Plant Microevolution and Conservation in Human-influenced Ecosystems

Half-title......Page 3
Title......Page 5
Copyright
......Page 6
Contents......Page 7
Preface......Page 17
Acknowledgements......Page 19
Abbreviations......Page 21
Human influences: implications for conservation......Page 23
Outline of the chapters......Page 25
2 Studying change......Page 31
Defining terms and questioning assumptions......Page 32
Darwin’s scientific method......Page 33
Elements of experimental design......Page 34
'Proof ’ and falsification......Page 36
Predicting the future......Page 37
Concluding remarks......Page 38
3 Key concepts in plant evolution......Page 40
Darwin’s ideas about the evolution of species......Page 43
Cyto-genetic studies......Page 44
Chemical basis of hereditary information......Page 45
Genetic mutation......Page 47
Chromosome changes......Page 48
Populations......Page 50
Gene flow and population structure......Page 51
Effects of chance in populations......Page 52
Animal and plant interactions......Page 53
Plants are different from animals......Page 54
Different modes of natural selection......Page 56
K-selection......Page 57
Neutral theory of selection......Page 58
Post-Darwinian models of speciation......Page 60
Speciation and founder effects......Page 61
Introgressive hybridisation......Page 62
Cytogenetics of polyploidy......Page 63
The success of polyploids......Page 65
Mass extinctions......Page 66
Punctuated equilibrium......Page 67
Orbital variations......Page 68
Conclusions......Page 69
The origin of humans......Page 72
Human uses of plants......Page 73
Reaching 5 million: hunter-gatherers......Page 74
The process of domestication of plants......Page 75
Reaching half a billion: the spread of agriculture from 2000 BC to AD 1500......Page 77
The first billion humans: from subsistence to commercial farming 1500–1825......Page 78
Populations rising to 2 billion: the expanding frontiers of agriculture 1825–1927......Page 79
From 2 to over 6.5 billion: the rise of industrial food production 1927 to the present day......Page 80
What is the present extent of human-modified ecosystems?......Page 81
The rise of concern about the environment......Page 84
Conservation through protection......Page 85
The wise use of resources......Page 86
Environmental concerns about pollution......Page 87
Atmospheric pollution......Page 88
The greenhouse effect and global climate change......Page 89
Nitrogen (N) compounds......Page 91
Pesticides......Page 92
Confronting the adverse effects of introduced organisms......Page 93
Soil erosion and salination......Page 94
The inexorable rise of human populations......Page 95
Ecological footprints......Page 96
Conclusions......Page 98
Cultural landscapes......Page 99
Is there any wilderness left?......Page 102
Wilderness and the 'Pristine Myth’......Page 103
Cultural landscapes and fire......Page 104
How 'virgin’ is virgin rainforest?......Page 105
Wild areas in Europe......Page 106
The first conservationists......Page 108
Man and nature......Page 109
Human activities: the concept of niche construction......Page 110
Ecosystems: natural and human influenced......Page 113
Conclusions......Page 117
Early ideas about species......Page 119
Species concepts......Page 120
Conservation uses of the term 'species’......Page 122
How many plant species are there in the world?......Page 123
Lines of evidence concerning status......Page 126
Fossil evidence......Page 132
Reproductive pattern......Page 133
Possible means of introduction......Page 134
Wildlife......Page 135
Wild and cultivated plants......Page 136
Feral plants......Page 137
Weeds......Page 138
Invasive plants......Page 139
Endangered species......Page 140
Species–area curves......Page 142
The current extinction rate and prospects for the future......Page 143
Assessing the threat of extinction......Page 145
Threats to cultivated plants and forest trees......Page 146
Conclusions......Page 147
Natural selection......Page 149
Studies of wild populations: some early experiments......Page 150
Methods of detecting natural selection used in plant studies......Page 151
Reciprocal transplant experiments......Page 152
The use of molecular markers in microevolutionary studies......Page 153
Sampling......Page 159
Estimating fitness......Page 160
The relationship of microevolution to conservation......Page 161
Changing goals: preservation vs. conservation of evolutionary potential......Page 162
Conclusions......Page 163
Managed grasslands, rangelands etc.......Page 164
Forests......Page 165
The antiquity of grassland management for pasture and hay......Page 166
Artificial selection experiments......Page 169
Seasonal ecotypes......Page 170
4–8 internodes......Page 171
15 plus internodes......Page 172
Comparative studies of pasture and hay ecotypes......Page 173
Park Grass Experiment: Anthoxanthum odoratum......Page 176
Selection in lawns and golf courses......Page 179
Temperature-controlled germination......Page 180
Disruptive selection in Poa annua......Page 181
Grazed areas......Page 183
Plantago major......Page 184
The responses of Achillea in mown and tall plots......Page 185
Gene flow in grasslands by movement of hay......Page 186
Gene flow by dispersal of seeds in animal husbandry......Page 187
Concluding remarks......Page 188
9 Harvesting crops: arable and forestry......Page 190
Arable weedy populations: general purpose genotypes or specialist races?......Page 191
Seed mimicry......Page 192
Crop mimicry in flax......Page 193
Crop mimicry in wheat......Page 195
Crop mimicry in rice......Page 196
Growth strategies in relation to land use......Page 197
Speed of development in relation to weeding pressures......Page 198
Vernalisation and the winter and summer annual habit......Page 200
Dormancy......Page 201
Seed production and soil seed banks......Page 202
Herbicide resistance......Page 203
Incidence of herbicide resistance......Page 204
Speed with which resistance develops......Page 206
Fitness: costs and benefits......Page 208
Withdrawal of herbicide treatment......Page 210
How have weed populations changed under herbicide treatments?......Page 211
Selection pressures associated with the development of modern agricultural practices......Page 212
Deforestation......Page 213
Demographic changes......Page 214
Habitat alteration......Page 215
Introduction of new tree species and variants......Page 217
Effects of logging on population variation......Page 218
Coda......Page 219
10 Pollution and microevolutionary change......Page 222
Reductionist approaches in the study of the effects of pollution......Page 223
Pollution from 'point sources’......Page 224
Studies of the rate of development of resistance......Page 225
Ozone pollution......Page 226
The evolution of ozone resistance......Page 229
Resistance to heavy metals......Page 231
Sources of anthropogenic heavy metal pollution......Page 232
Heavy metals in soils......Page 233
Testing for metal tolerance......Page 234
Origin of tolerant variants......Page 236
Restraints on the evolution of tolerance......Page 238
Gene flow and selection......Page 239
Copper refinery......Page 241
Electricity pylons......Page 242
Other species growing around pylons......Page 244
Conclusions......Page 245
11 Introduced plants......Page 247
2 The utilitarian phase......Page 249
3 The aesthetic phase......Page 251
Establishment: founder effects, genetic drift and multiple introductions......Page 252
Establishment in naturalised populations: founder effects......Page 253
Establishment: a case of successive founder effects......Page 255
Establishment: insights from the use of molecular markers......Page 256
Establishment: tracing the spread of Bromus tectorum......Page 258
Some species are successfully introduced but many fail to establish......Page 261
Establishment of introduced species: the importance of mutualisms......Page 263
Development of introduced populations: the lag phase......Page 264
Allee effects......Page 265
Watercourses......Page 266
Lag phases: causes unknown......Page 267
Ecotypic differentiation......Page 268
General-purpose genotypes......Page 270
Evolutionary changes in animal populations linked to introduced plants......Page 271
Natural selection: which species are likely to succeed as invaders?......Page 272
The evolution of invasiveness......Page 273
The novel weapons hypothesis......Page 274
The propagule pressure hypothesis......Page 275
Co-evolution......Page 276
Introduced herbivorous animals......Page 277
Parasitism and diseases......Page 278
Introduced animals......Page 279
Coda......Page 280
12 Endangered species: investigating the extinction process at the population level......Page 283
A general model of declining populations......Page 284
Rare plants in cultural landscapes......Page 285
Populations declining to extinction......Page 286
Counting plants......Page 288
Soil seed banks......Page 289
Demography studies......Page 291
Pollen limitation in plant populations......Page 292
Pollination disruptions......Page 293
Allee effects in plants: self-incompatibility......Page 294
The extinction vortex: stochastic events......Page 297
The concept of the idealised population and how declining populations depart from the 'ideal’......Page 299
2 Rare species are less variable genetically than common plants......Page 301
4 Genetic variation within species is positively correlated with population size......Page 302
6 Adaptive genetic variation decreases in declining populations......Page 303
7 Declining populations are subject to an increasing risk of inbreeding depression......Page 304
How large do populations have to be to ensure long-term survival?......Page 305
PVA predictions and conservation......Page 307
Metapopulations......Page 308
Concluding comments......Page 310
Will new species quickly evolve to take the place of those that become extinct?......Page 312
The evolution of a new polyploid in Spartina......Page 313
The origin of Senecio cambrensis......Page 315
Evolution of new Tragopogon species......Page 316
The rarity of recent polyploidy in wild plants......Page 317
What happens when human activities cause a breakdown of reproductive isolation?......Page 318
Hybridisation and introgression: the use of molecular markers to test hypotheses......Page 319
Breakdown of ecological isolation in Iris: species interactions......Page 320
Introgression between introduced species: is hybridisation a stimulus to invasiveness?......Page 325
How might hybridisation stimulate invasiveness?......Page 326
Invasiveness following intraspecific hybridisation......Page 327
Crop–wild–weed interactions......Page 328
Hybridisation increases the extinction risk in endangered species......Page 329
Transgenic crops and their interactions with wild and weedy relatives......Page 330
The microevolution of weed beets......Page 332
Transgenic beet......Page 334
Keeping the transgene within the crop......Page 336
Ex situ conservation......Page 337
Extinction of endangered species through hybridisation and introgression......Page 338
Endangerment of a rare endemic through hybridisation......Page 339
Conservation of hybridising species......Page 340
Concluding remarks......Page 341
Botanic gardens......Page 345
History of botanic gardens......Page 346
Traditional botanic gardens: what do they contain?......Page 347
Botanic gardens: Victorian relics or twenty-first century challenge?......Page 348
Gardeners and conservation......Page 349
Aims of ex situ plant conservation......Page 350
Botanic gardens and zoos......Page 351
Problems of continuity......Page 352
Disastrous events......Page 353
Documentation and misidentification......Page 354
Ex situ conservation: seed banks of wild species......Page 355
Micropropagation......Page 357
Other types of gene bank......Page 358
Collecting samples......Page 359
Growing plants from wild-collected samples in gardens......Page 361
Gene banks: sampling and the regeneration process......Page 362
Reassessing the size of samples in gene banks......Page 363
Wild plants in botanic gardens: selective forces acting on living plants......Page 364
Ex situ conservation of whole ecosystems......Page 365
Hybridisation......Page 366
1 Botanical expeditions: how far have gardens succeeded in conserving the field collections of germ plasm?......Page 367
2 How far has ex situ conservation of palms been successful?......Page 368
3 Has ex situ conservation of threatened European species of plants been a success?......Page 369
Botanic gardens and the conservation message......Page 370
Future prospects for ex situ conservation in botanic gardens......Page 371
Will ex situ conservation lead to domestication?......Page 372
Conclusions......Page 374
Early parks and 'reservations’......Page 376
Protection of forests and preservation of sites of scenic beauty......Page 378
The establishment of American National Parks......Page 379
The concept of human exclusion......Page 380
Feeding the animals......Page 381
Protection of forest against insects......Page 382
Policy of natural regulation......Page 383
The establishment of parks and reserves in Europe......Page 384
Managing reserves in cultural landscapes: Wicken Fen as a case study......Page 386
Conservation management: a Darwinian perspective......Page 387
Reintroducing traditional management......Page 389
Ecosystem management in the past......Page 390
Restoration of traditional practices......Page 391
The role of experiments in conservation management......Page 392
A call for evidence-based conservation......Page 395
Conflicts in conservation management......Page 397
Water resources......Page 398
Invasive plants......Page 399
Introduced animal species......Page 400
National parks and reserves: threats from illegal activities......Page 402
Conclusions......Page 404
16 Creative conservation through restoration and reintroduction......Page 406
Native stocks......Page 408
Mix or match?......Page 415
Site preparation and selection......Page 417
Decisions on population size......Page 418
Demographic costs of reintroduction......Page 419
Co-ordinated efforts involving ex situ and in situ conservation......Page 420
Avoiding bottleneck effects in creative conservation......Page 421
Does restoration require ongoing management?......Page 422
Complex ecosytems: understanding succession......Page 423
Re-wilding......Page 425
Changes in management style: implications for microevolution......Page 427
Restoration and management: gardening the wild......Page 428
Concluding remarks......Page 430
Reserve design......Page 434
The application of the theory of island biogeography to conservation......Page 435
Fragmentation......Page 438
Impact of fragmentation......Page 439
The matrix surrounding reserves......Page 440
Edge effects......Page 441
The proximity of reserves to migration corridors......Page 443
Corridors in the landscape......Page 444
Evidence for functioning corridors......Page 445
Reserves and the conservation of particular species......Page 447
The location of present-day reserves in relation to biodiversity 'hotspots’......Page 449
Aquatic freshwater ecosystems in parks, reserves and matrix......Page 450
Concluding comments......Page 451
The greenhouse effect and climate change......Page 456
Sea level rise......Page 458
Assessment of climate change in the future......Page 459
Climate change sceptics......Page 463
Tackling the problems of climate change......Page 464
Carbon dioxide......Page 465
Rising temperatures......Page 467
Drought......Page 468
Interacting factors......Page 469
Recent changes in the timing of various life cycle events......Page 470
Range shifts: vegetation zones and individual species......Page 471
Are apparent range changes the result of changing climate?......Page 473
Phenological and range-shift changes are microevolutionary responses......Page 475
Plant responses to previous climate changes......Page 476
Adaptation and migration of species: is there a significant role for selection?......Page 477
Migration in the post-glacial......Page 478
Comparison of ancestral and descendant populations......Page 479
Microevolutionary changes in animals......Page 480
Interactions amongst species and the effects of climate change......Page 481
Co-evolved mutualisms......Page 482
Migration in man-disturbed environments......Page 483
The likely long-term effect of migrations......Page 484
Concluding remarks......Page 486
The Fourth IPCC Assessment Report, April 2007......Page 488
Climate change in areas of high conservation significance......Page 490
The mandates of national parks......Page 493
Choice of stocks to use in restoration and management......Page 494
The conservation of endangered species......Page 495
Wildlife corridors......Page 496
Stepping stone areas to encourage migration......Page 498
Assisted migration......Page 501
Climate change: our response to the warning signs......Page 503
Human adaptation: the threats this poses to areas of conservation interest......Page 505
Conclusions......Page 506
Cultural landscapes......Page 509
Conservation strategies......Page 510
Sustainable development......Page 511
Human activities impose selective forces......Page 513
Human activities and domestication......Page 515
Maintaining species in a 'wild’ state in managed environments......Page 516
From the domesticated to the feral......Page 517
Co-evolution of humans, domesticated cattle and plants......Page 519
Kulturfolger......Page 520
Will humankind make the necessary adaptation to bring climate change under control?......Page 522
References......Page 527
Index......Page 606