Ecological Methods
Description
More details
Other editions
Additional editions
Persons
T. R. E. Southwood, Lecturer, Department of Zoology, University of Oxford, UK.
Content
Prefaces xiii
About the Companion Website xix
1 Introduction to the Study of Animal Populations 1
1.1 Population estimates 2
1.1.1 Absolute and related estimates 2
1.1.2 Relative estimates 3
1.1.3 Population indices 4
1.2 Errors and confidence 4
References 5
2 The Sampling Programme and the Measurement and Description of Dispersion 7
2.1 Preliminary sampling 7
2.1.1 Planning and fieldwork 7
2.1.2 Statistical aspects 10
2.2 The sampling programme 16
2.2.1 The number of samples per habitat unit (e.g. plant, host or puddle) 16
2.2.2 The sampling unit, its selection, size and shape 20
2.2.3 The number of samples 21
2.2.4 The pattern of sampling 24
2.2.5 The timing of sampling 26
2.3 Dispersion 27
2.3.1 Mathematical distributions that serve as models 28
2.3.2 Biological interpretation of dispersion parameters 40
2.3.3 Nearest-neighbour and related techniques: measures of population size or of the departure from randomness of the distribution 48
2.4 Sequential sampling 51
2.4.1 Sampling numbers 51
2.5 Presence or absence sampling 55
2.6 Sampling a fauna 57
2.7 Biological and other qualitative aspects of sampling 59
2.8 Jack knife and Bootstrap techniques 60
References 62
3 Absolute Population Estimates Using Capture-Recapture Experiments 77
3.1 Capture-recapture methods 78
3.1.1 Assumptions common to most methods 79
3.1.2 Estimating closed populations 86
3.1.3 Estimations for open populations 93
3.2 Methods of marking animals 103
3.2.1 Handling techniques 105
3.2.2 Release 107
3.2.3 Surface marks using paints and solutions of dyes 108
3.2.4 Dyes and fluorescent substances in powder form 112
3.2.5 Pollen 114
3.2.6 Marking formed by feeding on or absorption of dyes 114
3.2.7 Marking by injection, panjet or tattooing 116
3.2.8 External tags 116
3.2.9 Branding 117
3.2.10 Mutilation 118
3.2.11 Natural marks, parasites and genes 118
3.2.12 Rare elements 119
3.2.13 Protein marking 120
3.2.14 Radioactive isotopes 120
3.2.15 Radio and sonic tags 120
References 121
4 Absolute Population Estimates by Sampling a Unit of Habitat - Air, Plants, Plant Products and Vertebrate Hosts 139
4.1 Sampling from the air 139
4.2 Sampling apparatus 140
4.2.1 Exposed cone (Johnson-Taylor) suction trap 140
4.2.2 Enclosed cone types of suction trap including the Rothamsted 12 m trap 141
4.2.3 Rotary and other traps 143
4.3 Comparison and efficiencies of the different types of suction traps 144
4.3.1 Conversion of catch to aerial density 145
4.3.2 Conversion of density to total aerial population 146
4.4 Sampling from plants 146
4.4.1 Assessing the plant 147
4.4.2 Determining the numbers of invertebrates 147
4.4.3 The extraction of animals from herbage and debris 155
4.4.4 Methods for animals in plant tissues 163
4.4.5 Special sampling problems with animals in plant material 165
4.5 Sampling from vertebrate hosts 166
4.5.1 Sampling from living hosts 166
4.5.2 Sampling from dead hosts 169
4.5.3 Sampling from vertebrate 'homes' 170
References 171
5 Absolute Population Estimates by Sampling a Unit of Aquatic Habitat 183
5.1 Open water 183
5.1.1 Nets 183
5.1.2 Pumps 187
5.1.3 Water-sampling bottles 187
5.1.4 The Patalas-Schindler volume sampler 187
5.1.5 Particular methods for insects 188
5.2 Vegetation 190
5.2.1 Floating vegetation 191
5.2.2 Emergent vegetation 192
5.2.3 Submerged vegetation 194
5.3 Bottom fauna 195
5.3.1 Hand net sampling of forest litter 196
5.3.2 Sampling from under stones 197
5.3.3 The planting of removable portions of the substrate 199
5.3.4 Cylinders and boxes for delimiting an area 200
5.3.5 Trawls, bottom sledges and dredges 201
5.3.6 Grabs 205
5.3.7 Dendy inverting sampler 208
5.3.8 Box samplers and corers 209
5.3.9 Air-lift and suction devices 211
5.4 Poisons and anaesthetics used for sampling fish in rock pools and small ponds 211
References 213
6 Absolute Population Estimates by Sampling a Unit of Soil or Litter Habitat: Extraction Techniques 221
6.1 Sampling 221
6.2 Bulk staining 224
6.3 Mechanical methods of extraction 224
6.3.1 Dry sieving 224
6.3.2 Wet sieving 225
6.3.3 Soil washing and flotation 226
6.3.4 Flotation separation of plankton, meiofauna and other small animals 229
6.3.5 Separation of plant and insects by differential wetting 231
6.3.6 Centrifugation 233
6.3.7 Sedimentation 233
6.3.8 Elutriation 234
6.3.9 Sectioning 235
6.3.10 Aeration 236
6.4 Behavioural or dynamic methods 236
6.4.1 Dry extractors 237
6.4.2 Wet extractors 243
6.5 Summary of the applicability of the methods 248
References 250
7 Relative Methods of Population Measurement and the Derivation of Absolute Estimates 259
7.1 Factors affecting the size of relative estimates 259
7.1.1 The 'phase' of the animal 260
7.1.2 The activity of the animal 261
7.1.3 Differences in the response between species, sexes and individuals 263
7.1.4 The efficiency of the trap or searching method 264
7.2 The uses of relative methods 266
7.2.1 Measures of the availability 266
7.2.2 Indices of absolute population 266
7.2.3 Estimates of absolute population 267
7.2.4 Removal trapping or collecting 268
7.2.5 Collecting 272
7.3 Relative methods: catch per unit effort 272
7.3.1 Observation by radar 272
7.3.2 Hydroacoustic methods 273
7.3.3 Fish counters 274
7.3.4 Electric fishing 274
7.3.5 Aural detection 275
7.3.6 Exposure by plough 276
7.3.7 Collecting with a net or similar device 276
7.3.8 Visual searching and pooting 279
7.4 Relative methods: trapping 280
7.4.1 Interception traps 281
7.4.2 Flight traps combining interception and attraction 290
7.4.3 Light and other visual traps 294
7.5 Traps that attract animals by some natural stimulus or a substitute 304
7.5.1 Shelter traps 304
7.5.2 Trap host plants 305
7.5.3 Baited traps 305
7.5.4 The use of vertebrate hosts or substitutes as bait for insects 308
7.6 Using Sound 314
References 314
8 Estimates of Species Richness and Population Size Based on Signs, Products and Effects 337
8.1 Arthropod products 337
8.1.1 Exuviae 337
8.1.2 Frass 338
8.2 Vertebrate products and effects 341
8.3 Effects due to an individual insect 342
8.4 General effects: plant damage 343
8.4.1 Criteria 344
8.5 Determining the relationship between damage and insect populations 347
References 348
9 Wildlife Population Estimates by Census and Distance Measuring Techniques 355
9.1 Census methods 356
9.2 Point and line survey methods 357
9.2.1 Indices of abundance using transects 357
9.2.2 Methods based on flushing 357
9.2.3 Line transect methods: the Fourier series estimator 360
9.2.4 Point transects 365
9.3 Distance sampling software in R 365
9.4 Spatial distribution and plotless density estimators 367
9.4.1 Closest individual or distance method 367
9.4.2 Nearest-neighbour methods 368
References 369
10 Observational and Experimental Methods for the Estimation of Natality, Mortality and Dispersal 373
10.1 Natality 373
10.1.1 Fertility 373
10.1.2 Numbers entering a stage 375
10.1.3 The birth-rate from mark and recapture data 382
10.2 Mortality 382
10.2.1 Total 382
10.2.2 The death-rate from mark and recapture data 383
10.2.3 Climatic factors 383
10.2.4 Biotic factors 383
10.2.5 Experimental assessment of natural enemies 390
10.3 Dispersal 396
10.3.1 Detecting and quantifying jump dispersal 397
10.3.2 Quantifying neighbourhood dispersal 397
10.4 The measurement and description of home range and territory 410
10.4.1 The minimum convex polygon area method for estimating home range 411
10.4.2 The kernel estimation method for home range 412
10.5 The rate of colonisation of a new habitat and artificial substrates 413
10.6 The direction of migration 413
References 413
11 The Construction, Description and Analysis of Age-specific Life-tables 429
11.1 Types of life-table and the budget 429
11.2 The construction of a budget 430
11.3 Analysis of stage-frequency data 431
11.3.1 Southwood's graphical method 432
11.3.2 Richards & Waloff's first method 432
11.3.3 Manly's method 434
11.3.4 Ruesink's method 435
11.3.5 Dempster's method 435
11.3.6 Richards & Waloff's Second Method 436
11.3.7 Kiritani, Nakasuji & Manly's method 437
11.3.8 Kempton's method 438
11.3.9 The Bellows and Birley Method 439
11.4 The description of budgets and life-tables 440
11.4.1 Survivorship curves 440
11.4.2 Stock-recruitment (Moran-Ricker) curves 440
11.4.3 The life-table and life expectancy 443
11.4.4 Life and fertility tables and the net reproductive rate 444
11.4.5 Population growth rates 446
11.4.6 The calculation of r 448
11.5 The analysis of life-table data 449
11.5.1 The comparison of mortality factors within a generation 449
11.5.2 Survival and life budget analysis 451
11.5.3 Sibley's ¿ contribution analysis 458
References 459
12 Age-grouping, Time-specific Life-tables and Predictive Population Models 465
12.1 Age-grouping 465
12.2 Aging young by developmental stage 466
12.3 Aging by using structures 467
12.3.1 Annelids 467
12.3.2 Crustaceans 467
12.3.3 Insects 467
12.3.4 Molluscs 472
12.3.5 Fish 473
12.3.6 Lampreys 474
12.3.7 Reptiles and amphibians 474
12.3.8 Birds 475
12.3.9 Mammals 475
12.4 Time-specific life-tables and survival rates 476
12.4.1 Physiological time 478
12.4.2 Life-table parameters 479
12.4.3 Recruitment in the field 479
12.4.4 Empirical models 479
12.4.5 Intrinsic rate models and variable life-tables 480
12.4.6 Lewis-Leslie matrices and R packages 481
References 484
13 Species Richness, Diversity and Packing 495
13.1 Diversity 496
13.1.1 Description of a- and ¿-diversity 497
13.1.2 Species richness 498
13.1.3 Models for the S:N relationship 505
13.1.4 Non-parametric indices of diversity 509
13.1.5 Which model or index? 512
13.1.6 Comparing communities - diversity ordering 513
13.1.7 Procedure to determine a-diversity 515
13.1.8 Determining ß-diversity 517
13.2 Similarity and the comparison and classification of samples 520
13.2.1 Measures of complementarity 521
13.2.2 Similarity indices 521
13.2.3 Multivariate analysis 525
13.3 Species packing 530
13.3.1 Measurement of interspecific association 530
13.3.2 Measurement of resource utilisation 534
13.3.3 Niche size and competition coefficients 540
References 542
14 The Estimation of Productivity and the Construction of Energy Budgets 551
14.1 Estimation of standing crop 553
14.1.1 Measurement of biomass 553
14.2 Determination of energy density 554
14.3 Estimation of energy flow 555
14.4 The measurement of production 557
14.5 The measurement of feeding and assimilation 560
14.5.1 The quality of the food eaten 560
14.6 Feeding and assimilation rates 561
14.6.1 Radiotracer techniques 561
14.6.2 Gravimetric techniques 563
14.6.3 Indicator methods 564
14.6.4 Measurement of faecal output 565
14.7 The measurement of the energy loss due to respiration and metabolic process 565
14.7.1 Calorimetric 565
14.7.2 The exchange of respiratory gases 565
14.7.3 The respiratory rate 567
14.8 The energy budget, efficiencies and transfer coefficients 573
14.8.1 The energy budget of a population (or trophic level) 573
14.8.2 Energy transfer across trophic links 574
14.9 Identification of ecological pathways using stable isotopes 576
14.10 Assessment of energy and time costs of strategies 577
References 578
15 Studies at Large Spatial, Temporal and Numerical Scales and the Classification of Habitats 587
15.1 Remote sensing data from satellites 589
15.2 Remote sensing using piloted and unmanned aircraft 591
15.3 Long-term studies 592
15.3.1 Planning spatial and temporal sampling 593
15.3.2 The classification of time series 593
15.3.3 Detecting synchrony 603
15.3.4 Measuring temporal variability 603
15.3.5 Detecting break-points 604
15.4 Geographical information systems 607
15.5 Detection of density dependence in time series 608
15.5.1 Bulmer's (1975) test 608
15.5.2 Pollard et al.'s (1987) randomisation test 609
15.5.3 Dennis and Taper's (1994) bootstrap approach 611
15.5.4 Using a battery of approaches to detect density dependence 611
15.6 Citizen science projects 613
15.7 Ecosystem services 613
15.8 Habitat classification 614
15.8.1 Qualitative 614
15.8.2 Quantitative 616
References 617
Index 623
Prefaces
Preface to fourth edition
My coauthor for the Third Edition, and the original author of Ecological Methods, Sir Richard Southwood FRS, known to his many colleagues and friends as Dick, died on 26th October 2005. For those interested in reading about his long and highly distinguished career his Wikipedia page http://en.wikipedia.org/wiki/Richard_Southwood will direct you to obituaries and his Royal Society biographical memoir. Dick was a wonderful man to work with and a fine head of department. While achieving senior academic positions at an unusually young age, he retained an open and pleasant manner, a love of natural history, and remained accessible to the most junior members of staff, all of whose names he would invariably know. When he was head of the Department of Zoology at Imperial College and I was a first-year undergraduate, I was astonished that he knew the name of every undergraduate in his department.
I was keen to revise Ecological Methods in part to honour Dick's memory, but also because, I feel, the book still serves a useful purpose acting as an ecologist's handbook of methods and sources of information. While The Web now gives ecologists, even in isolated spots, access to a huge amount of information it can be difficult to glean the full range of possibilities for experimental approaches, sources of information and sampling gears. The old problem of how to design a successful sampling scheme and build samplers remains with us.
The trends in ecological research that we noted in the Preface to the Third Edition have continued at an accelerating pace. Computation and data handling has advanced greatly, and the present edition includes many references to R, the computing language and environment for statistical analysis and graphics. The dramatic growth in R packages for ecologists, all of which are offered free of charge, is one of the most important developments since the publication of the Third Edition. I have included many examples of R code in the present edition. Electronic developments in radar, sonar, remote sensing satellites, miniature tags, geographical positioning, movement detectors, lights, digital cameras, mobile phones and batteries have all greatly increased the opportunities for data acquisition. These advances, combined with novel biochemical techniques such as species detection from amplified DNA fragments, are creating tremendous opportunities for ecological research. We now have tools and resources that would have seemed incredible to a 1950s or 1960s ecologist. Yet, many of the techniques we use are still based on the ideas developed and refined between 1930 and 1980. Indeed, some of our sampling methods would have been familiar to our hunter-gatherer ancestors. One of my aims has been to maintain continuity with this great body of earlier knowledge. In part, this is because earlier papers are able to describe techniques and equipment in far more detail than is normal today. But, it is also the case that our predecessors often had great insight, and in many cases we can re-apply their ideas using our superior electronics and data handling to good effect. It is heartening to note that as journals have fully digitised their back numbers, many earlier papers are being regularly cited.
Early ecologists suffered from a lack of long-term time series. With each passing decade datasets are becoming larger and the opportunities for more detailed analysis of temporal dynamics increases. In addition, remote sensing and large-scale observation, as undertaken in particular by bird and butterfly watchers, has greatly extended the opportunity for spatial analysis. Recent concerns about species loss, habitat destruction and fragmentation, and the effects of climate change are dependent on the collection and analysis of temporally and spatially extensive data sets. The collection and handling of these data and the computation of indices of change, species richness and diversity are important fields which continue to develop.
Dick Southwood is still included as an author of Ecological Methods Fourth Edition because there are still many parts of the book which were originally authored by him and have been little changed. However, I answer for the inadequacies of the present edition. Finally, I would like to express my gratitude to all my collegues, including Clive Hambler and Anne Magurran in particular, who have directed me to interesting work and techniques for inclusion. This edition has been much improved by the careful and accurate work of the copyeditor, Mr William Down. The book would have many irritating errors without his thoughtful attention to detail. A considerable task for a book of this size and complexity.
Peter Henderson
Lymington, February 2015
Preface to third edition
We have been encouraged to prepare this third edition by the continuing use of the earlier editions. In doing so we have been struck by contrast between the advances in some areas, especially data handling, and the enduring value of various other techniques. Ecology has continued its advance into the popular and political domain, though far from everything that has gained the 'eco-' prefix falls within our purview. The underlying paradigm of ecology has however shifted. In particular the concept of the metapopulation is now recognised as central to the understanding of the distribution and abundance of animals and its exploration aided by the accessibility of numerous data sets, often with large temporal or spatial scales. The availability of molecular techniques has encouraged the consideration of genetic and phylogenetic aspects and has permitted the growth of quantitative comparative analyses described by P.H. Harvey and M.D. Pagel (1991) The Comparative Method in Evolutionary Biology (Oxford).
The extent to which we have felt that revision was necessary has varied greatly in different parts of the book. Where there has been little change in the method, we have retained the early references. We have done this on the bases that journal editors formerly permitted more detailed description of methods, that these papers will not be located by computer searches and that these pioneers continue to deserve credit. Other portions have required considerable modification; we have deleted one chapter (12) and added a new one (15), as well as reorganising the structure in some places. Although the primary focus remains on insects, which are in terms of species the dominant animals, we have taken the opportunity to explicitly expand the coverage to all major macroscopic groups.
The widespread availability of high capacity PCs, with software packages and access to the internet, has totally changed the speed and ease of handling (and sometimes accessing) data. We have therefore given references to some relevant software packages and web sites, whilst eliminating many descriptions of time consuming graphical methods. However, we believe that the advice given in the preface to the second edition is even more applicable today. The researcher, who relies entirely on the output of a computer, is in danger of drawing false conclusions and overlooking possible insights. It is essential to understand the features of the data (are there any outliers?), the assumptions of the methods, the biological basis of the analysis and to acquire a feel for the capabilities and responses of the species under study.
The interpretation of 'ecological methods' remains as described in the Preface to the First Edition, namely those methods peculiar to ecologists, either in their origin or in modification. Just as the measurement of physical factors, using the methods of the physical sciences, has always been outside the book's scope, so are the methods of molecular biology. These are described in a number of works such as Molecular markers for population ecology (1998), Ecology 79, 359-425, edited by A.A. Snow and P.G. Parker.
We are most grateful to many ecologists who sent comments on the second edition. In particular generous help has been given by Drs C. Henderson, D.J. Rogers, A.E. Magurran, W.D. Hamilton, G.R.W. Wint and Mr C. Hambler.
T. R. E. Southwood
P. A. Henderson
Oxford, October 1998
Preface to second edition
In the twelve years since the First Edition was prepared there have been remarkable developments in ecology. The subject has changed its lay image, from a rather recondite branch of biology, to something that is widely considered 'good', but only vaguely understood. The public's focus on environmental problems and the insights into these that ecology can provide are a great challenge to ecologists to develop their subject: they need to be able to provide reliable quantitative inputs for the management of the biosphere. The enormous volume of work that it has been necessary to review for this edition is evidence of the extent to which ecologists are seeking to meet this challenge.
I believe that the theme of the first edition, the need for precise measurement and critical analysis, is equally valid today; although many recent studies show levels of sophistication that were beyond my wildest hopes when I embarked on the preparation of the first edition. In his review of the first edition Dr R.R. Sokal was kind enough to say it was an 'unusual book' for it covered both traps and mathematical formulae, topics that were usually of interest to different people. This, I am glad to say, is now no longer generally true. The computer and the electronic calculator have revolutionised the...
