r s , 1975)-, The observations and r e s u l t s from the d e t r i t a l aspects of t h i s study i n d i c a t e there i s a slow release of n u t r i e n t s from the marsh; each species c o n t r i b u t e s at i t s own rate. S o f t , f l e s h y stemmed vegetation such as T. maritima, S. ameriaanus, and S. virginioa breaks down r e a d i l y and disappears r a p i d l y from the marsh surface; more r e s i s t a n t s pecies, such as C. lyngbyei and S. maritimus o f f e r a slower release of n u t r i e n t s which are a v a i l a b l e when the e a s i l y degraded m a t e r i a l s have been used up. - 144 -T r a n s p l a n t a t i o n studies and h i s t o r i c a l and present observations i n d i c a t e that a simple succession occurs in the Fraser River foreshore emer-gent marshes where percursors such as S. maritimus or S. ameriaanus, a l t e r t h e i r h a b i t a t s enough, to a l l o w a more complex marsh f l o r a such as S. validus, T. maritima, C. lyngbyei, and Potentilla paaifioa to grow. The marsh is a s e n s i t i v e system as can be seen from rapid changes o c c u r r i n g after, minor environmental m o d i f i c a t i o n s . In conclusion i t may be stated that,a 1 though s i g n i f i c a n t m o d i f i c a t i o n of the Fraser River foreshore marshes has occurred, those areas of the marsh which c o n t r i b u t e most s i g n i f i -c a n t l y to the e s t u a r i n e system are v i r t u a l l y i n t a c t and r a r e expanding. The major conclusions of t h i s study may be summarized as f o l l o w s : 1. Marsh e l e v a t i o n s in r e l a t i o n s to t i d e s played an important r o l e in vege-t a t i o n d i s t r i but ion ; 1 i t t l e ;p;l ant growth occurred below the 2.82 m (above chart datum) l e v e l in the main po r t i o n of the Brunswick Point marsh. '.Carex lyngbyei became dominant at the 3-05 m level'and graded i n t o a mixed community at the 3-35 m l e v e l . The upper l i m i t of marsh growth i s l i m i t e d by dyking. 2. T h e F r a s e r River moderates s a l i n i t y in the Brunswick Point marsh; lowest s a l i n i t i e s occur during f r e s h e t . S a l i n i t y i s influenced by the density of vegetation probably as a r e s u l t of reduced temperatures and evapora-t i o n in densely vegetated areas. 3. The peak aboveground phytomass averaged over a l l s i t e s , f o r each species was: Carex lyngbyei 909 g/m^ Sairpus ameriaanus 397 g/m2 Sairpus maritimus 565 g/m^ - 145 -4; C. lyngbyei_ occurring near the river and drainage channels^exper ienced the most rapid growth in spring reaching an-apparent peak in July and declining thereafter. 5- Standing crops increased as elevation increased for both Carex lyngbyei and Sairpus maritimus. 6. The number of reproductive shoots in C. lyngbyei decreased as elevation increased. 7. Shoot density, for C. lyngbyei was negatively associated with distance from the river. Nitrogen content for all species reached a peak in May with an overall mean of 2.75 percent. The growth rate of Carex lyngbyei was very high at a l l stations in the Brunswick Point marsh; the values were comparable to those of the Squamish River Delta marshes. 10. Of the four species tested T.. maritimus decomposed most rapidly in l i t t e r bags . 11. C. lyngbyei was least readily decomposed but had the highest gammarid am-phipod counts of a l l the plant species enclosed in l i t t e r bags. 12. Laboratory conditions confirmed the relative decomposition rates of T. maritima, C. lyngbyei, and S. maritimus as determined by l i t t e r bags. 8. 9--13- Sairpus maritimus was the species which best survived t r a n s p l a n t i n g under the c o n d i t i o n s of the t r i a l s . 14. A r e l a t i v e l y high e l e v a t i o n s i t e w i t h low ambient s a l i n i t i e s was most con-dusive to tra n s p l a n t success. 15- A e r i a l photographs and hydrographic charts i n d i c a t e that the Brunswick Point marsh has undergone a s e r i e s of dramatic changes over the past 150 years,and has more than doubled in areal extent during the past 50 years. 16. A simple pattern of succession occurs in the Brunswick Poin,t marshes with S. amer%aanus and S. mar%t%mus o c c u r r i n g as precu r s o r s , followed by -T. maritima and C. lyngbyei. - 147 -BIBLIOGRAPHY Becker, R.E., 1971. An e c o l o g i c a l perspective of the Fraser River Delta foreshore. M.Sc. essay, Dept. Plant Science, U.B.C. Benedict, A.H.; K.J. H a l l £• F.A. Koch, 1973- P r e l i m i n a r y water q u a l i t y survey of the lower Fraser River system. Westwater Research Centre. Tech:. Rept. (2) . Bernard, J.M., 1973. Production ecology of wetland sedges: the genus Carex. P o l . Arch. Hydrobiol. 20:207-214. Bernard, J.M.,-1974. Seasonal Changes in standing crop and primary production in a sedge wetland and an adjacent dry o l d - f i e l d i n c e n t r a l Minnesota. Ecology 55:350-359-Blunden, R.H., 1973. Urban geology o f Richmond, B.C. Dept. Geol. S c i . U.B.C. Rept... (15). 13 pp and f i g u r e s . Burkholder, P.R. £ G.H. Bornside, 1957. Decomposition of marsh grass by aerobic marine b a c t e r i a . Burgess, T.E., 1970. Food and ha b i t a t of four a n a t i n i d s w i n t e r i n g on the Fraser d e l t a t i d a l marshes. M. Sc. . thes i s , Dept. of Zoology, U.B.C, 124 pp. Burton, B.A., 1977- Ecology of Lesser Snow Geese Wintering on the Fraser River Delta T i d a l Marshes. M.Sc. t h e s i s , Dept. of Animal Science, U n i v e r s i t y of B.C. Chapman, V.J., 1934. The ecology of Sc o l t Head Island. The Norfolk and Norwich N a t u r a l i s t s ' S o c i e t y . Norwich. Chapman, V.J., 1938. Studies in s a l t marsh ecology l - l I I. J . Ec o l . 26: 144-179-Chapman, V.J., 1939- Studies in s a l t marsh ecology IV-V. J . E c o l . 27: 160-201. Chapman, V.J., I960. S a l t Marshes and S a l t Deserts of the World. London, Leonard H i l l , 392 p. Chapman, V.J., 1974. S a l t Marshes and S a l t Deserts of the World, p. 3-19 in Reimold, F.J. & W.H. Queen (eds) Ecology of Halophytes. Academic Press, Inc. Clausen, J . , D.D. Keck & W.M. Hiesey, 1940. Experimental studies on the var i e d environments on western North American p l a n t s . Publ . Carneg. Instn. #564. -•148 -Clausen, J . , D.D. Keck & W.M. Hiesey, 1948. Experimental studies on the nature of species 111. Environmental responses of c l i m a t i c races of Achillea. Carnegie Inst. Washington Pub. No. 581, 129 pp. Conrad, H.S. , 1935. The plant a s s o c i a t i o n s of c e n t r a l Long Island. Amer. Midland Natur. 16:433-516. de l a Cruz, A.A. 196-5. A Study of P a r t i c u l a t e Organic D e t r i t u s in a Georgia S a l t Marsh Estuarine Ecosystem. U n i v e r s i t y of Georgia, Ph.D. 1965. de l a Cruz, A.A. & B.C. Gabriel , 1974.- C a l o r i c , elemental & n u t r i t u v e changes in decomposing Juncus voemerianus leaves. Ecology 55(4) 882-886. de l a Cruz, Armando, 1975- P r o x i m a t e " n u t r i t i v e value changes during decomposition of s a l t marsh p l a n t s . Hydro b i o l o g i a 47. D a r n e l l , R. , 1967- The organic d e t r i t u s problem. Pages 374-375 i n : G.H. Lauff (ed.), E s t u a r i e s . Washington, D.C. Assoc. f o r the Advance-ment of Sci ence. Dredged M a t e r i a l Research. 1976. V o l . D-76-7. U.S. Army Corps of Engineers. Information Exchange B u l l e t i n . E i l e r s , H.P.,1975- P l a n t s , plant communities, net production and t i d e l e v e l s : the e c o l o g i c a l biogeography of the Nehalem s a l t marshes, Tillamook County, Oregon. Ph.D. T h e s i s , Oregon State U n i v e r s i t y . 368 pp. Fenchel , T., 1970. Studies on the Decomposition of organic d e t r i t u s derived from the t u r t l e grass, Thalassia testudinum. Limnology & Oceanog. 15(0:14-20. Fenchel, T. & P. H a r r i s o n , 1976. The s i g n i f i c a n c e of b a c t e r i a l grazing and mineral c y c l i n g f o r the decomposition of p a r t i c u l a t e d e t r i t u s , pp. 285-299 i n : Anderson, J.N. £ A. Macfadyen (eds) The Role of T e r r e s t r i a l , and Aquatic Organisms in Decomposition Processes. Blackwell S c i . Publ. London, 1976. Forbes, R.D., 1972. A f l o r a l d e s c r i p t i o n of the Fraser River estuary and Boundary and Mud Bays, B.C. B.C. Dept. Rec. S Cons. Fish & W i l d l i f e Branch. 94 pp. Gagnong, W.F., 1903. The vegetation of the Bay of Fundy s a l t and diked marshes: an e c o l o g i c a l study. Bot. Gaz. 36. Gates, B.R., 1967. The status of wetland reserves in the lower mainland of B.C. B.C. Fi s h and W i l d l i f e Branch Report. Ginsburg, R.N. and Lowenstam, H.A., 1958. The inf l u e n c e of marine bottom communities on the depositiona1 environment of sediments. J . Geol., 66, 310-318. - \ks -Good, R.E., 1972. S a l t marsh production and s a l i n i t y . B u l l . E c o l . Soc. Amer. 53:22. F i s h e r i e s Nanaimo. Gorham, E., 1974. The r e l a t i o n s h i p between standing crop in sedge meadows and summer temperature. J . of Ecology 62 (2) : 487-^91. Gosselink, J.G. & C . J . K i r b y , 1974. Decomposition of s a l t marsh grass, Spartina alterniflora L o i s e l . Limnol. 6 Oceanogr. 19(5) :825-832. Halladay, D.R., 1968. Avian ecology as i t r e l a t e s to the b i r d hazard problem at Vancouver A i r p o r t . M.Sc. The s i s , Dept. Plant Science, U.B.C. H a r r i s , R.D. & E.W. T a y l o r , 1973- Human impact on es t u a r i n e h a b i t a t . Canadian Wi1d1ife S e r v i c e , D e l t a , B.C. Harr i s o n , P.G. & K.H. Mann, 1975. D e t r i t u s formation from eelgrass (Zostera marina L) : The r e l a t i v e e f f e c t s of fragmentation, leaching and decay. Limnology & 0ceanography:20 (6):924~934. Heslop-Harrison, J . , 1964. Forty Years of Genecology. Advances in Ec o l o g i c a l Research (2 ) :159-247. H i l l a l e y , F.B. & D.T. B a r r e t t , 1976. Vegetation communities of a Fraser River s a l t marsh. Environment Canada, F i s h e r i e s and Marine S e r v i c e . Technical Report Series No. Pac/T -76 - l4 . Hinde, H.P., 1954. V e r t i c a l d i s t r i b u t i o n of s a l t marsh phanerogams in r e l a t i o n to t i d e l e v e l s . E c o l . Monog. 24 , 209-225. Hoos, L.M. £ G.A. Packman. The Fraser River Estuary Status of Environ-mental Knowledge to 1974. Special Estuary Series No. 1, Environment Canada. J e f f e r s o n , C.A., 1975. Plant communities and succession in Oregon coastal s a l t marshes. Oregon State U n i v e r s i t y , Ph.D., Ecology. J e f f r i e s , R.L., 1971. Aspects of Salt-Marsh Ecology with P a r t i c u l a r Reference to Inorganic Plant N u t r i t i o n . In: The Estuarine Environment. Barnes, R.S.K. & J . Green, 1971. Applied Science P u b l i s h e r s . J e r v i s , R.A., 1969- Primary production i n the freshwater marsh ecosystems of Troy Meadows, New Jersey. B u l l . Torrey Bot. Club, 96:209-231. Johnson, Duncan S. & Harlan H. York, 1915. The Re l a t i o n of Plants to t i d e l e v e l . Carnegie I n s t i t . of Washington. Keefe, C.W., 1972. Marsh Production: A Summary of the L i t e r a t u r e . C o n t r i b u t i o n s in Marine Science I 6 : l63~ l8 l . K e l l e r h a l l s , P. S J.W. Murray, 1969- T i d a l F l a t s at Boundary Bay, Fraser River D e l t a , B.C. B u l l , of Canadian Petroleum Geo. Vol 17 :67-91. - 150 -Levings, CD. & A. I . Moody, 1976. Studies of i n t e r t i dal vascular p l a n t s , e s p e c i a l l y sedge (Carex lyngbyei) on the disrupted Squamish River d e l t a , B r i t i s h Columbia. F i s h . Res. Bd. Can. Technical Rept. No. 6 0 6 , 5 1 pp. L e v i t t , J . , 1972. Responses of Plants to Environmental Stresses. Academic Press, New York. Lomnicki, A., E. Bandia £ K. Jankowska, 1968. M o d i f i c a t i o n of the Wiegeot -Evans method f o r es t i m a t i o n of net primary production. Ecology 4 9 : 1 4 7 - 1 4 9 . Luternauer, J.L., 1974. Geology Section i n r Hoos,L.M. £ G.A. Packman, 1974. The Fraser River Estuary Status of Knowledge to 1974. Luternauer, J . L . , £ J . Murray, 1973- Sedimentation on the western d e l t a -fr o n t of the Fraser R i v e r , B.C. Can. J . Earth S c i . 1 0 ( 1 1 ) : 1 6 4 2 - 1 6 6 3 . MacDonald, K.B. £ M.G. Barbour, 1974. Beach and s a l t marsh vegetation of the North American P a c i f i c Coast. In: Reimold, R.J. £ W.H. Queen, 1974. Biology of Halophytes. Academic Press, N.Y. 605 pp. McNaughton, S.J. , 1974. Developmental Control of net p r o d u c t i v i t y in Typha l a t i f o l i a ecotypes. Ecology 5 5 ( 4 ) . p. 8 6 4 - 8 6 9 . McLaren, K.A., 1972. A vegetation study of the is l a n d s and associated marshes in the south arm of the Fraser R i v e r , B.C. from the Deas Island Tunnel to the Wesham Island foreshore. Fish and W i l d l i f e Branch, B.C. Dept. of Rec. and Cons., V i c t o r i a , B.C. Mann, K.H., 1976. Decomposition of Marine Macrophytes. p. 2 4 7 - 2 6 7 In: Anderson, J.M. £ A. Macfadyen (eds.). The Role of T e r r e s t r i a l and Aquatic Organisms in Decomposition Processes. Blackwell S c i e n t i f i c P u b l i c a t i o n s , Oxford, London, Edinburgh, Melbourne. Mathews, W.H. £ F.P. Shepard, 1962. Sedimentation of the Fraser River d e l t a , B.C. B u l l . Amer. Assoc. P e t r o l . Geol. 4 6 ( 8 ) : 1 4 1 6 - 1 4 3 8 . Mathews, W.H., J . G . Fyles £ H.W. Nasmith, 1970. P o s t - g l a c i a l c r u s t a l movements in southwestern B r i t i s h Columbia and adjacent Washington St a t e . Can. J . Earth S c i . 7 ( 2 ) : 6 9 0 - 7 0 2 . Medley, E. & J . L . Luternauer, 1976. Use of a e r i a l photographs to map sediment d i s t r i b u t i o n and to i d e n t i f y h i s t o r i c a l changes on a t i d a l f l a t . Geol. Surv. Can. Paper 7 6 - l c . Moody, A.I. £ J.L. Luternauer, 1978. Plant Sediment R e l a t i o n s Along the Fraser River Foreshore. ( i n preparation) Mooring, M.T., A.W. Cooper £ E.D. Seneca, 1971 . Seed germination response and evidence f o r heigh ecophenes in Spartina a l t e r n i f l o r a from North C a r o l i n a . Amer. J . Bot. 5 8 : 4 8 - 5 5 . - 151 -Newell, R. , 1965- The role of d e t r i t u s in the n u t r i t i o n of two marine deposit feeders, the prosobranch• Hydrobia ulvae and the b i v a l v e Maaoma ' -balttaa. Proc. Zool. Soc. London 144(1) :25-45 . N i c h o l s , G.E., 1920. The vegetation o f Connecticut. V I I . The a s s o c i a -t i o n s of de p o s i t i n g areas along the seacoast. Torrey Bot. Club B u l l . 47:511 -548. Northcote, T.G., 1974. Biology of the lower Fraser R i v e r : a review. Westwater Research Centre Tech. Rept. ( 3 ) . 94 pp. Odum, E.P., 1961. The r o l e of t i d a l marshes in es t u a r i n e production. The C o n s e r v a t i o n i s t 15 :12 -13. Odum, E.P., 1963. Ecology. New York, Holt Rinchart and Winston, 152 pp. Odum, E.P. & Cruz, A.A. de l a , 1967. P a r t i c u l a t e organic d e t r i t u s in a Georgia s a l t marsh - e s t u a r i n e ecosystem. E s t u a r i e s . Publ. No. 83 . American Assoc. f o r the Advancement of Science, Washington, 383-388. Odum, E.P. & A.E. Smalley, 1959. Comparison of population energy flow of a herbivorous ad dep o s i t - f e e d i n g i n v e r t e b r a t e in a s a l t marsh ecosystem. Proc. Natn. Acad. S c i . , U.S.A., 45, 617-622. Odum, W.E., J.C. Zieman & E.J. Heald, 1972. The importance of vas c u l a r p l a n t d e t r i t u s to e s t u a r i e s , p. 9 1 - l l 4 , i n : R. Chabuck (ed.) Proc. Coastal Marsh £ Estuary Management Symp. Louisiana State Univ. Baton Rouge. Parsons, CO., 1975. Vegetation pattern in a s a l t marsh at Boundary Bay, B.C. Lambda 1 (2) :45-52-. Pearson, 1972. Fraser River Development Study. Penfound, W.T. & Hathaway, E.S., 1938. P l a n t Communities in the Marshlands of Southern L o u i s i a n a . E c o l . Monog., 8 :1 -56 . Pestrong; R., 1965. The development of drainage patterns on t i d a l marshes. Stanford U n i v e r s i t y P u b l i c a t i o n s in the Geological Sciences, V o l . 10, No. 2 , 87 pp. Pestrong, Raymond, 1972. T i d a l - f l a t sedimentation at Cooley Landing, Southwest San Francisco Bya. Sediment. Geol., 8 :251-288. P i c k a r d , G.L., 1970. D e s c r i p t i v e P h y s i c a l Oceanography. Pomeroy, W.M., 1977. Benthic A l g a l Ecology and Primary Pathways of Energy Flow on the Squamish River d e l t a , B r i t i s h Columbia. Ph.D. Thesis, U.B.C Dept. of Botany. - 152 -P u r e r , E.A., 1942. P l a n t e c o l o g y o f t h e c o a s t a l s a l t marshes o f San Diego County C a l i f . E c o l . Monog., 12, 81-111. R a n w e l l , D.S., 1967- World r e s o u r c e s o f Spartina townsendii (Seno Lato) and economic use o f Spartina m a r s h l a n d . J . E c o l . , 55:239-256. R e d f i e l d , A . C , 1971. Development o f a New England S a l t Marsh. E c o l . Monog., 42, #2, p 201-237. Reed, J . F . , 1947- The r e l a t i o n o f the Spartiniturn glabrae near B e a u f o r t , N o r t h C a r o l i n a t o c e r t a i n e d a p h i c f a c t o r s . Amer. M i d i . Nat. 28:605-14. S c u l t h o r p e , C D . , 1967. The b i o l o g y o f a q u a t i c v a s c u l a r p l a n t s . Edward A r n o l d L t d . , London. Sencea, E.D., 1974. S t a b i l i z a t i o n o f C o a s t a l Dredge S p o i l w i t h Spartina a l t e r n i f l o r a i n : R e i m o l d , F . J . & W.H. Queen ( e d s . ) , 1974. E c o l o g y o f Ha l o p h y t e s . Academic P r e s s , Inc. S m a l l e y , A.E.- 1959- The r o l e o f two i n v e r t e b r a t e p o p u l a t i o n s Littorina irrorata and Orchelimwm fidicinium i n the energy f l o w o f a s a l t marsh eco s y s t e m . Ph . D. t'hes.i s Un i v. G e o r g i a r e f e r e n c e d i n L i m n o l . S Oceanogr. 19(5) p 832. S t a l t e r , R. S Wade T. B a t s o n , I969. T r a n s p l a n t a t i o n o f S a l t Marsh V e g e t a -t i o n , Georgetown, South C a r o l i n a . E c o l o g y 50(6), I987-IO89. T a b a t a , S., 1972. The movement o f F r a s e r R i v e r i n f l u e n c e d s u r f a c e w a t e r i n t he S t r a i t o f G e o r g i a as deduced from a s e r i e s o f a e r i a l p h o t o g r a p h s . Mar. S c i . D i r e c t , Pac. Reg. Rept. (72-6) 69 pp. T a y l o r , E.W., 1974. The Vancouver I n t e r n a t i o n a l A i r p o r t E x p a n s i o n P r o p o s a l s and P o s s i b l e Impact on W i l d l i f e o f t h e F r a s e r R i v e r E s t u a r y . Canadian W i l d l i f e S e r v i c e R e p o r t , D e l t a , B.C. T e a l , J.M., 1962. Energy f l o w i n t h e s a l t marsh e c o s y s t e m o f G e o r g i a . E c o l o g y 43:614-624. T e a l , J.M. & Kanwisher, J.W., 1970. T o t a l energy b a l a n c e i n s a l t marsh g r a s s e s . E c o l o g y V o l . 51 #4, p. 690-695. T u r n e r , R.E., 1976. G e o g r a p h i c v a r i a t i o n s i n s a l t marsh macrophyte p r o d u c t i o n : a r e v i e w . C o n t r . Mar. S c i . 20:47-68. T y l e r , G., 1971b. D i s t r i b u t i o n and t u r n o v e r o f o r g a n i c m a t t e r and m i n e r a l s i n a sh o r e meadow ec o s y s t e m . S t u d i e s i n the e c o l o g y o f B a l t i c s e a - s h o r e meadows. Oikos 22,3. 265-291. V a l i e l a , I. & J.M. T e a l , 1974. N u t r i e n t l i m i t a t i o n i n s a l t marsh v e g e t a t i o n , p. 547-563.in: R e i m o l d , R.J. & W.H. Queen, 1974. E c o l o g y o f H a l o p h y t e s , Academic P r e s s . - 153 -Vogl, R.J., 1966. Salt-marsh vegetation of Upper Newport Bay, C a l i f . Ecology 47:80-87. Wade, L. , 1972. Sturgeon Banks: an e c o l o g i c a l study. A report to Richmond Nature Park, 31 pp. Wais e l , Y. , 1972. Biology of Halophytes. Academic Press, New York. Waldichuck, M., I967. Currents from a e r i a l photography in coastal p o l l u -t i o n s t u d i e s . Advances in water pol1ution research. Proc. 3rd Intern. Conf. on Water P o l l u t i o n Res., Munich, Germany. Sept. 5 - 9, 1966. 3: 263-284. Water P o l l u t i o n Control Federation, Washington, D.C. Westlake, D.F., 1963. Comparisons of plant p r o d u c t i v i t y . Bio. Review. 38, 385-425. Westlake, D.F., 1965- Some basic data f o r i n v e s t i g a t i o n s of the product-i v i t y of aqu a t i c macrophytes. p. 229-248 i n : CR. Goldman (ed.) Primary p r o d u c t i v i t y in aquatic environments. Mem. 1st. I t a l . I d r o b i o l o . Univ. C a l i f , press, Berkley, C a l i f o r n i a . Wiegert, R.G. & F.C. Evans, 1964. Primary production and the disappearance of dead vegetation on an o l d f i e l d in southeastern Michigan. Ecology 45: 49-63. Wiegert, R.G. & J.T. McGinnis, 1975. Annual Production and Disappearance of D e t r i t u s on three South C a r o l i n a Old F i e l d s . Ecology 56:129-140. W i l k i n s , D.A., i960. Recognizing adaptive v a r i a n t s . Proc. Limn. Soc. London, Session 171, 122-126. Woodhouse, W.W. J r . , E.D. Seneca S S.W. Broome. Propagation of Spartina alterniftora f o r Substrate S t a b i l i z a t i o n and S a l t Marsh Development. Technical Memorandum No. 46, August 1974. U.S. Army, Corps, of Engineers, Coastal Engineering Research Centre, Kingman B u i l d i n g , Fort B e l v o i r , Va. 22060. Yamanaka, K., 1975. Primary p r o d u c t i v i t y of the Fraser River Delta f o r e -shore: y i e l d estimates of emergent v e g e t a t i o n . Unpubl. M.Sc. Thesis (Plant Science) U.B.C Zar, J.H., 1974. B i o s t a t i s t i c a l a n a l y s i s . P r e n t i c e - H a l l Inc., New Jersey. 620 pp. 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            data-media="{[{embed.selectedMedia}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
https://iiif.library.ubc.ca/presentation/dsp.831.1-0094285/manifest

Comment

Related Items