Megaherbivores: The Influence of Very Large Body Size on Ecology

385 Pages·1989·14.868 MB·English

by  R. Norman Owen-Smith

Cambridge Studies in Ecology presents balanced, comprehen­
sive, up-to-date, and critical reviews of selected topics within
ecology, both botanical and zoological. The Series is aimed at
advanced final-year undergraduates, graduate students, re­
searchers, and university teachers, as well as ecologists in
industry and government research.
It encompasses a wide range of approaches and spatial,
temporal, and taxonomic scales in ecology, including quanti­
tative, theoretical, population, community, ecosystem, histor­
ical, experimental, behavioural and evolutionary studies. The
emphasis throughout is on ecology related to the real world
of plants and animals in the field rather than on purely theo­
retical abstractions and mathematical models. Some books in
the Series attempt to challenge existing ecological paradigms
and present new concepts, empirical or theoretical models, and
testable hypotheses. Others attempt to explore new approaches
and present syntheses on topics of considerable importance
ecologically which cut across the conventional but artificial
boundaries within the science of ecology.

CAMBRIDGE STUDIES IN ECOLOGY
Editors:
R. S. K. Barnes Department of Zoology, University of Cambridge
H.J. B. Birks Botanical Institute, University of Bergen
E. F. Connor Department of Environmental Science, University of Virginia
R. T. Paine Department of Zoology, University of Washington, Seattle
Megaherbivores
The influence of very large body size on ecology
Also in the series
H. G. Gauch, Jr Multivariate Analysis in Community Ecology
R. H. Peters The Ecological Implications of Body Size
C. S. Reynolds The Ecology of Freshwater Phytoplankton
K. A. Kershaw Physiological Ecology of Lichens
R. P. Mcintosh The Background of Ecology: Concept and Theory
A. J. Beattie The Evolutionary Ecology of Ant-Plant Mutualisms
F. I. Woodward Climate and Plant Distribution
J. J. Burdon Diseases and Plant Population Biology
J. I. Sprent The Ecology of the Nitrogen Cycle
N. G. Hairston, Sr Community Ecology and Salamander Guilds
H. Stolp Microbial Ecology: Organisms, Habitats and Activities
R. N. Owen-Smith Megaherbivores: the Influence of Large Body
Size on Ecology
J. A. Wiens The Ecology of Bird Communities:
Volume I Foundations and Patterns
Volume 2 Processes and Variations
N. G. Hairston, Sr Ecological Experiments
R. Hengeveld Dynamic Biogeography
C. Little The Terrestrial Invasion: an Ecophysiological Approach to
the Origins of Land Animals
P. Adam Saltmarsh Ecology
M. F. Allen The Ecology of Mycorrhizae
D. J. von Willert et al. Life Strategies of Succulents in Deserts: With
Special Reference to the Namib Desert
J. A. Matthews The Ecology of Recently-deglaciated Terrain: a
Geoecological Approach to Glacier Fore/ands
Megaherbivores
The influence of very large body
size on ecology
R.NORMAN OWEN-SMITH
University of the Witwatersrand
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Contents
Preface xiii
1 Prologue
2 Morphology, evolutionary history and recent distribution 6
Introduction 6
Morphology 6
Evolutionary origins and relationships 16
Paleontological diversity 20
Distribution of extant species 21
3 Food and other habitat resources 30
Introduction 30
Food 30
Water and other habitat needs 45
Comparisons with smaller ungulates so
4 Space-time patterns of habitat use 53
Introduction 53
Temporal patterning of activities 53
Utilization of space 61
Comparisons with smaller ungulates 67
5 Body size and nutritional physiology 69
Introduction 69
Metabolic requirements 70
Gut anatomy 71
Food intake and digestion 72
6 Body size and feeding ecology 82
Introduction 82
Diet quality 82
Foraging time 87
Home range extent 95
Trophic ecology of megaherbivores: summary 98
Contents
x
7 Social organization and behavior IOI
Introduction IOI
Group structure IOI
Male dominance relations I09
Courtship and mating l I6
Responses to predators I24
Comparisons with smaller ungulates I3I
8 Life history 133
Introduction I33
Infancy and juvenilehood I33
Adolescence and puberty 138
Reproduction by females I44
Reproduction by males I5I
Mortality and lifespan I52
Comparisons with smaller ungulates 159
9 Body size and sociobiology I60
Introduction 160
Grouping patterns 160
Male dominance systems I67
Female mate choice I77
Summary I79
10 Body size and reproductive patterns I8I
Introduction 18I
Seasonality of reproduction I83
Age at first conception I85
Birth intervals 186
Maternal investment in reproduction I90
Offspring sex ratio 195
Summary 198
11 Demography 200
Introduction 200
Population structure 200
Population growth 2I2
Population density and biomass 22I
Comparisons with smaller ungulates 225
12 Community interactions 226
Introduction 226
Impact on vegetation 226
Effects on other large herbivores 239
Comparisons with smaller ungulates 245