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medium grain size. The sediment below these macroalgal mats also became significantly more reduced. While the communities under E. prolifera mats became dominated by C. capitata, those under V. subsimplex mats were dominated by P. elegans. The effect of sediment disturbance on the faunal communities of Drum Sands was investigated by studying the initial colonisation of defaunated sediments. P. elegans numerically dominated the early stages of succession only during periods of high larval availability, C. capitata dominated at other times. Furthermore, P. elegans larval recruitment and adult immigration to defaunated sediments within P. elegans patches were higher compared with non-patch defaunated sediments. The micro-scale spatial distribution of P. elegans within small-scale patches was examined. P. elegans was found to be non-randomly distributed throughout the year, patches formed were commonly less than 3cm2. Correlation analyses implied that these micro-scale patches may have been generated and maintained by adult-juvenile interactions and/or sediment heterogeneity. Small-scale P. elegans patches were found to be distinct ecological areas when compared with surrounding sediments. Sediment properties and invertebrate community structure of P. elegans patches were significantly different to those of non- patch areas. These findings emphasise the ecological importance of patches of tube- building spionid polychaetes in allowing certain species to occur in habitats where they would otherwise be unable to survive. iv
ACKNOWLEDGEMENTS I am indebted to my supervisors Dr. Teresa Fernandes, Professor Paul Read and Dr. Dave Raffaelli for their guidance, encouragement and constructive criticism throughout the course of this study. I am also very grateful to a number of other people for their help in various aspects of my study. These are namely Mike Richards for his help in the field, Jill Sales for her help with statistical analyses, Peter Gibson for helping with faunal identification, Dr. Richard Ladle for reading through and commenting on the thesis, Marina Marcogni for her invaluable help with computing and Dagmar Rothaug and Karen Miller for helping me with fieldwork and sample sorting. I must also thank a number of other people who I have contacted for specialist advice. These are Dr. Simon Thrush for his help during the early stages of my research, Dr. Helgi Gudmundsson and Dr. Torin Morgan for information about Pygospio elegans, Dr. Pierre Legendre for advice about numerical analyses, Dr. Martin Wilkinson for identifying my weed samples and Dr. Steve Hull for his advice about macroalgal mat implantation. I would like to acknowledge my colleagues in the laboratory, my thanks go to them for keeping me 'entertained' over the years. My last thanks, but by no means least, go to Thi for her enduring patience and understanding over the past couple of years.
Page 1 and 2: AN INVESTIGATION INTO THE PROCESSES
Page 3: ABSTRACT The spionid polychaete Pyg
Page 7 and 8: Results. . 65 Size distribution of
Page 9 and 10: CHAPTER 9. GENERAL DISCUSSION . . 2
Page 11 and 12: Figure 5.4 Figure 5.5 Figure 6.1 Fi
Page 13 and 14: LIST OF TABLES Table 2.1 Statistica
Page 15 and 16: BACKGROUND CHAPTER 1 INTRODUCTION A
Page 17 and 18: The scales of observation, or the s
Page 19 and 20: systematic sampling design to inves
Page 21 and 22: aised sediment within an otherwise
Page 23 and 24: Fauchald and Jumars (1979) describe
Page 25: Dalmeny House and sewage discharged
Page 28 and 29: E 7— E 6-ac. MHWS MHWN t co 4 —
Page 30 and 31: variance (TTLQV) techniques (see Lu
Page 32 and 33: analysis using Moran's and Geary's
Page 34 and 35: Holme and McIntyre (1984). Percenta
Page 36 and 37: Pattern Analysis - Grid Surveys Sur
Page 38 and 39: 57 64 1=1 0 0 0 0 0 0 0 O 0 0 0 0 0
Page 40 and 41: Maps produced by kriging and other
Page 42 and 43: 200 180 1160 140 100 1-3 80 g 60 c.
Page 44 and 45: 2.5 1.5 0.5 0 3 T (i) % Silt/clay%
Page 46 and 47: v : m pattern Id pattern Ip pattern
Page 48 and 49: " v : m pattern Id pattern Ip patte
Page 50 and 51: The results show that at the smalle
Page 52 and 53: Nephtys hombergii's spatial distrib
Page 54 and 55:
(vii) G. duebeni (ix) % Organic con
Page 56 and 57:
8m survey - spatial patterns Figure
Page 58 and 59:
(1) P. elegans (iii) L. conchilega
Page 60 and 61:
a) Ts 1.4 0.6 u 0.2 -0.2 1.4 'E5 0.
Page 62 and 63:
200m 150m 100m 50m (ix) C. edule 56
Page 64 and 65:
73 ‘a• el 1.4 (ix) G. duebeni 1
Page 66 and 67:
DISCUSSION The main aims of this st
Page 68 and 69:
formed patches less than 1m2 and th
Page 70 and 71:
stutchbutyi, at Wirroa island, New
Page 72 and 73:
exhibited by the tube-building poly
Page 74 and 75:
CHAPTER 3 THE POPULATION STRUCTURE
Page 76 and 77:
Asexual reproduction by fragmentati
Page 78 and 79:
METHODS Survey design - It has been
Page 80 and 81:
RESULTS The species abundances in e
Page 82 and 83:
corresponds to 44 setigers using Eq
Page 84 and 85:
1 0000000 00 rg 0 00 d- - Xauanbau
Page 86 and 87:
Reproductive activity of Pygospio e
Page 88 and 89:
P. elegans larvae at Drum Sands hav
Page 90 and 91:
Pygospio elegans showed great seaso
Page 92 and 93:
Previous studies have produced simi
Page 94 and 95:
The sole reliance on a planktonic m
Page 96 and 97:
abundance are highly seasonal, were
Page 98 and 99:
CHAPTER 4 THE EFFECTS OF MACROALGAL
Page 100 and 101:
studies may have been completely di
Page 102 and 103:
METHODS Study site - The exact posi
Page 104 and 105:
1 C N W 4----111" 1.5m 2 NW C Contr
Page 106 and 107:
sediment sampling, together with re
Page 108 and 109:
RESULTS Species abundances - The me
Page 110 and 111:
; 15 35 — 30 — 25 — 10 — 5
Page 112 and 113:
statistical difference from net plo
Page 114 and 115:
Pygospio elegans size distribution
Page 116 and 117:
used, approximately equivalent to t
Page 118 and 119:
artefacts associated with the metho
Page 120 and 121:
present in high numbers around sewa
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lack, hydrogen sulphide-smelling se
Page 124 and 125:
CHAPTER 5 THE EFFECTS OF MACROALGAL
Page 126 and 127:
METHODS Survey design - During late
Page 128 and 129:
The sediments could not be sampled
Page 130 and 131:
RESULTS Species abundances - Table
Page 132 and 133:
90 — 80 — "-e-' 70 — 60 — 4
Page 134 and 135:
35 — *** 30 25 — 1.) = .-c‘l
Page 136 and 137:
Pygospio elegans size distributions
Page 138 and 139:
which is difficult to compare with
Page 140 and 141:
eason why some invertebrates showed
Page 142 and 143:
This study did not set out to expli
Page 144 and 145:
This reliance upon the early establ
Page 146 and 147:
CHAPTER 6 INITIAL COLONISATION OF D
Page 148 and 149:
esulting community at any stage of
Page 150 and 151:
ambient sediment had been removed.
Page 152 and 153:
emoved since they were the only tax
Page 154 and 155:
All statistics were performed using
Page 156 and 157:
RESULTS Univariate analysis of spec
Page 158 and 159:
3.5 3 5 2 11 5 1 0.5 0 40 35 Ca 30
Page 160 and 161:
of non-patch areas (Figure 6.3(vi))
Page 162 and 163:
the individuals colonising patch az
Page 164 and 165:
Multivariate analysis of community
Page 166 and 167:
Month Sample statistic (Global R) N
Page 168 and 169:
2NP 3NP 4NP .•,, 6NP 5NP 6P 1NP i
Page 170 and 171:
Figure 6.8: Two-dimensional MDS ord
Page 172 and 173:
- - 5P ... 4P . 6P • .‘2NP 1NP
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I 50. 1 60. 70. 80. 90. 100. BRAY-C
Page 176 and 177:
'P2-AZ P3-AZ N2-AZ .- - - " .„ ..
Page 178 and 179:
o • o -o + 350 — 300 = 250 7 g
Page 180 and 181:
The importance of the ambient commu
Page 182 and 183:
In April, when P. elegans larval av
Page 184 and 185:
not only for errant polychaetes, bu
Page 186 and 187:
observed in this study. How crucial
Page 188 and 189:
Micro-scale spatial patterns of mac
Page 190 and 191:
METHODS Experimental design - A pre
Page 192 and 193:
study. These individuals would not
Page 194 and 195:
RESULTS Pilot survey - The pilot su
Page 196 and 197:
Transect survey - Micro-scale patte
Page 198 and 199:
Month v:m ratio pattern Id pattern
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(i) March 1997, replicate 1 -iAlmiA
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(xix) October 1997, replicate 1 (ra
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The new recruits were only sufficie
Page 206 and 207:
The results of correlation analyses
Page 208 and 209:
cf.) . crt N ,—, Cr) C,1 ,—, Cr
Page 210 and 211:
1.2 -0.4 "a 0.8 > (i) % Water conte
Page 212 and 213:
examine the micro-scale spatial pat
Page 214 and 215:
Invertebrate larvae, those of polyc
Page 216 and 217:
laboratory observations are needed
Page 218 and 219:
CHAPTER 8 THE FAUNAL COMMUNITIES OF
Page 220 and 221:
Other theories have been postulated
Page 222 and 223:
RESULTS Univariate analysis of spec
Page 224 and 225:
-T. g 80 g 50 40 30 20 10 (i) Adult
Page 226 and 227:
in significant differences in size
Page 228 and 229:
8.2). This was mainly because of th
Page 230 and 231:
120 100 80 60 - 40 20 0. cn1 c.n (i
Page 232 and 233:
3NP 6NP 4NP 1 NP 5NP 2NP : 3P 1P 6P
Page 234 and 235:
4P 3P 5P 5NP 6P 2P 1P Figure 8.8: T
Page 236 and 237:
Figure 8.10 shows the dendrogram pr
Page 238 and 239:
NP1 NP2 NP2 NP2 NP1 NP1 NP2 NP2 NP2
Page 240 and 241:
Sediment water, organic and silt/cl
Page 242 and 243:
5 350 — 300 250 200 — ISO — 1
Page 244 and 245:
abundances of P. ciliata had more d
Page 246 and 247:
levels of silt/clay and organics. S
Page 248 and 249:
1973; Noji and Noji, 1991). Competi
Page 250 and 251:
shown to consume up to 68% of a 0-g
Page 252 and 253:
In Chapter 7 the micro-scale spatia
Page 254 and 255:
and positions of patches. Consequen
Page 256 and 257:
epresent those found establishing i
Page 258 and 259:
distribution at the micro-scale. Ad
Page 260 and 261:
provide a rich food source for deme
Page 262 and 263:
Armonies W., 1988. Active emergence
Page 264 and 265:
Cha M.W., in prep. Macroalgal mats
Page 266 and 267:
Dobbs F.C. and Vozarik J.M., 1983.
Page 268 and 269:
Flach E.C., 1996. The influence of
Page 270 and 271:
Hall SI, Raffaeni D.G., Basford DJ.
Page 272 and 273:
Keckler D., 1997. Surfer for Window
Page 274 and 275:
Levin L.A. and Creed E.L., 1986. Ef
Page 276 and 277:
Mileikovsky S.A., 1971. Types of la
Page 278 and 279:
Ong B. and Krishnan S., 1995. Chang
Page 280 and 281:
Raffaelli D.G., Hildrew A.G. and Gi
Page 282 and 283:
Scheltema R.S., 1974. Biological in
Page 284 and 285:
Soulsby P.G., Lowthion D., Houston
Page 286 and 287:
McArdle B.H., Morrisey D., Schneide
Page 288 and 289:
Wharfe J.R., 1977. An ecological su
Page 290 and 291:
Zajac R.N. and Whitlatch R.B., 1982
Page 292 and 293:
- C'e) oc0000mooF,o•-ooNtn-coo-00
Page 294 and 295:
APPENDIX 1.2: SPECIES ABUNDANCES FR
Page 296 and 297:
ON In co In ° ken n00000N---0g0N-.
Page 298 and 299:
o m000eno,-0-. 0 0000en ,-. 0.-00 o
Page 300 and 301:
APPENDIX 2: SPECIES ABUNDANCES FROM
Page 302 and 303:
0.- CV N - , .- CI E.104 ..r cv g.,
Page 304 and 305:
cv en 0 a .- ,- .- .- g c', ,- ,- g
Page 306 and 307:
PI — — — Pi n — — - R., .
Page 308 and 309:
P . en .2 Co in ,.. ne .- cq . -- -
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