research techniques in animal ecology - luigi boitani

Research Techniques in
Animal Ecology
Methods and Cases in Conservation Science
Mary C. Pearl, Editor
Methods and Cases in Conservation Science
Tropical Deforestation: Small Farmers and Land Clearing in the Ecuadorian Amazon
Thomas K. Rudel and Bruce Horowitz
Bison: Mating and Conservation in Small Populations
Joel Berger and Carol Cunningham,
Population Management for Survival and Recovery: Analytical Methods and Strategies in
Small Population Conservation
Jonathan D. Ballou, Michael Gilpin, and Thomas J. Foose,
Conserving Wildlife: International Education and Communication Approaches
Susan K. Jacobson
Remote Sensing Imagery for Natural Resources Management: A First Time User’s Guide
David S. Wilkie and John T. Finn
At the End of the Rainbow? Gold, Land, and People in the Brazilian Amazon
Gordon MacMillan
Perspectives in Biological Diversity Series
Conserving Natural Value
Holmes Rolston III
Series Editor, Mary C. Pearl
Series Advisers, Christine Padoch and Douglas Daly
Research Techniques in
Animal Ecology
Controversies and Consequences
Luigi Boitani and Todd K. Fuller
Editors
C
COLUMBIA UNIVERSITY PRESS
NEW YORK

Columbia University Press
Publishers Since 1893
New York Chichester, West Sussex
Copyright © 2000 by Columbia University Press
All rights reserved
Library of Congress Cataloging-in-Publication Data
Research techniques in animal ecology : controversies and consequences / Luigi Boitani
and Todd K. Fuller, editors.
p. cm. — (Methods and cases in conservation science)
Includes bibliographical references (p. ).
ISBN 0–231–11340–4 (cloth : alk. paper)—ISBN 0–231–11341–2 (paper : alk. paper)
1. Animal ecology—Research—Methodology. I. Boitani, Luigi. II. Fuller, T. K. III.
Series.
QH541.2.R47 2000
591.7′07′2—dc21 99–052230
ϱ
Casebound editions of Columbia University Press books are printed on permanent and
durable acid-free paper.
Printed in the United States of America
c 10 9 8 7 6 5 4 3 2 1
p 10 9 8 7 6 5 4 3 2 1
For
Stefania and Caterina
and
Susan and Mollie
for their patience, love, and support
Contents
authors xv
list of illustrations xix

list of tables xxiii
preface xxv
Chapter 1: Hypothesis Testing in Ecology
Charles J. Krebs 1
Some Definitions 1
What Is a Hypothesis? 3
Hypotheses and Models 4
Hypotheses and Paradigms 6
Statistical Hypotheses 8
Hypotheses and Prediction 10
Acknowledgments 12
Literature Cited 12
Chapter 2: A Critical Review of the Effects of Marking on the
Biology of Vertebrates
Dennis L. Murray and Mark R. Fuller 15
Review of the Literature 16
Which Markers to Use? 17
Effects of Markers Among Taxa 17
Critique of Marker Evaluation Studies 35
Review of Current Guidance Available for Choosing Markers 37
Critique of Guidelines Available for Choosing Markers 39
viii CONTENTS
Survey of Recent Ecological Studies 40
Future Approaches 42
Study Protocols and Technological Advances 43
Marker Evaluation Studies 44
Acknowledgments 46
Literature Cited 46
Chapter 3: Animal Home Ranges and Territories and Home
Range Estimators

Roger A. Powell 65
Definition of Home Range 65
Territories 70
Estimating Animals’ Home Ranges 74
Utility Distributions 75
Grids 77
Minimum Convex Polygon 79
Circle and Ellipse Approaches 80
Fourier Series 80
Harmonic Mean Distribution 81
Fractal Estimators 82
Kernel Estimators 86
Home Range Core 91
Quantifying Home Range Overlap and Territoriality 94
Static Interactions 95
Dynamic Interactions 97
Testing for Territoriality 98
Lessons 100
Acknowledgments 103
Literature Cited 103
Chapter 4: Delusions in Habitat Evaluation: Measuring Use,
Selection, and Importance
David L. Garshelis 111
Terminology 112
Methods for Evaluating Habitat Selection, Preference, and Quality 114
Use–Availability Design 114
Site Attribute Design 117
Demographic Response Design 118
Problems with Use–Availability and Site Attribute Designs 118
Defining Habitats 118

Measuring Habitat Use 120
Measuring Habitat Availability 122
Assessing Habitat Selection: Fatal Flaw 1 127
Inferring Habitat Quality: Fatal Flaw 2 139
Advantages and Problems of the Demographic Response Design 144
Applications and Recommendations 147
Acknowledgments 153
Literature Cited 153
Chapter 5: Investigating Food Habits of Terrestrial Vertebrates
John A. Litvaitis 165
Conventional Approaches and Their Limitations 166
Direct Observation 166
Lead Animals 167
Feeding Site Surveys 167
Exclosures 170
Postingestion Samples 170
Evaluating the Importance of Specific Foods and Prey 175
Use, Selection, or Preference? 175
Availability Versus Abundance 175
Cafeteria Experiments 176
Innovations 176
Improvements on Lead Animal Studies 176
Use of Isotope Ratios 177
Experimental Manipulations 177
The Role of Foraging Theory in Understanding Food Habits 179
Lessons 181
Sample Resolution and Information Obtained 181
Improving Sample Resolution and Information Content 182
Literature Cited 183
Chapter 6: Detecting Stability and Causes of Change in

Population Density
Joseph S. Elkinton 191
Detection of Density Dependence 193
Analysis of Time Series of Density 193
Analysis of Data on Mortality or Survival 196
Detection of Delayed Density Dependence 199
CONTENTS
ix
x CONTENTS
Detection of Causes of Population Change 201
Key Factor Analysis 201
Experimental Manipulation 205
Conclusions 208
Literature Cited 209
Chapter 7: Monitoring Populations
James P. Gibbs 213
Index–Abundance Relationships 214
Types of Indices 214
Index–Abundance Functions 215
Variability of Index–Abundance Functions 217
Improving Index Surveys 220
Spatial Aspects of Measuring Changes in Indices 221
Monitoring Indices Over Time 222
Power Estimation for Monitoring Programs 223
Variability of Indices of Animal Abundance 224
Sampling Requirements for Robust Monitoring Programs 227
Setting Objectives for a Monitoring Program 228
Conclusions 229
Acknowledgments 232
Appendix 7.1 233

Literature Cited 247
Chapter 8: Modeling Predator–Prey Dynamics
Mark S. Boyce 253
Modeling Approaches for Predator–Prey Systems 254
Noninteractive Models 255
True Predator–Prey Models 260
Stochastic Models 269
Autoregressive Models 270
Fitting the Model to Data 273
Bayesian Statistics 273
Best Guess Followed by Adaptive Management 273
Choosing a Good Model 275
How Much Detail? 275
Model Validation 277
Recommendations 279
Remember the Audience 279
Conclusion 281
Acknowledgments 281
Literature Cited 282
Chapter 9: Population Viability Analysis: Data Requirements and
Essential Analyses
Gary C. White 288
Qualitative Observations About Population Persistence 290
Generalities 290
Contradictions 292
Sources of Variation Affecting Population Persistence 293
No Variation 293
Stochastic Variation 293
Demographic Variation 295
Temporal Variation 297

Spatial Variation 300
Individual Variation 300
Process Variation 303
Components of a PVA 303
Direct Estimation of Variance Components 305
Indirect Estimation of Variance Components 312
Bootstrap Approach 313
Basic Population Model and Density Dependence 314
Incorporation of Parameter Uncertainty into Persistence Estimates 319
Discussion 322
Conclusion 325
Literature Cited 327
Chapter 10: Measuring the Dynamics of Mammalian Societies:
An Ecologist’s Guide to Ethological Methods
David W. Macdonald, Paul D. Stewart, Pavel Stopka,
and Nobuyuki Yamaguchi
332
Social Dynamics 332
Context 334
Why Study Social Dynamics? 335
Evolution of Sociality 335
Conservation Applications 335
Understanding Ourselves 336
How to Describe Social Dynamics 337
CONTENTS
xi
xii CONTENTS
Action, Interaction, and Relationships 337
Social Networks 338
Social Structure, from Surface to Deep 339

Behavioral Parameters 340
The Bout 340
Stationarity 343
The Ethogram 343
Beware Teleology 345
Classifications of Behavioral Interactions 347
Methods for Behavioral Measurement 362
Identifying the Individual 362
Sampling and Recording Rules 364
Ad Libitum Sampling 365
Focal Sampling 365
Time Sampling 366
Techniques for Behavioral Measurement 368
Analysis of Observational Data 369
Statistical Rationality 370
Matrix Facilities: Analyzing Sequential Data 371
Lag Sequential and Nested Analysis 374
Searching for a Behavioral Pattern (Markov Chain) 375
Predictability of Behavior 376
Sequences Through the Mist 378
Acknowledgments 380
Literature Cited 380
Chapter 11: Modeling Species Distribution with GIS
Fabio Corsi, Jan de Leeuw, and Andrew K. Skidmore 389
Terminology 391
Habitat Definitions and Use 392
General Structure of GIS-Based Models 396
Literature Review 401
Modeling Issues 403
Clear Objectives 403

Assumptions 405
Spatial and Temporal Scale 408
Data Availability 412
Validation and Accuracy Assessment 413
Discussion 422
Conclusions 424
Acknowledgments 425
Notes 425
Literature Cited 426
index 435
CONTENTS
xiii
Authors
Luigi Boitani
Dipartimento Biologia Animale dell’Uomo
Università di Roma “La Sapienza”
Viale Università 32
00185 Rome, Italy
Mark S. Boyce
Department of Biological Sciences
University of Alberta
Edmonton, Alberta T6G 2E9, Canada
Fabio Corsi
Institute of Applied Ecology (IAE)
Via L. Spallanzani 32
00161 Rome, Italy
Joseph S. Elkinton
Department of Entomology and Graduate Program in Organismic
and Evolutionary Biology

University of Massachusetts
Amherst, MA 01003, USA
xvi AUTHORS
Mark R. Fuller
USGS Forest and Rangeland Ecosystem Science Center
Snake River Field Station
and Boise State University
970 Lusk Street
Boise, ID 83706, USA
Todd K. Fuller
Department of Natural Resources Conservation and Graduate
Program in Organismic and Evolutionary Biology
University of Massachusetts
Amherst, MA 01003-4210, USA
David L. Garshelis
Minnesota Department of Natural Resources
1201 E. Highway 2
Grand Rapids, MN 55744, USA
James P. Gibbs
State University of New York
College of Environmental Science and Forestry
Faculty of Environmental and Forest Biology
350 Illick Hall, 1 Forestry Drive
Syracuse, NY 13210, USA
Charles J. Krebs
Department of Zoology
University of British Columbia
6270 University Blvd.
Vancouver, BC V6T 1Z4, Canada
Jan de Leeuw

Division of Agriculture, Conservation, and the Environment
International Institute for Aerospace Survey
P.O. Box 6
7500 AA Enschede, The Netherlands
John A. Litvaitis
Department of Natural Resources
University of New Hampshire
Durham, NH 03824, USA
David W. Macdonald
Wildlife Conservation Research Unit
Department of Zoology
University of Oxford
South Parks Road
Oxford OX1 3PS, UK
Dennis L. Murray
Department of Fish and Wildlife Resources
University of Idaho
Moscow, ID 83844, USA
Roger A. Powell
Department of Zoology
North Carolina State University
Raleigh, NC 27695-7617, USA
Andrew Skidmore
Division of Agriculture, Conservation, and the Environment
International Institute for Aerospace Survey
P.O. Box 6
7500 AA Enschede, The Netherlands
Paul D. Stewart
Wildlife Conservation Research Unit
Department of Zoology

University of Oxford
South Parks Road
Oxford OX1 3PS, UK
Pavel Stopka
Wildlife Conservation Research Unit
Department of Zoology
University of Oxford
South Parks Road
Oxford OX1 3PS, UK
AUTHORS
xvii
xviii AUTHORS
Gary C. White
Department of Fishery and Wildlife Biology
Colorado State University
Fort Collins, CO 80523, USA
Nobuyuki Yamaguchi
Wildlife Conservation Research Unit
Department of Zoology
University of Oxford
South Parks Road
Oxford OX1 3PS, UK
List of Illustrations
1.1 Classic illustration of the density-dependent paradigm of population
regulation
3.1 Location estimates for adult female bear 61 in the Pisgah Bear Sanctu-
ary, North Carolina
3.2 Location estimates and contours for the probability density function
for adult female black bear 87
3.3 Locations of (a) an adult female black bear, (b) an adult wolf, and (c)

an adult male stone marten
3.4 A complex, simulated home range
3.5 The 95% fixed kernel home range for adult female black bear 61 in
1983
3.6 Possible relationships between probability of use and percentage of
home range
3.7 Core area and home range for an adult female bear
4.1 Hypothetical movements of an animal overlaid on five habitat types
4.2 Hypothetical relationships between area and use of habitat
4.3 The assumed linear relationship between use and availability of
resources
4.4 The assumed linear relationship between use and availability of habi-
tats
5.1 Comparison of four methods used to investigate prey use by wolves
5.2 Relationship between
13
C signatures of the diet of equilibrated plasma
in black bears and polar bears
5.3 Relationship between
15
N signatures of the diet of equilibrated plasma
in black bears and polar bears
xx ILLUSTRATIONS
5.4 Internal and external factors affecting foraging decisions by a lago-
morph
5.5 Information content and sample resolution of common methods used
to investigate vertebrate food habits
6.1 Change in gypsy moth density
6.2 (a) Percentage mortality of gypsy moth, and (b) time series of percent-
age mortality of gypsy moth

6.3 Graphic detection of delayed density dependence
6.4 Use of time series to detect delayed density dependence
6.5 Key factor analysis of a population of the partridge Perdix perdix L. in
England
7.1 Relationship between population indices and actual animal abundance
7.2 Variation between habitats in index–abundance relationships
7.3 Variation in the index–abundance relationship over time
8.1 Graphic representation of a single-species model for prey abundance
8.2 Stable-limit cycle from a two-species predator–prey model
8.3 Illustrations of hypothetical type I, II, and III functional responses for
wolves preying on elk
8.4 Functional and numerical responses for wolves preying on moose
8.5 Stability map for a second-order autoregressive process
8.6 Population dynamics emerging from second-order autoregressive mod-
els
9.1 Deterministic model of population growth
9.2 Three examples of the outcome of the population model with only
demographic variation
9.3 Persistence of a population as a function of initial population size
9.4 Examples of the beta distribution, all with mean 0.5
9.5 Persistence of a population of 100 animals at t = 0 to t = 100 years
9.6 Effect of individual variation on population persistence
9.7 Three examples of possible relationships of recruitment per individual
to population size
9.8 Example of how an Allee effect is created by a declining birth rate at
low densities
10.1 Data on the interactions between male and female wood mice
10.2 The proportion of time spent grooming different portions of the body
surface
10.3 Barplots of badger allogrooming behavior

10.4 What constitutes proximity between individuals differs between
species
10.5 Considerations in scoring indices of association
10.6 Exploration of patterns of spatial proximity
10.7 The goal of translating indices of social behavior into evolutionary
consequences
10.8 The same observations of social interactions expressed in three ways
10.9 The flow of rubbing between a group of four cats
10.10 The flow diagram (state-space representation) of the sex-dependent
nose-to-nose interaction
11.1 Percentage of papers dealing with habitat modeling
11.2 General data flow of the two main categories of GIS species distribu-
tion models identified
11.3 Population dynamics event in relation to time and space scales
ILLUSTRATIONS
xxi
List of Tables
2.1 Survey of marker evaluation studies in fish
2.2 Survey of marker evaluation studies in reptiles and amphibians
2.3 Survey of marker evaluation studies in birds
2.4 Survey of marker evaluation studies in mammals
2.5 Review of treatment of potential marking effects in the ecological liter-
ature
3.1 Simple probability index for home range overlap of adult female black
bears, wolves and wolf packs, and stone martens
4.1 Effect of habitat availability on perceived selection
4.2 Effect of altered availability (floor space) on perceived selection of
rooms in a house
4.3 Habitat use, availability, and perceived selection for Gaur and Banteng

in Thailand during the dry season
5.1 Evaluation of methods used to investigate vertebrate food habits
5.2 Application of digestion correction factors (CF) used to estimate the
biomass
7.1 Monte Carlo simulation procedure used to estimate the power of pop-
ulation-monitoring programs to detect trends
7.2 Variability estimates for local populations
7.3 Sampling intensities needed to detect overall population changes
10.1 Matrix of frequencies of transitions from fight to avoidance and fre-
quencies of allogrooming behavior among nine wood mice
11.1 Classification scheme of the term habitat
11.2 Classification of reviewed papers
11.3 Typical error matrix
Preface
As science, ecology is often accused of being weak because of its basic lack of
predictive power (Peters 1991) and the many ecological concepts judged vague
or tautological (Shrader-Frechette and McCoy 1993). Also, important para-
digms that dominated the ecological scene for years have been discarded in
favor of new concepts and theories that swamp the most recent ecological
literature (e.g., the abandoning of the island biogeography theory in favor of
the metapopulations theory; Hanski and Simberloff 1997). The apparent ease
with which such changes seem to be accepted could be taken as an intrinsic
weakness of ecological disciplines; in fact, many ecologists seem to have an infe-
riority complex with respect to sciences considered more rigorous, such
as physics or chemistry. Thus, when ecology has to provide the basis for envi-
ronmental conservation and management, this presumed weakness is easily
instrumentalized by those opposing conservation. In the often sterile debates
that are heard, ecology loses credibility and is easily victimized by its detractors.
It is not surprising that many ecological theories and concepts have still not

been defined precisely, given the enormous complexity of ecological systems.
Yet ecology is rooted in the scientific method applied to the observation and
experimentation of natural facts. Rather than a discipline whose experimental
practice is informed by laws and invincible paradigms, ecology is a classically
bottom-up discipline in which the application of the scientific method to real
facts and processes gradually builds a body of knowledge that can give rise to
useful generalizations. But the complexity of ecological processes and their
variability is such that any generalization conflicts with the need to account for
all possible variations. It is in this light that the rigor of the results achieved in
the study of real cases takes on fundamental value. Without embracing such