Insect diversity conservation

356 Pages·2005·7.616 MB·English

by  Michael J Samways

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Insect Diversity Conservation
This groundbreaking book is an up-to-date global synthesis of the rapidly
developing and important field of insect conservation biology. Insects are
by far the most speciose organisms on earth, yet barely known. They play
important roles in terrestrial ecological processes and in maintaining the
world as we know it. They therefore present particular conservation chal-
lenges, especially as a quarter may well become extinct in the next few
decades.
This book first addresses the ethical foundation of insect conservation,
andaskswhyweshouldconcernourselveswithconservationofabutterfly,
beetle or bug. The success of insects and their diversity, which have sur-
vived the comings and goings of glaciers, is now facing a more formidable
obstacle:themassiveimpactofhumans.Afteraddressingthreats,frominva-
sive alien plants to global climate change, the book then explores ways in
which insects and their habitats are prioritized, mapped, monitored and
conserved. Landscape and species approaches are considered. Restoration,
andtheroleofconventionsandsocialissuesarealsodiscussed.Thebookis
for undergraduates, postgraduates, researchers and managers both in con-
servation biology or entomology and in the wider biological and environ-
mentalsciences.
MICHAEL J. SAMWAYS is Professor of Entomology at the University of
Stellenbosch, South Africa. He is internationally known as a conservation
biologistandpolicyadvisor.

Insect
Diversity
Conservation
MICHAEL J. SAMWAYS
UniversityofStellenbosch,SouthAfrica
  
Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo
Cambridge University Press
TheEdinburghBuilding,Cambridge,UK
Published in the United States of America by Cambridge University Press, New York
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© Michael J. Samways 2005
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Contents
Preface page ix
Cover picture xi
Part I The need for insect diversity conservation 1
1 Ethical foundation for insect conservation 3
1.1 Introduction 4
1.2 Environmental philosophy and insect conservation 4
1.3 Insect utility 9
1.4 Insect rights and species conservation 11
1.5 Spiritual conceptions 13
1.6 Summary 15
2 The special case of insects in conservation biology 16
2.1 Introduction 16
2.2 Insect radiation 18
2.3 Bauplan, flight and insect conservation 22
2.4 Polymorphisms 23
2.5 Insect diversity and the landscape 25
2.6 Global insect species richness 28
2.7 Survival in prehistorical times 29
2.8 Current extinctions 32
2.9 The taxonomic challenge 33
2.10 The perception challenge 35
2.11 Pest insects and population crashes 36
2.12 Summary 37
3 Insects and the conservation of ecosystem processes 39
3.1 Introduction 39
3.2 Insects as keystone organisms 40
3.3 Insect ecosystem engineers and soil modifiers 41
3.4 Insects as food for other animals 42
3.5 Insect dispersal 42
3.6 Insect pollinators 45
3.7 Insect herbivores 46
3.8 Insect parasitoids and predators 49
3.9 Insects and disease 50
v
vi Contents
3.10 Ecosystem diversity and insect diversity 52
3.11 Insects and the naturally changing landscape 52
3.12 Significance of ecological connectance 53
3.13 Summary 54
Part II Insects and the changing world 57
4 Degradation and fragmentation of ecosystems 59
4.1 Introduction 59
4.2 Environmental contamination 61
4.3 Pesticides 63
4.4 Agriculture and afforestation 65
4.5 Urbanization and impact of structures 68
4.6 Deforestation and logging 73
4.7 Transformation of grasslands, savanna and
Mediterranean-type ecosystems 78
4.8 Deterioration and loss of aquatic systems 80
4.9 Pressure on special systems 84
4.10 Overcollecting 86
4.11 Summary 87
5 Responses by insects to the changing land mosaic 89
5.1 Introduction 89
5.2 Behavioural responses 90
5.3 Population response and local extinction 98
5.4 Community response and long-term prognosis 100
5.5 Genetic changes 107
5.6 Summary 110
6 Threats from invasive aliens, biological control and genetic
engineering 113
6.1 Introduction 114
6.2 Invasive alien plants 114
6.3 Invasive alien vertebrates 118
6.4 Invasive alien insects 119
6.5 Risks of introducing insect natural enemies 124
6.6 Risks of introducing insect pathogens 127
6.7 Risks of genetic engineering 130
6.8 Summary 134
7 Global climate change and synergistic impacts 136
Contents vii
7.1 Introduction 136
7.2 Ecosystem response to global climate change 137
7.3 Changes in species’geographical ranges 143
7.4 Synergisms and future perspectives 145
7.5 Summary 149
Part III Conserving and managing insect diversity 153
8 Methods, approaches and prioritization criteria 155
8.1 Introduction 155
8.2 Towards an ‘Earth ethic’ 156
8.3 Identifying geographical areas for conservation action 158
8.4 Systematic reserve selection 162
8.5 Use of surrogates in conservation planning 163
8.6 Coarse and fine filters 167
8.7 Plant surrogates 173
8.8 Animal surrogates 174
8.9 Phylogenetic considerations 175
8.10 Are ‘umbrella’and ‘flagship’species of value in
conservation planning? 176
8.11 Summary 178
9 Mapping, inventorying and monitoring 180
9.1 Introduction 180
9.2 Mapping 181
9.3 Inventorying 186
9.4 Monitoring 192
9.5 Red Listing 195
9.6 Application of IUCN Red List Criteria at regional or
national levels 198
9.7 Insects as bioindicators 199
9.8 Reference sites 203
9.9 Summary 203
10 Managing for insect diversity 206
10.1 Introduction 206
10.2 Importance of parks, reserves and remnant patches 207
10.3 Importance of landscape heterogeneity 212
10.4 Countryside-wide management 215
10.5 Importance of patch size relative to habitat quality 217
10.6 Simulating natural conditions and traditional practices 222
viii Contents
10.7 Corridors 226
10.8 Landscape management in urban areas 231
10.9 Summary 232
11 Restoration of insect diversity 234
11.1 Introduction 234
11.2 Principle of restoration triage 235
11.3 Restoration of species or processes? 237
11.4 Coarse-filter and fine-filter approaches to restoration 240
11.5 Insect gardening 244
11.6 Species-specific recovery plans 246
11.7 Summary 250
12 Conventions and social issues in insect diversity conservation 252
12.1 Introduction 252
12.2 The international arena 253
12.3 National issues 256
12.4 Overcoming the perception challenge 257
12.5 Butterfly houses and increasing conservation awareness 259
12.6 Deadstock trade 261
12.7 Butterfly farming 262
12.8 Summary 263
References 266
Index 316