Table Of ContentThe Ecology, Exploitation, and Conservation of
RIVER TURTLES
A Massacre of Turtles (From St. Cricq, 1874).
DON MOLL AND EDWARD O. MOLL
The Ecology, Exploitation, and Conservation of
RIVER TURTLES
OXPORD
UNIVERSITY PRESS
2004
OXPORD
UNIVERSITY PRESS
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Library of Congress Cataloging-in-Publication Data
Moll, Don.
The ecology, exploitation, and conservation of river turtles / Doll Moll, Edward O. Moll.
p. cm.
Includes bibliographical references (p. ).
ISBN 0-19-510229-0
1. Turtles-Ecology. 2. Stream animals-Ecology. 3. Endangered species. 4. Wildlife
conservation. I. Moll, Edward O. II. Title.
QL666.C5M57 2004
597.92'l764-dc21 2003049881
246897531
Printed in the United States of America
on acid-free paper
This book is dedicated to the memory of
our parents for their love and devotion.
_cePrefacee
The following account is a tribute to the diverse and often spectacular turtles which
live in the world's rivers. Some are truly beautiful animals with finely chiseled and
ornamented carapaces, and with the gaudiest colors imaginable adorning their
shells and heads and limbs. Others, such as the softshells, are most unturtle-like
in appearance with flattened, leathery shells and alien-strange faces. A number of
soft-shelled and hard-shelled forms attain sizes which approach and sometimes
exceed proportions more commonly associated with marine species. Many of these
species are capable of attaining incredible abundance in prime habitat, and this
fact, as well as data available from research concerning the life histories and
ecology of several riverine species suggest that they play key ecological roles
which affect the dynamics of their river ecosystems in important ways.
In spite of all these attributes the river turtles remain some of the least known
vertebrate species on earth—ignored by aquatic biologists and herpetologists alike.
To some extent this remains inexplicable to us, but lacking the charisma and
cuteness of many endangered warm-blooded species, or even the widespread
concern increasingly evident for the magnificent, but dwindling marine turtles
(largely due to the late Archie Carr's eloquent writing on the subject), endangered
river turtles have been slow to receive the public awareness, research funding, and
researchers that their desperate circumstances demand. The fact that many species
live secretive lives in great rain forest rivers of remote, often politically unstable,
regions where study and law enforcement are difficult at best has not helped
matters at all. Collectively, these factors have masked the magnitude of the destruc-
tion of these species without mitigating the tragedy of its reality, both for those
who depend upon them as an important source of food and for the complex
ecosystems in which they have played unique roles. Unfortunately, river turtles
fpREFACEacVII
haveneverbeennignorednyignored by people who valuethem and/or their egg
many protein-hungry parts of the world, or as ingredients in their traditional
medicines. As human populations have grown to their modern levels, and use
and trade in river turtles has increased accordingly, many river turtle species have
precipitously declined—a process accelerated in some species by river habitat
degradation and alteration, and their utilization in the international pet trade.
There is mounting concern over the welfare of these species, but our ability to
develop effective conservation and management strategies for many of them is
often hampered as much by our ignorance of their needs as it is by legislative
and cultural concerns.
In chapters 2 and 3 in this book we have presented an overview of both the
identities of the world's river turtles and that which is known of their ecology. It
will be obvious that although there has been a surge in interest and research
concerning river turtles in recent years, we still know very little about them. We
hope that these gaps in our knowledge stimulate the investigations of younger
turtle enthusiasts and researchers in the near future. In chapters 4-6 we explore
the threats that river turtles face from direct exploitation for various uses, and from
indirect factors related to human alteration and degradation of their river ecosys-
tems. In chapter 7 we provide an overview of considerations related to the con-
servation and management of river turtles, and provide our opinions concerning
the best methodology and approaches available for the task at hand. We consider
river turtles' future prospects in the epilogue.
This book is written for all those interested in river turtles, whether they are
amateur turtle enthusiasts, conservationists, river managers, aquatic biologists, or
professional turtle biologists. It incorporates both information gleaned from the
research of a legion of dedicated biologists and conservationists, and original
information contributed by the authors that is presented for the first time in this
book. We have written the book to be as "user friendly" as possible to accommo-
date this broad intended readership with a minimum of jargon and widespread use
of common names (most adopted from the Checklist of the Turtles of the World with
English Common Names [Iverson, 1985]).
We wish to thank all of the turtle biologists and conservationists who have
conducted the research upon which this book is based. Often frustrating (e.g.,
when the traps remain empty), physically difficult, and conducted far from home
and families, it is for most truly a labor of love. Many of these people have
generously shared their extensive knowledge of river turtles, provided insights
into the mysteries of turtle lives, and encouraged our efforts to complete this
book. We especially mention the following: Eric Bellinger, Donald Broadley,
Arthur Georges, John Iverson, Dale Jackson, Christopher Phillips and Scott
Thomson reviewed portions of the manuscript. Christophe Arvy, John Behler,
Michael Ewert, Oscar Flores-Villela, Scott Gritters, John Legler, Anders Rhodin
and John Tucker provided difficult to obtain and unpublished information.
Michael Dreslik, Robert Fischer, and Kipp Kruse advised on statistical matters.
Indraneil Das, Richard Funk, James Harding, Kevin Jansen, Wachira Kitimasak,
Russell Mittermeier, and Lynn Robbins generously allowed us to use their photo-
vili PREFACE
graphs in this book. We are deeply grateful to our wives Judy (of EOM) and Janice
(of DM) for their assistance and emotional support and encouragement during all
phases in the development of this book. Janice especially deserves our gratitude for
her time and effort devoted to typing and proofreading of our final drafts of the
manuscript. Southwest Missouri State University provided a Faculty Summer
Research Fellowship to DM which assisted in the preparation of this book. We
both wish to specifically acknowledge our major professors for our Ph.D. studies—
Dr. J. M. Legler (for EOM) and Dr. Lauren E. Brown (for DM). Although their
contributions to this work have perhaps been more indirect than on our disserta-
tion work, their influence on our professional careers has been profound. Finally
we wish to pay tribute to our late parents to whom this book is dedicated. Their
love, patience, and tolerance of our proclivities for critters—especially turtles—
helped shape the direction of our lives long before we became professional biol-
ogists.
Contents
1 Introduction 3
2 River Turtle Diversity, Adaptations, and Roles in the River Ecosystem 7
Taxonomic Composition of the World's River Turtles 11
Adaptations to River Life 11
Optimum Habitat 21
Big Waters, Big (and not so Big) Turtles 28
Sexual Dimorphism 36
Reproduction 40
Hatchling Ecology 60
The Roles of Turtles in Riverine Food Webs 64
Morphology 77
3 Communities and Habitats 83
A Brief Review of the Study of Chelonian Communities 85
A Global Overview of River Turtle Communities 86
Community Composition, Species Richness, and Diversity 125
Community Characteristics, Species Composition, and Replacement 125
Guild Composition of Chelonian Communities 133
Correlates of Turtle Richness 138
Islands and Peninsulas 140
Resource Partitioning and Species Interactions 144
Species Interactions 149
4 Traditional Exploitation Methods, Efficiency, and Consequences for River
Turtles 151
Capturing Turtles in the Water by Diving 152
