Marine Hard Bottom Communities: Patterns, Dynamics, Diversity, and Change [1 ed.] 3540927034, 9783540927037

Table of contents :
3540927034......Page 1
Contents......Page 8
Part I: Habitat, Substrata and Communities......Page 26
Introduction......Page 28
1.1 Particularities of the Aquatic Medium......Page 32
1.2 Life Forms in Hard Bottom Communities......Page 35
References......Page 41
2.1 Patterns on Temperate Hard Substrata......Page 44
2.3 The Role of Substrata in the Colonisation and Development of Assemblages......Page 47
2.4 Future Focus......Page 55
References......Page 56
3.1 Islands in a Sea of Mud......Page 64
3.2 Types of Hard Substrata in the Deep Sea......Page 65
3.3 Major Groups of Deep-Sea Organisms......Page 68
3.4 Population and Community Ecology of Hard-Bottom Deep-Sea Epifauna......Page 70
3.5 Conclusions......Page 79
References......Page 80
4.2 Establishment of an Epibiotic Community......Page 86
4.3 Consequences of Epibioses......Page 88
4.4 Distributional Patterns of Epibioses......Page 90
4.5 Responses of the Host......Page 92
References......Page 94
Part II: Diversity Patterns and Their Causes......Page 98
Introduction......Page 100
5.1 Introduction......Page 106
5.2 Case Studies......Page 107
5.3 Discussion......Page 109
References......Page 110
6.1 Introduction......Page 114
6.2 Regional Diversity—Biotic Interchange and Speciation......Page 115
6.3 Influence of Regional Species Pools on Local Diversity......Page 117
6.4 Local Diversity......Page 119
6.5 Conclusions......Page 121
References......Page 122
7.1 Introduction......Page 126
7.2 Zonation......Page 128
7.3 Gaps in Knowledge......Page 131
7.4 Concluding Remarks......Page 132
References......Page 134
8.2 Evolutionary Process......Page 138
8.3 Regional Biogeographic Patterns......Page 141
8.4 Discussion......Page 146
References......Page 147
9.1 Introduction......Page 152
9.2 A Framework for Investigating Ecological Variability......Page 153
9.3 Observational Approaches: Variability in Ecological Responses......Page 155
9.4 Experimental Approaches: Manipulation of Intensity and Variance of Ecological Drivers......Page 157
9.5 Future Directions......Page 161
9.6 Conclusions......Page 163
References......Page 164
Part III: Community Dynamics......Page 168
Introduction......Page 170
10.1 Introduction......Page 174
10.3 Main Topics in Fertilization Ecology of Rocky Shore Species......Page 175
10.4 Gamete Traits that Influence Fertilization Success......Page 178
10.5 Gamete Mixing......Page 181
10.6 Risk of Polyspermy and the Role of Polyspermy Blocks......Page 183
10.7 Fertilization Compatibility......Page 184
References......Page 185
11.2 Variability in the Production of Larvae......Page 190
11.3 Mortality in the Plankton......Page 192
11.4 Scales of Dispersal and Larval Supply......Page 194
11.5 Genetic Consequences of Variation in Larval Production and Dispersal......Page 197
References......Page 198
12.2 Definitions of Settlement and Recruitment......Page 202
12.3 Patterns of Settlement and Recruitment on Hard Substrata......Page 203
12.4 Behaviour at Settlement......Page 205
12.5 Biological and Physical Interactions at Settlement......Page 206
12.6 Early Post-Settlement Survival......Page 208
12.7 Consequences of Variation in Settlement and Recruitment......Page 209
References......Page 211
13.1 Introduction......Page 216
13.2 Causes, Cues and Clocks......Page 217
13.3 Identifying Drivers and Responses......Page 218
13.4 From Intertidal Habitats to Deep-Sea Communities......Page 220
References......Page 223
14.1 Definitions......Page 226
14.2 Disruptions as Unique Events......Page 230
14.3 Disruption as a Chronically Recurring Process......Page 232
References......Page 236
15.2 Concepts and Terminology......Page 238
15.4 Early Colonisation by Microorganisms......Page 240
15.5 Macrobiotic Succession on Rocky Shores......Page 241
15.6 Succession, Species Diversity and Ecosystem Processes......Page 243
15.7 Overview and Concluding Remarks......Page 245
References......Page 246
16.2 Intraspecific Interactions......Page 250
16.3 Interspecific Interactions......Page 252
16.4 Community Interactions......Page 256
References......Page 259
Part IV: Changing Biodiversity......Page 264
Introduction......Page 266
17.1 Introduction......Page 272
17.2 Scales of Disturbances Affecting Distributions and Abundances......Page 273
17.3 Conclusions......Page 279
References......Page 280
18.2 Global-Scale Change......Page 282
18.3 Regional-Scale Change......Page 286
18.4 Local-Scale Change......Page 288
References......Page 291
19.1 Human Changes to Coastal Habitats......Page 294
19.2 Causes of Habitat Loss......Page 295
19.3 Trends of Habitat Loss......Page 296
19.4 The Addition of Artificial Hard Substrata......Page 299
19.5 The Importance of Regional and Historical Contexts......Page 301
19.6 The Case for Mitigating Habitat Loss......Page 302
References......Page 303
20.1 Introduction......Page 306
20.3 Types of Stressors and Responses......Page 307
20.4 Temporal Stressors......Page 308
20.6 Empirical Evidence of Stressor Effects......Page 309
References......Page 316
21.2 Porifera......Page 320
21.3 Cnidaria......Page 321
21.5 Echinoderms......Page 325
21.7 Extinctions and Massive Mortalities: Effects on Benthic Communities......Page 326
References......Page 328
22.2 The Arrival of Introduced Species: Vectors and Propagule Pressure......Page 334
22.3 What Makes a Good Invader?......Page 336
22.4 Which Communities Are More Susceptible to Invasion?......Page 337
22.5 The Effects of Invasions......Page 340
References......Page 342
23.2 Habitat Distribution of Non-native Species in North America......Page 346
23.3 Integrating Substratum Heterogeneity and Spatial Scale......Page 354
References......Page 356
24.1 Introduction......Page 358
24.2 Rehabilitation of Marine Habitats......Page 359
24.3 Evaluating Success of Rehabilitation......Page 363
References......Page 366
25.2 Protection Outside Reserves......Page 370
25.3 Reserves as Protection—Principles......Page 373
25.4 Reserves as Protection—Practice......Page 374
25.5 What Happens Outside Reserves?......Page 375
25.6 Assessing Effectiveness of Marine Reserves......Page 377
References......Page 378
Part V: Role of Diversity......Page 382
Introduction......Page 384
26.1 Introduction......Page 386
26.2 How and Why Biodiversity Can Be Linked to Ecosystem Performance......Page 387
26.3 Roles of Species in Mediating Ecosystem Performance......Page 388
26.4 Biodiversity and Primary Production......Page 389
26.5 The Role of Consumer Diversity......Page 391
26.6 The Role of Within-Species Diversity......Page 392
26.7 Conclusions and Outlook......Page 393
References......Page 394
27.2 Defining Diversity......Page 400
27.3 Operational Characterisation of Functional Diversity......Page 402
27.4 How to Test the Validity and Value of Particular Methods/Groupings......Page 406
27.5 Evidence from Hard Substrata Regarding Sensitivity of Systems to Changes in Functional Diversity......Page 409
27.6 The Relative Importance of Functional and Taxonomic Diversity: Summary of Current Knowledge and Suggestions for the Future......Page 411
References......Page 412
28.1 Introduction......Page 416
28.2 Measures of Stability......Page 418
28.3 Three Mechanisms Relating Stability to Diversity......Page 419
28.4 Diversity–Stability Relationships in Assemblages of Rocky Shores......Page 423
28.5 Discussion......Page 428
References......Page 430
29.1 Introduction......Page 434
29.2 Aesthetics......Page 435
29.3 Ethics......Page 437
29.4 Conclusions......Page 443
References......Page 444
Part VI: Appropriate Research Methods......Page 448
30.1 Field Methods in Marine Ecology......Page 450
30.2 Experimental and Sampling Designs......Page 453
References......Page 459
B......Page 462
D......Page 463
F......Page 464
I......Page 465
M......Page 466
R......Page 467
S......Page 468
V......Page 469
Z......Page 470

Citation preview

Ecological Studies, Vol. 206 Analysis and Synthesis

Edited by M.M. Caldwell, Washington, USA G. Heldmaier, Marburg, Germany R.B. Jackson, Durham, USA O.L. Lange, Würzburg, Germany H.A. Mooney, Stanford, USA E.-D. Schulze, Jena, Germany U. Sommer, Kiel, Germany

Ecological Studies Further volumes can be found at springer.com Volume 189 Ecology of Harmful Algae (2006) E. Granéli and J.T. Turner (Eds.) Volume 190 Wetlands and Natural Resource Management (2006) J.T.A. Verhoeven, B. Beltman, R. Bobbink, and D.F. Whigham (Eds.) Volume 191 Wetlands: Functioning, Biodiversity Conservation, and Restoration (2006) R. Bobbink, B. Beltman, J.T.A. Verhoeven, and D.F. Whigham (Eds.) Volume 192 Geological Approaches to Coral Reef Ecology (2007) R.B. Aronson (Ed.) Volume 193 Biological Invasions (2007) W. Nentwig (Ed.) Volume 194 Clusia: A Woody Neotropical Genus of Remarkable Plasticity and Diversity (2007) U. Lüttge (Ed.) Volume 195 The Ecology of Browsing and Grazing (2008) I.J. Gordon and H.H.T. Prins (Eds.) Volume 196 Western North American Juniperus Communites: A Dynamic Vegetation Type (2008) O. Van Auken (Ed.)

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Volume 197 Ecology of Baltic Coastal Waters (2008) U. Schiewer (Ed.)

Volume 205 Coral Bleaching: Patterns, Processes, Causes and Consequences (2009) M.J.H. van Oppen and J.M. Lough (Eds.)

Volume 198 Gradients in a Tropical Mountain Ecosystem of Ecuador (2008) E. Beck, J. Bendix, I. Kottke, F. Makeschin, R. Mosandl (Eds.)

Volume 206 Marine Hard Bottom Communities: Patterns, Dynamics, Diversity, and Change (2009) M. Wahl (Ed.)

Martin Wahl Editor

Marine Hard Bottom Communities Patterns, Dynamics, Diversity, and Change

Editor Prof. Dr. Martin Wahl IFM-GEOMAR Düsternbrookerweg 20 24105 Kiel, Germany [email protected]

ISBN 978-3-540-92703-7 e-ISBN 978-3-540-92704-4 DOI 10.1007/978-3-540-92704-4 Springer Dordrecht Heidelberg London New York Ecological Studies ISSN 0070-8356 Library of Congress Control Number: 200992151 © Springer-Verlag Berlin Heidelberg 2009 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Cover illustrations: The book cover shows a small selection of typical hard bottom community species of the temperate North Atlantic, with a tropical gorgonian in the background. While the two cephalopods are occasional visitors to hard bottom systems, the star fish and the mussel tend to prefer hard over soft bottom habitats, and the remaining forms are exclusively found on natural hard bottom. The species shown represent the important trophic functional types of predators, grazers and suspension feeders. Cover design: WMXDesign GmbH, Heidelberg, Germany Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

Preface

Hard-bottom communities represent some of the most productive and diverse ecosystems on our planet. They include very dissimilar types of assemblages such as hydrothermal vent communities, kelp forests, tropical coral reefs, fouling on manmade structures or epibioses on living surfaces. These communities are composed of microbial and macrobial organisms which are sessile, sedentary or motile, auto-, mixo- or heterotrophic, solitary or colonial, and represent most of the marine phyla. Due to their impressive taxonomical and functional diversity, as well as their internal dynamics, these communities provide irreplaceable ecosystem services such as nutrient cycling, water purification, benthic–pelagic coupling, or nursery grounds for juveniles. Besides this, they represent an evolutionary heritage which in species richness is comparable, but in functional diversity is superior to tropical rainforests. As a large proportion of the worldwide hard-bottom communities are located in shallow and near-shore regions, they are particularly prone to the impacts of human activities and global change. In the course of the ongoing shift of abiotic variables associated with climate change, and in combination with more directly maninduced pressures like over-fishing, eutrophication, invasions or the restructuring of coastlines, it can be expected that marine hard-bottom communities will structurally reorganize over the coming decades. If this change in species composition is associated with a change in functional group richness, then shifts in ecosystem services will ensue. In an effort to improve our understanding of the value, dynamics, diversity and change of marine hard-bottom communities, in this book more than 50 marine ecologists report on various aspects of these systems from a large number of biogeographic regions. The result is a comprehensive picture of the particularity of these communities, the dynamics of their reproduction, recruitment and interactions, and the patterns of their taxonomic and functional diversity at a variety of spatial and temporal scales. The role and value of diversity regarding community stability and ecosystem services, and the present challenges to this diversity and the associated risks are highlighted. Finally, suitable measures to protect or restore community diversity are presented and discussed. The book ends with some recommendations on new and appropriate research tools.

v

vi

Preface

We hope that this work will help scientists, decision makers and students—as the coming responsible generation—to recognize, understand and hopefully master the challenges associated with global change. To whatever extent this books fulfils these expectations, its value reflects the cumulated input of numerous colleagues and, particularly, the efficient and competent effort of the parts coordinators. I deeply appreciate all the enthusiastic and insightful contributions, comments, suggestions and discussions. The highly competent editorial assistance by Nina Blöcher greatly facilitated the task. All in all, it was a highly rewarding experience. February 2009

Martin Wahl Kiel, Germany

Contents

Part I Habitat, Substrata and Communities Coordinated by Andrew R. Davis Introduction .................................................................................................... Andrew R. Davis

3

1

Habitat Characteristics and Typical Functional Groups ..................... Martin Wahl

7

1.1 Particularities of the Aquatic Medium .............................................. 1.2 Life Forms in Hard Bottom Communities ........................................ References ..................................................................................................

7 10 16

The Role of Mineral, Living and Artificial Substrata in the Development of Subtidal Assemblages ........................................ Andrew R. Davis

19

2

2.1 2.2 2.3

3

Patterns on Temperate Hard Substrata .............................................. The Colonisation Process.................................................................. The Role of Substrata in the Colonisation and Development of Assemblages ..................................................................................... 2.3.1 Artificial Substrata ................................................................ 2.3.2 Mineral Substrata .................................................................. 2.3.3 Biogenic Living Surfaces ...................................................... 2.4 Future Focus...................................................................................... References ..................................................................................................

19 22

Communities on Deep-Sea Hard Bottoms ............................................. Craig M. Young

39

3.1 3.2

39 40 40 41 41

Islands in a Sea of Mud..................................................................... Types of Hard Substrata in the Deep Sea.......................................... 3.2.1 Substrata Formed by Volcanism ........................................... 3.2.2 Polymetallic Nodules and Manganese Crusts ....................... 3.2.3 Carbonates ............................................................................

22 23 25 28 30 31

vii

viii

Contents

3.2.4 Methane Hydrate................................................................... 3.2.5 Biogenic Surfaces ................................................................. 3.2.6 Organic Remains from the Upper Ocean .............................. 3.3 Major Groups of Deep-Sea Organisms ............................................. 3.4 Population and Community Ecology of Hard-Bottom Deep-Sea Epifauna............................................................................ 3.4.1 Chemosynthetic Communities .............................................. 3.4.2 Seamounts, Continental Slopes, and Islands ........................ 3.4.3 Deep Coral Reefs .................................................................. 3.4.4 Ferromanganese Nodules ...................................................... 3.4.5 Organic Materials from the Upper Ocean ............................. 3.4.6 Epizooism ............................................................................. 3.5 Conclusions ....................................................................................... References .................................................................................................. 4

42 42 42 43 45 45 49 51 52 52 53 54 55

Epibiosis: Ecology, Effects and Defences ............................................... Martin Wahl

61

4.1 Sessile Mode of Life ......................................................................... 4.2 Establishment of an Epibiotic Community ....................................... 4.3 Consequences of Epibioses ............................................................... 4.4 Distributional Patterns of Epibioses .................................................. 4.5 Responses of the Host ....................................................................... References ..................................................................................................

61 61 63 65 67 69

Part II Diversity Patterns and Their Causes Coordinated by Sean D. Connell Introduction .................................................................................................... Sean D. Connell 5

6

75

Latitudinal Patterns of Species Richness in Hard-Bottom Communities ................................................................ João Canning-Clode

81

5.1 Introduction ....................................................................................... 5.2 Case Studies ...................................................................................... 5.3 Discussion ......................................................................................... References ..................................................................................................

81 82 84 85

Regional-Scale Patterns ........................................................................... Jonne Kotta and Jon D. Witman

89

6.1 6.2 6.3 6.4

89 90 92 94

Introduction ....................................................................................... Regional Diversity—Biotic Interchange and Speciation .................. Influence of Regional Species Pools on Local Diversity .................. Local Diversity ..................................................................................

Contents

7

8

9

ix

6.5 Conclusions ....................................................................................... References ..................................................................................................

96 97

Patterns Along Environmental Gradients ............................................. Antonio Terlizzi and David R. Schiel

101

7.1

Introduction ....................................................................................... 7.1.1 Definitions of Diversity......................................................... 7.2 Zonation ............................................................................................ 7.2.1 Intertidal Zone....................................................................... 7.2.2 Subtidal Zone ........................................................................ 7.3 Gaps in Knowledge ........................................................................... 7.4 Concluding Remarks......................................................................... References ..................................................................................................

101 102 103 103 105 106 107 109

Evolutionary Patterns of Diversity and Their Causes .......................... Sharyn J. Goldstien and David R. Schiel

113

8.1 8.2 8.3

Introduction ....................................................................................... Evolutionary Process......................................................................... Regional Biogeographic Patterns ...................................................... 8.3.1 North America ...................................................................... 8.3.2 Australasia ............................................................................ 8.3.3 Europe ................................................................................... 8.4 Discussion ......................................................................................... References ..................................................................................................

113 113 116 117 118 119 121 122

Environmental Variability: Analysis and Ecological Implications .............................................................................................. Lisandro Benedetti-Cecchi

127

9.1 Introduction ....................................................................................... 9.2 A Framework for Investigating Ecological Variability ..................... 9.3 Observational Approaches: Variability in Ecological Responses ................................................................... 9.4 Experimental Approaches: Manipulation of Intensity and Variance of Ecological Drivers .................................................. 9.5 Future Directions .............................................................................. 9.6 Conclusions ....................................................................................... References ..................................................................................................

127 128 130 132 136 138 139

Part III Community Dynamics Coordinated by Christopher D. McQuaid Introduction .................................................................................................... Christopher D. McQuaid

145

x

10

Contents

Fertilization Strategies........................................................................... Ester A. Serrão and Jon Havenhand

149

10.1 10.2

149 150 150

Introduction ................................................................................... Scope and Definition of Terms ..................................................... 10.2.1. Definitions........................................................................ 10.3 Main Topics in Fertilization Ecology of Rocky Shore Species ................................................................ 10.4 Gamete Traits that Influence Fertilization Success....................... 10.4.1 In Broadcast Spawners .................................................... 10.4.2 In Spermcasters ............................................................... 10.4.3 In Copulatory Fertilizers ................................................. 10.5 Gamete Mixing ............................................................................. 10.5.1 Role of Hydrodynamics .................................................. 10.5.2 Role of Density/Aggregation Spawning ......................... 10.5.3 Role of Spawning Synchrony ......................................... 10.6 Risk of Polyspermy and the Role of Polyspermy Blocks ............. 10.7 Fertilization Compatibility ............................................................ 10.8 Conclusions ................................................................................... References ................................................................................................ 11

12

150 153 153 154 155 156 156 157 157 158 159 160 160

Larval Supply and Dispersal................................................................. Dustin J. Marshall, Craig Styan, and Christopher D. McQuaid

165

11.1 11.2

Introduction ................................................................................... Variability in the Production of Larvae ......................................... 11.2.1 Variation in Fecundity ..................................................... 11.2.2 Variation in Fertilisation ................................................. 11.3 Mortality in the Plankton .............................................................. 11.3.1 Estimates of Mortality in the Field ................................. 11.3.2 Sources of Planktonic Mortality ..................................... 11.3.3 Phenotypic Degradation of Larvae in the Field .............. 11.4 Scales of Dispersal and Larval Supply ......................................... 11.5 Genetic Consequences of Variation in Larval Production and Dispersal ................................................................................. 11.6 Conclusions ................................................................................... References ................................................................................................

165 165 165 166 167 167 168 168 169

Settlement and Recruitment ................................................................. Stuart R. Jenkins, Dustin Marshall, and Simonetta Fraschetti

177

12.1 12.2 12.3 12.4

177 177 178 180

Introduction ................................................................................... Definitions of Settlement and Recruitment................................... Patterns of Settlement and Recruitment on Hard Substrata .......... Behaviour at Settlement ................................................................

172 173 173

Contents

13

14

12.5 Biological and Physical Interactions at Settlement....................... 12.6 Early Post-Settlement Survival ..................................................... 12.7 Consequences of Variation in Settlement and Recruitment .......... 12.8 Summary ....................................................................................... References ................................................................................................

181 183 184 186 186

Seasonal Dynamics ................................................................................. Josep-Maria Gili and Peter S. Petraitis

191

13.1 Introduction ................................................................................... 13.2 Causes, Cues and Clocks .............................................................. 13.3 Identifying Drivers and Responses ............................................... 13.4 From Intertidal Habitats to Deep-Sea Communities..................... 13.5 Future Directions .......................................................................... References ................................................................................................

191 192 193 195 198 198

Disruption, Succession and Stochasticity............................................. J. Timothy Wootton, Mathieu Cusson, Sergio Navarrete, and Peter S. Petraitis

201

14.1

201 202 202 203 204 205 207 211

Definitions..................................................................................... 14.1.1 Anthropogenic Versus Natural Disturbance.................... 14.1.2 Physical Disturbance Versus Consumers ........................ 14.1.3 Other Ecological Disruptions .......................................... 14.1.4 Stochasticity .................................................................... 14.2 Disruptions as Unique Events ....................................................... 14.3 Disruption as a Chronically Recurring Process ............................ References ................................................................................................ 15

xi

Changes in Diversity and Ecosystem Functioning During Succession .................................................................................. Laure M.-L.J. Noël, John N. Griffin, Paula S. Moschella, Stuart R. Jenkins, Richard C. Thompson, and Stephen J. Hawkins 15.1 Introduction ................................................................................... 15.2 Concepts and Terminology ........................................................... 15.3 Creation of New Space ................................................................. 15.4 Early Colonisation by Microorganisms ........................................ 15.5 Macrobiotic Succession on Rocky Shores .................................... 15.6 Succession, Species Diversity and Ecosystem Processes ............. 15.6.1 Diversity .......................................................................... 15.6.2 Functional Consequences................................................ 15.7 Overview and Concluding Remarks ............................................. References ................................................................................................

213

213 213 215 215 216 218 218 219 220 221

xii

16

Contents

Simple and Complex Interactions ........................................................ Markus Molis and Bernardo A.P. da Gama

225

16.1 16.2 16.3 16.4

225 225 227 231 232 234

Introduction ................................................................................... Intraspecific Interactions ............................................................... Interspecific Interactions ............................................................... Community Interactions................................................................ 16.4.1 Multiple Predator and Prey Effects ................................. References ................................................................................................ Part IV Changing Biodiversity Coordinated by Angus C. Jackson and M. Gee Chapman

Introduction ...................................................................................................... 241 Angus C. Jackson and M. Gee Chapman 17

Anthropogenic Changes in Patterns of Diversity on Hard Substrata: an Overview.......................................................... Brianna G. Clynick, David Blockley, and M. Gee Chapman 17.1 17.2

Introduction ................................................................................... Scales of Disturbances Affecting Distributions and Abundances ............................................................................ 17.2.1 Effects of Disposal of Waste Material and Spills............ 17.2.2 Changes to Habitat Provided by Hard Substrata............. 17.2.3 Direct Effects on Species ................................................ 17.3 Conclusions ................................................................................... References ................................................................................................ 18

247 247 248 250 251 252 254 255

Shifts in Abiotic Variables and Consequences for Diversity .............. Christopher D.G. Harley and Sean D. Connell

257

18.1 18.2

257 257 258 259 259 260 260 261 261 262 262 263 263

Introduction ................................................................................... Global-Scale Change .................................................................... 18.2.1 Changes in Water Temperature ....................................... 18.2.2 Changes in Sea Level ...................................................... 18.2.3 Increasing Frequency and Intensity of Storms................ 18.2.4 Changes in Upwelling and Circulation ........................... 18.2.5 Ocean Acidification ........................................................ 18.2.6 Increasing UV Radiation................................................. 18.3 Regional-Scale Change ................................................................. 18.3.1 El Niño–Southern Oscillation (ENSO) ........................... 18.3.2 Other Interannual Oscillations ........................................ 18.4 Local-Scale Change ...................................................................... 18.4.1 Permanent Abiotic Shifts: a Catchment Perspective.......

Contents

xiii

18.4.2

Regional and Middle-Scale Contingencies of the Catchment Perspective .......................................... 18.4.3 Departures: Abiotic Shifts Can Be Subtle and Disconnected from Their Source.............................. 18.5 Conclusions ................................................................................... References ................................................................................................ 19

265 266 266

The Loss of Natural Habitats and the Addition of Artificial Substrata ............................................................................ Laura Airoldi, Sean D. Connell, and Michael W. Beck

269

19.1 19.2 19.3

269 270 271

Human Changes to Coastal Habitats............................................. Causes of Habitat Loss.................................................................. Trends of Habitat Loss .................................................................. 19.3.1 A Case History: the Decline of Native Oyster Reefs in Europe ............................................................... 19.3.2 Habitat Conversion: Switches from Canopy Habitats to Barrens/Turfs ................................................ 19.4 The Addition of Artificial Hard Substrata .................................... 19.5 The Importance of Regional and Historical Contexts................... 19.5.1 Regional Contexts of Habitat Change ............................. 19.5.2 Historical Habitat Loss and the Shifting-Baseline Syndrome ........................................................................ 19.6 The Case for Mitigating Habitat Loss........................................... References ................................................................................................ 20

264

Multiple Stressors and Disturbances: When Change Is Not in the Nature of Things ..................................... David R. Schiel 20.1 20.2 20.3 20.4 20.5 20.6

Introduction ................................................................................... A Framework of Disturbance by Multiple Stressors .................... Types of Stressors and Responses................................................. Temporal Stressors ........................................................................ Spatial Patterns of Stressors .......................................................... Empirical Evidence of Stressor Effects ........................................ 20.6.1 Sedimentation ................................................................. 20.6.2 Species Reductions ......................................................... 20.6.3 Extractions, Harvesting, Removals ................................. 20.6.4 Non-indigenous Species (NIS) ....................................... 20.6.5 Climate Change ............................................................... 20.6.6 Other Stressors ................................................................ 20.7 Conclusions ................................................................................... References ................................................................................................

271 272 274 276 276 277 277 278

281 281 282 282 283 284 284 285 286 287 288 289 290 291 291

xiv

21

Contents

Mass Mortalities and Extinctions ......................................................... Carlo Cerrano and Giorgio Bavestrello

295

21.1 21.2 21.3

295 295 296 296 298 299 300 300 301

Introduction ................................................................................... Porifera.......................................................................................... Cnidaria ......................................................................................... 21.3.1 Hexacorals—Hard Corals ............................................... 21.3.2 Other Hexacorals............................................................. 21.3.3 Octocorals ....................................................................... 21.4 Molluscs ........................................................................................ 21.5 Echinoderms ................................................................................. 21.6 Ascidians ....................................................................................... 21.7 Extinctions and Massive Mortalities: Effects on Benthic Communities .................................................. References ................................................................................................ 22

Biological Invasions: Insights from Marine Benthic Communities........................................................................................... Christopher D. McQuaid and Francisco Arenas 22.1 22.2

Introduction ................................................................................... The Arrival of Introduced Species: Vectors and Propagule Pressure .................................................... 22.3 What Makes a Good Invader? ....................................................... 22.4 Which Communities Are More Susceptible to Invasion? ............. 22.4.1 Biotic Resistance, Competition, Predation and Facilitation: Interactions Between Native and Invasive Species ............................................ 22.4.2 The Role of Diversity in the Susceptibility of Communities to Invasion ............................................ 22.4.3 Disturbance and the Susceptibility to Invasion ............... 22.5 The Effects of Invasions ................................................................ 22.6 Overview ....................................................................................... References ................................................................................................ 23

Habitat Distribution and Heterogeneity in Marine Invasion Dynamics: the Importance of Hard Substrate and Artificial Structure ........................................................ Gregory M. Ruiz, Amy L. Freestone, Paul W. Fofonoff, and Christina Simkanin 23.1 23.2

Introduction ................................................................................... Habitat Distribution of Non-native Species in North America .......................................................................... 23.2.1 Importance of Hard Substrata for Marine Invasions..........................................................................

301 303

309 309 309 311 312

312 313 314 315 317 317

321

321 321 322

Contents

xv

23.2.2

Temporal Pattern of Marine Invasions on Hard Substrata ............................................................ 23.2.3 Distribution of Non-native Species Among Bays, Estuaries and Outer Coasts ............................................. 23.2.4 Role of Artificial Hard Substrata in Marine Invasions.......................................................................... 23.3 Integrating Substratum Heterogeneity and Spatial Scale ........................................................................... References ................................................................................................ 24

25

323 324 327 329 331

Rehabilitation of Habitat and the Value of Artificial Reefs ............... Paris J. Goodsell and M. Gee Chapman

333

24.1 24.2

Introduction ................................................................................... Rehabilitation of Marine Habitats................................................. 24.2.1 Removal of Obstructions to Natural Recovery ............... 24.2.2 Adding Biota or Structure to Existing Habitat ................ 24.2.3 Providing Novel Habitat ................................................. 24.2.4 Constructing Biotic Habitat ............................................ 24.3 Evaluating Success of Rehabilitation............................................ 24.4 Conclusions ................................................................................... References ................................................................................................

333 334 334 335 336 337 338 341 341

Protection of Biota and the Value of Marine Protected Areas ...................................................................................... Paris J. Goodsell and A.J. Underwood

345

25.1 25.2

Introduction ................................................................................... Protection Outside Reserves ......................................................... 25.2.1 Contaminants .................................................................. 25.2.2 Harvesting ....................................................................... 25.3 Reserves as Protection—Principles .............................................. 25.4 Reserves as Protection—Practice ................................................. 25.5 What Happens Outside Reserves? ................................................ 25.6 Assessing Effectiveness of Marine Reserves ................................ 25.7 Conclusions ................................................................................... References ................................................................................................

345 345 346 347 348 349 350 352 353 353

Part V Role of Diversity Coordinated by Tasman P. Crowe, Heather E. Sugden, and Stephen J. Hawkins Introduction ...................................................................................................... 359 Tasman P. Crowe, Heather E. Sugden, and Stephen J. Hawkins

xvi

26

Contents

The Role of Biodiversity for the Functioning of Rocky Reef Communities .................................................................. Lars Gamfeldt and Matthew E.S. Bracken 26.1 Introduction ................................................................................... 26.2 How and Why Biodiversity Can Be Linked to Ecosystem Performance ............................................................ 26.3 Roles of Species in Mediating Ecosystem Performance............... 26.4 Biodiversity and Primary Production ............................................ 26.5 The Role of Consumer Diversity .................................................. 26.6 The Role of Within-Species Diversity .......................................... 26.7 Conclusions and Outlook .............................................................. References ................................................................................................

27

Functional and Taxonomic Perspectives of Marine Biodiversity: Functional Diversity and Ecosystem Processes ................................... Tasman P. Crowe and Roly Russell 27.1 27.2 27.3

Introduction ................................................................................... Defining Diversity......................................................................... Operational Characterisation of Functional Diversity .................. 27.3.1 Trophic Position .............................................................. 27.3.2 Ad-hoc Groupings Based on Individual Characteristics ................................................................. 27.3.3 Classifications Based on Multiple Traits ........................ 27.3.4 Generalisable Quantifications of Functional/Trait Diversity ........................................... 27.4 How to Test the Validity and Value of Particular Methods/Groupings....................................................................... 27.4.1 Correlational Approaches ............................................... 27.4.2 Experimental Approaches ............................................... 27.4.3 Modelling Approaches .................................................... 27.5 Evidence from Hard Substrata Regarding Sensitivity of Systems to Changes in Functional Diversity ............................ 27.6 The Relative Importance of Functional and Taxonomic Diversity: Summary of Current Knowledge and Suggestions for the Future .................................. References ................................................................................................ 28

361 361 362 363 364 366 367 368 369

375 375 375 377 378 378 379 380 381 382 383 384 384

386 387

Mechanisms Underpinning Diversity–Stability Relationships in Hard Bottom Assemblages........................................ Lisandro Benedetti-Cecchi

391

28.1 28.2

391 393

Introduction ................................................................................... Measures of Stability ....................................................................

Contents

xvii

28.3

Three Mechanisms Relating Stability to Diversity ....................... 28.3.1 The Statistical Averaging (Portfolio) Effect ................... 28.3.2 The Covariance Effect..................................................... 28.3.3 Overyielding.................................................................... 28.4 Diversity–Stability Relationships in Assemblages of Rocky Shores ............................................................................ 28.5 Discussion ..................................................................................... References ................................................................................................ 29

The Aesthetic Value of Littoral Hard Substrata and Consideration of Ethical Frameworks for Their Investigation and Conservation ............................................ Heather E. Sugden, A.J. Underwood, and Stephen J. Hawkins 29.1 29.2

Introduction ................................................................................... Aesthetics ...................................................................................... 29.2.1 Rocky Shores .................................................................. 29.2.2 Diving.............................................................................. 29.2.3 Impacts on Aesthetic Value ............................................. 29.3 Ethics............................................................................................. 29.3.1 A Brief Background ........................................................ 29.3.2 Experimental Ecology ..................................................... 29.3.3 Recoverability ................................................................. 29.3.4 Slow Recovery or Non-reversible Manipulations ........... 29.3.5 Biogeographic Studies and Non-native Species ............. 29.3.6 Genetic Considerations ................................................... 29.4 Conclusions ................................................................................... References ................................................................................................ Part VI 30

394 394 396 398 398 403 405

409

409 410 410 410 411 412 412 414 414 415 415 416 418 419

Appropriate Research Methods

Field and Research Methods in Marine Ecology ................................ A.J. Underwood and Angus C. Jackson

425

30.1

425 425 426 426 427 427 428 428 428 429

Field Methods in Marine Ecology ................................................ 30.1.1 Sampling Organisms and Habitats .................................. 30.1.2 Plankton .......................................................................... 30.1.3 Settlement of Organisms ................................................. 30.1.4 Measuring Behaviour ...................................................... 30.1.5 Measuring Physical and Chemical Variables .................. 30.1.6 Data Handling ................................................................. 30.2 Experimental and Sampling Designs ............................................ 30.2.1 Why Do We Need Experiments? .................................... 30.2.2 What Are Experiments? ..................................................

xviii

Contents

30.2.3 Why Are Statistical Procedures Necessary? ................... 30.2.4 Experimental and Sampling Designs .............................. 30.2.5 Some Major Issues with Experimental Designs ............. References ................................................................................................

431 431 432 434

Index .................................................................................................................. 437

Contributors

L. Airoldi Dipartimento di Biologia Evoluzionistica Sperimentale and Centro Interdipartimentale di Ricerca per le Scienze Ambientali, Università di Bologna, Via S. Alberto 163, 48100 Ravenna, Italy [email protected] F. Arenas Laboratory of Coastal Biodiversity, Centro Interdisciplinar de Investigação Marinha e Ambiental–CIIMAR, Universidade do Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal [email protected] G. Bavestrello Dipartimento di Scienze Mare, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy [email protected] M.W. Beck The Nature Conservancy and Institute of Marine Sciences, 100 Shaffer Road-LML, University of California, Santa Cruz, CA 95060, USA [email protected] L. Benedetti-Cecchi Dipartimento di Biologia, University of Pisa, Via A. Volta 6, 56126 Pisa, Italy [email protected] D. Blockley Centre for Research on Ecological Impacts of Coastal Cities, Marine Ecology Laboratories A11, University of Sydney, NSW 2006, Australia [email protected] M.E.S. Bracken Marine Science Center, Northeastern University, 430 Nahant Road, Nahant, MA 01908, USA [email protected]

xix

xx

Contributors

J. Canning-Clode Leibniz Institute of Marine Sciences at the University of Kiel, Duesternbrooker Weg 20, 24105 Kiel, Germany; University of Madeira, Centre of Macaronesian Studies, Marine Biology Station of Funchal, 9000-107 Funchal, Madeira, Portugal [email protected], [email protected] C. Cerrano Dipartimento per lo studio del Territorio e delle sue Risorse, Università di Genova, Corso Europa 26, 16132 Genova, Italy [email protected] M.G. Chapman Centre for Research on Ecological Impacts of Coastal Cities, Marine Ecology Laboratories A11, University of Sydney, NSW 2006, Australia [email protected] B.G. Clynick Centre for Research on Ecological Impacts of Coastal Cities, Marine Ecology Laboratories A11, University of Sydney, NSW 2006, Australia [email protected] S.D. Connell Southern Seas Ecology Laboratories, DP 418, University of Adelaide, SA 5005, Australia [email protected] T.P. Crowe School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland [email protected] M. Cusson Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 Boulevard de l’Université, Chicoutimi, Québec G7H 2B1, Canada [email protected] B.A.P. da Gama Departamento & Programa de Pós-Graduação em Biologia Marinha, Universidade Federal Fluminense, C.P. 100644, 24001-970 Niterói, Rio de Janeiro, Brazil [email protected] A.R. Davis School of Biological Sciences, University of Wollongong, NSW 2522, Australia [email protected] P.W. Fofonoff Smithsonian Environmental Research Center, P.O. Box 28, Edgewater, MD 21037, USA [email protected]

Contributors

xxi

S. Fraschetti Laboratorio di Zoologia e Biologia Marina, Dipartimento di Scienze e Technologie Biologiche ed Ambientale, Università del Salento, CoNISMa, 73100 Lecce, Italy [email protected] A.L. Freestone Smithsonian Environmental Research Center, P.O. Box 28, Edgewater, MD 21037, USA [email protected] L. Gamfeldt Department of Marine Ecology, Göteborg, University of Gothenburg, Box 461, 40530 Göteborg, Sweden [email protected] J.-M. Gili Departamento Biología Marina y Oceanografía, Institut de Ciències del Mar (CSIC), Passeig Maritim de la Barceloneta 37–49, 08003 Barcelona, Spain [email protected] S.J. Goldstien Marine Ecology Research Group, School of Biological Sciences, University of Canterbury, Private Bag 4800, 8140 Christchurch, New Zealand [email protected] P.J. Goodsell Centre for Research on Ecological Impacts of Coastal Cities, Marine Ecology Laboratories A11, University of Sydney, NSW 2006, Australia [email protected] J.N. Griffin The Marine Biological Association of the UK, Citadel Hill, Plymouth PL1 2PB, UK; Marine Biology and Ecology Research Centre, Marine Institute, School of Biological Sciences, University of Plymouth, Plymouth PL4 8AA, UK [email protected] C.D.G. Harley Department of Zoology, University of British Columbia, 6270 University Blvd., Vancouver, BC V6T1Z4, Canada [email protected] J. Havenhand Department of Marine Ecology, Tjärnö, University of Gothenburg, 45296 Stromstad, Sweden [email protected]

xxii

Contributors

S.J. Hawkins The Marine Biological Association of the UK, Citadel Hill, Plymouth PL1 2PB, UK; School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey LL59 5AB, UK [email protected] A.C. Jackson Centre for Research on Ecological Impacts of Coastal Cities, Marine Ecology Laboratories A11, University of Sydney, NSW 2006, Australia; Present address: Environmental Research Institute, North Highland College, UHI Millennium Institute, Castle Street, Thurso, Caithness KW14 7JD, UK [email protected] S.R. Jenkins School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey LL59 5AB, UK [email protected] J. Kotta Estonian Marine Institute, University of Tartu, Mäealuse 10a, 12618 Tallinn, Estonia [email protected] D.J. Marshall School of Biological Sciences, University of Queensland, 4072 Queensland, Australia [email protected] C.D. McQuaid Department of Zoology and Entomology, Rhodes University, Grahamstown 6140, South Africa [email protected] M. Molis Biologische Anstalt Helgoland, Alfred-Wegener-Institute for Polar and Marine Research, Kurpromenade 201, 27498 Helgoland, Germany [email protected] P.S. Moschella The Marine Biological Association of the UK, Citadel Hill, Plymouth PL1 2PB, UK; Commission Internationale pour l’Exploration Scientifique de la Mer Méditerranée, 16 Bd de Suisse, MC 98000, Monaco, [email protected]

Contributors

xxiii

S. Navarrete Estación Costera de Investigaciones Marinas & Center for Advanced Studies in Ecology and Biodiversity, Pontificia Universidad Católica de Chile, Casilla 114-D, Alameda 340, Santiago, Chile [email protected] L.M.-L.J. Noël The Marine Biological Association of the UK, Citadel Hill, Plymouth PL1 2PB, UK; Marine Biology and Ecology Research Centre, Marine Institute, School of Biological Sciences, University of Plymouth, Plymouth PL4 8AA, UK [email protected] P.S. Petraitis Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA [email protected] G.M. Ruiz Smithsonian Environmental Research Center, P.O. Box 28, Edgewater, MD 21037, USA [email protected] R. Russell CIESIN, The Earth Institute, Columbia University, 2910 Broadway, MC 3277, New York, NY 10025, USA; The Sandhill Institute, 5800 Edwards Road, Grand Forks, BC V0H 1H9, Canada [email protected] D.R. Schiel Marine Ecology Research Group, School of Biological Sciences, University of Canterbury, Private Bag 4800, 8140 Christchurch, New Zealand [email protected] E.A. Serrão CCMAR-CIMAR, Universidade do Algarve, Gambelas, 8005-139 Faro, Portugal [email protected] C. Simkanin Department of Biology, University of Victoria, P.O. Box 3020 STN CSC, Victoria, BC V8W 3N5, Canada [email protected] C. Styan RPS Environment, Level 2, 47 Ord St, West Perth WA 6005, P.O. Box 465, Subiaco WA 6904 [email protected]

xxiv

Contributors

H.E. Sugden School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey LL59 5AB, UK [email protected] A. Terlizzi Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, CoNISMa, 73100 Lecce, Italy [email protected] R.C. Thompson Marine Biology and Ecology Research Centre, Marine Institute, School of Biological Sciences, University of Plymouth, Plymouth PL4 8AA, UK [email protected] M. Wahl IFM-GEOMAR, Duesternbrookerweg 20, 24105 Kiel, Germany [email protected] J.D. Witman Department of Ecology and Evolutionary Biology, Box G-W, Brown University, Providence, RI 02912, USA [email protected] J.T. Wootton Department of Ecology & Evolution, The University of Chicago, 1101 East 57th Street, Chicago, IL 60637, USA [email protected] A.J. Underwood Centre for Research on Ecological Impacts of Coastal Cities, Marine Ecology Laboratories A11, University of Sydney, NSW 2006, Australia [email protected] C.M. Young Oregon Institute of Marine Biology, University of Oregon, P.O. Box 5389, Charleston, OR 97420, USA [email protected]

Part I

Habitat, Substrata and Communities Coordinated by Andrew R. Davis

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Introduction Andrew R. Davis

In terrestrial systems, the substratum is acknowledged as playing a highly significant role in community organisation; rock type determines soil composition as well as nutrient availability and, in turn, the floral and faunal communities that will be supported. In the marine realm, in contrast, organisms adhere to surfaces but rarely do organisms derive benefit from these (see Chisholm et al. 1996 for an intriguing exception). While it is well known that the orientation and slope of surfaces in the subtidal zone will influence incident light and sedimentation and, therefore, the resultant community, it is assumed that the nature of the substratum will be of minor importance. The chapters in this opening Part I of the book explore this notion in a range of subtidal systems. In the opening chapter, Wahl first examines the unique features of the subtidal zone, providing a foundation for discussion of hard bottom communities. He then applies the concept of functional groups to these communities across an unprecedented scale, with data from a global experiment using identical substrata—PVC panels. Given the hard-won nature of data from subtidal communities, his examination of alternative approaches to exploring ecological pattern and process is laudable. Indeed, it is useful not to be constrained by taxonomy, particularly as the taxonomic identity of some subtidal organisms—in particular, sponges and colonial ascidians—can be difficult to determine. This is further clouded by the presence of species’ complexes or cryptic species (Davis et al. 1999). Although Wahl’s dataset is from a relatively short time period and the panels small, it is nevertheless a starting point and underscores the power of adopting the same methodology across a broad geographic scale; it is rare to have direct comparisons across distinct fauna in disparate coastal zones. Overall, the functional group approach is worthy of closer scrutiny. In the second chapter, Davis contrasts the communities that develop on mineral, living and artificial substrata in shallow water (i.e. accessible by SCUBA). Artificial surfaces have proven particularly useful in understanding patterns of settlement and recruitment but the small spatial and temporal scales over which most such experiments are done questions their utility in understanding general ecological pattern and process. Moreover, panels are often at some distance from natural processes affecting the benthos. Living or biogenic surfaces represent a special case as substrata because strong selection pressures are expected to be operating, and their ability to attract, M. Wahl (ed.), Marine Hard Bottom Communities, Ecological Studies 206, DOI: 10.1007/978-3-540-92704-4_I, © Springer-Verlag Berlin Heidelberg 2009

3

4

A.R. Davis

deter or remove colonisers is well established. The recent finding that surface microtopography may be an important settlement deterrent is particularly exciting. Microtexture has become apparent for a variety of organisms, including on bivalve shells, molluscan egg masses and cetaceans. In relation to mineral surfaces, it is becoming clear that surface mineralogy may play an important structuring role for subtidal communities. First, the degree to which surfaces are pitted or their surface rugosity modified due to mineral dissolution may affect patterns of propagule settlement and recruitment. Second, the cracks and crevices associated with certain rock types may be an important ecological driver in some circumstances. Third, surprising evidence is mounting that the mineralogy of surfaces has direct effects on the settlement and survivorship of propagules even over broad scales, although this notion needs further examination with well-replicated experiments. The next two chapters treat hard bottom communities in special environments: the deep sea and on living surfaces. In Chapter 3, Young extends our understanding of patterns and processes for hard bottom communities into the deep ocean. Although this habitat is usually considered a ‘sea of mud’, Young reveals that hard surfaces can be extensive in the deep ocean and that deep coral reefs may exceed in area that of their shallow-water tropical counterparts. Striking features of his contribution include the variety of hard surfaces that are available for colonisation, the specialisations of some of the colonisers and the significant progress that has already been made in understanding patterns and processes in this environment. Given the difficulties in working at depth, progress on this latter point is particularly impressive. In addition, ecological work in this environment provides an opportunity to test the generality of ecological theory already developed in less logistically (and financially) challenging environments (Lawton 1996, 1999). On a sobering note, these environments may be no more immune to anthropogenic effects than are shallow-water reefs; anticipated changes in the calcite and aragonite saturation horizons stemming from fossil fuel-generated CO2 threaten the dissolution of key elements in these habitats (Guinotte et al. 2006). In the final chapter in this book part, Wahl brings us up to date with recent developments in the field of epibiosis (fouling). Historically, this area has stood on the interface of natural products chemistry, invertebrate ecology and microbial biology. Increasingly, particularly with the advent of cultureless microbial techniques, molecular biologists are becoming involved. Wahl’s contribution emphasises the increasing complexity being revealed in the ‘arms race’ between the host (basibiont) and the fouler (epibiont). The responses of the key players and the outcomes of their interactions can be astoundingly variable.

Conclusion To conclude, these chapters have highlighted recent developments in these disparate habitats; they have also outlined some of the challenges we face in moving our field forward. In my view, these chapters underscore two important points and,

Introduction

5

although, my observations are not particularly novel, they are worth emphasising. First, there is the overarching importance of an experimental approach (sensu Hurlbert 1984) in seeking to better understand natural systems. Even the seemingly intractable deep sea offers possibilities in this regard. My second point is the power of using identical methodology to explore pattern and process in disparate locations. The application of both of these approaches to subtidal communities can only strengthen our field.

References Chisholm JRM, Dauga C, Ageron E, Grimont PAD, Jaubert JM (1996) ‘Roots’ in mixotrophic algae. Nature 381:382 Davis AR, Roberts DE, Ayre DJ (1999) Conservation of sessile marine invertebrates: you don’t know what you’ve got ‘til it’s gone. In: Ponder W, Lunney D (eds) The other 99%: the conservation and biodiversity of invertebrates. Mosman, Transactions of the Royal Society of New South Wales, pp 325–329 Guinotte JM, Orr J, Cairns S, Freiwald A, Morgan L, George R (2006) Will human-induced changes in seawater chemistry alter the distribution of deep-sea scleractinian corals? Frontiers Ecol Environ 4:141–146 Hurlbert SH (1984) Pseudoreplication and the design of ecological field experiments. Ecol Monogr 54:187–211 Lawton J (1996) Patterns in ecology. Oikos 75:145–147 Lawton J (1999) Are there general laws in ecology. Oikos 84:177–192

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1

Chapter 1

Habitat Characteristics and Typical Functional Groups

2 3

Martin Wahl

4

1.1

5

Particularities of the Aquatic Medium

In the aquatic environment, evolution has produced a number of life forms which are rare or missing in terrestrial ecosystems. These include sessile organisms, i.e. microbes, plants and animals living attached to hard substrata without trophically depending on these substrata. These life forms constitute the bulk of the hard bottom communities treated in this book. Consequently, hard bottom communities are typically aquatic, and reach their highest diversity and largest biomasses in the marine realm. Important examples are coral reefs and kelp forests. The reason why many of the functional groups which compose marine hard bottom communities are missing on land lies in the fundamental differences between the media, air and salt water, with regard to a number of physicochemical properties with biological relevance. In the following, I will briefly review some of these and their ecological consequences (Fig. 1.1). Water is denser and more viscous than air, and the ratios of these parameters (approx. 80:1 and 100:1 respectively) change with temperature, salinity and pressure. Additionally, the dipole nature of water molecules makes this fluid the ‘universal solvent’ for an extremely wide range of elements and molecules. As a further consequence of the dipole nature, water molecules interlinking by hydrogen bonds form clusters. The existence of such clusters is the basis for the high viscosity of water. Cluster forming also is the reason for the remarkable heat capacity of water as compared to other liquids: much solar energy is used to break up hydrogen bonds which link the molecules in a cluster, rather than raising water temperature. This stored energy is released during cooling when the clusters form. The released heat slows down the cooling. A further difference between the terrestrial and the aquatic environment concerns the availability of light for photosynthesis or optical orientation. Water molecules, and particulate or dissolved matter in the water, absorb light much more efficiently than does air, or the low concentration of molecules or particles in air. Absorption is strongest in the ultraviolet, yellow, red and infrared wavelengths. As a consequence, light changes with water depth both in quantity and quality. The role of solar radiation as a source of energy and information is virtually

M. Wahl (ed.), Marine Hard Bottom Communities, Ecological Studies 206, DOI: 10.1007/978-3-540-92704-4_1, © Springer-Verlag Berlin Heidelberg 2009

7

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

8

M. Wahl H

H (1) O

dipole nature of liquid water

H

Medium Water

O H (4) O H

H O

H

H (2)

H

(3) O H

better heat storage

vector for salts DOM, POM

less fluctuation

suspensionfeeding

less anabioses & less resting stages (in the sea) no desiccation

Viscosity

Density 80x 'universal higher than air solvent'

100x higher frictional resistance than air, doubling per 20° of cooling

slow diffusion: O2-depletions hydrodynamic shapes

no need for locomotion or roots 'benign' medium

increased drag requirement for attachment

sessile animals

many epibioses thin epithelia

Light reflection & absorption

endosymbioses

vertical light gradient

spatial competition between algae & animals

parasitisms

Fig. 1.1 Causal pathways illustrating how the high density, viscosity and solvent power of water enable the existence of the functional group of sessile suspension feeders, one of the most important components of hard bottom communities 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55

nil below the first couple of hundred meters. On the other hand, the aquatic medium is better suited than air as a vector for acoustic, electric and chemical information. These physicochemical properties, singly or in their interaction, have consequences which strongly affect marine life, enabling the evolution of life forms which have never made their way onto land. The high density of water reduces the relative weight of aquatic organisms. The proportions of heavy mineral skeletons, almost neutral organic tissue and buoyant gaseous or lipid inclusions determine the net weight of submerged organisms. This will always be lower than for a similarly built organism in air. One consequence of this is that floating in water consumes less energy, and aqueous nekton and plankton are incomparably richer in biomass and diversity than their aerial counterparts. The other side of the low-weight coin is a dramatic reduction in friction between bottom-dwelling organisms and the substratum. Reduced friction in conjunction with the elevated viscosity of the medium poses a challenge to ‘staying put’ in a water current. To avoid being entrained, aquatic organisms must swim or attach. Permanent attachment on land usually is possible only when the substratum also serves as a source for food, e.g. soil for plants, and hosts for parasites. Since water acts as a vector for a rich load of suspended organic material (seston, plankton, nekton), attached heterotrophic organisms may acquire all energy they need by filter feeding or by capturing deposited particles. Animals usually require more food than is available within the immediate reach of their teeth or tentacles. They must exploit larger areas or volumes. The relative

1

Habitat Characteristics and Typical Functional Groups

9

movement between consumer and ‘food space’ is assured by locomotion of terrestrial and motile aquatic animals, and by currents around sessile animals in the sea. In addition, the by-flowing ‘universal solvent’ provides gases (O2, CO2), nutrients used by algae, and organic compounds, and it eliminates excreted waste products. Many of these solutes may be taken up as additional energy sources (lipids, sugars, peptides), may enable intraspecific communication (various infochemicals), or may drive other interactions (interspecific cues, defence metabolites). Gametes and propagules may also be disseminated by the flowing medium. While the attached mode of living is energetically beneficial, one shortcoming is the inability to escape local biotic or abiotic stress. Consumption and overgrowth may be limited by the evolution of structural or chemical defences. Adverse abiotic conditions are more difficult to avoid. If the abiotic conditions in the sea were as variable as they are on land, then permanently attached animals would have to be extremely tolerant, capable of homoeostasis, or able to pass stressful phases in a state of reduced activity (e.g. anabiosis). However, the underwater ‘climate’ in a given subtidal location varies much less in time than is the case for the terrestrial climate. Due to the high heat capacity, temperature is virtually constant below 1,000m, and at shallow depths of polar and tropical regions. Even in shallow (x2/week (F) ~x2/month (M)