Parasites in Ecological Communities: From Interactions to Ecosystems

by Melanie J. Hatcher , Alison M. Dunn

• ISBN13: 9780521718226
• ISBN10: 0521718228
• Format: Paperback
• Copyright: 2011-07-11
• Publisher: Cambridge University Press

Summary

Interactions between competitors, predators and their prey have traditionally been viewed as the foundation of community structure. Parasites long ignored in community ecology are now recognized as playing an important part in influencing species interactions and consequently affecting ecosystem function. Parasitism can interact with other ecological drivers, resulting in both detrimental and beneficial effects on biodiversity and ecosystem health. Species interactions involving parasites are also key to understanding many biological invasions and emerging infectious diseases. This book bridges the gap between community ecology and epidemiology to create a wide-ranging examination of how parasites and pathogens affect all aspects of ecological communities, enabling the new generation of ecologists to include parasites as a key consideration in their studies. This comprehensive guide to a newly emerging field is of relevance to academics, practitioners and graduates in biodiversity, conservation and population management, and animal and human health.

Author Biography

Melanie J. Hatcher is Visiting Research Fellow, School of Biology, University of Bristol, UK, and Senior Research Fellow, Institute of Integrative and Comparative Biology, University of Leeds, UK. Alison M. Dunn is Reader in Evolutionary Ecology, Institute of Integrative and Comparative Biology, Faculty of Biological Sciences, University of Leeds, UK.

Table of Contents

Acknowledgements	p. xiii
List of abbreviations	p. xiv
Introduction	p. 1
Concepts from epidemiology	p. 5
Concepts from community ecology	p. 9
Parasites	p. 12
Aims of this book	p. 17
Parasites and competitors	p. 20
Introduction	p. 20
Parasitism in modules of competition	p. 21
One-hostùone-parasite systems	p. 22
Population dynamics	p. 23
Competitive release	p. 30
Apparent competition	p. 32
Baseline theory	p. 32
Implications for biological control	p. 37
Empirical evidence for apparent competition	p. 39
Parasite-mediated competition	p. 49
Specialist parasite-mediated competition	p. 49
Shared parasite-mediated competition	p. 50
Parasite-modified competition	p. 56
Examples from conservation and management	p. 59
Red squirrels, grey squirrels and poxvirus	p. 59
Grey partridge, pheasants and nematodes	p. 63
White-tailed deer, moose and brainworm	p. 66
Red grouse, deer, mountain hare, sheep and louping ill virus	p. 68
Competition between parasites	p. 72
Competition for resources	p. 77
Apparent and host-mediated competition	p. 78
Coinfections and trait-mediated indirect effects	p. 81
Conclusions	p. 86
Parasites and predators	p. 90
Introduction	p. 90
Overview of predation modules	p. 90
Parasites of prey with specialist predators	p. 92
Baseline theory	p. 92
Empirical examples	p. 100
Parasites of prey with generalist predators	p. 104
Baseline theory	p. 104
Empirical examples	p. 107
Evolutionary dynamics and predation	p. 115
Parasites of predators	p. 118
Baseline theory	p. 118
Empirical examples	p. 119
Parasites of predators and prey	p. 123
Patterns and evolution of manipulation and trophic transmission	p. 124
Theoretical impacts on populations and communities	p. 126
Applications: predator control and harvesting	p. 129
Do predators keep the herds healthy?	p. 129
Biological control	p. 133
Harvesting infected populations	p. 135
Conclusions	p. 138
Parasites and intraguild predation	p. 141
Introduction	p. 141
Parasitism and IGP	p. 142
Predictions from basic IGP theory	p. 143
Ecological significance of IGP	p. 145
IGP as a unifying framework for competition and predation	p. 149
Parasites intrinsic to IGP	p. 151
IGP in trophic transmission	p. 152
Parasites and IGP in biological control	p. 155
Biological control scenarios with IGP	p. 156
Parasites extrinsic to IGP	p. 164
Parasite-modified IGP	p. 165
The potential for parasitism to interact with IGP	p. 168
Models of parasitism extrinsic to IGP	p. 169
IGP and the evolution of host-parasite relationships	p. 171
Conclusions	p. 173
Plant pathogens and parasitic plants	p. 176
Introduction	p. 176
Differences between animal and plantùparasite systems	p. 177
Parasites of plants	p. 179
Soil-borne pathogens	p. 182
The Janzen-Connell effect	p. 183
Plant-soil feed back	p. 186
Pathogen-modified and apparent competition	p. 190
Plant defence strategies	p. 194
Chemical signalling pathways	p. 194
Multiple enemies: positive and negative cross-talk	p. 196
Signalling and manipulation	p. 200
Above- and below- ground interactions	p. 203
Parasitic plants	p. 205
Dodder (Cuscuta)	p. 208
Mistletoe (Santalales)	p. 210
Broomrape (Orobanchaceae)	p. 213
Endophtyes	p. 217
Endophyte effects on communities	p. 217
Endophyte interactions with plant parasites and mutualists	p. 221
Conclusions	p. 222
Parasites and invasions	p. 224
Introduction	p. 224
Parasite introduction and acquisition	p. 226
Loss of parasites by invaders: enemy release	p. 229
Community studies of parasitism in invasive versus indigenous species	p. 231
Biogeographical studies of parasitism in the native versus invasive range	p. 234
Enemy release from vertically transmitted parasites	p. 240
Invasions and host-parasite co-evolution	p. 244
Local adaptation	p. 244
Evolution of increased competitive ability	p. 245
Plant-soil feed back	p. 246
The impact of parasitism on biological invasions	p. 248
Parasite dilution by invading hosts	p. 248
Invading hosts as infection reservoirs	p. 249
Native hosts as infection reservoirs	p. 256
Nativeùinvader interactions mediated by parasites	p. 259
Conclusions	p. 263
Ecosystem parasitology	p. 265
Introduction	p. 265
Trophic cascades	p. 267
Density-mediated trophic cascades	p. 270
Trait-mediated trophic cascades	p. 273
Parasite dynamics in multi-host communities	p. 274
Baseline model: parasite establishment in multiple host species	p. 275
Reservoir versus dilution and host competence	p. 277
Lyme disease risk, dilution and reservoir hosts	p. 279
Biodiversity and disease	p. 283
Determinants of disease spread	p. 283
Transmission models and biodiversity relationships	p. 284
Parasites in the food web	p. 286
Functional role and interaction strength	p. 287
Parasitism and food web topology	p. 291
Implications for community stability	p. 298
Bioenergetic implications of parasitism	p. 301
Parasite biomass	p. 301
Parasite productivity	p. 302
Ecosystem engineering	p. 304
Ecosystem health	p. 308
Integrating population and community approaches to the study of ecosystems	p. 308
Are parasites indicators of healthy ecosystems?	p. 311
Evolutionary considerations	p. 316
Conclusions	p. 318
Emerging diseases in humans and wildlife	p. 320
Introduction	p. 320
Emerging approaches to the problem of EIDs	p. 321
What are the problems caused by EIDs?	p. 321
The process of disease emergence	p. 323
Spillover	p. 324
Persistence	p. 326
Pandemic emergence	p. 328
Heterogeneity in R0: superspreaders and their effect on disease dynamics	p. 333
The evolution of emergence	p. 336
Virulence evolution of emerging diseases	p. 340
Phylogenetic and temporal patterns of emergence	p. 342
Which diseases emerge, and in which hosts?	p. 342
Are EIDs increasing?	p. 344
Environmental change and emergence	p. 348
Land use changes	p. 349
Trade and transport changes	p. 354
Climate change and emerging diseases	p. 358
Conservation and control	p. 364
Monitoring	p. 365
Contact reduction	p. 371
Vaccination	p. 379
Conclusions	p. 383
Where do we go from here?	p. 386
References	p. 393
Index	p. 439
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