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Primary production of the Fraser River delta foreshore : yield estimates of emergent vegetation Yamanaka, Koji 1975

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PRIMARY PRODUCTIVITY OF' THE FRASER'RIVER DELTA FORESHORE YIELD ESTIMATES OF EMERGENT VEGETATION. by KOJI YAMANAKA "BvSc, Miyazaki University, 1969 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in the Department of Plant Science We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA March, 1975; In present ing th is thes is in p a 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 sha l l make it f r ee ly ava i l ab le for reference and study. I fur ther agree that permission for extensive copying of th is thes is for scho la r ly purposes may be granted by the Head of my Department or by h is representa t ives . It is understood that copying or p u b l i c a t i o n of th is thes is for f i n a n c i a l gain sha l l not be allowed without my wri t ten permiss ion. Department of The Un ivers i ty of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date i i ABSTRACT The emergent v e g e t a t i o n of t i d a l marshes o f the F r a s e r R i v e r f o r e -shore i s p r o b a b l y o f g r e a t importance to the r i c h l i f e o f t h e f o r e s h o r e , e s p e c i a l l y t o w a t e r f o w l and f i s h . The v e g e t a t i o n " f i x e s " s o l a r r a d i a t i o n w h ich i s " r e l e a s e d " as o r g a n i c m a t t e r i n the b r a c k i s h marsh and s a l t water marsh ecosystems. Much of the f o r e s h o r e v e g e t a t i o n , however, has been d e s t r o y e d by d i k i n g and i n d u s t r i a l development and more d e s t r u c t i o n from many s o u r c e s i s t h r e a t e n e d . My s t u d y was i n i t i a t e d t o a s s a y p r e s e n t s t a n d i n g c r o p s o f emergent v e g e t a t i o n i n t h e major a r e a s from P o i n t Grey to the I n t e r n a t i o n a l Boundary and a l s o t o e s t a b l i s h semi-permanent t r a n s e c t s f o r t h e s t u d y of f u t u r e v e g e t a t i o n change. F o u r t e e n semi-permanent t r a n s e c t s , the combined l e n g t h o f which i s 7,550 meters (4.7 m i l e s ) , were e s t a b l i s h e d from shore seawards a t p o i n t s i n the a r e a from P o i n t Grey to C r e s c e n t Beach, r o u g h l y a d i s t a n c e of 30 k i l o m e t e r s (19 m i l e s ) . B o t h p l a n t and s o i l samples were c o l l e c t e d a l o n g t h e t r a n s e c t s , a t i n t e r v a l s , i n 1973 and 1974; d r y m a t t e r y i e l d , ash, n i t r o g e n and l i g n i n were det e r m i n e d f o r p l a n t samples; pH, o r g a n i c m a t t e r and e l e c t r i c c o n d u c t i v i t y were determined on s o i l samples. The s t a n d i n g c r o p o f t h e t i d a l marshes, e s t i m a t e d to occupy 1,901 h e c t a r e s (4,697 a c r e s ) was a p p r o x i m a t e l y 9,408 m e t r i c t o n s of d r y m a tter w i t h an average d.m. y i e l d o f 4.9 t o n s per h e c t a r e (4,400 l b . / a c r e ) . E i g h t marsh p l a n t s c o n t r i b u t e d o v e r w h e l m ingly t o th e d.m. y i e l d : Carex lyngbyei, Soirpus conericanus and Soirpus paludosus a l o n e a c c o u n t e d f o r 81% of t h e s t a n d i n g c r o p i n 1974. i i i TABLE OF CONTENTS 1. INTRODUCTION 1 2. DESCRIPTION OF THE STUDY AREA 2 2.1 Location 2 2.2 Climate 4 2.3 Geology and s o i l 8 2.4 Vegetation 9 2.5 Other features 11 3. LITERATURE REVIEW 13 3.1 The role of t i d a l brackish marshes 13 3.2 Innate factors 20 3.3 Primary productivity 26 3.4 The foreshore environment of the Fraser River Delta 29 4. MATERIALS AND METHODS 34 4.1 Field sampling, general 34 4.2 Soil samples 34 4.3 Plant samples 37 4.4 Laboratory analyses 39 5. OBSERVATIONS AND RESULTS 42 5.1 Area, standing crop and quality estimates for the total marsh area 42 5.2 Observations on individual species 47 5.3 Area, standing crop and quality estimates along individual transects. Point Grey-Sturgeon Bank (Transects No. 1-6) 50 5.3.1 Point Grey Transect (No. 1) 53 iv 5.3.2 Iona Island Transect (No. 2) 55 5.3.3 Sea Island Transect (No. 3) 57 5.3.4 Westminster Highway Transect (No. 4) 62 5.3.5 Francis Road Transect (No. 5) 66 5.3.6 Steveston Highway Transect (No. 6) 71 5.4 Area, standing crop and quality estimates along tran-sects in the Roberts Bank area, (Transects No. 7-9) 75 5.4.1 Reifel Island Transect (No. 7) 78 5.4.2 34th Street Transect (No. 8), Superport 82 5.4.3 Tsawwassen Road, (Roberts Bank jetty) Transect (No. 9) 84 5.5 Area, standing crop and quality estimates along tran-sects in the Boundary Bay area (Transects No. 10-14) 90 5.5.1 Beach Grove Transect (No. 10) 93 5.5.2 72 St. Transect (No. 11) 95 5.5.3 88 St. Transect (No. 12) 98 5.5.4 112 St. Transect (No. 13) 101 5.5.5 Crescent Beach Transect (No. 14) 103 6. DISCUSSION 106 6.1 Vegetation types and habitat factors 106 6.2 Primary productivity 112 6.3 Man's impact 114 7. SUMMARY AND CONCLUSIONS 116 8. LITERATURE CITED 119 APPENDIX 1. Species l i s t and a Cover Map (\W V'ocutT^ 125 APPENDIX 2. Photographs for assistance in locating semi-permanent transects 126 APPENDIX 3. Estimated contribution of particulate organic matter 133 to the waters of the Georgia Strait. APPENDIX 4. Conversion tables for British and Metric Measure 134 v LIST OF TABLES Table I Mean daily temperature and mean total precipitation in Lower Fraser Valley, B.C. (31 years record). Table II Transect designations, total length, length occupied by vegetation and quadrat intervals, 1974. Table III Intervals of plant height measurement, 1974. Table IV Species frequency indices for transect quadrats. Table V Estimates of the area and dry matter yields of principal species for the whole area, 1974. Table VI Estimates of the area and dry matter yields of emergent vegetation for the whole area and i t s major parts, 1974. Table VII Estimates from meter square quadrats of several phytomass and chemical fractions for four (4) principal species, Reifel Island Transect (No. 7.), and one (1) 88 St., B.B. Transect (No. 12), 1973. Table VIII Estimates of the area and dry matter yields of emergent vegetation of the several sections for the Point- Grey - Sturgeon Bank area, 1974. Table IX Point Grey Transect (No. 1); s o i l and plant analyses, 1974. Table X Iona Island Transect (No. 2); s o i l and plant analyses, 1974. 35 38 39 43 43 48 52 54 56 Table XI Sea Island Transect (No. 3); s o i l and plant analyses, 1974. 6 1 Table XII Westminster Highway Transect (No. 4); s o i l and plant analyses, 1974. 65 Table XIII Frances St. Transect (No. 5); s o i l and plant analyses, 1974. Table XIV Steveston Highway Transect (No. 6); s o i l and plant analyses, 1974. 70 72 Yields, unless otherwise stated, are annual. v i Table XV Principal species log for transects (No. 1-6) off Point Grey, Sea Island and Lulu Island, 1974. 73 Table XVI Estimates of the area and dry matter yields of emergent vegetation of several sections of the Roberts Bank area, 1974. 77 Table XVII Reifel Island Transect (No. 7); s o i l and plant analy-ses, 1974. 81 Table XVIII 34th St., (Superport) Transect (No. 8); s o i l and plant analyses, 1974. 83 Table XIX Tsawwassen Rd. Transect (No. 9); s o i l and plant analyses, 1974. 88 Table XX Principal species log for transects (No. 7-9) in the Roberts Bank area, 1974. 89 Table XXI Estimates of the area and dry matter yields of emergent vegetation of the several sections for the Boundary Bay area, 1974. 92 Table XXII Beach Grove Transect (No. 10); s o i l and plant analyses, 1974. 94 Table XXIII 72 St. Boundary Bay Transect (No. 11); s o i l and plant analyses, 1974. 96 Table XXIV 88 St. Boundary Bay Transect (No. 12); s o i l and plant analyses, 1974. 100 Table XXV 112 St. Mud Bay Transect (No. 13); s o i l and plant analyses, 1974. 102 Table XXVI Crescent Beach Transect (No. 14); s o i l and plant analyses, 1974. 104 Table XXVII Principal species log for the transects (No. 11-14) of the Boundary Bay area, 1974. 105 v i i LIST OF FIGURES Figure 1 General location of the t i d a l marshes of the Fraser River Delta Foreshore and Boundary Bay. 3 Figure 2 Mean monthly temperature and mean monthly precipita-tion for Vancouver International Airport, Sea Island, B.C. (30 year record). 5 Figure 3 July to August mean temperature in Lower Fraser Valley (A), and average annual precipitation in Lower Fraser Valley (B). 7 Figure 4 Some major vegetation areas. 10 Figure 5 Surface distribution of salinity at the Fraser River estuary, May 29 - June 1, 1950. 12 Figure 6 Major invertebrate growing and fisheries areas. 15 Figure 7 Foreshore areas of importance to waterfowl. 16 Figure 8 Land presently in agriculture. 30 Figure 9 Sensitive areas for fish and wi l d l i f e which should be set aside as minimal conservation habitats. 32 Figure 10 A food chain of Fraser Estuary; (a) a simple Fraser estuary food chain; (b) a somewhat more complex Fraser estuary food chain; (c) a food chain of even greater complexity. 33 Figure 13 Changes in plant height in cm. against distance in m. from dikes, 1973. Figure 14 Soirpus paludosus; photo taken from the dike looking seawards along Sea Island Transect (No. 3). Figure 15 Soirpus americanus; photo taken at 450 m. looking seawards along Sea Island Transect (No. 3), August, 1974. 36 Figure 11 Sketches of (a) generalized transect profiles; (b) a concrete block and cedar stake. 2 Figure 12 Averages of dry matter weights in grams per m (based on unequal numbers of variables per sample) against distance in meters from dikes, 1973. 45 46 49 49 Map to show areas of emergent vegetation and the location and vegetation of the line-transects (No.1-6) in the Point Grey-Sturgeon Bank area, 197A. Sea Island Transect (No. 3); dry matter weight and plant height, nitrogen % and lignin %, and s o i l organic matter, pH and conductivity, 1974. Vegetation micro-map for the Sea Island Transect (No. 3), 1974. Photographs of a small channel (A) and a large channel (B), Lulu Island marsh, 1974. Francis St. Transect (No. 5); dry matter weight and height, nitrogen % and lignin %, and s o i l organic matter, pH and conductivity, 1974. Photographs of a small pool (A) on the Westminster Highway Transect (No. 4), Lulu Island, and a large channel (B) near the Francis St. Transect (No. 5), Lulu Island, 1974. Vegetation micro-map for the Francis St. Transect (No. 5), Sturgeon Bank, 1974. Map to show the areas of emergent vegetation and the location and vegetation of the line-transects (No. 7-9) in the Roberts Bank area, 1974. Photographs of a typical mud f l a t (A) 900 m. from the dike on Reifel Island, Westham Island area and (B) of a large channel with i t s adjacent island of emergent vegetation (Scirpus amevioanus) also Reifel Island Transect (No. 7), 1974. Reifel Island Transect (No. 7); dry matter weight and height, nitrogen % and lignin %, and s o i l organic matter, pH and conductivity, 1974. Photographs of a weakly developed channel (A) and mud f l a t (B) looking seawards from 600 m. both on the Tsawwassen Road Transect (No. 9), 1974. Tsawwassen Rd. Transect (No. 9); dry matter weight and height, nitrogen % and lignin % and s o i l organic matter, pH and conductivity, 1974. ix Figure 28 Map to show areas of emergent and the location and vegetation of the line-transects (No. 10-14) in the Boundary Bay area, 1974. 91 Figure 29 Photograph of d r i f t wood and flotsam on a seaward side of the dike, foot of 72 St. Transect (No. 11) Boundary Bay (Delta Municipality). 97 Figure 30 Vegetation micro-map for the 88 St. Transect (No. 12), Boundary Bay, 1974. 99 ACKNOWLEDGEMENTS The a u t h o r w i s h e s t o acknowledge the s u p e r v i s i o n and gu i d a n c e o f f e r e d by Dr. V.C. B r i n k , P r o f e s s o r , t h e Department o f P l a n t S c i e n c e , U n i v e r s i t y of B r i t i s h Columbia. My g r a t i t u d e i s a l s o extended t o t h e o t h e r members o f t h e Committee, Dr. V.C. R u n e c k l e s , Dr. R.J. Hudson,t Dr. A . J . Renney, a l l o f t h e U n i v e r s i t y o f B.C. and Mr. D.R. H a l l a d a y , o f t h e F i s h and W i l d l i f e Branch, B.C. Department of R e c r e a t i o n and C o n s e r v a t i o n , f o r t h e i r s u g g e s t i o n s and c r i t i c i s m s . P a r t i c u l a r thanks a r e due to Mr. I . D e r i c s , S e n i o r T e c h n i c i a n , Department o f P l a n t S c i e n c e , U.B.C, f o r h i s h e l p i n a n a l y z i n g p l a n t samples and to Mr. John Shaw, summer s t u d e n t who a s s i s t e d me i n t h e f i e l d . Acknowledgement i s a l s o g i v e n t o Dr. G.W. Ea t o n f o r h i s a d v i c e on s t a t i s t i c a l a n a l y s i s . To M e s s r s . S. Parmar, B.H. Ogwang and J . E . H i l t o n , f e l l o w g r a d u a t e s t u d e n t s , go my thanks f o r t h e i r h e l p d u r i n g the f i e l d and w r i t i n g s t a g e s o f my p r o j e c t . I am g r a t e f u l t o the F i s h and W i l d l i f e Branch, B.C. Department of R e c r e a t i o n and C o n s e r v a t i o n f o r f i n a n c i a l a s s i s t a n c e . t Now a t t h e U n i v e r s i t y o f A l b e r t a , Department o f Ani m a l S c i e n c e . 1. INTRODUCTION The emergent v e g e t a t i o n o f the t i d a l f l a t s and marshes o f Boundary Bay and the f o r e s h o r e o f t h e d e l t a o f the F r a s e r R i v e r i n s o u t hwestern B.C. i s the p r o d u c t of c o m p l i c a t e d i n t e r r e l a t i o n s h i p s between the s a l t w aters of the G u l f of G e o r g i a , the f r e s h waters o f the F r a s e r R i v e r and l e s s e r streams, the many s u b s t r a t e s , t h e m a r i t i m e c l i m a t e , the fauna and o t h e r v a r i a b l e s . I t i s c l e a r t h a t the emergent v e g e t a t i o n , as a p r i m a r y p r o d u c t i o n element i n the b i o l o g i c a l system of the e s t u a r y , i s i m p o r t a n t to the more s e v e r a l m i l l i o n w a t e r f o w l , r e s i d e n t and t r a n s i e n t , , to t h e l o c a l a g r i c u l t u r e , and, to the r i c h f i s h e r y o f the g u l f and r i v e r s . I t i s a l s o c l e a r t h a t the emergent v e g e t a t i o n , o f a l l the components of the system, has been most m o d i f i e d and i s , c u r r e n t l y , most t h r e a t e n e d by man's d i k e s , booming grounds, f l o t s a m and j e t s a m , a i r p o r t s , m a rinas, p o r t f a c i l i t i e s , urban e f f l u e n t s , d r e d g i n g and f i l l i n g . In the work r e p o r t e d here I have (a) e s t a b l i s h e d and s t u d i e d t r a n s e c t s , h o p e f u l l y "permanent", r u n n i n g from d i k e s seawards on which changes i n s u b s t r a t e and v e g e t a t i o n can be r e c o r d e d over a p e r i o d o f y e a r s and (b) i n i t i a t e d measurement o f trophodynamic p r o c e s s e s , which may be important i n the c o n s e r v a t i o n o f t h e n a t u r a l r e s o u r c e s , and, a knowledge of which, may be i m p o r t a n t i n e n v i r o n m e n t a l r e p a i r o r enhancement. 2. 2. DESCRIPTION OF THE STUDY AREA 2.1 Location The study area i s located on the P a c i f i c Coast of southwestern B r i t i s h Columbia where the 1,400 km. long Fraser River meets the sea, and where Vancouver Ciry, a major Canadian metropolis, i s located. The study area includes the larger part of the estuarine marsh of the Fraser River; the r i v e r and estuary are the largest i n the P a c i f i c Coast of Canada. These t i d a l marshes may be sub-divided into three sections from north to south, v i z . those of Sturgeon Bank, of Roberts Bank and of Boundary Bay (Fig. 1). The Sturgeon Bank marshes are northern-most and closest to Vancouver City and l i e off two d e l t a i c islands, i . e . Sea Island and Lulu Island. The Roberts Bank marshes, l y i n g off Westham Island and the Tsawwassen area, are less accessible than those off Sturgeon Bank and are more removed from r e s i d e n t i a l areas; they are, however, strong candidates for i n d u s t r i a l s i t e s such as a m u l t i - m i l l i o n d o l l a r o i l refinery and a (4 m i l l i o n metric ton) st e e l m i l l . The Boundary Bay marshes are most removed from the Fraser River influences and are located on a broad low gradient t i d a l f l a t which i s used for recreation. J u r i s d i c t i o n of the tide lands i s not well defined. In general i t would seem that the federal authority i s dominant i n areas seaward from the dykes and the p r o v i n c i a l authority i s dominant on land and much of the water within the dykes. Several cooperative, federal and provincial projects, such as those r e l a t i n g to dyking and waterfowl, relate closely to the foreshore habitat. 3. Figure 1. General location of the tidal marshed of the Fraser River Delta Foreshore and Boundary Bay. 4. 2.2 Climate The climate of Lower Fraser Valley, apart from the usual l a t i t u d i n a l influences, i s mainly influenced by three factors, the prevailing westerly winds, the moist P a c i f i c a i r from the warm Japan Current, and the mountain barri e r . The climate of the study area f a l l s into the general category of the West Coast Marine type, although v a r i a b i l i t y i s marked. Fig. 2 shows that much of the t o t a l p r e c i p i t a t i o n occurs during the s i x months, i . e . May to October; the highest and lowest mean dai l y temperatures • vary from 2.4°C for January and 17.4°C for July. The large l o c a l differences i n sunshine, temperature and pr e c i p i t a t i o n over short geographical distances, e.g. between Vancouver and White Rock, are shown i n Table I; Vancouver receives much more r a i n f a l l ; i n the four months from November through February, Vancouver receives fewer sunshine hours (219) than i n the single month of July (280) (Canada Department of the Environment, 1970). This i s i n part because the nearby Coast Mountains force cloudy, warm, moist P a c i f i c a i r to r i s e and to release moisture. Storm tracks i n winter bring maximum p r e c i p i t a t i o n and much cloud. The general v a r i a b i l i t y of Lower Fraser Valley climates i s more c l e a r l y shown i n Fig. 3 (a) and (b). The July to August mean temperatures increase from south to north. I t can be seen that between Ladner and North Vancouver, there i s a large difference i n mean annual p r e c i p i t a t i o n with the highest figure for the l a t t e r centre. 5. Table I: Mean dally temperature and mean t o t a l p r e c i p i t a t i o n i n Lower Fraser Valley, B.C. (30 year record)'. -Location J F M A M J J A S O N D Year Vancouver, U.B.C, (Lat. 49 15 N, Long. 123 15 N, Elev. 9.5 m. A.S.L.) M.D. Temp. (°C) 2.8 4.7 5.9 8.6 12.0 14.7 17.1 16.8 14.5 10.4 6.3 4.1 9.3 M.T. Precip. (mm) 71 132 101 68 53 48 32 48 67 150 167 195 1230 Vancouver Int. Airport, (Lat. 49 18 N, Long. 123 07 N, Elev. 5 m. A.S.L.) M.D. Temp. (°C) 2.4 4.4 5.8 8.9 12.4 15.3 17.4 17.1 14.2 10.1 6.1 3.8 9.8 M.T. Precip. (mm) 147 117 95 61 48 45 ' 30 37 61 122 141 165 1069 Ladner Monitor Station, (Lat. 49 04 N, Long. 123 07 W, Elev. 0 m. A.S.L.) M.D. Temp. (°C) 2.3 4.2 5.7 8.6 11.8 14.6 16.4 16.1 13.5 9.6 5.9 4.3 9.4 M.T. Precip. (mm) 115 99 83 52 38 45 24 31 50 99 125 143 903 Steveston, (Lat. 49 07 N, Long. 123 11 W, Elev. 1.3 m. A.S.L.) M.D. Temp. (°C) 2.2 4.1 5.6 8.6 11.9 14.7 16.7 16.3 13.7 9.6 5.7 3.5 9.4 M.T. Precip (mm) 138 106 82 56 45 42 26 37 57 117 137 152 994 White Rock, (Lat. 49 02 N, Long. 122 50 W, Elev. 17 A.S.L.) M.D. Temp (°C) 2.6 4.7 5.9 8.7 11.9 14.3 16.2 16.1 13,9 10.2 6.2 4.2 9.6 M.T. Precip. (mm) 138 U l 91 66 52 50 27 43 60 117 139 154 1047 6, C mm 18 180 J F M A M J J A S 0 IM • D M o n t h Figure 2, Mean monthly temperature and mean monthly precipitation for Vancouver International Airport, Sea Island, B. C. (30 year record). 7. ( B ) Figure 3. July to August mean temperature i n Lower Fraser Valley ( A ) , and average annual precipitation in Lower Fraser Valley ( B ) . (Stager and Wallis, 1968). 8, 2.3 Geology and S o i l A v a i l a b l e e v i d e n c e s u g g e s t s t h a t t h e p r e s e n t 1,400 km. l o n g F r a s e r R i v e r d e l t a began to f a n out from the gap i n the P l e i s t o c e n e uplands a t New Westminster about 8000 y e a r s ago. The d e l t a has s i n c e advanced i n t o the S t r a i t o f G e o r g i a a t an e s t i m a t e d r a t e of 13 x 10 c u b i c meters per y e a r and has b u i l t up d e p o s i t s 100 to 200 meters t h i c k or 0.42 mm. per y e a r on t h e average f o r the l a s t 4350 y e a r s o v e r P l e i s t o c e n e sediments ( K e l l e r h a l s et al., 1969; Mathews et al., 1962). The 23 x 104 square k i l o m e t e r d r a i n a g e b a s i n o f the F r a s e r R i v e r i s u n d e r l a i n by p l u t o n i c , v o l c a n i c , metamorphic and s e d i mentary r o c k and g l a c i a l d e p o s i t s . M a c k i n t o s h et.al. (1966) have n o t e d t h a t "sediments c o n t r i b u t e d to the lower F r a s e r v a l l e y by t h e F r a s e r R i v e r a r e composed l a r g e l y o f q u a r t z , f e l d s p a r , c h l o r i t e , mica and amphibole. The f i n e r c o l l o i d a l c l a y p a r t i c l e s , m o s t l y d i s p e r s e d through the d e l t a ' s d i s t r i b u t a r y system d u r i n g the f r e s h e t months o f May, June and J u l y , f l o c c u l a t e as the r i v e r water mixes w i t h sea water and s e t t l e out g r a v i t a t i o n a l l y a t the o u t e r edge of the d e l t a and seaward. The f i n e r suspended sediment has been o b s e r v e d to c o n t a i n almost e q u a l p r o p o r t i o n s o f m o n t m o r i l l o n i t e , i l l i t e , and c h l o r i t e ( G r i f f i n et al., 1968). The f o r e s h o r e of t h i s a l l u v i u m r o u g h l y c o n s i s t s o f Sturgeon Bank, Rob e r t s Bank, Mud Bay and Boundary Bay. The two banks t o g e t h e r form about 15,000 h e c t a r e s o f s i l t y or c l a y e y i n t e r t i d a l a r e a . The t i d a l f l a t s o f the two bays extend 4 km. seaward and c o v e r an a r e a of c a . 65 square k i l o m e t e r s . Mud Bay and Boundary. Bay were p a r t o f t h e F r a s e r d e l t a system i n the Recent g e o l o g i c a l p a s t . They a r e s t i l l i n f l u e n c e d by c u r r e n t s g e n e r a t e d by the F r a s e r R i v e r , and p r e s e n t l y have a f r e s h water i n p u t from the S e r p e n t i n e and Nicomekl R i v e r s ( K e l l e r h a l s et al., 1969; T i f f i n , 1969). Mud Bay i s s i l t y o r c l a y e y and Boundary Bay sandy. 9. 2.4 V e g e t a t i o n In t h e v e g e t a t i o n o f t h e t i d a l marshes t h e r e i s , as elsewhere i n the w o r l d ' s t i d a l marshes, l i t t l e d i v e r s i t y i n f l o r i s t i c c o m p o s i t i o n . In the sutdy a r e a the most common f i v e t i d a l marsh communities a r e Carex lyngbyei, Soirpus amerioanus, Soirpus paludosus, Typhi latifolia and Salioomia validus i n o r d e r o f d e c r e a s e d s t a n d i n g c r o p y i e l d . The Soirpus a. community may be the most a g g r e s s i v e and s u c c e s s f u l l y e s t a b l i s h e d and c e r t a i n l y i t o c c u p i e s t h e l a r g e s t a r e a and a t the lowest t i d a l f l a t s . The Carex 1. community, not f a r from d i k e s , i s a l s o i m p o r t a n t because o f i t s h i g h e s t s t a n d i n g crop y i e l d per u n i t o f a r e a . The v e g e t a t i o n o f the Boundary Bay a r e a i s i n f l u e n c e d the l e a s t by the F r a s e r R i v e r and t h e r e f o r e d e v e l o p s on a more s a l i n e s u b s t r a t e t h a n t h e s u b s t r a t e s of the marshes o f the n o r t h and s o u t h arms o f the F r a s e r R i v e r . I t m a i n l y c o n s i s t s o f Salioornia V.3 Distiohlis striata and Trigloohin maritimum. These s p e c i e s a r e l e s s i m p o r t n a t i n terms o f the t r o p h i c system due to t h e i r low d r y m a t t e r y i e l d p e r u n i t a r e a and t h e i r l i m i t e d d i s t r i b u t i o n . The low s t a t u r e i s a c h a r a c t e r i s t i c f e a t u r e . The d i k e v e g e t a t i o n , t h e o b j e c t o f f r e q u e n t man-induced and n a t u r a l changes, shows most d i v e r s i t y i n p l a n t s p e c i e s . Some major v e g e t a t i o n a r e a s o f t h e o u t e r F r a s e r v a l l e y a r e shown i n F i g . 4. 2.5 Other features The oceanographic characteristics of the Fraser River estuary are strongly affected by quantity, quality and timing of the flow of freshwater, and by the tides and the winds of the S t r a t i s of Georgia. The surface current patterns, p a r t i c u l a r l y i n the northern part of the . '; estuary where the North Arm of the fraser River i s "trained" by the North Arm Jetty, are stongly dominated by the Fraser River flow (Fig. 5). The waters are not s u f f i c i e n t l y mixed by t i d a l and wind action to create v e r t i c a l homogeneity. Therefore, there exists a two-layered system which extends beyond the immediate esturay into the S t r a i t of Georgia, but not into the well mixed waters of the southern channels between the San Juan Islands (Hoos et al.} 1973). Characteristic of the P a c i f i c coast of North America, the tides of the S t r a i t of Georgia, including the Fraser River estuary, are of the mixed type. This means that the tides are a mixture of diurnal and semidiurnal inequality which affects both the time and height of the tide. This occurs p r i n c i p a l l y i n the height and i n the time of succeeding low tides. There i s an approxiamtely two week cycle i n t i d a l ranges, as well as a seasonal cycle. In the Fraser River estuary, as i n other parts of the S t r a i t of Georgia, the lowest tide occurs near midnight during the winter months and near midday during the summer (Hoos et al.3 1973). 12, Figure 5. Surface distribution of salinity at the Fraser River. estuary, May 29 - June 1, 1950. (Waldichuk, 1957). Sample numbers and salinity in ° / o o . 13 . 3. LITERATURE REVIEW 3.1 The role of the t i d a l brackish marshes Coastal tid a l marshes may be grouped into: a)-tidal fresh^-.. water marsh and b) t i d a l brackish marsh. A t i d a l brackish marsh exists at the mouth of a river, on the alluvium where the river enters the sea. Smith (1966) describes the formation of the t i d a l brackish marshes, which are .the concern of this report, as follows: the t i d a l brackish marshes begin in most cases as mud or sand f l a t s , at f i r s t colonized by algae and then, i f the water i s not too deep, by eelgrass (Zostera, a submerged species not found in fresh or slightly brackish waters). As organic debris and sediments accumulate, eelgrass i s replaced by the f i r s t brackish-marsh colonists or emergents. The tide flushes the brackish marsh with a diurnal regularity and, over a period of several weeks, makes the estuarine water more or less homogenous (de la Cruz, 1965). Although to the eye salt marshes may appear as waving acres of "grass" they are, instead, a complex of distinctive and clearly demarcated plant associations (Smith, 1966). There are several functions served by t i d a l marshes which confer on them an importance only recently recognized. In the f i r s t place, as Whittaker (1970) observes, salt marsh vegeta-tion i s , in comparison with many terrestrial communities, very productive of dry matter. Not only are they productive but they clearly produce an excess of organic matter which i s exported seawards (Odum, 1961); much of the organic matter, probably almost half (de l a Cruz, 1965) goes to the foreset beds of the delta where i t provides energy for the rich l i f e there. Secondly the s a l t marsh i s a region where fresh and s a l t water mix, and where because of their d i l u t i o n , the sa l t s of the sea may (again) become available as nutrients i n generous amounts to t e r r e s t r i a l plants and where s i l t s and organic debris brought down by the r i v e r may be "trapped". Daily the tides bring i n nutrients and remove waste so that there i s a good production of phytoplankton i n the general v i c i n i t y of the estuary which with the mudbank algae are a primary food source for the various consumer levels (Wagner, 1971). The main role of the sa l t marsh i s probably to supply food d i r e c t l y for animals grazing the l i v i n g plant tissues; not always apparent, t h i s role varies from place to place i n importance as do the grazers them-selves; they may be waterfowl, f i s h or invertebrates (Fig. 6 and Fig. 7). Species as diverse as the shrimp and the bluefish may spend a c r i t i c a l part of their l i f e cycle i n the t i d a l marsh (Massachusetts I n s t i t u t e of Technology, 1970). According to Gareth (1974) benthic invertebrates may feed on algae which are photosynthetic i n the i n t e r t i d a l area at times when tides are out and at times when the murky waters of the freshet or when the deep waters of the high tide screen out sunlight. Many investigators have reported on the importance of t i d a l marsh vegetation as a source of energy, i . e . organic d e t r i t u s , for numerous estuarine or marine consumers. Perkins (1974) estimates the contribution of particulate organic matter to the waters of the Georgia S t r a i t , B.C. 6 as greater than 1-2 x 10 tons per year. The sources of detritus are the many r i v e r s , logging a c t i v i t i e s along the coast, the flotsam and jetsam from ships, barges, etc. and the sewage and m i l l wastes from i n d u s t r i a l and suberban areas. Figure 6. Major invertebrate growing and fisheries areas (U.S. Mat. Parks and Parks Canada, 1973). Figure 7. Foreshore areas of importance to waterfowl. (Swan Wooster, 1967 and C.W.S., unpubl.) [More precise information is now available from the Canadian Wildlife Service and the B. C. Fish and Wildlife Branch], -17. The contribution of organic matter from the t i d a l marshes of the k Fraser, probably a magnitude of 10 tons per year (this study), as a possible contribution of l i t t e r may not seem to be great. I t i s , however, the contribution of only one estuary and, being herbaceous, i s r e l a t i v e l y "available" and "cycles" readily. I t i s doubtless a c r i t i c a l source of energy for many species of f i s h and other animals. A small part of the energy from s a l t marsh vegetation i s channeled through the c l a s s i c a l "grazing" food chain. Most of the net primary production, i t i s believed, i s directed through the. " d e t r i t u s " food chain (de l a Cruz, 1965). Smalley (1959) found that less than 5% of the net production by Spartina marsh grass i s consumed "on the st a l k " as i t were, by the insect and other eaters of or grazer's on the growing grass. He also states that most of the tremendous production of s a l t marshes i s destined to be used i n the form of organic detritus. As marsh vegetation dies, abundant micro-organisms: such as fungi and bacteria convert i t into p a r t i c l e s r i c h i n readily used proteins, carbohydrates and vitamins. This organic detritus i s distributed through-out the system. Darnell (in press) pointed out that this material represents also transport and buffer mechanisms f or the ecosystem. I t i s an energy store because organic matter produced at one time i s released l a t e r ; i t i s an energy transporter because i t carries the "energy-p a r t i c l e s " downstream from the point of production; i t i s an energy buffer because organic detritus i s available during seasons of low primary production. The process of decomposition of organic matter and i t s ultimate ) 18. fate are rather complex and many living organisms are involved. Kuenzler (1961) reported that excess organic matter in the marsh is transported into estuarine waters, where i t i s available to a whole host of decomposers and other detritus feeders, such as the horse mussel, important in the phosphorus cycle. While f i l t e r i n g water to obtain i t s food, the mussel excretes large ^ quantities of organic particles as pseudofeces, which sink to the bottom. Because of the importance of t i d a l action in nutrient cycling and production, the entire estuarine system, including marshes, f l a t s , creeks and bays, must be considered as one ecosystem or productive unit (Odum, 1961). Nowadays we are observing a lot of changes in estuaries which are not based on biological considerations (Odum, 1961). Especially, f i l l i n g of bays and estuaries i s detrimental. Once a salt marsh has been f i l l e d with waste, the options for preservation and continued renewal are forever lost, for there are limits to environmental reconstruction (Wagner, 1971). Ohba (1972), in Japan, stated recently that salt marshes are losing acreage rapidly because of endiking and also because of exploita-tion of the offshore sea weed Porphyra teneva, especially in South Japan. Slight and usually unpremeditated modifications of our environment can cause serious changes in the marsh environment. For example, Benson (1961) reported that the erection of jetties on Sea Island and near Tsaw-wassen in B.C. may be increasing the rate of s i l t deposition there. On the other hand the recent history of salt marshes in the northern part of Morecombe Bay, Norfolk, U.K. i s one of progressive marsh development, a process accelerated by the building of breakwaters and embankments in the upper parts of the estuaries, and by the piecemeal reclamation of land for agriculture or as a result of railway construction. The fluctua-tion of the low water channels of the rivers draining into the bay has a significant effect on marsh development, producing, at many sites, intermittent phases of erosion and growth (Gray, 1972). Knowing which areas a development w i l l destroy or alter or build, biologists can then estimate how much v i t a l habitat w i l l be lost, and hence what the impact on fisheries and waterfowl w i l l be (Gareth, 1974). The Massachusetts Institute of Technology (1970) recommends that the trend of the f i l l i n g of bays and estuaries should be monitored before a multitude of local encroachments has produced an irreversible global effect. 3.2 Innate factors Unlike the usual domesticated crop plants, marsh plants are influenced by a number of factors such as tide level, salinity and others. Plant distribution within salt marshes has been correlated with a variety of factors including salinity, s i l t a t i o n , t i d a l inundation, s o i l type, drain-age and biotic competition (Phleger, 1971). Vogal (1966) reports that in the salt marsh he studied, the emergent plant community i s extremely simple in the lowest area (4 species) but grades to a more complex, yet relatively simple, community in the highest regions of the marsh (15 species). Correspondingly, the lower zones had sparse vegetational cover and the higher zones supported heavier growth, both in size and numbers of individuals. Gray et al. (1972) in their studies of the salt marshes of Morecombe Bay, in Britain, report- that the major variations in vegetation are pro-vided by contrasting substrates reflecting the complex of factors assoc-iated with pedogenesis, i.e. between the vegetation of calcareous nutrient-poor sands and that of the comparatively f e r t i l e organic s i l t y soils. A second important component of variation i s the f l o r i s t i c s related to the s o i l sodium content which varied with elevation, and reflected factors related in turn to t i d a l submergence. Chabreck (1973) studied the effect of a hurricane on the marshes of the Mississippi River Delta and their recovery. He reports that the hurricane drasti-cally reduced the vegetation. Regrowth was rapid in the delta, rapid in the delta marshes and, after one year, plant coverage approached pre-hurricane levels; however, recovery was slower in ponds and lakes; water salinity in these increased with the hurricane but declined and by the following year the residual effect on marsh vegetation was scarcely observable. Fundamentally, tides are harmonic waves caused by the attraction of nearby heavenly bodies. Other influences on the height of tides are related to the depth and shape of basins and conformation of coast lines. Strong steady winds may augment or reduce the height of tides. The average lunar day i s 24 hours, 50 minutes and 38 seconds so each day the tide timing i s about 50 minutes later than the day before.. The average period between the tide extremes i s 6 hours, 12 minutes (Lemon, 1962). The effects of tides on ti d a l marshes have been studied by a number of investigators. Smith (1966) reports that the tides, perhaps, play the most significant role in marsh plant growth and development by depriving them of the f u l l insolation of the sun. Adams (1963) also reports that the distribution of species in regularly-flooded marshes is controlled primarily by tide-elevation influences. The pattern of the tides over the ti d a l marshes i s such .-'that during the summer, lower tides occur in daylight hours, and higher tides occur during the night. In winter, this pattern i s reversed, so that tides are relatively high during the shorter daylight hours. This pattern of diurnal low tides in summer aids the growth of the marsh plants (Burgess, 1970). Gray et al. (1972) report that where areas of continuous vegetation may be limited by ti d a l factors to elevations above 4.5 m. A.O.B-t Point-to-point variation in the vegetation above this level reflects the inter-action of such factors with local variation in s o i l type. Hinde (1954) t found that the glasswort (Salicorma sp.) occurs from 10.3 f t . above MLLW t • t t A.O.D. = Average of Datum. MLLW = Mean Low Low Water. 22, to 6.4 f t . above MLLW; and the salt grass (D-istiahZis sp.) i s found between 10.3 f t . and 7.15 f t . above MLLW. Bleakney (1972) reports that extreme tides expose organisms to a variety of stresses depending upon the time of year and weather con-ditions; as both weather and ti d a l extremes are acyclic relative to the l i f e span of short-lived species, there i s no opportunity for gene-t i c selection of suitable behavioural responses, such as those associated with seasonal changes in light and temperature. As i s true of a l l inter-t i d a l organisms, the emergent plant species are subject to sudden and dramatic changes in temperature and insolation as tide waters ebb and flow near them. Several studies have been done on the salinity of t i d a l marshes. Unhof (1941) reports that considerable controversy exists as to whether salt-marsh plants require saline conditions or merely tolerate them, i.e. are obligate or facultative halophytes (Daubenmire, 1947). Adams (1963) studied plant zonat ion in North Carolina salt marshes and reported that most salt-marsh species exhibit reduced growth and f e r t i l i t y with increasing salinity, and that salt concentrations equivalent to about 7% NaCl (twice sea strength) prohibited establishment and survival of a l l species. The efficiency of net production in cattails i s determined by the rate at which leaf tissue i s produced, rather than by inherent differences in the assimilation efficiency of that tissue (McNaughton, 1974). McNaughton (1974) compared photosynthetic characteristics of two low-altitude and two high-altitude populations of the broad-leaved c a t t a i l (Typha latifolia L.). The photosynthetic differences between the eco-23, types seem to have minor ecological significance, but reductions i n water and nutrient uptake upon root c h i l l i n g suggested strong natural selection i n the high-altitude s i t e for a b i l i t y to function e f f i c i e n t l y i n cold s o i l s . Of concern to emergent vegetation i s s i l t , probably a factor of importance i n some estuaries; i t does not seem to have been given much attention except insofar as i t may modify the chemical analysis of the plants. Bacte r i a l decomposition i s an important part of the detritus break-down, and the bacteria, algae, and associated detritus are a l l food for detritus feeders (Krebs, 1972). The protein i s calculated to be deficient as a nitrogen source for marine animals, and i t i s suggested that microbial conversion of autrophs may act to step up the potential value of the pool of protein i n the sea (Burkholder, 1956). Keefe et al. (1973) investigated the standing crop of s a l t marshes surrounding Chinocoteague Bay, Maryland-Virginia, U.S.A. Chemical analysis indicated that phosphorus and potassium were rapidly leached from the dead plants while magnesium tended to be retained. Live:dead ratios changed from 0.9 to 2.3 and were lower than those found i n regularly flooded marshes. Stewart (1963) states that estuarine areas are p a r t i c u l a r l y r i c h i n vitamin B 1 2, a growth factor which i s essential for the growth of many of the marine micro-algae which are important primary producers i n the sea and ocean around the B i r i t s h I s l e s . Burkholder et al. (1957) found that aerobic, heterotrophic, marine bacteria p a r t i -cipate actively i n the decomposition of Spartina. He also estimated that about 11% of the annual crop of marsh grass may be rapidly converted to bacteria (dry weight basis). Microbial u t i l i z a t i o n of crude f i b e r takes place more slowly than decomposition and use of protein and soluble carbohydrate constituents. Animals l i v i n g i n the t i d a l marsh must be able to survive or avoid the great changes i n s a l i n i t y , temperature and exposure. The limited number of animals which have adapted to these extremes appears to be r e l a t i v e l y free from competing species and enemies. Once adapted to the marsh, the lack of competition from s i m i l a r animals has perhaps allowed them to occupy a broader niche and be more abundant than would otherwise be possible. In areas of dense crab populations the entire surface of the marsh i s "worked over" between successive high tides. Both by "the working over" of the marsh surface and the concentration of organic matter i n thei r feces, the crab w i l l have considerable i n -fluence upon other organisms, especially the nematodes, annelids and bacteria (Teal, 1962). A colony of mussels w i l l c i r c u l a t e every two and a half days as much phosphorus as the water holds i n suspended p a r t i c l e s , as we l l as a considerable quantity of dissolved phosphorus. Therefore, a constant • amount of t h i s material remains on the surface i n any given f l a t , and i s not carried out by the tides (Louise et al. 3 1969). Tidal marshes are not always accessible, because the ground i s soft and muddy and the tide l e v e l i s always changing. For this reason, new or improved methods of studying marshes are s i g n i f i c a n t . Seher (1973) studied color and color-infrared a e r i a l photographs of waterfowl habitats to determine thei r usefulness for marsh vegetation evaluation and attempted to determine the optimum film type, scale, time of day, and time of year for best results. Reimold et ai. (1973) considered remote sensing to provide quantitative data on primary production in ti d a l marsh ecosystems, focusing on: (1) differentiation of vegeta-tive types (species), and (2) assessment of primary production between each vegetative type (species) and within the dominant species, Spartina altevniflora. 3.3 Primary productivity The photosynthetic production of organic matter involves conversion of part of the sun's radiant energy into a form which can be used by other l i v i n g organisms. Some of the organic matter i n i t i a l l y produced i s respired by the plant to provide energy for i t s own metabolism and the rest accumulates i n the plant body. The part that i s not respired i s commonly termed the net production, which i s contrasted with the i n i t i a l gross production. The net production i s available for consumption, either before or after the death of the plant, by animals, bacteria and fungi, which cannot create new organic matter themselves. Primary production i s defined as the weight of new organic matter created by photosynthesis over a period; expressed as a rate i t becomes productivity. Biomass i s defined as the t o t a l weight of plant present at a p a r t i c u l a r time. Crop, y i e l d and standing crop are comparable with production, productivity and biomass respectively (Westlake, 1963). At Sapelo (Odum, 1961), three d i s t i n c t production units may be l i s t e d as follows i n order of the i r importance as food makers for the system as a whole: (1) The vast area of Spartina (cord grass) marshes; (2) The benthic or "mud algae" which grows throughout the i n t e r t i d a l sediments but especially on the creek banks and; (3) The phytoplankton i n the water (Odum, 1961). He also states that the annual production of the marsh, or the estuary as a whole, may be double or t r i p l e that of ordinary agriculture simply becuase i t grows twice or three times as long. Even in northern latitudes he suspects - pro-duction by microflora may occur when land plants are inactive. Teal (1962) investigated energy flow in the salt marsh ecosystem of Georgia State, U.S.A. and reported that gross production i s 6.1% of the incident light energy; however, net production over light i s a l i t t l e less than 1.4%. Odum (1961) estimates that Sapelo marshes and estuaries taken together in the southern U.S.A. have an estimated gross primary production of somewhere around 2,500 grams of dry matter per square meter per year. It i s thought that about 500 of these grams are used by the plants in their own respiration leaving about 2,000 grams net production average for each meter of the system. Bernard (1974) reports that in freshwater marshes in Minnesota, the Carex rostrata standing crop of green material varied from a minimum 2 2 of 114 g/m frozen in the winter ice to a high of 852 g/m in late August. Westlake (1963) reports that the phytoplankton of lakes and oceans are relatively. improductive even on f e r t i l e sites, with an annual dry matter production only 1-9 m.t./ha. and that benthic marine plants in shallow waters may produce more, i.e. from 25-33 m.t./ha. in the temperate zone. There are many d i f f i c u l t i e s in determining the primary productivities. For example, Westlake (1963) also points out that the underground parts may be five times as great as the weight of harvested shoots. The roots are wholly or in part renewed annually and rhizomes may persist for many or few years. The annual production has been estimated as 0.64 of the biomass or four times the standing crop of tops. Investigating primary productivity, Teal (1962) in the Southern U.S.A. reports that, since the net production was determined by short-term harvesting, i t is necessary to add the 305 Kcal/m yr. consumed by the insects to arrive at the true net plan t production. Wiegert and Evans (1964) pointed out that net primary production of natural vegetation i s often estimated by determining a peak standing crop and calling this value net primary production. They cite several errors inherent in this kind of approach. It does not take into account mortality of green plants prior to the time when the peak standing crop i s attained. This represents growth which would not be measured by standing crop determinations. Also, growth which might occur after the peak standing crop i s not measured. Another problem involved with using the peak standing crop as the estimate of net primary productions i s that i t does not take into account the fact that different species may reach their peak standing crop at different times. 3.4 The foreshore environment of the Fraser River Delta One hundred years ago there were, in a l l probability, about 18,000 hectares (45,000 acres) of marsh (open wetland) in the Lower Fraser Valley; now only about 3,000 hectares (8,000 acres) remains and most of i t l i e s along the Fraser delta foreshore, the focus of this study. Wetland and waterfrontage in the Lower Mainland, although exten-sive, has been alienated for a multitude of purposes and with astonish-ing rapidity. They may now be deemed to be scarce and v a l u a b l e commodities. Wharfage, booming grounds, marinas, industry and dikes have alienated hundreds of miles of shoreline and the problems assoc-iated with their development and use have been pointed up by a Lower Mainland Regional Planning Board report "Our Southwestern Shores" (1968) and by other•studies. The forward dikes of the delta, largely constructed for the rec-lamation of alluvium for farming late in the last century destroyed much of the marsh. Since the day of dike construction much of the.'..land reclaimed for agriculture has been occupied by suburbia and industry and now human activities of many kinds are extending to land beyond the dikes at an increasingly rapid rate (Fig. 8). Becker (1971) recently and generally has reviewed these activities and has indicated their current patterns as they relate to the foreshore from Burrard Inlet to the International boundary from around the 49th parallel, north. They are not reviewed here because of the earlier coverage but, obviously they constitute a raison d'etre for this study. The magnitude and nature of the contribution of the emergent vege-tation to the Fraser estuarine system (or for that matter v i r t u a l l y a l l Figure 8. Land presently in agriculture. (After Hoos et a l . , 1974). 31. estuarine systems) i s largely unknown. Simple observation of the digestive tracts of dead waterfowl confirms the review that the estuaring vegetation i s important i n the l i v e s of the m i l l i o n s of birds using the P a c i f i c flyway. A heavy dependence of brant on the submergent eelgrass (Zostera sp.) i n the Fraser system has been indicated by Morrison (1967). Burgess (1970) has noted the use of rhizorms and seeds of emergent plants by other waterfowl. I t i s now believed, but not documented, that i n indirect ways the emergent vegetation plays a role i n the feeding of salmon ( f r y , parr, smolt or g r i l s e ) as they move to the sea and as they move toward fresh water to spawn; perhaps emergent vegetation functions as egg beds for other f i s h , e.g. herring (Fig. 9 and Fig. 10). However, as Hoos et al. (1974), generally investigating and summarizing the available information of Fraser River estuary, stated, l i t e r a t u r e dealing with primary producers i n any environment, aquatic or t e r r e s t i a l , was lacking. The study by Perkins (1963) aforementioned seems to be the only study i n which detritus associated with the Fraser system i s given any attention as a contributor of energy. The emergent vegetation may not loom large r e l a t i v e to sewage and forest industry waste but lacking broad quantitative assessments of detritus i n the Fraser system there i s some a priori evidence (Odum, 1961) for believing that this natural component i s very important to the survival of the l i v i n g organisms of the system. CM CO , i r u r e 9 . Sensitive areas for f i s h and w i l d l i f e which should he set .side as minimal conservation habitat. (rloos et a l , 1974). for f i s h and w i l d l i f e which should be set cside cs nm i n a l 33. Figure 10. A food chain of Fraser estuary. BIRDS, SEALS a MAN JUVENILE SALMON a HERRING, BIRDS (a) A simple CLAMS, MUSSELS, Fraser estuary CRABS, AMPHIPODS, food chain; ISOPO0S 8 OTHER BENTHIC INVERTEBRATES DEATH ft DECAY PHYTOPLANKTON ' JUVENILE SALMON 8 HERRING, BIRDS (t>) A somewhat more complex Fraser estuary food chain;] (c) A food chain of even greatei complexity. (Hoos et a l . , 1974T. DECOMPOSERS 34. 4. MATERIALS AND METHODS The salt marshes were surveyed by means of a series of line tran-sects projected at right angles, more or less, to the coastline. Field work was conducted in the summers of 1973 and 1974. Nine transects were established in the summer of 1973 and vegetation and s o i l along the transects were studied. In 1974, five more transects were added to the nine of 1973. In a l l , fourteen line transects have been established. The shortest transect was 100 m and the longest, 1100 m (Table I I ) . Soil and plant samples were collected once at a stage judged to be at the maximum vegetative development. The emergent plant species were identified according to Hitchcock et at. (1973) and listed in Appendix 1. 4.1 Field sampling Line transects: The transect sites were selected so as to cover the whole study area and a maximum range of vegetation types. The exact positions; of transect lines were determined by the extent of salt marsh and the nearness of some permanent markers, such as power poles, trees, landscape features, etc. which would make the line transects easy to find. A l l transects began at either the upper margin of the marsh or the coastline. A measuring tape was laid out along the line of the transect, and stakes were driven at 50 m intervals. Further, a 5 x 5 cm and 1 m long cedar stake was driven 60 cm deep every 100 m and a concrete block was buried at the beginning and end of each transect (Fig. 11). Fourteen semi-permanent transects were thus established which could be T a b l e I I : T r a n s e c t d e s i g n a t i o n s , , t o t a l l e n g t h , l e n g t h occupied, by v e g e t a t i o n and quadrat i n t e r v a l s , 1974. T r a n s e c t No. L o c a t i o n L e n g t h (m) Le n g t h o c c u p i e d by v e g e t a t i o n Sampling I n t e r v a l 1 P o i n t Grey 400$ 440 50 2 Iona I s l a n d 300 0 50 3 Sea I s l a n d 900 500 100 4 Westminster Hwy. 850 815 100 5 F r a n c i s S t . 1,000 1,022 100 6 S t e v e s t o n Hwy. 900 885 100 7 R e i f e l I s l a n d 1,100 1,050 100 8 34 S t . , Su p e r p o r t 100 70 50 9 Tsawwassen Rd. 600 545 100 10 Beach Grove 250 0 50 11 72 S t . , Boundary Bay 450 410 50 12 88 S t . , Boundary Bay 250 210 50 13 112 S t . , Mud Bay 150 100 25 14 C r e s c e n t Beach 300 5 50 T o t a l L e n g t h 7,550 6,042 * The end p o i n t was s e t c o n v e n i e n t l y a t 400 m., a l t h o u g h t h e v e g e t a t i o n ended a t 440 m. 36. cross d j k e section (m) 0 3 0 0 top view c o n c r e t e block ^ - c e d a r stake c r o s s section T o p in r e d mar ine paint 23 x 23 x 23 cm weight l O K g m 1 P i l a s t e r conc re te block Cedar s t a k e Figure 11. Sketches of (a) generalized"'"- transect profiles and (b) concrete blocks and a cedar stake. 37. used to study from time to time future changes in vegetation and s o i l . 2 Quadrats: 1 x 1 m quadrats were used to sample plants at 25, 50 or 100 m intervals along a transect. The quadrats were laid by placing the stakes at the upper l e f t corner of quadrats plotted in 1973. The quadrats were laid at random around the stakes in 1974 to avoid any effects of the 1973 sampling. Samples were obtained from 190 quadrats (81 on 9 transects in 1973 and 109 on 14 transects in 1974) on 14 transects. 4.2 Soil samples Soil was sampled with a core-type sampler (5.5 cm diameter and 5.5 cm height). One core was taken from the center of each quadrat on 9 transects in the summer of 1973. Three cores were taken at random from each quadrat on a l l 14 transects in the summer of 1974. Soil samples were taken from every quadrat, lai d to collect plant samples and, addit-ionally, s o i l samples were collected along the transects on those tran-sects and parts of transects which were not vegetated. 4.3 Plant samples Height: Plant heights were measured 20 times at each 50 m interval as shown in Table III along each transect. The intervals from one reading to another reading were not always exactly 2.5 m. Species frequency: Each vascular plant species and i t s frequency on every quadrat were recorded using frequency indices as shown in Table IV. 38, T a b l e I I I : I n t e r v a l s o f p l a n t h e i g h t measurement, 1974. The i n t e r v a l s chosen depended on the l e n g t h o f t h e t r a n s e c t s and some t e r r a i n f a c t o r s . Each s o l i d l i n e r e f e r s to an i n t e r v a l o f 50 meters and 20 r e a d i n g s o f p l a n t h e i g h t . T r a n s e c t No. L o c a t i o n 1 P o i n t Gray 2 Iona I s l a n d 3 Sea I s l a n d 4 Westminster Hwy. 5 F r a n c i s S t . 6 S t e v e s t o n Hwy. 7 R e i f e l I s l a n d 8 34 S t . , S u p e r p o r t 9 Tsawwassen Rd. 10 Beach Grove 11 72 S t . , Boundary Bay 12 88 S t . , Boundary Bay 13 112 S t . , Mud Bay 14 C r e s c e n t Beach 0 t H-t I n t e r v a l (m ) 200 ,• 400 600 800 1000 i + The a r e a was b u l l d o z e d and d e s t r o y e d b e f o r e the s u r v e y o f 1974. »+it A c a t t l e c o r r a l l i e s on the f i r s t 0-150 m i n t e r v a l o f t h e t r a n s e c t . 39. Table IV: Species frequency indices for transect quadrats Cuseuta (Dodder) sp. frequency was not included. Index 2 Stalks/m 5 1 - 5 10 6-14 25 15 - 39 70 40-99 100 100 -Aerial plant material: The above-ground materials were obtained by clipping a l l " l i v i n g " and "dead" materials at 5 cm high from the s o i l line in each quadrat. Plant parts lying on the ground and no longer attached to the plant were also included in the "dead" materials. Most samples were immediately sorted into l i v i n g and dead portions based on whether or not the harvest contained green tissue. The ground condi-tion in the marsh, i.e. wet and muddy, prevented accurate dead material collections in many cases. The above-ground materials were collected for dry matter weight and chemical analysis. Since sampling was done near the peak of the growing season, the portion of the samples was expected to represent "maximum summer stand-ing crop" or "cumulative growth" of the current year per square meter. Below-ground materials were not sampled from the one square meter quadrats. 4.4 Laboratory analysis 40. 4.4 Laboratory Analysis Soil: Soil samples were air dried at 40°C and sieved through a 2 mm mesh before physical and chemical analyses were made. Both s o i l and plant analyses were done in the Plant Science Dept. laboratory, The University of B.C. pH: A 1:2 soil-water slurry was prepared by mixing 50 g of each s o i l sample with 100 ml of d i s t i l l e d water in a plastic jar. Some samples, however, needed a 1:4 soil-water ratio, to obtain a reasonable slurry. Each sample was stirred at 15 minutes intervals for one hour. The sample was then thoroughly stirred and, within one minute, the electrode of a Beckman pH meter was inserted. Salinity: Electrical conductivity of the s o i l samples was meas-ured with a "Soil-Tester Solubridge" and expressed in millimhos per cubic centimeter. The preparation steps were the same as for s o i l pH measurement preparation. Organic Matter: Organic matter content was determined by a wet oxidation procedure according to Gilchrist (1967). Plant Analysis: The plant samples collected from the marsh were air-dried at 40°C for about two days in a large tunnel dryer; then they were hammer-milled. The representative sub-sample taken from the hammer-m i l l sample was again milled in a Wiley m i l l to pass a 0.6 mm mesh, and oven-dried to constant weight at 100°C in a forced-draft oven. The sub-sample prepared as above was used for nitrogen and lignin analyses. Dry Weight: The plant samples were weighed.after they were com-pletely air-dried (at 40°C for about two days, sometimes four days). Nitrogen: Total nitrogen content was determined by a semi-micro Kjeldahl procedure (Nelson et al., 1973). Lignin: Lignin was determined by the acetyl bromide technique after Morrison (1972). Ash: Ash content was determined by weighing approximately 2 gm of a hammer-milled sub-sample and ashing i t at 550°C u n t i l the ash weight remained constant. 5. OBSERVATIONS AND RESULTS 5.1 Area, productivity and quality estimates for the t o t a l marsh area The area and dry matter y i e l d for each p r i n c i p a l plant species and for each band or island were estimated by the help of air-photos, following f i e l d reconnaissance and data c o l l e c t i o n during the summers of 1973 and 1974. The study area was divided into three sections, i . e . (a) Sturgeon Bank, (b) Roberts Bank and (c) Boundary Bay. Each, respectively, accounted for 41%, 54% and 5% of the t o t a l standing crop of emergents i n 1974. Westham Island occupied 33% of the marsh land and accounted for 43% of the t o t a l standing y i e l d (Table VI). The t o t a l area of the marsh studied was 1901 hectares and 9408 metric tons of dry matter of various marsh plants were produced. The average y i e l d was 4.9 tons per hectare. The four species giving, i n decreasing order, highest standing yields were Carex lyngbyei, Soirpus americanus, Soirpus paludosus and Typha latifolia. Soirpus americanus occupied 40% of the marsh land and accounted 32% of the t o t a l standing y i e l d i n 1974. D r i f t wood (Fig. 29) was important and occupied 56 hectares, an area equal to one-th i r d of the marsh land of Sea Island (Table V and Table VI). The dry matter y i e l d of (maximum) standing crop per unit d i f f e r s from area to area. However, there i s a roughly lin e a r decrease i n dry matter weight with increasing distance from the dikes. The data for 43. Table V: Estimates of the area and dry matter yields of principal species for the whole area, 1974. Species ha. Area (%) Standing Crop Yield Totals tons (%) Standing Crop Average Yields tons/ha. Carex Z. 366 ( 19) 3,393 ( 36) 9.3 Scirpus a. 752 ( 40) 3,039 ( 32) 4.0 Scirpus p. 247 ( 13) 1,225 ( 13) 5.0 Typha Z. 144 ( 8) 684 ( 7) 4.8 SaZicornia v. 140 ( 7) 452 ( 5) 3.2 Scirpus v. 63 ( 3) 305 ( 3) 4.8 TrigZochin m. 91 ( 5) 165 ( 2) 1.8 DistichZis s. 42 ( 2) 145 ( 2) 3.5 Drift wood' 56 ( 3) 0 ( 0) 0 Total 1,901 (100) 9,408 (100) 4.9 Table VI: Estimates of the area and dry matter yields of emergent vegetation for the whole area and i t s major parts, 1974 Location Area of Marsh Standing Crop Standing Crop Yield Totals Average Yields ha. (%) tons ( :%) tons/ha Point Grey - Sturgeon Bank Point Grey 75 ( 3) 410 ( 5) 5.5 Sea Island 169 ( 9) 931 ( 10) 5.5 Lulu Island 543 ( 29) 2,475 ( 26) 4.6 Total 787 ( 41) 3,816 ( 41) 4.8 Roberts Bank Area Westham Island 629 ( 33) 4,040 ( 43) 6.4 Brunswick 164 ( 9) 807 ( 8) 4.9 Tsawwassen 84 ( 4) 277 ( 3) 3.3 Total 877 C 46) 5,124 ( 54) 5.8 Boundary Bay Area Boundary Bay Total Ground Total 237 ( 13) 237 ( 13) 1,901 (100) 468 468 9,408 ( 5) ( 5) (100) 2.0 2.0 4.9 dry matter weight, c o l l e c t e d from eight transects i n 1973, were plo t t e d against distance from the dikes (Fig. 12). The plant height of the same eight transects was also p l o t t e d against the distance from the dikes (Fig. 13). There were s i g n i f i c a n t differences i n height with distance within each of the eight l i n e -transects. There were no s i g n i f i c a n t differences i n plant height between l i n e - t r a n s e c t s . Plant height of a l l the transects except Tsawwassen Rd. Transect (No. 9) decreased s i g n i f i c a n t l y from the dikes and that the pattern of change i n plant height remains much the same from transect to transect (Fig. 13). 45. 80 0 I 40 0 D i s t a n c e f r o m d i k e ( m } seaward 2 Figure 12. Averages of dry matter weights m grams per m (based on unequal numbers of variable per sample) against distance i n meters from dikes, 1973. 46. 18 0 0 200 4 0 0 600 8 0 0 1000 « .^ D i s t a n c e f r o m d i ke l m ) s e a w a r d Figure 13. Changes in plant height in cm. against distance in m. from dikes, 1973. (Each point is an average of 20 observations.) 1 - Point Grey Transect 4 - Westminster Hwy. Transect 5 - Frances St. Transect 6 - Steveston Kwy. Transect 7 - Reifel Island Transect 9 ~ Tsawwassen Rd. Transect 11 .- 72 St. Boundary Bay Transect 12 - 99 St. Boundary Bay Transect (- - -) Area covered by debris, mainly logs 5.2 Principal species Five principal species from representative stands were collected from Reifel marsh and 88th St. transects in the middle of September, 1973. They were Typha latifolia, Carex lyngbyei, Soirpus americanus, Soirpus validus and Salicornia virginica (Table VII). Each was observed in the f i e l d . Later, samples were analyzed for nitrogen, lignin and ash. An important species not included in the 1973 study was Soirpus paludosus (Fig. 14). Carex lyngbyei showed markedly different growth from the others as expressed in number of stalks per unit area, top/root ratio and t 2 lignin percentage. Carex 1. averaged 739 shoots/m and had the largest weights of liv i n g material per m , but Typha 1. had the largest combined weight of living and dead material. Inflorescence bearing shoots of Carex 1. were shorter than those not bearing inflorescences. The top/root ratios .of Soirpus a. (Figv 15) and Sdtioornia v. were approximately 0.6 and 0.2 respectively and showed the greatest v a r i a b i l i t y among the five. The height of shoots with and without inflorescences was measured; i t was found that, in the cases of Carex 1. and Soirpus v., the inflorescence-bearing shoots were shorter than those not bearing inflorescences. The lignin percentages of Typha 1. and Carex 1. were higher than those of the other species, but the differences were small. The very high percentages of ash were unquestionably due to mud adhering to the stalks which were not washed for chemical analysis (Table VII). Abbreviations are not standard; i t was deemed useful for the purposes of this study to give the generic name in f u l l and to abbreviate the specific name. 48 Table VII: Estimates from meter square quadrats of several phytomass and chemical fract i o n s for four (4) p r i n c i p a l species, R e i f e l Island transect (No. 7), and one (1) 88 St., Boundary Bay transect (No. 12), 1973. Sampling date Location Distance from dike ( m ) Typha l a t i f o l i a Sept. 11, 1973 R e i f e l (No. 7) 50 Carex lyngbyel Sept. 13, 1973 R e i f e l (No. 7) 150 Scirpus amerlcanus Sept. 12, 1973 R e i f e l (No. 7) 300 Scirpus validus S a l i c o m i a v i r g i n i c a Sept. 15, 1973 Sept. 12, 1973 R e i f e l (No. 7) 88 St.,B.B. (No.12) 300 150 GROSS PLANT FRACTIONS No. and height (cm ) of: No. ( cm ) No. ( cm ) No. ( cm ) No. ( cm ) No. ( cm ) Shoots, with inflorescence 1 ( - ) 151 ( 57) 245 ( 74) 46 (169) _ Shoots without inflorescence 26 ( 160) 588 ( 109) 296 ( 7 5 ) 80 ( 144) _ Total and average 27 ( 160) 739 ( 98) 541 ( 75) 126 (153) - ( 8) GROSS PHYTOMASS FRACTIONS Dry matter weight, g. (%) g- ( X ) 8- ( Z ) g- ( Z ) g- ( z ) g- ( Z ) Inflorescence (Husk and seed) 16 ( 0.4) 62 (1.7) 7 ( 0.5) 12 ( 0.4) 0 ( 0) L i v i n g and senescent top 517 (12.6) 1,070 (29.8 844 (57.9) 385 (14.0) 304 (18.4) Dead 755 (18;4) 0 ( 0) 0 ( 0) 0 ( 0) 0 ( 0 ) Detritus 1,324 (32.3) 0 ( 0) 0 ( 0) 282 ' (10.2) 0 ( 0) Crowns and underground shoot root^ 1,221 (29.8) 772 (21.5) 152 (10.4) 1,714 (62.1) 230 (13.9) Root (10 cm. deep) Total g /ra^ 270 ( 6.5) 1,691 (47.0) 454 (31.2) ' 366 (13.3) 1,120 (67.7) A, 103 (100.0) 3,595 (100.0) 1,457 (100.0) 2,759 (100.0) 1,654 (100.0) CHEMICAL FRACTIONS Plant Analyses:. L i v i n g Top (L) and Dead(D) L D L D L D L D L D Dry matter, ash free 479 286 944 - 640 - 346 _ 216 _ Nitrogen (Z) 0.48 0.28 0.61 - 0.67 _ 0.53 0.60 _ Nitrogen (g/m^) 5.0 4.2 6.5 - : 5.7 _ 2.0 _ 1.8 _ Nitrogen, ash free (Z) 0.51 0.74 0.69 - 0.38 _ 0.59 0.84 _ Lignin (Z) 11.1 12.5 11.5 - 9.0 _ 8.6 6.5 _ • Lignin, ash free (Z) 12.0 . 33.0 13.0 _ 11.9. 9.6 9.1 Ash (Z) 7.3 62.1 11.7 - 24.2 - 10.1 28.8 • • + Crowns and underground shoot root include material below 5 cm from ground l e v e l . Three samples were collected with a core-type sampler (12.5 cm diameter and 10 cm height) and converted to one meter square. ( A ) Figure 14. Scirpus paludosus; Photo taken from the dike looking seawards along the transect, Sea Island, August, 1974. 5.3 Area, productivity and quality estimates for Sturgeon Bank-Point Grey (Transect No. 1-6) Sturgeon Bank was divided into three sub-areas; (a) Point Grey, (b) Sea Island and (c) Lulu Island (Table VIII and Fig. 16). A total of six transects were set out and s o i l and plant samples, collected from each transect, were subjected to physical and/or chemical analy-sis. The five principal species of Sturgeon Bank were Soirpus a. 3 Soirpus p.3 Soirpus v.3 Carex I. and Typha 1. In Sea Island, sub-area (b), Soirpus p. occupied 44% (75 hectares) of the marsh area and accounted for 41% (382 tons) of the standing crop dry matter. In the Lulu Island, sub-area (c), Carex 1. 3 Soirpus a. and Soirpus p. accounted for 33%, 33% and 30% of the standing crop dry matter respectively. The average unit area yields (ton/ha) of three sub-areas were much the same (Table VIII). 51 a. Figure 16. Map to show the vegetational areas and the location and vegetation of the line-transects (No. 1-6) in the Point Grey-Sturgeon Bank area, 1974. Legend 1 2 3 4 5 6 Point Grey Transect Iona Island Transect Sea Island Transect Westminster Hwy. Transect Francis St. Transect Steveston Hwy. Transect (Swishwash Island i s included with Lulu Island) Carex lyngbyei Distichlis striata Salicomia virginica Scirpus americanus Scirpus paludosus o o o o © © e 6 • • A A Scirpus validus Trigtochin maritimum Typha • latifolia D r i f t wood 51 . b Table VIII: Estimates of the area and dry matter yields of emergent vegetation of the several sections for the Point Grey_ r.Sturgeon (Bank Area, 1974. L o c a t i o n A r e a S t a n d i n g Crop Average Y i e l d , and d r y m a t t e r d r y m a t t e r S p e c i e s ha. (%) t o n (%) ton/ha. P o i n t Grey: Scirpus a. 18 ( 24) 148 ( 36) 8.2 Scirpus v. 40 ( 53) 124 ( 30) 3.1 Carex I. 7 C 10) 91 ( 22) 13.2 Typha I. 10 C 13) 47 ( 12) 4.7 Total 75 (100) 410 (100) 5.5 Sea Island: Scirpus p. 75 ( 44) 382 ( 41) 5.1 Scirpus a. 68 ( 40) 271 ( 29) 4.0 Carex 1. 17 ( 10) 185 ( 20) 10.6 Typha I. 9 ( 6) 93 ( 10) 10.6 Total 169 (100) 931 (100) 5.5 julu Island: Carex I. 147 ( 27) 825 ( 33) 5.6 IScirpus a. 201 ( 37) 807 ( 33) 4.0 Scirpus p. 153 ( 28) 749 ( 30) 4.9 Scirpus v. 14 ( 3) 77 ( 3) 5.6 Typha I. 28 ( 5) 17 ( 1) 3.3 Total . 543 (100) 2,475 (100) 4.6 53. 5.3.1 Point Grey Transect (No. 1) The highest dry matter yields in the entire study area were 2 obtained from the Point Grey transect in 1973 and 1974, i.e. 1,819 g/m 2 and 1,668 g/m , respectively. Vegetation: : The sub-area i s located along the North Arm of Fraser River. Although the area i s small and apparently "wasteland", the order of plant communities i s typical and representative of delta foreshore area (Table IV). Much of dead material, mostly Typha latifolia, remained in situ from 0 m up to 150 m from the road. The plant height varied greatly. This must be attributed, in part, to the s u r f i c i a l distur-bance of s o i l and vegetation by escaped logs. The dry matter yields were high at between 100 m and 250 m from the road,verge. The nigrogen percent-age increased further from the road. There were no special relationships between nitrogen percentage, nitrogen yield, lignin and ash percentage (Table IV). Soil: The organic content of soils from 50 m to 200 m was high and varied from 8% to 31%. The pH values at 50 m to 250 m were below 6, but were above 7 at 350 m and 400 m. The electric conductivity was approximately 1 mmhos at a l l places along the transect except at 0 m. The soils were s i l t y or clayey except those at 0 m which were sandy (Table IV). 54. Table IX: Point Grey Transect (No. 1): Soil and Plant Analyses, 1974-Distance from dike (in) 0 0 50 50 100 100 150 150 200 250 300 350 400 Principal species E.f. R.l. =-T . l . A.g. - T.l. A.g. - T.l. A.g. ..- C.l. C.l. T.l. S.v. T.m. S.v. T.m. S.a. S.v. Living (L) mat-erial; Dead (D) material L D L D L D L D L . L L L L Height (cm )Plants i l l 193 66 114 Interval (m) be-tween samples (0-50) (100-150) (200-•250) (300-350) Dry matter (g ) 317 240 360 173 686 962 377 409 968 1668 380 245 818. D. matter - ash (g ) 284 214 330 162 642 929 356 350 861 1512 394 216 665 Nitrogen (%) 0.41 0.36 0.66 0.49 0.44 0.35 0.64 0.35 0.54 0.55 0.81 0.88 0.75 2 Nitrogen (g/m ) 1.3 0.87 2.4 0.85 3.0 3.4 2.4 1.4 .5.2 9.2 3.1 2.2 6.1 Nitrogen in ash-free d.m. (%) 0.46 0.40 0.72 0.52 0.47 0.36 0.68 0.41 0.61 0.61 0.90 0.99 0.92 Lignin (%) 7.7 11.5 10.0 14.2 5.6 7.5 5.0 10.6 11.8 11.3 8.0 7.2 7.3 Lignin in ash-free d.m. (%) 8.6 12.9 10.9 15.2 6.0 7.8 5.3 12.4 13.3 12.5 8.9 8.1 9.0 Ash (%) 10.5 10.8 8.4 6.3 6.4 3.4 5.5 14.4 11.1 9.4 9.6 11.7 18.8 Soil organic matter (%) 6.2 - 31.2 21.8 - 8.2 9.9 6.8 2.8 2.6 2.3 Soil pH (1:2) 6.1 - 5.8 - 5.8 - ' 5.9 - 5.9 5.7 6.8 7.1 7.3 Electric con-ductivity (mmhos. 1:2) 0.22 • -. 0.74 0.74 0.75 0.82 0.92 1.00 1.02 0.83 5.3.2 Iona Island Transect (No. 2) This small island i s located on the south side of the North Arm of the Fraser River. The existence of a large sewage disposal unit on this island, given over to secondary treatment, i s a notable feature. It i s also worthy of note that the unit also serves as a storm sewer outlet and, on occasion, i t i s reported, raw sewage may reach the tida l areas when storm water flow i s heavy. Vegetation: L i t t l e plant l i f e exists on the Iona transect (No. 2). The level of the t i d a l f l a t was well below mean sea level, a factor to consider in plant establishment. Soil: Soil samples were taken at seven locations along the transect. The percentage of s o i l organic matter was low near the shoreline, but was higher further from the shoreline. The electric conductivity followed the organic matter content; i t was 4 mmhos at 300 m. The pH values were from ca. 7 from 0 m - 150 m, but became higher from 200 m - 300 m (Table X). Sedimentation seemed to be occurring with a resultant mosaic of s i l t and sand. Table X: Iona Island Transect (No. 2): S o i l and Plant Analyses, 1974. Distance from dike (m.) 0 50 100 150 200 250 300 P r i n c i p a l sea species weed _ _ _ _ _ _ Living (L) mat-e r i a l ; Dead (D) material D _ _ _ _ _ _ Height (cm.) Plants Interval (m.) be-tween samples Dry matter (g.) 340 _ _ _ _ _ _ D. matter - ash (g ) 142 _ _ _ _ _ _ Nitrogen (%) 0.76 - _ _ - - -2 Nitrogen (g/m ) 3.0 -Nitrogen i n ash-free d.m. (%) 2.1 - - - - - -Lignin (%) 2.8 - - - -Lignin i n ash-free d.m. (%) 7.9 Ash (%) 64.5 _ _ _ _ - -S o i l organic matter (%) 0.4 0.2 0.9 0.4 0.8 1.9 2.2 S o i l pH (1:2) 6.9 7.0 7.1 6.7 8.0 7.2 7.5 E l e c t r i c con-d u c t i v i t y (mmhos. 1:2) 0.48 0.90 1.14 1.06 1.10 2.30 2 t20 5.3.3 Sea Island Transect (No. 3) The emergent vegetation extends approximately 500 m from the dike; by contrast, emergent vegetation off Lulu Island extended 800 m to 1,000 m from the dike (Table I I ) . More t i d a l f l a t off Sea Island seemed to have been included in the past by dikes than off Lulu Island. As a result the Typha I. - Carex I. zone just outside the Sea Island dike is very narrow (Fig. 18 and Fig. 22). Vegetation: The f i r s t 0 m to 100 m of this transect was well vegetated by six species, that i s , by Scirpus paludosus3 Typha latifolia, Carex l3 Poten-tilla pacifica, Scirpus validus and Scirpus a. (Table VIII, Table XV and Fig. 16). This might imply that the area from the dike to 100 m had substantial environmental diversity to " f i t " these species. The areas from 100 m to 200 m and 200 m to 500 m were well established to Scirpus p. and Scirpus a., respectively. There was no dead material i n the quadrats on this transect. Plant height (x), starting from 122 cm at 0 m, gradually declined to 33 cm at 500 m, the transect end. The 2 highest yield obtained was 1,061 g/m from the 0 m quadrat; then yield 2 gradually decreased to 140 g from the m quadrat at 400 m. The nitrogen percentage of ash free d.m. increased from 0.66% at 0 m to 1.13% at 2 2 400 m, but the nitrogen yield decreased from 6.4 g/m to 1.4 g/m at 0 m and 400 m respectively. The lignin percentage also tended to decrease with distance from the dike. Ash percentage changed irregularly (Table XI). Soil: The pH values dropped from 7.0 at 0 m to 5.4 at 200 m, then grad-ually increased to 7.6 at 900 m. The organic matter percentage dropped from 6.1% at 0 m to 1.2% at 400 m, and thereafter remained at the latter figure. The electric conductivity followed the trend of s o i l organic matter (Fig. 17 and Table XI). 59, 0 200 400 600 800 1000 (b) ui 0 200 400 600 800 1000 D i s t a n c e (m) s e a w a r d (c) Figure 17 Sea Island Transect (lIo. 3); (a) dry matter weight and plant height, (b) nitrogen fo and lignin' % and (c) soi l organic matter, pH and conductivity, 1974. Legend • • X X X X o o o o Agrostis exarata Carex lyngbyei Potentilla paaifiaa Soirpus americanus Scirpus paludosus Scirpus validus Triglochin maritimum Typha latifolia Figure 18. Vegetation micro-map for the Sea Island Transect (No. 3), 1974. 60. b 61 . Table XI: Sea Island Transect (NC. 3): S o i l and Plant Analyses, 1974. Distance from dike ( m) 0 100 200 300 400 500 600 700 800 90 P r i n c i p a l species C . l . T . l . P . l S.p. S.a. S.p. S.a. S.p. S.a. - - - -Living (L) mat-e r i a l ; Dead (D) material L L L L L Height (cm.) Plants 122 113 61 33 Interval (m) be-tween samples (0-50) (150-200)(300- •350) (450-: 500)- - -Dry matter (g ) 1061 481 644 405 140 - - - -D. matter - ash (g ) 958 436 556 357 121 - - - -Nitrogen (%) 0.60 0.84 0.66 0.85 0,98 - - - -• 2 Nitrogen (g/m ) 6.4 4.0 4.2 3.4 1.4 - - - -Nitrogen i n ash-free d.m.(%) 0.66 0.93 0.76 0.96 1.13 - - — — - . Lignin (%) 9,1 11.6 11.0 8.5 6.6 - - -. Lignin i n ash-free d.m. (%) 10.1 12.8 12.7 9.6 7.6 - - -. Ash (%) 9.7 9.3 13.6 11.8 13.1 - - -• -S o i l organic matter (%) 6.1 4.6 3.6 1.5 1.2 0.7 0.8 1.0 0.9 i . : S o i l pH (1:2) 7.0 5.7 5.4 5.8 6.7 7.2 7.4 7.5 7.6 7.1 E l e c t r i c con-du c t i v i t y (mmhos. 1:2) 4.1 3.4 2.3 1.1 1.2 1.1 1.1 1.0 1.5 l . l 62. 5.3.4 Westminster Highway Transect (No. 4), Lulu Island The distinctive feature of this transect was the very marked roughness of the microtopography from 250 m to 350 m. Again the micro-topography of the transect surface from 600 m to 800 m was quite rough and many pools were to be seen at low tide (Fig. 19 and Fig. 21). There was a network of channels approximately 50 cm to 60 cm deep and 30 cm to 50 cm wide; the raised parts or "islands"were densely covered by Carex I. Often the Carex. foliage drooped into the channels. This transect showed the most diversity in plant species among the three transects off Lulu Island. Vegetation: Although this area showed more diversity in plant species, the order of the communities i s much the same as that of most other transects. Carex I. and Typha I. dominated the f i r s t 100 m followed by Scirpus v., Scirpus p., Tiglochin m and Scirpus a. (Table XV). The 0 m quadrat only yielded dead materials, while the others had no dead material. The plant stature gradually declined, from 126 cm at 0 m and to 17 cm at 800 m. The dry matter yield followed the trend of plant stature except for 2 the extremely high yield of 1,036 g/m at 300 m. The ash percentage varied from 8.2% to 15.2% and appeared to be without special patterns. A l l of the nitrogen percentages of ash free d.m. f e l l in the range of 0.49% and 1.05% except for that of the material harvested at 800 m,viz. 1.66%. The lignin percentages of ash free d.m. tended to decrease away from the dike (Table XII). Soil: The pH at 0 m was the lowest; then the pH gradually rose to 7.4 at 800 m. The organic matter was high at 0 m point, then gradually f e l l 63. to 1.2% at 800 m. The electric conductivity did not change very much and a l l values f e l l in the range of 0.7 and 1.8 mmhos (Table XII). 64. ( B ) Figure 19. Photographs of a small channel (A) and a large channel ( B ) , Lulu Island marsh, 1974. "Tater flows quite rapidly at times washing plants and carrying detritus which may be an energy source for the fauna of marsh and sea. 65. Table XII: Westminster Highway Transect (No. 4): Soil and Plant Analyses, 1974. Distance from dike (M9) 0 0 100 200 300 400 500 600 700 800 iPfBrine,d?p-al species C.l. P.p. T.l. - T.l. S.v. S.p. C.l. S.v. S.a. • S.a. T.m. S.a. T.m. S.a. S.a. Living (L) mat-e r i a l ; Dead (D) material L D L L L L L L L L Height (cm,) Plants Interval 0n ) 126 (0-50) 107 (200-250) 90 69 17 (400-450) (600-650) (800-85 Dry matter (g t) 794 558 563 608 1036 3317 501 328 287 35 D. matter - ash (g ) 691 418 517 555 879 274 448 281 250 31 Nitrogen (%) 0.64 0.37 0.80 0.61 0.67 0.79 0.69 0.90 0.72 1.47 2 Nitrogen (g/m ) 5.1 2.1 4.5 3.7 6.9 2.5 3.5 3.0 2.1 0.5 Nitrogen in ash-free d.m. (%) 0.73 0.49 0.87 0.67 0.79 0.91 0.77 1.05 0.83 1.66 Lignin (%) 10.6 13.8 8.5 10.5 8.8 7.2 7.8 7.4 6.4 6.0 Lignin in ash-free d.m. (%) 12.2 18.4 9.3 11.5 10.4 8.3 8.7 8.7 7.4 6.8 Ash (%) 12.9 25.2 8.2 8.7 15.2 13.5 10.7 14.5 13.0 11.7 Soil organic matter (%) 11.9 - 5.2 6.1 4.1 2.9 3.1 2.4 2.5 1.2 Soil pH (1:2) 5.7 - 5.7 5.9 6.3 6.3 6.7 6.4 6.8 7.4 Electric con-ductivity (mmhos. 1:2) 0.8 0.7 1.8 144 1.1 1.3 1.7 1.0 0.9 66. 5.3.5 Francis St. Transect (No. 5) This transect i s located almost i n the middle of f the Lulu Island foreshore. The dike was cleaned and reconstructed during the summer of 1974 (Photograph 9, Appendix 2). The surface of t h e . t i d a l f l a t was r e l a t i v e l y uniform but was traversed by a few well developed channels (Fig. 21). Vegetation: Carex 1. mainly dominated the 0 m to 200 m area, then Scirpus p.3 200 m to 400 m and Scirpus a. from 400 m to 1,000 m. Many small pools and bare places were observed over the area from 600 m to 900 m (Fig. 22 and Table IV). Dead material was obtained from quadrats at 100 m, 200 m and 700 m. The dry matter yields were high at 700 m, 1,000 m and 200 m 2 v i z . 855, 661 and 541 g/m respectively. The plant height varied from a low of 59 cm at 175 m and to a high of 108 cm at 325 m and at 725 m. Ash percentage showed l i t t l e pattern, but l i g n i n percentage of ash free d.m. tended to decrease with distance from the dike. Nitrogen % of ash free material varied from 0.64% to 1.14% (but was 0.39% for dead material at 700 m) (Fig. 20 and Table XI I I ) . S o i l : Organic matter % was high near the dike, but decreased substantially near the outward margin of the vegetated zone. The pH was 5.6 at 0 m, then gradually increased to 7.1 at 1,000 m (exception, 6.9 at 400 m and 7.2 at 700 m). E l e c t r i c conductivity was r e l a t i v e l y high, from 0 m to 600 m, but decreased to 0.8 mmhos at 1,000 m (Fig. 20 and Table X I I I ) . 1000 (a) CD CD OT O (b)_ tn o £ > X CL O 3 TJ C o o (c) 2 0 •6 12 8 4 0 200 4 0 0 600 8 0 0 l i g n i n 200 400 6 0 0 8 0 0 0 2 0 0 4 0 0 6 0 0 D i s t a n c e (m) 8 0 0 1000 1000 1000 s e a w a r d Figure 20. Francis St. Transect (No.; 5); (a) dry matter weight and height, (b) nitrogen f> and lignin fo and (c) soi l organic matter, pH and conductivity, 1974. 63 a . Figure 21. Photographs of a small pool (A) on the Westminster Highway Transect (No. 4), Lulu Is., and a large channel (B) near the Francis St. Transect (No. 5), Lulu Is., 1974. The small pool may support anadromous fis h even at low tide. The large channel, at high tide, i s shown as a rest area for waterfowl. ( B ) Legend D B Agrostis exarata Carex lyngbyei x x X X Totentilla paoifiaa Distahlis striata m Soirpus americanus m Scirpus paludosus Triglochin maritimum Figure 22. Vegetation micro-map for the Francis St. Transect (No. 5), Sturgeon Bank, 1974. 69. b 70. Table XIII: Francis St. Transect (No. 5): S o i l and Plant Analyses, 1974. Distance from dike (-) 0 100 100 200 200 300 400 500 600 700 700 800 900 1000 P r i n c i p a l species b u l l -dozed C . l . A. s. T.m. - D.8. S.p. - S.p. S.p. S.a. S.a. S.p. S.a. S.p. S.a. S.p S.a. S.a. S.a. Li v i n g (L) mat-e r i a l ; Dead(D) material - L D L D L L L L L D L L L Height (cm ) Plants - 59 108 78 61 108 86 Interval ('- ) between samples (150-200) (300-350) (450-500)(600-650) (750-800)(900-950) Dry matter (g ) - 428 704 541 32 381 222 254 425 855 61 315 370 661 D. matter -ash (g ) - 402 471 471 25 327 200 224 3fil 762 53 265 316 568 Nitrogen (%) - 0.81 0.53 0.68 0.59 0.94 0.67 0.76 0.97 0.57 0.34 0.79 0.68 0.77 Nitrogen (g/m ) - 3.5 3.7 3.7 0.2 3.6 1.5 1.9 4.1 4.9 0.2 2.5 2.5 5.1 Nitrogen i n ash-free d.m. (Z) - 0.86 0.79 0.78 0.79 1.09 0.74 0.86 1.14 0.64 0.39 0.94 0.79 0.90 Lignin (2) - 12.1 13.6 8.3 29.3 10.3 10.9 8.6 8.9 9.4 19.3 6.8 2.2 2.1 Lignin i n ash-free d.m. (%) - 12.9 20.3 9.5 38.1 12.1 12.1 9.8 10.5 10.6 22.3 7.9 2.6 8.3 Ash (Z) - 6.1 33.1 12.9 23.0 14.0 10.0 11.8 15.0 10.9 13.3 15.7 14.4 14.1 S o i l organic matter (%) 10.1 11.4 - 7.5 - 3.5 2.6 2.9 5.3 0.9 2.1 1.1 0.8 S o i l pH (1:2) 5.6 6.1 - 6.2 - 6.4 6.9 6.5 6.5 7.2 - 6.6 7.0 7.1 E l e c t r i c con-d u c t i v i t y (mmhos. 1:2) 3.4 4.4 5.0 3.7 3.5 3.1 3.1 1.3 2.4 1.5 0.8 71. 5.3.6 Steveston Highway Transect (No. 6) The transect off the end of the Steveston Highway i s near the Steveston j e t t y . There was not much surface disturbance and the topography was f a i r l y uniform. A c a t t l e holding yard made by a farmer occupied a large area, outside the dike; from 0 m to 200 m along the transect, where otherwise Distiohlis s., Carex I. or Typha 7. would grow (Photographs 11 and 12, Appendix 2), the vegetation had been grazed or trampled down. Vegetation: The f i r s t 200 m outside the^.cattle holding yard, and p a r a l l e l to the transect, was dominated by Typha 1. followed by Trigtochin m. and Scirpus a. with occasional Scirpus p. (Table XV). No dead material was obtained from t h i s transect. The plants were r e l a t i v e l y t a l l and varied i n height from 136 cm at 200 m to 81 cm at 800 m. The highest dry 2 2 matter y i e l d was 618 g/m at 700 m, and the lowest 144 g/m at 200 m. 2 The other yields varied from 347 to 588 g/m . The ash % was high especially at 300 m and at 400 m. The nitrogen % of ash free materials was f a i r l y constant and lay i n the range of 0.78% to 1.05%. Lagnin % decreased irregu-l a r l y (Table XIV). S o i l : Organic matter % was r e l a t i v e l y high and decreased gradually seawards from the dike, except at 200 m where an anomalous value w a s obtained. The pH value increased gradually from 5.6 to 7.2. The e l e c t r i c conductivity was r e l a t i v e l y high and ranged from 1.3 mmhos to 3.0 mmhos (Table XIV). 72, T a b l e XIV: S t e v e s t o n Highway T r a n s e c t (No. 6): S o i l and P l a n t A n a l y s e s , 1974. D i s t a n c e from d i k e Cm-) 0 100 200 300 400 500 600 700 800 P r i n c i p a l ? - c a t t l e p a d l o c k T . l . T.m. T.m. S.a. S.a. S.a. S.a. s p e c i e s ; b u l l d o z e d S.a. S.p. S.a. L i v i n g (L) mat-e r i a l ; Dead (D) - - L L L . L L L L m a t e r i a l H e i g h t (cm ) P l a n t s 136 81 48 91 81 I n t e r v a l (lm ) be-tween samples (150-200)(300-350) (450-500)(600--650) (750-8 Dry m a t t e r (g ) 144 588 404 450 367 618 347 D. m a t t e r - a s h (g,) 132 482 328 394 312 516 297 N i t r o g e n (%) 0.86 0.77 0.72 • 0.64 0.76 0.65 0.90 2 N i t r o g e n (g/m ) 1.2 4.5 2.9 2.9 2.8 4.0 3.1 N i t r o g e n i n a s h -f r e e d.m. (%) 0.93 0.94 0.89 0.73 0.90 0.78 1.05 L i g n i n (%) 5.6 8.0 5.1 3.7 7.1 2.9 3.4 L i g n i n i n a s h -f r e e d.m. (%) 6.1 9.8 6.3 4.2 8.4 3.5 4.0 Ash (%) 7.9 18.1 18.7 12.4 15.1 16.5 14.5 S o i l o r g a n i c m a t t e r (%) 10.7 3.6 3.4 2.4 1,6 1.7 1.3 S o i l pH (1:2) 5.6 6.2 6.3 6.5 6.8 6.9 7.2 E l e c t r i c con-d u c t i v i t y (mmhos. 1:2) 2.0 2.3 3.0 1.8 1.5 1.3 1.3 73. Table XV: Principal species log for transect (No. 1 - 6) of Point Grey, Sea Island and Lulu Island, 1974. Point Grey Transect (No. 1): Index Westminster Hwy. Transect (No. 4): Distance(m Species Distance m Species Index 0 Equisetum f. 100 0 Carex I. 100 0 Rubus I. 25 0 Potentilla p. 25 50 Typha I. 10 0 Lathyrus p. 10 50 Angelica g. 70 0 Typha I. 10 100 Typha I. 25 100 Typha I. 25 100 Angelica g. 25 200 Scirpus v. . 100 150 Typha I. 25 200 Scirpus p. 25 150 Angelica g. 2 300 Carex I. 100 200 Carex I. 100 300 Scirpus. v. 70 250 Carex I. 100 400 Scirpus a. 100 250 Typha I. 100 500 Scirpus. a. 100 300 Scirpus v. 100 500 Triglochin m. 5 300 Triglochin m. 100 500 Scirpus p. 5 350 Scirpus. v. 100 500 Scirpus v. 5 400 Scirpus a. . 100 600 Scirpus a. 100 400 Scirpus v. 70 600 Triglochin m. 100 700 Scirpus. a. 100 Sea Island Transect (No. 3):. Francis St. Transect (No.5): Distance(m) Species Index Distance(m) Species Index 0 Carex I. 100 0 •Typha I. 10 0 bulldozed -0 Potentilla p. 25 100 Carex I. 100 100 Scirpus p. 100 100 Triglochin m. 25 200 Scirpus a. 100 100 Potentilla: p. 15 200 Scirpus p. 100 100 Agrostis s. 100 300 Scirpus a. 100 200 Distfichlis^s. 100 300 Scirpus p. 70 200 Scirpus p. 70 400 Scirpus a. 100 200 Scirpus a. 10 300 Scirpus p. 100 400 Scirpus p. 100 400 . Scirpus a. 100 continued 74, Table XV: continued Francis St. Transect (continued): Distance pm) Species Index 500 Scirpus a. 100 500 Scirpus p. 70 600 Scirpus a. 100 600 Scirpus p. 25 700 Scirpus a. 100 700 Scirpus p. 100 800 Scirpus a. 100 900 Scirpus a. . 100 1000 Scirpus a. 100 Steveston Hwy. Transect (No. 6): Distance (in) Species Index 0 bulldozed -100 cattle paddock -200 Typha Z. 25 300 TrigZochin m. 100 300 Scirpus p. 5 300 Scirpus a. 100 400 TrigZochin m. 100 400 Scirpus a. 100 500 Scirpus a. 100 600 Scirpus a. 100 600 Scirpus p. 5 700 Scirpus a. 100 800 Scirpus a. 100 5.4 Area, productivity and quality estimates for Roberts Bank Area (Transect No. 7-9) The Roberts Bank Area was sub-divided into three areas; (a) West-ham Island, (b) Brunswick-Canoe Pass and (c) Tsawwassen. One transect was laid off Reifel Island in the Westham Island area; no transects were laid in the Brunswick area; two were laid in the Tsawwassen area (one near the Roberts Bank terminal and one near the Tsawwassen ferry terminal (Table XVI and Fig. 23). Tvigtodkin m. 3 Salicovnia v. and Distiohlis s., not found to be very important species in the area from Point Grey to Steveston, were common in this area in addition to the five dominants of Sturgeon Bank. The average yield (ton/ha) of emergent vegetation (standing crop) was the lowest on the Tsawwassen ferry tran-sect of the three transects charted; the d r i f t wood off the Tsawwassen Rd. alone accounted for 7 hectares. 76 a. Figure 23. Map to show the vegetational areas and the location and vegetation of the line-transects (No. 7-9) in the Roberts Bank Area, 1974. Legend 7 - Reifel Island Transect 8 - 34th St. (Superport) Transect 9 - Tsawwassen Rd. Transect o o o o A A Carex lyngbyei Distichlis striata Salioornia virginiaa l ^ j Scirpus americanus Scirpus paludosus Scirpus validus TrigZochin maritimum Typha lati folia Drift wood T a b l e XVI: E s t i m a t e s o f the a r e a and d r y m a t t e r y i e l d s o f emer-gent v e g e t a t i o n o f s e v e r a l s e c t i o n s o f t h e R o b e r t s Bank a r e a , 1974. A r e a S t a n d i n g Crop Average Y i e l d L o c a t l o n d r y m a t t e r and S p e c i e s ^ ( % ) t m ( % ) t o n / h a ; Westham I s l a n d : T Carex I. 173 ( 28) 2,043 ( 51) 11.8 Scirpus a. 350 C 56) 1,366 ( 34) 3.9 Typha I. 97 C 15) 527 ( 13) 5.4 Scirpus v. 9 C 1) 104 ( 2) 11.8 T o t a l 629 C1D0) 4,040 . (100) 6.4 Brunswick^': Scirpus a. 115 ( 70) 447 (55) 3.9 Carex I. 21 C 13) 249 ( 31) 11.8 Scirpus p. 19 C 12) 94 (12) 4.9 Triglochin m. 9 ( 5 ) 17 ( 2) 1.9 T o t a l 164 (100) 807 (100) 4.9 Tsawwassen: Salicornia v. 40 ( 48) 142 ( 51) 3.6 Distichlis s. 37 ( 44) 135 ( 49) 3.6 D r i f t w o o d 7 ( 8 ) 0 ( 0 ) 0 T o t a l 84 (100) 277 (100) 3.3 £ The d a t a f o r t h i s a r e a may n o t be c o r r e c t ; because o f deep c h a n n e l s , the a r e a was d i f f i c u l t t o r e a c h and the e s t i m a t e s a r e o c u l a r based on e s t i m a t e s from o t h e r a r e a s . 78. 5.4.1 Reifel Island Transect (No. 7) This transect had the widest vegetation belt to cross, i.e. 1050 m, of the 14 transects (Table I I ) . The surface was much the same as that off Francis St., Lulu Island. There were a number of well developed channels (Fig. 24) which, at high tide, became excellent resting areas for waterfowl (Fig. 21 (B)). The vegetation was quite uniformly dis-tributed but the pools observed on the Francis St. transect (Fig. 22) were not encountered here. Vegetation: The changes of the principal plant species from the dike to the open sea are broadly recorded as Typha Z. to Carex Z. to Scirpus a. (Table XX). Minor communities were Scirpus v., TrigZochin m. and Scir-pus p. The 0 m Typha Z. quadrat had theonly dead material on this tran-sect. The gradual decline of the plant height curve without sudden change may be compared to the irregularity of the dry matter weight. The plant height heavily depended on the species rather than on the "density" of the species. The nitrogen % of the ash free material tended to increase to a high in the middle and to the end of the transect; the nitrogen 2 2 yield per square meter declined from 3.8 g/m at 0 m to 1.2 g/m at 1000 m but with exceptionally high values at 100 m and at 400 m. The lignin % of ash free materials f e l l in the range of 9.1% to 6.1% (except 13.2% at 100 m). The ash % varied from 6.9% to 28.9% (Fig. 25 and Table XVII). Soil: The s o i l organic matter % decreased from 4.1% at 0 m to 1.5% at 100 m. The pH values were on a slightly different pattern to those of similar transects, but pH increased in general as going from the dike seawards. The electric conductivities along the transect were slightly above or below 1 mmhos at a l l places (Fig. 25 and Table XVII). 79 a. Figure 24. Photographs of a typical mud f l a t (A) 900 m from the dike on the Reifel Island, Westham Island area and of a large channel with i t s adjacent of emergent vegetation ( S c i r p u s americanus) also Reifel Island Transect (No. 7), 1974. 79. b ( B ) (a) 1000 800 _. 0> 600 o _E 400 >» ' _. Q 200 0 rt 2 0 a> a> 1 6 « 4 -J _ 10 12 - 8 c c o> 4 _J 0 Cb) to o _ c 6 e > o CL 3 C o o LU (c) 0 0 8 6 4 2 w e i g h t ( l iv ing) •o o • 9 i -a 1 1 1 l 2 0 0 200 4 0 0 6 0 0 8 0 0 400 6 00 8 0 0 PH 0 0 0 (000 0 200 4 0 0 600 D i s t a n c e ( m ) 8 00 s e a w a r d 1000 Figure 25. Reifel Island Transect (No. 7); (a) dry matter weight and height, (b) nitrogen fo and lignin 7° and (c) soi l organic matter, pH and conductivity, 1974. 81 . Table XVII: Reifel Island Transect (No. 7): Soil and Plant Analyses, 1974. Distance from dike (m) 0 100 200 300 400 500 600 700 800 900 1000 Principal species T.l. -S.v. C.l. T.l. S.a. S.v. S.p. S.a. S.a. T.m. S.v. S.a. S.a. S.a. - S.a. S.a. Living (L) mat-erial; Dead (D) material L D L L L L L L L - L L Height (cm) Plants 158 _ 119 93 _ 64 64 _ 62 71 _ Interval (m) between samples (0-50) (150-200)(300-350) (450-500)(600-650) (750-800X900-95 Dry matter (g) 542 831 1179 520 388 1090 482 292 396 - 222 114 D. matter - ash (g) 504 429 994 488 340 775 407 249 336 - 186 99 Nitrogen (%) 0.71 0.22 0.52 0.53 0.65 0.70 0.87 0.71 0.65 - 1.18 1.02 2 Nitrogen (g/m ) 3.8 1.8 6.1 2.8 2.5 7.6 4.2 2.1 2.6 • - 2.6 1.2 Nitrogen in ash-free d.m. (%) 0.76 0.43 0.62 0.58 0.74 0.98 1.03 0.83 0.77 -• 1.40 1.17 Lignin (%) 6.5 6.5 11.1 8.3 6.4 6.0 7.2 6.2 6.7 6.6, 5.3 Lignin in ash-free d.m. (%) 7.0 12.6 13.2 9.1 7.3 8.4 8.5 7.3 7.9 - 7.9 6.1 Ash (%) 6.9 48.3 15.7 9.1 12.3 28.9 15.7 14.8 15.3 - 16.0 13.0 Soil organic matter (%) 4.1 - 4.5 3.5 2.0 2.2 1.9 1.6 1.6 1.2 1.4 1.5 Soil pH (1:2) 7.0 - 6.1 6.7 6.7 6.9 7.2 7.2 6.6 7.3 7.3 7.1 Electric con-ductivity (mmhos. 1:2) 0.68 0.95 1.31 1.25 1.14 0.70 0.67 0.88 0.49 0.36 0.58 5.4.2 34th Street Transect (No. 8), (Superport) This transect i s located south of Canoe Pass and north of the Superport jetty (Fig. 23). The vegetation extended only 70 m from the dike. The ti d a l f l a t , however, extended a long distance beyond the veg-etation. Some of the tid a l f l a t was covered by algae. Small vegetation islands were also observed on this t i d a l f l a t , but they were not far from the dike. Vegetation; Triglochin m. and Scirpus a. were the main species. No dead material was found. The plants were only about 30 cm high. Nitrogen % of ash free materials was relatively high, but that of lignin was low. The ash % was exceptionally high (Table XVIII and Table XX). Soil: The s o i l organic matter percentages were about 2%. The pH changed from 6.9, 6.1 to 7.2 at 0m, 50 m and 100 m respectively. The electric conducitvities were high and varied from 5.4 to 8.0 mmhos (Table XVIII). Table XVIII: 34th St. (Superport) Transect (No. 8) S o i l and Plant Analyses, 1974. Distance from dike (im ) 0 50 Br ine i p a l spec ies; v T.m. S.a. T.m. L i v i n g (L) material; Dead (D) material L L Height (cm-) Plants 31 I n t e r v a l (im,) (0-50) Dry matter (g ) 190 190 D. matter - ash (g. ) 137 156 Nitrogen (%) 0.79 1.07 2 Nitrogen (g/m ) 1.5 • 2.0 Nitrogen i n ash-free d.m. (%) 1.10 1.30 L i g n i n (%) 4.7 2T8 L i g n i n i n ash-free d.m. (%) 6.5 3.4 Ash(%) 28.2 18.0 S o i l organic matter (%) 1.7 1.6 S o i l pH (1:2) 6.9 6.1 E l e c t r i c con-d u c t i v i t y (mmhos. 1:2) 5.4 5.5 5.4.3 Tsawwassen Road, (Roberts Bank jetty) Transect (No. 9). This transect differed from the others in many respects. The surface was f l a t seawards to the end of emergent vegetation and then a sharp break (gradient) was encountered beyond which, on the f l a t , there was no emergent vegetation. Some small weakly developed channels were observed (Fig. 26). This area was not inundated even at high tides while the study took place during the summers of 1973 and 1974. The area i s located in front of the Tsawwassen Indian reserve; the residen-t i a l area i s well isolated from other residential areas. Large quanti-ties of d r i f t logs and flotsam occupied the area on the seaward side of Tsawwassen Rd. (Fig. 23). Vegetation: This transect crossed vegetation predominantly given to Distiohtis s. and Salicom-ia V. admixed with minor species such as Atviplex patula, Grindelia integvifotia and Hordeum jubatum (Table XX). The quadrats, except one at 100 m, had more dead material ( l i t t e r ) than l i v i n g material in terms of dry matter weight per square meter. The plant height was lowest at 300 m, but i t varied only from 26 cm to 40 cm along the transect. The vegetation was uniformly distributed and the dry matter weights per 2 square meter were relatively constant, varying from 209 to 341 g/m . Nit-rogen percentages of ash free materials were high and constant with the exception of those at 0 m (0.75%) and at 500 m (0.93%). The nitrogen percentages of dead material were lower than those of l i v i n g material; 2 however, the nitrogen yields (g/m ) were higher than those of the li v i n g material. The lignin % of ash free li v i n g material varied from 8.4% to 10.1% with exception of 13.1% and 18.6% at 0 m and 500 m respectively. The l i g n i n p e r c e n t a g e s o f a s h f r e e dead m a t e r i a l were h i g h e r than t h o s e of the l i v i n g m a t e r i a l , the l o w e s t , 13.2%, a t 300 m, and t h e h i g h e s t , 16.5%, a t 400 m. The a s h p e r c e n t a g e s o f b o t h l i v i n g and dead m a t e r i a l s v a r i e d s u b s t a n t i a l l y w i t h t h e l o w e s t , 5.0%, a t 0 m and the h i g h e s t , 18.6%, a t 200 m ( F i g . 26, F i g . 27 and T a b l e X I X ) . S o i l : The o r g a n i c m a t t e r p e r c e n t a g e s i n t h e s o i l d e c r e a s e d s t e a d i l y from 22.5% a t 100 m t o 0.5% a t 500 m except a t 0 m where i t was 3.6%. pH v a l u e s were g e n e r a l l y below 6 e x c e p t a t 0 m (6.7) and 600 m (6.7). The e l e c t r i c c o n d u c t i v i t i e s were e x t r e m e l y h i g h , but d e c r e a s e d a t 500 m and 600 m ( T a b l e X I X ) . ( A ) ( B ) Figure 2 6 . Photographs of a weakly developed channel ( A ) and mud f l a t ( B ) looking seawards from 6 0 0 m both on the Tsawwassen Road Transect (No. 9)» 1974. Figure 27 Tsawwassen Rd, Transect (No. 9); (a) dry matter weight and height, (b) nitrogen fo and lignin fo and (c) s o i l organic matter, pH and conductivity, 1974. Table XIX: Tsawwassen Rd. Transect (No. 9): Soil and Plant Analyses, 1974. Distance from dike (m) 0 0 100 100 200 . 200 300 300 400 400 500 500 600 Principal p D i Ti.a. D.s. D.s. D.s. Sa.v. species E.m! " S a* v* " S a ' v ' " S a ' v ' " S a- V- ~ D- s-A.p. A.p. A.p. A.p. A.p. Living (L) mat- ' erial; Dead (D) L D L D L D L D L D L D material Height (cm ) Plants 40 28 26 31 Interval (">) (0-50) (150-200) (300-350) (450-500) Dry matter (g ) 275 628 415 137 257 423 428 ! 568 336 779 305 611 D. matter -ash (g) 261 568 341 115 209 357 284 498 306 643 259 450 -Nitrogen (%) 0.64 0.61 0.92 0.81 0.97 0.79 0.90 0.64 0.97 0.59 0.79 0.73 Nitrogen (g/m2) 1.8 3.8 3.8 1.1 2.5 3.3 3.0 3.6 3.3 '4.6 2.4 4.5 Nitrogen in ash-free d.m. (%) 0.75 0.67 1.12 0.96 1.19 0.94 1.04 0.73 1.06 0.72 0.93 0.89 Lignin (%) 11.1 14.1 7.2 13.0 ' 7.8 11.3 7.3 11.6 9.2 13.6 15.8 11.0 -Lignin in ash-free d.m. (%) 13.1 15.9 8.8 15.4 9.6 13.4 8.4 13.2 10.1 16.5 18.6 13.4 Ash (%) 5.0 9.5 17.8 15.5 18.6 15.6 13.5 12.2 8.9 17.5 15.0 18.2 Soil organic matter (%) 3.6 - 22.5 - 12.3 - 9.8 - 9 . 9 - 5.1 - 0.5 Soil pH (1:2) 6.7 - 5.2 - 5.6 - 5.8 = 5.4 - 5.7 - 6.7 Electric con-ductivity (mmhos. 1:2) <0.1 - >10 - >10 - >10 - >10 -'.-'A; 7.3 - 4.7 89. T a b l e XX: P r i n c i p a l s p e c i e s l o g f o r t r a n s e c t s (No. 7 - 9) i n t h e R o b e r t s Bank a r e a , 1974. R e i f e l I s l a n d T r a n s e c t (No. 7): Distance_(m) S p e c i e s Index 0 Typhas I. 25 100 Typha I. 5 100 Soirpus V. 100 100 Carex I. 100 200 Scirpus a. 100 200 Soirpus v. 100 200 Soirpus p. 25 200 S a g i t t a r i a o. 5 300 Soirpus a. 100 300 S a g i t t a r i a a. 5 400 T r i g l o c h i n m. 100 400 Soirpus v. 5 400 Scirpus a. 100 400 Soirpus p. 5 500 Scirpus v. 100 500 Scirpus a. 100 600 Scirpus a. 100 600 T r i g l o c h i n m. 5 700 Scirpus a. 100 800 no v e g e t a t i o n -900 Scirpus a. 100 1000 Scirpus a. 100 34th S t . ( S u p e r p o r t ) T r a n s e c t (No. 8): D i s t a n c e ( m) S p e c i e s Index 0 T r i g l o c h i n m. 100 0 Spergularia m. 5 50 Scirpus a. 100 50 T r i g l o c h i n m. 100 Tsawwassen Rd. T r a n s e c t (No. 9): D i s t a n c e d ) S p e c i e s Index 0 Poa p. 100 0 Elymus m. 70 100 D i s t i c h l i s s. 100 100 Salioomia V. 100 100 A t r i p l e x p. 100 200 D i s t i c h l i s s. 100 200 S a l i o o r n i a V. 100 200 A t r i p l e x p. 25 300 D i s t i c h l i s s. 100 300 S a l i o o r n i a V. 100 300 A t r i p l e x p. 70 400 D i s t i c h l i s s. 100 400 S a l i o o r n i a V. 70 400 A t r i p l e x p. 70 500 S a l i o o r n i a V. 100 500 D i s t i c h l i s s. 100 500 A t r i p l e x p. 100 500 Grindelia i. 25 500 Hordeum j. 5 5.5 Area, productivity and quality estimates for the Boundary Bay area (Transect No. 10-14). Boundary Bay, largely under the influence of the salt waters of the Gulf and lightly under the influence of the fresh waters of the Nicomekl and Serpentine rivers has a magnificent t i d a l f l a t . None-theless the dry matter yield of emergent vegetation produced from Boundary Bay accounted for only 5% of that of the whole study area. Three species, Salioornia v,3 Triglochin m. and Distichlis s. were the principal species. Salioornia V. accounted for 68% of the dry matter yield of the periphyton of Boundary Bay. The average yield of the area was only 2.0 ton/ha. Drift wood occupied a large area (49 hec-tares) near the dike which could be potentially supportive of vegetation (Table XXI and Fig. 28). Zostera marina which grew plentifully on Boundary Bay as a submergent far from the dike was not included in this study. 91a. Figure 28. Map to show the vegetational areas and the location and vegetation of the line-transects (No. 10-14) in the Boundary Bay area, 1974. Legend 10 - Beach Grove Transect 11 - 72 St. Boundary Bay Transect 12 - 88 St. Boundary Bay Transect 13 - 112 St. Mud Bay Transect . 14 - Crescent Beach Transect Saiioovnia virginiaa Trigloahin maritimum D r i f t wood 9 1 . b Table XXI: Estimates of the area and dry matter yields of emergent vegetation of the several sections for the Boundary Bay area, 1974. Location A r e a Standing Crop Average Yield and Species ha. (%) ton (%) ton/ha. Boundary Bay: Salioornia v. 102: ( 43) 317 ( 68) 3.1 Triglochin m. 83 ( 35) 148 ( 31) 11.8 Distichlis s. 3 ( 1) 3 ( 1) 1.1 Drift wood 49 C 21) 0 ( 0) 0 Total 237 (100) (100) 2.0 5.5.1 Beach Grove Transect (No. 10) This transect was located some distance from fresh water sources and much of i t s s o i l was sandy (Fig. 28). The transect was close to private residences. Both permanent stakes and blocks were destroyed by vandalism within a month after their establishment. The transect length was only 250 m (Table I I ) . Vegetation: There were no higher plants growing on this transect except Zostera marina and i t grew far from the shore (Table XXII). Soil: The organic matter percentages were extremely low and the pH values were below 7 but increased with distance from the shore. The electric conductivities were between 3.8 and 5.0 mmhos except at 0 m where i t was less than 0.1 mmhos (Table XXII). T a b l e XXII: Beach Grove T r a n s e c t (No. 10): S o i l and P l a n t A n a l y s e s , 1974. D i s t a n c e from d i k e (Mn) 0 50 100 150 200 250 E/ranoipal s p e c i e s - - _ _ _ _ _ L i v i n g (L) m a t e r i a l ; Dead (D) m a t e r i a l - - - - - -H e i g h t (cm.) P l a n t s - - - - - -I n t e r v a l (tin,) - - - - - -Dry m a t t e r (g -) - -D. m a t t e r - ash (g ) N i t r o g e n (%) 2 N i t r o g e n (g/m ) - - • - - - -N i t r o g e n i n a s h -f r e e d.m. (%) - - - - ' -L i g n i n (%) - -L i g n i n i n a s h -f r e e d.m. (%) - -Ash (%) - - - -S o i l o r g a n i c m a t t e r (%) 1.2 0.4 0.3 0.4 0.3 0.3 S o i l pH (1:2) 6.2 6.1 6.6 6.3 6.5 6.8 E l e c t r i c con-d u c t i v i t y (mmhos. 1:2) 0.1 5.0 4.2 4.1 3.8 4.3 5.5.2 72 St. Transect (No. 11) Drift wood from Fraser River accounted for approximately 170 m of the 450 m transect (Fig. 29). The dike was well vegetated and was seldom disturbed except by recreational horsemen (Photograph 27, Appendix 2). Vegetation: Salioornia v., Grindelia i.3 Atriplex p.and Distichlis s. were the dominant species of this area. Atriplex p. particularly was widely distributed in this area. It appeared in most of the quadrats (Table XXVII). Dead material was found at 0 m only. A l l species were of short stature but the dry matter yields were not so low relative to height as compared to other transects. The nitrogen percentages of ash free materials varied from 0.56% to 1.18% while those for lignin in ash free materials varied from 4.5% to 10.8%. The ash percentages were over 20% with exception of 6.2% and 9.2% at 0 m and 250 m respectively (Table XXIII). Soil: Organic matter percentages were extremely high except at 300 m, 350 m and 400 m. This due to the decay of the d r i f t wood. The pH values were below 7 and varied only from 5.5 to 6.5. The electric conductivity was above or about 10 mmhos except at 0 m (0.9 mmhos) and 100 m (0.1 mmhos) (Table XXIII). 96. Table XXIII: 72 St., Boundary Bay Transect (No. 11): Soil and Plant Analyses, 1974. Distance from dike (?m) 0 0 50 100 150 200 250 300 350 Principal species* E.m. S.c. -S.a.v. G.i. A.p. -G.i. D.s. A.p. A.p. H.j. G.i. S.a.v. A.p. D.s. S.a.v T.m. D.e. Living (L) mat-e r i a l ; Dead (D) material L D - L - L L L L Height (cm,)Plants 41 16 29 Interval ( I m ) (0-50) (150-200) (300-350) Dry matter (g,,) 515 523 - 309 - 107 784 455 178 D. matter- ash (g,) 483 481 - 239 - 84 712 357 133 Nitrogen (%) 0.64 0.69 - 0.78 - 0.93 0.51 0.76 0.55 2 Nitrogen (g/m ) 3.3 3.6 - 2.4 - 1.0 4.0 3.5 1.0 Nitrogen in ash-free d.m. (%) 0.68 0.75 - 1.01 - 1.18 0.56 0.97 0.74 Lignin (%) 4.2 13.6 - 4.1 - 4.1 9.1 8.5 4.6 Lignin in ash-free d.m. (%) 4.5 14.8 5.3 - 5.2 10.0 10.8 6.1 Ash (%) 6.2 8.0 - 22.7 - 21.4 9.2 21.6 25.2 Soil organic matter (%) 52.8 - 41.4 29.5 27.1 24.3 21.1 4.2 9.9 Soil pH (1:2) 6.2 - 5.6 5.5 5.7 6.0 5.9 5.8 5.9 Electric con-ductivity (mmhos. 1:2) 0.9 >10 <0.1 >10 >10 >10 >10 8.3 97 a. Figure 29. Photograph of d r i f t wood and flotsam on the seaward side of the dike, foot of 72 St. (Transect No. 11), Boundary Bay (Delta Municipality), 1974. 5.5.3 88 St. Transect (No. 12). This transect was much the same as the one at 72 St. (No. 11), Boundary Bay in many respects. The emergent vegetation, however, extended only ca. 200 m from the dike and i t s growth and composition were limited (Fig. 30). Some half-decayed d r i f t wood l i e s along the dike. Vegetation: The commonest higher plant was Salicovnia v. followed by Trig-lochin m. (Table XXVII). The dead material except that of 0 m listed in Table XXIV was largely Zosteva m. brought to shore by wind and tide from the bay. The plants of this transect except those at 0 m were short and the dry matter per square meter was also low (Photographs 23 and 24, Appendix 2). Nitrogen percentages of ash free l i v i n g material were 2 quite constant, but the nitrogen yield (g/m ) dropped sharply as the dry matter yield dropped. The lignin percentages of ash free material tended to decrease seawards. Ash percentages were above 30% except at 0 m where i t was 8.7% (Table XXIV). Soil: The organic matter percentages were very low, except at 0 m where they were extremely high at 43.0%, and except for this single value, ranged from 0.4% to 3.1%. The s o i l pH values were below 7 but tended to increase from the dike to the sea. The electric conductivities, except at 0 m (2.0 mmhos) were above 8.9 mmhos (Table XXIV). 99 a. Figure 30. Vegetation micro-map of the 88 St. Transect, Boundary Bay, 1974. The surface from 25 m to 50 m was apparently lower than that at 100 m. Spergularia marina and Triglochin maritimum of the higher plants grew over the longest distances from the dike. Legend V V V V A A A A over 10 species Puccinellia nuttalliana Salioornia virginica • • • • Spergularia marina Triglochin maritimum Agrostis exarata 100, T a b l e XXIV: 88 S t . . Boundary Bay T r a n s e c t (No. 12): S o i l and P l a n t A n a l y s e s , 1974. D i s t a n c e from d i k e (F) 0 0 50 100 100 150 150 200 200 250 T r i n c l p a l A # r . Sa.v. Sa.v. g a < v > — — i.m. — i.m. — „ — — species'- 1 D.e. _ _ S.m. P.n. P.n. L i v i n g (L) mat-e r i a l ; Dead (D) L D - L D L D L D m a t e r i a l H e i g h t (cm ) P l a n t s 27 8 16 6 I n t e r v a l (Mn) (0-50)(50-100) (100-150) (150-200) Dry m a t t e r (g ) 645 362 - 243 96 127 78 8 34 -D. m a t t e r - ash (g, ) 589 328 - 167 64 89. 56 5 11 -N i t r o g e n (%) 0.74 0.49 - 0.64 0.80 0.67 0.48 0.66 0.35 N i t r o g e n (g/m 2) 4.8 1.8 - 1.6 0.77 0.85 0.38 0.05 0.12 N i t r o g e n i n a s h -f r e e d.m. (%) 0.81 0.54 - 0.93 1.2 0.96 0.67 0.97 1.10 L i g n i n (%) 8.8 12.0 - 6.0 9.9 4.0 10.8 4.9 2.9 L i g n i n i n a s h -f r e e d.m. (%) 9.6 13.2 - 8.7 14.9 5.7 15.1 7.2 9,1 Ash (%) 8.7 9.3 - 31.3 33.7 30.4 28.5 32.3 68.3 S o i l o r g a n i c m a tter (%) 43.0 - 1.6 3.1 - 0.6 - .,0.3 - 0.4 S o i l pH (1:2) 5.4 - 6.6 5.5 - 5.8 - 6.5 - 6.4 E l e c t r i c con-d u c t i v i t y (mmhos. 1:2) 2.0 - >10 >10 - >10 - >10 - 8.9 101. 5.5.4 112 St. Transect (No. 13) The transect was located just inside Mud Bay proper where access roads were not available. The emergent vegetation extended only 100 m from the dike. Occasional Zosteva m. plants were observed in tiny pools along the transect. The soils were blackish and some gave off sulphurous gas indicative of poor aeration. Vegetation: The principal species was Triglochin m., though Spergularia marina occurred in small areas (Table XXVII). The dead material collected was mainly Zostera m. carried in by the tide. The vegetation did not grow uniformly and formed vegetation islands; the values for average plant 2 height and dry matter yield (g/m ) were thus much reduced. The nitrogen percentages of ash free material were very high, i.e. above 1.38%, and lignin percentages of ash free material were below 5.4%. Ash percentages of both living and dead materials were above 22.1% and 37.3% respectively (Table XXV). Soil: Organic matter percentages except at 50 m (2.0%) decreased from 1.3% to 0.4% from the dike to the sea. Soil pH changed irregularly over short distances; electric conductivity was high (Table XXV). 102. Table XXV: 112 St. Mud Bay Transect (No. 13): S o i l and Plant Analyses, 1974. Distance from dike (Jiii) 0 25 25 50 50 75 100 125 151 [Principal species 5* Sea Weed T.m. E.m. -T.m. S .m. -T.m. - - -Living (L) mat-e r i a l ; Dead (D) material D L D L D L Height (cm.) Plants Interval (Mm) 4 (0-50) 5 (50-100) Dry matter (g*,) 478 89 131 84 163 165 - - -D. matter - ash (g.) 300 70 65 60 95 127 - - -Nitrogen (%) 0.58 1.16 0.78 0.98 0.76 1.13 - - -2 Nitrogen (g/m ) 2.8 1.0 1.0 0.8 1.2 1.9 - - -Nitrogen i n ash-free d.m. (%) 0.93 1.49 1.58 1.38 1.31 1.47 - - -Lignin (%) 13.6 4.2 5.2 3.8 6.9 3.5 - - -Lignin i n ash-free d.m. (%) 21.7 5.4 , 10.5 5.3 11.9 4.5 - - -Ash (%) 37.3 22.1 50.7 29.0 41.8 22.9 - - -S o i l organic matter (%) 1.3 1.3 - 2.0 - 0.9 0.5 0.5 o.. S o i l pH (1:2) 6.5 6.0 - 5.4 - 6.4 6.2 6.1 6. E l e c t r i c con-d u c t i v i t y (mmhos. 1:2) 8.3 9.8 >10 5.9 6.0 8.8 7.. 103. 5.5.5 Crescent Beach Transect (No. 14) This transect was in a part of the large t i d a l f l a t of Boundary Bay. The s o i l was sandy and vir t u a l l y no emergent vegetation was growing. The area was much used for recreation during the summer of 1974. Vegetation: Very limited vegetation existed on the seaward side of the Burling-ton Northern railroad track which skirted the outwash bluffs. The vege-tation consisted of four species (Table XXVII) which grew on relatively good s o i l free of salt. The ground level dropped sharply from this point to the next sampling point (50 m) where no vegetation existed (Table XXVI). So i l : The organic matter percentages were below 0.3%. The pH values decreased from 8.0 at 50 m to 6.3 at 300 m. The electric conductivity changed within the range of 3.3 and 5.5 mmhos. The s o i l values, however, at 0 m did not f a l l within the above ranges (Table XXVI). Table XXVI: Crescent Beach Transect (No. 14): Soil and Plant Analyses, 1974. Distance from dike (m) 0 50 100 150 200 250 300 P.a. Pjfotnfcl-p.ai species* E.m. - -H.l Living (L) mat-e r i a l ; Dead (D) L - - - -. -material Height -(cm.-) Plants 10 Interval (M) (0-50) Dry matter (g.) 908 - - -. -D. matter - ash (g) 829 _ _ _ _ _ _ Nitrogen (%) 0.86 2 Nitrogen (g/m ) 7.8 Nitrogen in ash-free d.m. (%) 0.94 Lignin (%) 7.8 - - - - - -Lignin in ash-free d.m. (%) 8.5 - - - - - -Ash (%) 8.7 - - - - - -Soil organic matter (%) 3.4 0.2 0.3 0.3 0.2 0.3 0.2 Soil pH (1:2) 6.7 8.0 7.5 7.0 6.5 6.1 6.3 Electric con-ductivity (mmhos. 1:2) 0.3 4.4 3.9 5.5 3.3 3.5 4.8 105. Table XXVII: Principal species log for the transects (No. 11 - 14) of the Boundary Bay area, 1974. 72 St. Boundary Bay Transect (No. 11) Distance(m) Species 0 0 50 100 100 100 100 150 200 200 200 250 250 250 250 300 300 300 350 350 350 350 SoZidago a. Elymus m. Drift wood Atriplex p. Grindelia i. Hordeum j . Salicornia v. Drift wood Atviplex p. Grindelia i. Distiohlis s. Atviplex p. Hordeum j . Grindelia i. Salicornia v. Saliaornia v. Atriplex p. Distiohlis s, Saliaornia v. Triglochin m. Atriplex p. Desahampsia a. Index 10 25 0 70 100 10 100 0 10 100 70 100 100 100 70 100 100 100 100 25 5 25 88 St. Boundary Bay Transect (No. 12): Distance-( m)' Series Index 0 Agropyron r. 100 0 Desahampsia a. 25 0 Grindelia i. 5 88 St. Boundary Bay Transect (continued) Distanced") Species Index 0 Aster e. 5 0 Junaus spp. 5 50 no vegetation 0 100 Saliaornia v. 100 100 Triglochin m. 25 100 Puaainellia n. 10 150 Saliaornia v. 100 150 Triglochin m. 25 150 Spergularia m. 10 150 Puaainellia n. 70 200 Salicornia v. 70 200 Spergularia m. 5 112 St. Mud Bay Transect (No . 13): Distance Species Index 0 no vegetation 0 25 • Triglochin m. 70 25 •Zostera m. 25 50 Triglochin m. 100 50 , ' Spergularia m. 10 , 75 Triglochin m. 70 Crescent,'Beach Transect (No. 14): Distance (m) Species Index 0 Phalaris a. 100 0 Elymus m. 25 0 ! Eole.us I. 10 0 Cirsium a. 5 106. 6. DISCUSSION 6.1 Vegetation types and habitat factors The emergent vegetation of the t i d a l marsh develops in an environ-ment substantially different from that in which most terrestrial vegetation develops. Admittedly, as for most terr e s t r i a l vegetation, there i s a s o i l substrate but in this instance i t i s highly modified by flooding and by saline waters, to varying degrees and at varying times. The aerial environment i s , when the tide is out, much lik e that of the aerial environment i n which most terr e s t r i a l vegetation develops. As the tide comes in the ambient medium changes dramatically but changes in degree from tide to tide. In varying degree then, the a l l important reception of radiant energy by the plant is modified by tides. The seasons and storms, the substrate, river flood, coastline conformation and other factors interact to make the environment, in which the emergent vegetation of the t i d a l marsh develops and grows, singular. The functions of the tide in the marsh ecosystem are cardinal and vary from physical to chemical. Important aspects of tide are t i d a l elevation, salinity and pH. In the case of the Fraser River foreshore the fresh water of the Fraser River obviously dilutes the sea water to create complex mixtures and substantially alters chemical properties. *i* o The salinity of standard sea water i s about 35 /oo or 48 millimhos/cm at 20°C (Cox, 1971) and i t s pH 7.5 to 8.4 (Home, 1969). The electric conductivity measurements of the study area soils clearly showed the ^ Salinity is defined as the total amount of solid material, in grams, contained in one kilogram of seawater after certain precautionary steps have been taken. Salinity i s , roughly speaking, a measure of the total salt content of the sea water (Home, 1969). 107. c o m p l e x i t y o f the i n f l u e n c e o f t h e seawater and f r e s h w a t e r on the s o i l s o f F r a s e r R i v e r f o r e s h o r e . The s o i l s c l o s e t o the N o r t h Arm o f t h e F r a s e r R i v e r , such as those on the t r a n s e c t s o f f P o i n t Grey, Sea I s l a n d and Westminster Hwy. ( L u l u I s l a n d ) , showed lower s a l i n i t y than t h o s e o f the a r e a s f u r t h e r from F r a s e r R i v e r such as t h o s e o f f F r a n c i s S t . ( L u l u I s l a n d ) , Tsawwassen Rd., and Boundary Bay. The s o i l s o f t h e Mud Bay t r a n s e c t s a l s o showed s l i g h t l y lower s a l i n i t y due t o Nicomekl R i v e r and S e r p e n t i n e R i v e r i n f l u e n c e s . Among the 14 t r a n s e c t s , R e i f e l I s l a n d t r a n s e c t (Westham I . ) , c l o s e t o the f r e s h water o f the South Arm o f the F r a s e r R i v e r showed t h e lo w e s t s a l i n i t y . The s a l i n i t y o f t h e t i d a l marshes seems t o be i n f l u e n c e d by many f a c t o r s such as water volume o f F r a s e r R i v e r , the d i f f e r e n c e o f water d e n s i t i e s between t h e seawater and the f r e s h w a t e r by seasons, t i d e l e v e l , the c u r r e n t movements i n S t r a i t o f G e o r g i a , d i k e s and s t r u c t u r e s such as j e t t i e s and groynes c o n s t r u c t e d on the t i d a l f l a t s . E x t e n s i v e s t u d i e s would be r e q u i r e d t o show p r e c i s e l y t h e manner i n which t h e s e f a c t o r s i n f l u e n c e t h e s a l i n i t y o f the t i d e s and hence t h a t o f s u b s t r a t e s ( s o i l s ) and waters i n which emergent marsh v e g e t a t i o n grows and d e v e l o p s . C o n s i d e r i n g t h e whole s t u d y a r e a one a s c e r t a i n s t h a t t h e marshes from P o i n t Grey t o Brunswick a r e r e a l l y " f r e s h water marshes" i n which Soirpus americanus, Soirpus paludosus, Carex lyngbyei and Typha latifolia a r e p r i n c i p a l s p e c i e s . These s p e c i e s a r e common i n f r e s h water marshes which a r e n o t t i d a l . On the o t h e r hand, marshes o f Tsawwassen and Boun-d a r y Bay a r e a s a r e t r u l y " s a l t marshes", i n which Distichlis striata, Salioornia virginica and Triglochin maritimum a r e common s p e c i e s - s p e c i e s found i n s a l i n e h a b i t a t s i n l a n d and a l o n g o t h e r c o a s t s . The d i s t r i b u t i o n o f the s p e c i e s i n " f r e s h water marsh" and " s a l t water marsh" a r e by no means u n i f o r m . Sairpus amerioanus appears t o grow a t t h e lo w e s t l e v e l i n r e l a t i o n t o mean water l e v e l i n the f r e s h water a r e a s ; on Sturgeon Bank, Soirpus paludosus i s common but n o t a t l e v e l s as low as t h o s e f o r 5. amerioanus. Carex lyngbyei d e v e l o p s a t s l i g h t l y lower l e v e l s e s p e c i a l l y n e a r R o b e r t s Bank and Typha latifolia i s i n v a r i a b l y found a t the h i g h e s t l e v e l s c l o s e t o the d i k e s . There i s then an apparent v e r t i c a l z o n a t i o n r e l a t i v e t o mean t i d e l e v e l which, however, may be m o d i f i e d . h o r i z o n t a l l y , i t would appear, by s a l i n i t y and o t h e r f a c t o r s . The above s i m p l e d e l i n e a t i o n o f t h e t i d a l marshes seems t o i n d i -c a t e t h a t s a l i n i t y and s o l i d s u b s t r a t e l e v e l a r e t h e two most c r i t i c a l f a c t o r s , among many o t h e r s , a s s o c i a t e d w i t h the t i d a l marshes; s a l i n i t y l a r g e l y d i v i d e s the marshes i n t o two t y p e s , i . e . " b r a c k i s h " and " s a l t " marshes, and t h e s o i l s u r f a c e f u r t h e r d i v i d e s them i n t o c l e a r l y demarcated p l a n t a s s o c i a t i o n s . The s a l i n i t y f a c t o r has been d i s c u s s e d i n t h e l i t e r a -t u r e r e v i e w but t h e s o i l s u r f a c e l e v e l o r marsh p r o f i l e was not i n c l u d e d i n t h i s study. Burgess (1970), however, s t u d i e d two t i d a l marsh p r o f i l e s , one o f f L u l u I s l a n d N o r t h and one o f f R e i f e l I s l a n d , i n r e l a t i o n t o t h e marsh s o i l s u r f a c e l e v e l and suggested a s t r o n g r e l a t i o n s h i p between t h e marsh s o i l s u r f a c e l e v e l and the d i s t r i b u t i o n o f s i x p r i n c i p a l p l a n t s p e c i e s . The marsh s o i l l e v e l i s , o f c o u r s e , d i r e c t l y r e l a t e d t o the t i d a l i n u n d a t i o n which may a l s o be c o n s i d e r e d t o be a d e t e r m i n a n t i n the d i s -t r i b u t i o n o f the p r i n c i p a l s p e c i e s . The l e v e l i t s e l f i s changing< t h e 109, sedimentation from transect :to transect.by differential sedimentation. Dyer (1972) investigated the mechanism of sedimentation, summarized as follows: the small particles carried i n suspension by the river are mainly clay -minerals; they normally have a negative surface charge and each particle i s surrounded by absorbed anions; flocculation occurs as the ion concentration of the surrounding water rises, i.e. above a salinity of 4%; during the second stage the sediment w i l l gradually con-solidate, as the current increases at the next stage of the tide, erosion may not be intense enough to remove a l l of the material deposited. Sedimentation rates for the estuarine muds of Fraser River average 1 millimeter each year (Eisbacher, 1973). Dyer (1972) also pointed that flocculation was reversible, and that the presence of sewage and industrial wastes would obviously affect the processes of both flocculation and deflocculation. The other interesting aspect of sedimentation i s the hs.'ubstantial amount of s i l t consolidated on the emergent vegetation, but the significance of the vegetation on the sedimentation has not received much attention. The pH's in the study area showed patterns. The pH tends to be below 7.0 where marsh plants flourish, but as one goes further seaward, pH rises, generally, to 7.0 - 7.5. The higher pH i s probably the influence of the seawater (pH = 7.0 - 8.5), while the low pH may be a result of microbial activity. The pH of the ti d a l marshes changes over short distance; less than 100 m, may be of significance, since pH can influence many other factors, directly or indirectly, such as microbial activity, nutrient av a i l a b i l i t y , etc. Soil organic matter of the t i d a l marshes i s usually high near the 110. d i k e s where t i d a l water c o v e r s f o r s h o r t e r p e r i o d s (because o f , i n r e l a t i v e terms, h i g h e r s u r f a c e s ) . A prime f a c t o r c o n c e r n i n g o r g a n i c mat-t e r l e v e l s i s d r i f t wood and f l o t s a m d e c a y i n g on land n e a r the d i k e s . The s o i l a s s o c i a t e d w i t h d r i f t wood n o r m a l l y had v e r y h i g h o r g a n i c m a t t e r c o n t e n t ; the c o n t r i b u t i o n o f t h i s wood as a s o u r c e o f o r g a n i c d e t e r i t u s o r energy f o r m a rine a n i m a l s i s not known ( P e r s o n a l communication w i t h Dr. B r i n k ) . The c l e a r f a c t , h o wever£ i s t h a t the d r i f t wood o c c u p i e s a l a r g e a r e a (56 ha o r 3% o f t o t a l v e g e t a t i o n a rea) where o t h e r w i s e marsh p l a n t s would grow. Much of i t no doubt r e f l e c t s man's l o g g i n g a c t i v i t i e s a l o n g the c o a s t over the l a s t c e n t u r y . G e n e r a l l y s p e a k i n g , t h e change o f s o i l o r g a n i c m a t t e r c o n t e n t means change i n s o i l , p r o p e r t i e s and hence change i n v e g e t a t i o n c o m p o s i t i o n . The change of s o i l and v e g e t a t i o n , observed i n most o f the s t u d y a r e a , may have meaning i n the f u t u r e o f the f o r e s h o r e ecosystem. The t i d a l marsh p l a n t s a r e t h e e x c e l l e n t i n d i c a t o r s o f any e n v i r o n -m e n t a l changes o f the t i d a l marsh ecosystem, s i n c e t h e i r z o n a t i o n , s p e c i e s c o m p o s i t i o n , o r even d i s a p p e a r a n c e a r e s t r o n g l y s u b j e c t to the h a b i t a t f a c t o r s , e s p e c i a l l y t i d a l f a c t o r s and s e d i m e n t a t i o n . The t h r e e v e g e t a t i o n maps o f Sea I s l a n d , L u l u I s l a n d and Boundary Bay r e p r e s e n t i n g t h e study a r e a may be used as a comparison f o r t h e f u t u r e v e g e t a t i v e changes. The s e r i e s o f semi-permanent t r a n s e c t s ( F i g . 11) e s t a b l i s h e d f o r t h i s purpose i n 1973 and 1974 w i l l be used tor-•fS-t-ud-yivany future'', changes i n t h e v e g e t a t i o n and i t s h a b i t a t s . The e s t a b l i s h m e n t o f t h e semi-permanent t r a n s e c t s was d i f f i c u l t and time-consuming. Some p a r t s and markers of the e s t a b l i s h e d t r a n s e c t s , n o n e t h e l e s s , were q u i c k l y d e s t r o y e d by v a n d a l i s m and o t h e r f a c t o r s , such as l a r g e r o l l i n g l o g s on the marshes. The w r i t e r hopes that the present semi-permanent transect would last ten years. The stakes used, however, are short, 30 cm (1 foot) above ground level, and often already covered by the mud. Therefore the transects would be best traced back in spring when the marsh land i s not covered by any vegetation. The improvement of permanent transects is definitely important, because vandalism and t i d a l action are significantly destructive. Forbes (1972) designed and discussed concrete markers for permanent transects. These concrete markers are heavy and strong, and hopefully w i l l stand against vandalism, sedimentation, erosion and storm. However, none of them have been used and their effectiveness cannot therefore be known. 1 1 2 . 6.2 P r i m a r y p r o d u c t i v i t y The h i g h e s t e s t i m a t e s o f d r y m a t t e r y i e l d i n the e n t i r e s t u d y a r e a were o b t a i n e d from the P o i n t Grey t r a n s e c t i n 1973 and a g a i n i n 1974, 2 2 i . e . 1,819 g/m and 1,668 g/m a t 250 m from t h e r o a d , r e s p e c t i v e l y . . 2 The second h i g h e s t i n 1973 and 1974 were 1,369 g/m a t 150 m from the 2 d i k e a t the end o f F r a n c i s S t . and 1,179 g/m a t 100 m from the R e i f e l 2 I s l a n d d i k e . The average y i e l d f o r the whole a r e a was 490 g/m i n 1974. The sewage e f f l u e n c e o f the a d j a c e n t Iona I s l a n d may account f o r t h e s e h i g h y i e l d s . However the average y i e l d s o f the P o i n t Grey a r e a was 4.9 to n s / h a , lower than 5.8 tons/ha o f t h e R o b e r t s Bank a r e a i n 1974. The v e g e t a t i o n o f t h i s p a r t i c u l a r l o c a t i o n was composed o f Typha I. and Carex 1. The r e a s o n f o r t h e s e e x t r e m e l y h i g h y i e l d s from the P o i n t Grey t r a n -s e c t i s p a r t l y due t o h i g h y i e l d Carex Z. These two s p e c i e s were w e l l mixed w i t h p l a n t h e i g h t more than 200 cm and showed u p r i g h t l e a f o r i e n t a -t i o n which might maximize l i g h t i n t e r c e p t i o n . The s o i l pH, e l e c t r i c c o n d u c t i v i t y and o r g a n i c m a t t e r were 5.6, 5.7; 1.8, 0.92 mmhos; 6.4, 6.8%; i n 1973 and 1974 r e s p e c t i v e l y , i n d i c a t i n g low pH, low s a l i n i t y and h i g h o r g a n i c m a t t e r . F u r t h e r i n t e n s i v e study would be r e q u i r e d t o know the e x a c t r e a s o n s f o r t h e s e e x t r e m e l y high, y i e l d s . I t must be r e c o g n i z e d t h a t a l l y i e l d e s t i m a t e s a r e c o n s e r v a t i v e and do not t a k e i n t o a c c o u n t l o s s e s from senescence, decay a b r a s i o n , o r g a i n s and l o s s e s i n t h e under-ground environment; moreover, y i e l d s may n o t have been t a k e n a t t h e p r e c i s e time o f maximum d r y m a t t e r p r o d u c t i o n . The e s t i m a t e o f t h e average y i e l d s o f t h e p r i n c i p a l s p e c i e s f o r t h e whole a r e a ( T a b l e V ) were Carex I., 9.3 t o n s / h a ; Scirpus p., 5.0 t o n s / h a ; 113. Typha Z.3 4.8 t o n s / h a ; Scirpus v., 4.8 t o n s / h a ; Scirpus a., 4.0 t o n s / h a i n 1974. T h i s r e s u l t i n d i c a t e s t h a t Carex Z. i s almost t w i c e as " p r o -d u c t i v e " as o t h e r s p e c i e s . The h i g h e r t o t a l and average y i e l d s o f f Westham I s l a n d was m a i n l y due t o t h i s s p e c i e s . The combined dry matter weight of crowns, underground shoot and r o o t of the above f o u r s p e c i e s ( d a t a o f Scirpus p. not a v a i l a b l e ) were r e s p e c t i v e l y f o r Carex Z. 3 2,463 2 • 2 2 2 g/m ; Typha 1.3 1,491 g/m ; Scirpus v.3 1,350 g/m ; Scirpus a. 3 606 g/m . By these comparisons, Carex Z.3 i t i s s u g g e s t e d , i s the most e f f i c i e n t f i x e r o f s o l a r energy. The low s a l i n i t y o f Westham I s l a n d ( T a b l e V I I ) , i n comparison w i t h a l l o t h e r a r e a s , i s b e l i e v e d t o be t h e r e a s o n why Carex Z. grows so w e l l i n t h i s l o c a t i o n . Burgess (1970) a l s o p o i n t e d out the p o s s i b i l i t y o f low s a l i n i t y o f f t h i s a r e a and d i s c u s s e d , " R e i f e l and Westham I s l a n d s , w i t h p o s s i b l y the l o w e s t s a l i n i t y , s u p p o r t more s p e c i e s , produce the most e x t e n s i v e growth of Typha Z. and Scirpus V. and grow v e r y l i t t l e Scirpus p. compared to the o t h e r marsh". However, as p o i n t e d out above by him, v e r y l i t t l e Scirpus p. (a n o n - h a l o p h y t i c s p e c i e s ) i s found ( T a b l e XX). The r e a s o n may be s a l i n i t y o r o t h e r f a c t o r s which may i n h i b i t the v e g e t a t i v e p r o p a g a t i o n o f Scirpus p. i n s p r i n g ( p e r s o n a l communication w i t h D.R. H a l l a d a y ) . I t appears t h a t Carex Z. i s t h e main r e a s o n f o r the h i g h y i e l d s o f f b o t h P o i n t Grey and Westham I s l a n d . S i n c e d i f f e r e n t f a u n a l organisms r e q u i r e and depend on d i f f e r e n t f l o r a l s p e c i e s , of d i f f e r e n t form o r " q u a l i t y " , and s i n c e the marsh ecosystem i s v e r y complex, f u r t h e r s t u d y would be n e c e s s a r y to d e f i n e the s i g n i f i c a n c e o f t h e Carex Z. c o n t r i b u t i o n t o the F r a s e r ecosystem. 114. 6.3 Man's impact The t i d a l marsh ecosystem o f F r a s e r R i v e r f o r e s h o r e has been t h r e a t e n e d by a s e r i e s of man's a c t i v i t i e s such as d i k i n g , f i l l i n g , e t c . s i n c e t h e t u r n of t h e l a s t c e n t u r y . Moreover the q u a l i t y of t h e marsh ecosystem may be p o o r e r because of p o l l u t i o n by heavy m e t a l s , sewage and c o u n t l e s s o t h e r s . No doubt t h e r e a r e " b e n e f i c i a l " e f f e c t s o r a d d i t i o n s , t o o . S i n c e t h e r e seems to be more a l i e n a t i o n and i n t r u -s i o n p r o j e c t e d f o r t h i s a r e a , i . e . A i r p o r t e x p a n s i o n , marina c o n s t r u c t i o n , e t c . , t h e i r p o s s i b l e impact on the t i d a l marsh ecosystem may be worth b r i e f d i s c u s s i o n . There i s no argument t h a t any type o f f i l l i n g o f the t i d a l marshes w i l l t o t a l l y d e s t r o y t h e i r prime r o l e as energy f i x e r s and s u p p l i e r s o f d e t r i t u s and energy to t h e r i c h l i f e a s s o c i a t e d w i t h the marsh eco-system. T h i s type o f impact to t h e consumers would be a c u t e and p r o b a b l y p r o p o r t i o n a l to a r e a d e s t r o y e d , s i n c e much l e s s energy, i . e . o r g a n i c d e t r i t u s , l i v i n g p l a n t s , e t c . has been produced and r e l e a s e d n a t u r a l l y t h a n decades ago. The c o n f o u n d i n g of n a t u r a l and a r t i f i c i a l i n f l u e n c e s i s l i k e l y t o be v e r y i m p o r t a n t but assessment o f the r e l a t i v e r o l e s w i l l r e q u i r e much more stu d y . A good example o f massive f i l l i n g and d e s t r u c t i o n o f the t i d a l marshes would be the I n t e r n a t i o n a l A i r p o r t e x a p n s i o n o f f Sea I s l a n d . The e x t e n s i v e e x p a n s i o n of t h i s A i r p o r t would b r i n g v a r i o u s e c o l o g i c a l r a l i g n -ments on the t i d a l marsh ecosystem. One o f them w i l l be t h e p o s s i b l e change of v e g e t a t i o n c o m p o s i t i o n o f f L u l u I s l a n d , because p a t t e r n of t i d e s , s e d i m e n t a t i o n and F r a s e r R i v e r water f l o w i n t o t h e sea may w e l l change g r e a t l y . The s a l i n i t y o f the water o f f L u l u I s l a n d w i l l change and may become lower o r h i g h e r because of th e extended f l o w o f f r e s h water seawards. T h i s lower or h i g h e r s a l i n i t y , f o r example, w i l l have impact on Soirpus p. which i s c r i t i c a l l y growing a t s l i g h t l y h i g h e r s o i l s a l i n i t y than the o t h e r n o n - h a l o p h i c s p e c i e s ( T a b l e X I , F i g . 22 and T a b l e X V I I ) . The h e i g h t o f t h e t i d e s and s e d i m e n t a t i o n near the A i r p o r t w i l l a l s o change depending on the s i z e and shape o f the e x p a n s i o n . The p a t t e r n of s e d i m e n t a t i o n a t L u l u I s l a n d w i l l a l s o change w i t h t h e t i d a l and water f l o w changes. S e d i m e n t a t i o n may then o c c u r l a r g e l y i n the deep water seaward from the f o r e s e t beds of the d e l t a . 7. SUMMARY AND CONCLUSIONS In spite of i t s great probable importance to the rich l i f e of the Fraser river delta foreshore, especially to waterfowl and fishery, the emergent vegetation of the foreshore ecosystem i s being lost by diking and industrial development. Loss of the foreshore has led also to the alienation of the "back up" lands which are highly productive agricultural areas. As one of many studies by many agencies which seek to delineate in the delta ecosystem and to ascertain relative values to the large human community, this study was undertaken to (a) obtain an estimate of the standing crop of emergent vegetation of the ti d a l zone; (b) to discern some of the important environmental-factors determining plant species distribution and (c) to record present vegetation on semi-permanent transects for comparisons which might be made in the future; comparative study of the plant communities, really a product of inter-acting environmental variables, might well be a most useful indication of the significance of changes which portend. The study area, extending from Point Grey to the International Boundary, roughly a distance, north to south, of 30 km (19 miles), was divided into three sections, i.e. tidelands off Point Grey and Sturgeon Bank, tidelands off Roberts Bank and tideland associated with Boundary Bay. Fourteen semi-permanent transects, with combined length of 7,550 m (4.7 miles), were established at points along the foreshore. Both plant and s o i l samples were collected in 1973 and 1974 along the tran-sects at intervals; plant samples were analyzed for ash, nitrogen and lignin and s o i l samples for pH, organic matter and electric conductivity. 117. The standing crop of the t i d a l marshes, harvested at roughly peak y i e l d was estimated to occupy 1,901 hectares (4,697 acres) and to y i e l d approximately 9,408 metric tons of dry matter with average d.m. y i e l d of 4.9 tons per hectare (4,400 l b / a c r e ) . Eight marsh plants con-trib u t e d overwhelmingly to the d.m. y i e l d ; three marsh plants, Carex Zynghyei, Scirpus americanus and Scirpus paludosus alone accounted f o r 81% of the standing crop i n 1974. ^^l/ftsm^t^T^^^^f^eoii. Bank, 'Roberts Bank area and Boundary Bay area accounted f o r 41%, 46% and 13% of the t o t a l area of the marsh, and for 4%, 51% and 5% of the t o t a l standing crop of emergentSNr^spe'e't-iveiy'Jie SomelxqbseEva^tio'ras ,r: ca1s"tse_-arg-e-ly-as probable trends, may be summarized as follows: 1. Vegetation: (a) There i s a l i n e a r decrease i n dry matter weight of emergent vegetation with distance from the dikes seaward (Y = 663-0.54 X, where X = distance from dikes seawards i n meters and Y = d.m. weight i n grams). (b) The higher plant d i v e r s i t y was greatest near the dikes on most transects; however, the f l o r a of the foreshore i s a small one. (c) The t i d a l marsh from Point Grey to BrunswickvPoint may be characterized as brackish marsh, and that from Tsawwassen to Crescent Beach as s a l t marsh. (d) Substantial amounts of s i l t , which adhere t i g h t l y to the lower parts of brackish marsh plants, constitutes a factor of importance i n chemical analysis of plant materials; the emergent plants appear to be a factor of importance i n sedimentation. 118. 2. Edaphic factors: (a) Soil organic matter tends to decrease from dike seawards. (b) The s o i l pH of the brackish marshes tends to increase grad-ually from dike seawardfeand to become higher than pH value 7. The s o i l pH of the saline marsh was variable and was often below pH 7.0; however, the salt marsh was confined, on the whole, to narrower zones. (c) The soils of brackish marshes are clayey or s i l t y , but the soils of salt marshes are more or less sandy. 3. Other factors: (a) More tid a l f l a t off Sea Island seems to have been included in the past by dikes than off Lulu Island or Westham Island. 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United States National Parks Service and Parks Canada,"An Inventory of International Park P o s s i b i l i t i e s : Point Roberts, Boundary Bay, San Juan and Gulf Islands Archipelago," International Point Roberts Board Jo i n t Rept. (Various papers, and f i g u r e s ) , 1973. Uphof, J.C., "Halophytes," Botan. Rev.. V o l . 1, pp. 1-58, 1941. Vogl, R.J., "Salt-marsh vegetation of Upper Newport Bay, C a l i f o r n i a , " Ecology, Vol. 47, No. 1, pp ='p '3 8 0i87, Bfg^'.-Wagner, R.H., Environment and Man, 1st ed., New York, W.W. N o r t o n & Company, I n c . , 1971. Westlake, D.F., "Comparisons o f P l a n t P r o d u c t i v i t y , " B i o l . Rev., V o l . 38, pp. 385-425, 1963. W h i t t a k e r , R.H., Communities and Ecosystems, London, The M a c M i l l a n Company, 1970. Waldichuk, M., " P h y s i c a l Oceanography o f the S t r a i t o f G e o r g i a , " J . F i s h . Res. Bd. Can., V o l . 14, No. 3, pp. 321-486, 1957. Waldichuk, M., "Oceanography o f the S t r a i t o f G e o r g i a , " V I I , Water Masses, Pac. Coa s t S t n . , F i s h . Res. Bd. Can. Prog. Rept. (108), pp. 3-6, 1957. W i e g e r t , R.G., Evans, F . C , " P r i m a r y P r o d u c t i o n and the D i s a p p e a r a n c e of Dead V e g e t a t i o n on an O l d F i e l d i n S o u t h e a s t e r n M i c h i g a n , " E c o l o g y , V o l . 45, pp. 49-63, 1964. 125, • APPENDIX 1: S p e c i e s L i s t S c i e n t i f i c Name A b b r e v i a t i o n Common Name Agropyron repens (L.) Beav. A . r . Quackgrass Agrostis semiverticillata ( F i o r s k . ) C. C h r i s t Water Bent Angelica genuflexa N u t t . A.g. A n g e l i c a Aster eatonii (Gray) Howell - A s t e r Atriplex patula L. A.p. S a l t b u s h Carex lyngb.y e£ Ho mem C . l . Sedge Cirsium arvense (L.) Scop. - T h i s t l e Cuscuta salina Engelm. - Dodder, L o n e - t a n g l e Deschampsido: cespitosa (L.) Beauv. - H a i r Grass Distichlis striata ( T o r r . ) Rydb. D.s. S a l t g r a s s Elymus -.mollis T r i n . E.m. American Dunegrass Equisetum fluviatile L. E . f . H o r s e t a i l Festuca rubra L. - Red Fescue Grindelia integrifolia DCC-.,, G . i . Gumweed Holcus lanatus L. H . l . V e l v e t - g r a s s Hordeum jubatum L. H . j . F o x t a i l ^ B a r l e y Juncus spp. - Rush Lathyrus palustris L. F — V e t c h l i n g Phalaris arundinacea L. P.a. Canary g r a s s Poa palustris L. P . p i . Fowl B l u e g r a s s Potentilla pacifica Howell P.p. F i v e - f i n g e r Puccinellia nuttalliana ( S h u l t . ) H i t c h c . P.n. A l k a l i g r a s s Rubus leucodermis D o u g l . R . l . R a s p b e r r y Sagittaria cuneata S h e l d . S.cu. Arrowhead Salicornia virginica L. Sa.v. S a l t w o r t Scirpus americanus P e r s . S.a. T h r e e - s q u a r e b u l r u s h Scirpus paludosus S.p. S e a c o a s t b u l r u s h Scirpus validus V a h l . S.v. S o f t s t e m b u l r u s h Soldago canadensis L. S.c. Goldenrod Spergularia marina ( ( L i ) G r i s e b . S .m. Sandspurry Triglochin maritimum L. T.m. Arrow-grass Typha l a t i f o l i a L. T . l . C a t - t a i l Zostera marina L. Z ,m. E e l - g r a s s Sium sauve - W a t e r - p a r s n i p APPENDIX 2: Photographs t o g i v e a s s i s t a n c e i n l o c a t i n g semi-permanent t r a n s e c t s . Pt. Grey T. (No.l) 0 m point, taken from Pt. Grey Rd. Length of transect: 400 m Pt. Grey T. (No.l) 400 m point, looking toward 0 m point. Sea Island T.(No.3) 0 m point, look-ing toward 900 m point. Length of transect: 900 m . Sea Island T.(No.3) 900 m point, look-ing toward 0 m point. 1 2 7 . b Westminster Hwy. Transect (No.4) 0 m point, taken from road. Length of transect: 850 m Westminster Hwy. Transect (No.4) 0 m point, looking toward 850 m point. Westminster Hwy. Transect (No.4) 800 m point, look-ing toward 850 m point. Westminster Hwy. Transect (No.4) 200 m point, look-ing toward 0 m point. 128.b Francis St. Tran-sect (No. 5) 0 m point, taken from road. Length of transect: 1,000 m Francis St. Tran-sect (No. 5) 1,000 m point, looking toward 0 m point. Steveston Hwy. Transect (No.6) 150 m point, looking toward 0 m point. Length of transect: 900 m Steveston Hwy. Transect (No.6) 450 m point, looking toward 900 m point. 129.b Reifel Island Transect (No.7) 0 m point, taken from dike. Length of transect: 1100 m Reifel Island Transect (No.7) 1,100 m point, looking toward 0 m point. 34 St., Superport Transect (No.8) 0 m point, taken from road. Length of transect 100 m 34 St., Superport Transect (No.8) 100 m point, look-ing toward 0 m point. Tsawwassen Rd. Transect (No.9) 0 m point, taken from road. Length of transect: 600 m Tsawwassen Rd. Transect (No.9) 600 m point, looking toward 0 m point. Beach Grove Tran-sect (17A Ave.) • (No. 10) 0 m point, taken from beach. Length of transect 250 m Beach Grove Transect (No.10) 250 m point, looking toward 0 m point. 132 a. 21. 72 St. Boundary Bay Transect (No. 11) 0 m point, taken from dike. Length of transect: 450 m 22. 72 St. Boundary Bay Transect (No. 11) 450 m point, look-ing toward 0 m point. 23. 80 St. Boundary Bay Transect (No.12) 0 m point, taken from dike. Length of transect: 250 m 24. 88 St. Boundary Bay Transect (No. 12) 250 m point, look-ing toward 0 m point. 133. Appendix 3. Estimated contribution of particulate organic matter to the waters of the Georgia Strait. Source Form Estimated contribution (t year--'-) Authority Rivers Particulate organic 200,000 Seki et a l (1969) Rivers Total organic 1-2 x 10 6 Seki et a l (1969) Wood Activity of Bankia setacea.upon stored wood 15,000-3.00,000 Perkins 3 Wood Harbour structures, trees on the seas margin >, (15,000-300,000) Perkins 3 Wood Wood pulp industry - as fibre 31,000 Perkins 3 Wood " Toilet paper, sanitary towels disposablennapkins, etc. 4,000 Perkins 3 Sewage Faecal waste >23,000 Perkins 3 Estimates by Perkins (1963) derived from information by Trussell (1959, 1967), I.D.D., British Columbia Hydro and Power Authority Survey (1966), U.S. Department of the Interior Report (1967) and by his personal enquiry. 134. Appendix 4. Conversion tables for B r i t i s h and metric measure. The figures i n the central of the three columns i n each table represent either one or the other of the two side columns, as required, e.g. 1 kg = 2.205 l b , 1 lb = 0.454 kg, 100 ha = 247.105 ac, 100 ac = 40.469 ha. Temperature conversion formula: °C = 5/9 ( F - 32). WEIGHT AREA Kilograms kg or lb Pounds (lb) Hectares ha or ac Acres 0.454 1 2.205 0.405 1 2.417 0.907 2 . 4.409 0.809 2 4.942 1.361 3 6.614 1.214 3 7.413 1.814 4 8.819 1.619 4 9.884 2.268 5 11.023 2.023 5 12.355 2.722 6 13.228 2.428 6 14.826 3.175 7 15.432 2.833 7 17.297 3.629 8 17.637 3.237 8 19.769 4.082 9 19.842 3.642 9 22.240 4.536 10 22.046 4.047 10 24.711 LENGTH Centi- cm or Inches metres i n . 2.540 1 0.394 5.080 2 0.787 7.620 3 1.181 10.160 4 1.575 12.700 5 1.969 15.240 6 2.362 17.780 7 2.756 20.320 8 3.150 22.860 9 .3.543 25.400 10 3.937 WEIGHT/AREA kg/ha kb/ha or lb/ac lb/ac 1.121 1 0.892 2.242 2 1.784 3.363 3 2.677 4.484 4 3.569 5.605 5 4.461 6.726 6 5.353 7.848 7 6.245 8.969 8 7.138 10.090 9 8.030 11.211 10 8.922 i APPENDIX 1. Mao to show the vegetational areas and location and vegetation of the l i n e transects (No. 1-14) for the whole study area, 197A. 9 10 11 12 13 14 Legend; 1 - Point Grey Transect 2 - Iona Island Transect 3 - Sea Island Transect 4 - Westminster Hwy. Transect 5 - Francis St. Transect 6 - Steveston Hwy. Transect 7 - R e i f e l Island Transect J - 34th St. (Sunerport) Transect Tsawwassen Rd. Transect Beach Grove Transect 72 St. Boundary Bay Transect 88 St. Boundary Bay Transect 112 St. Mud Bav Transect Crescent Beach Transect O O • • Cavex lyngbyei distichlis striata Salioornia virginica "cirrus americanus Sc'rrus raludosus Scirpus validus Triglochin rnaritimun Typha latifolia D r i f t wood 

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