keeping options alive

135 Pages·2006·13.44 MB·English

W O R LD R E S O U R C ES I N S T I T U TE
KEEPING OPTIONS ALIVE:
The Scientific Basis for
Conserving Biodiversity
WALTER V. REID
KENTON R. MILLER
KEEPING OPTIONS ALIVE:
The Scientific Basis for
Conserving Biodiversity
Walter V. Reid
Kenton R. Miller
W O R LD R E S O U R C ES I N S T I T U TE
A Center for Policy Research
October 1989
Library of Congress Cataloging-in-Publication Data
Reid, Walter V. C, 1956-
Keeping options alive.
(World Resources Institute Report)
Includes bibliographical references.
1. Biological diversity conservation. I. Miller,
Kenton. II. Title. III. Series.
QH75.R44 1989 333.9516 89-22697
ISBN 0-915825-41-4
Kathleen Courrier
Publications Director
Brooks Clapp
Marketing Manager
Hyacinth Billings
Production Manager
Organization of American States; Mike McGahuey, World Bank photo/James Pickerell
Cover Photos
Each World Resources Institute Report represents a timely, scientific treatment of a subject of public concern.
WRI takes responsibility for choosing the study topics and guaranteeing its authors and researchers freedom of
inquiry. It also solicits and responds to the guidance of advisory panels and expert reviewers. Unless otherwise
stated, however, all the interpretation and findings set forth in WRI publications are those of the authors.
Copyright © 1989 World Resources Institute. All rights reserved.
Reprinted 1993
Contents
I. Introduction 1 Global Warming 52
Cumulative Effects 55
II. Why is Biological Diversity Important? .. .3
V. What's Happening to Agricultural
The Role of Biodiversity in Ecosystems... 4 Genetic Diversity? 57
Ecological Processes 4
Uses of Genetic Diversity 57
Ecological Dynamics 6
In Situ Conservation 59
III. Where is the World's Biodiversity Ex Situ Conservation 61
Located? 9
VI. Biodiversity Conservation: What are the
General Patterns of Species Right Tools for the Job? 67
Distribution 9
Species Richness 10 Land-use Zoning and Protected Areas .. 67
Commonness or Rarity 17 Status of Protected Areas 69
Species of Current Economic Value 22 Potential Conservation Importance .... 70
Food 23 Reserve Size, Network Design, and
Medicines 27 Transition Zones 78
Industrial Uses 29 Ecological Restoration and
Rehabilitation 80
IV. Extinction: How Serious is the Ex Situ Conservation 81
Threat? 31 Zoos and Aquaria 82
Botanic Gardens 84
Trends in Species Extinctions 31
The Geography of Extinction 39 VII. Summary and Recommendations 87
Freshwater Ecosystems 40
Islands 41 Appendices 99
Mediterranean Climate Zones 43
Temperate Regions 44 1. Cascade Effects 99
Tropical Forests 45 2. Calculating Extinctions Due to
Causes of Extinction 45 Deforestation 102
Habitat Loss and Fragmentation 45 3. Protected Area Objectives 105
Over-exploitation 50 4. Glossary 106
Species Introductions 51
Pollution 52 References Ill
Foreword
A
s the 21st Century approaches, the Still another reason for optimism is the rapid
world is being impoverished as its strides now occurring in conservation biology
most fundamental capital stock—its and landscape ecology. Scientists' understand-
species, habitats, and ecosystems—erodes. Not ing of how to maintain viable breeding popula-
since the Cretaceous Era ended some 65 mil- tions of species and provide sufficient habitat
lion years ago have losses been so rapid and to support them has grown dramatically since
great. If the trend continues, one quarter of the the late 1970s, as has the availability of effec-
world's species may be gone by 2050. Desertifi- tive conservation techniques. Worldwide, more
cation, fisheries collapse, tropical deforestation- people trained in forestry, ecology, conserva-
such losses already attest amply to how much tion biology, and other key fields are needed,
biological impoverishment costs human beings. but their ranks are beginning to grow.
If we continue to borrow from the future, liter-
ally eating our seed corn, those costs will rise. For all these reasons, the chances of revers-
ing the current trends in many ways look bet-
An alarm has been sounded. In response, ter now than they did only a few short years
the number of international organizations, ago. But agreement is universal that current
national governments, and non-governmental efforts are insufficient. What is needed is a
organizations concerned about biodiversity and coordinated attack on the problem at its roots,
the breadth of their activities has increased one that both makes use of the best modern
dramatically during the last decade. Under science and reflects concern for the human
their wings, protected areas, zoos, botanical well-being of those most affected. Only when a
gardens, aquaria, seed banks, and other sanc- "critical mass" of participants are cooperating
tuaries and research stations have been set up in a "critical mass" of initiatives within the
to rescue and propagate endangered species. framework of a common strategy will biological
Some of the participants in this new movement diversity be saved. This cooperation must
are institutions working to demonstrate the involve an active participation among govern-
compatibility of ecosystem protection and eco- mental and non-governmental organizations in
nomic development; others are integrating both developing and industrial countries.
development planning and crafting an interna-
tional convention for preserving biodiversity. In a way, Keeping Options Alive is a "how to"
Some development assistance agencies are con- publication. Its timely premise is that the bio-
sidering how their grants and loans affect bio- logical sciences can help policy-makers identify
diversity, and various groups are exploring the threats to biodiversity, evaluate conserva-
new ways to finance the conservation of bio- tion tools, and come up with successful
logical diversity. management strategies to the crisis of biotic
v
impoverishment before it is full-blown. To of the financing, technology, and knowledge
these ends, Reid and Miller provide an over- needed to implement them. But creating a
view of where the world's species and genetic decision-making framework based on the most
resources are located and why they are valu- current and comprehensive scientific under-
able, a new analysis of species extinctions in standing of the world's biological wealth is
tropical forests that supports previous estimates essential when so much of it has yet to be
and reinforces the magnitude of the problem inventoried, much less evaluated, and when
that we face, and a survey of the most recent some of the potentially most important species
findings of conservation biology. The authors and ecosystems have few politically empow-
also suggest how these findings can best be ered constituents. Only by marrying scientific
put to work for both in situ and ex situ conser- fact to political and economic reality—as Keep-
vation, and they add to evidence that the bio- ing Options Alive strives to help policymakers
diversity crisis is not restricted to tropical do—can we hope to maintain the biological
forests, but threatens biological resources in wealth on which long-term economic develop-
temperate zones and marine ecosystems as ment depends.
well. Finally, this report underscores the
important interdependence between biological WRI would like to express its great apprecia-
diversity and human cultural diversity and the tion to The Rockefeller Foundation, Inc., John
policy implications of this critical bond. D. and Catherine T. MacArthur Foundation,
Town Creek Foundation, Inc., The Pew
Ultimately, of course, the solution to the bio- Charitable Trusts, W. Alton Jones Foundation,
diversity crisis will be political. It will require Inc., The Moriah Fund, Waste Management,
both improving planning and management and Inc., and HighGain, Inc., which have provided
redressing the social inequities that force peo- financial support for WRI's efforts in this area.
ple and nations to use resources unsustainably.
Indeed, many of the long-term actions that James Gustave Speth
Reid and Miller call for in Keeping Options Alive President
will not occur in the developing world unless World Resources Institute
the industrial countries provide their fair share
VI
Acknowledgments
W
e are grateful to Mohamed El-
Ashry, Nate Flesness, Tom Fox,
Vernon Heywood, Dan Janzen,
Nels Johnson, Jeffrey McNeely, Gordon
Orians, Peter Raven, Ulysses Seal, Dan
Simberloff, Michael Soule, Mark Trexler, and
Geerat Vermeij for their valuable comments on
all or parts of the draft report. Our thanks to
Kathleen Courrier for skillfully editing the
report and to Hyacinth Billings, Allyn Massey,
and Moira Connelly for their help preparing
the text and figures. Special thanks to Dee
Boersma, Kai Lee, Jeffrey McNeely, Gordon
Orians, and Robert Paine for many invaluable
discussions on ecology, conservation, and
development.
W.V.R.
K.R.M.
VII
I. Introduction
O
ur planet is a biologically impoverished "services"—such as the regulation of water
image of the world that supported discharge and the absorption and breakdown
humanity in past generations. We can of pollutants—are being degraded as compo-
no longer thrill to the sight of waves of migrat- nent species vanish from these ecosystems or
ing passenger pigeons—extinct since 1914—and as natural habitats are converted to other land
no tourist industry will be built around the uses. The erosion of the genetic diversity of
Caribbean monk seal, the last of which died in agricultural, forestry, and livestock species
1960. Losses of mangrove habitat in many diminishes the potential for breeding programs
Southeast Asian nations have diminished the to maintain and enhance productivity.
productivity of their coastal fisheries, and the
potential to boost agricultural productivity The diversity of life is an irreplaceable asset
worldwide has been reduced with the disap- to humanity and to the biosphere. It provides
pearance of crop varieties possessing unique both immediate and long-term benefits, and its
genetic adaptations. maintenance is essential to sustainable develop-
ment worldwide. Those components of life that
Today, we are depleting the world's biologi- vanish during the next decades will be gone
cal wealth at an ever-increasing rate, and the forever; those that remain will provide future
loss and degradation of the world's biological options for humanity. Few question that con-
resources are taking a toll on the well-being of serving biological diversity is a valuable under-
people in both industrialized and developing taking. But how valuable? How threatened is
nations. The world entered the current era of biodiversity? How should society decide which
geologic history with biological diversity close components of life most deserve conservation
to its all time high. But the exponential growth investments? And how can this task be
in human population and the even faster accomplished?
growth in consumption of the world's natural
resources have led to high rates of loss of Keeping Options Alive poses these fundamental
genes, species, and habitats. An estimated 25 questions and recommends scientifically
percent of the world's species present in the informed policies for conserving biological diver-
mid-1980s may be extinct by the year 2015 or sity. These policies are derived from current
soon thereafter (Raven 1988a, b), and signifi- knowledge of biogeography, conservation biol-
cant losses of genetic diversity of both wild ogy, genetics, and systematics, and from popu-
and domestic species are expected over this lation, community, and landscape ecology.
same period. Species of known and potential These sciences provide guidance for land-use
future value as foods, medicines, or industrial planning and management and afford insights
products are disappearing. Various ecosystem into the relationship between biodiversity and
ecological processes; the nature and scale of resource use and discourage local adaptation to
the threats to species, genes, and habitats; the environmental conditions.
basis for establishing conservation priorities;
the potential effectiveness of various conserva- Considering that each nation's biological
tion tools; and related topics of pressing con- diversity is a critical natural asset—for that
cern. Knowledge in these fields is far from country and, in some cases, the world-
complete, but it is sufficient to guide the quick developing strategies for maintaining, study-
action needed to conserve the world's biologi- ing, and using biological resources sustainably
cal resources, and that guidance can be refined should be national priorities. For that reason,
as more information is obtained. the principles and guidelines set forth in this
report must be applied in conjunction with
Keeping Options Alive does not address all changes in local, national, and international
aspects of biodiversity conservation. Indeed, economic and social policies that address the
such important considerations as the economic root causes of biotic impoverishment. In partic-
valuation of biodiversity, the importance of cul- ular, new approaches to conservation financing
tural diversity, methods for financing conserva- that don't place undue burdens on the
tion projects, and the use of conservation developing world are needed (WRI 1989).
strategies are scarcely discussed. However, the
policies recommended in this report do reflect Many of the policy and institutional reforms
the broader social, political, and economic con- needed to halt biotic impoverishment would be
text in which biodiversity is threatened and in difficult under any circumstances. With the
which its conservation must take place relentless pressures of population growth and
(McNeely et al. 1989). The complex root causes the necessity of meeting people's immediate
of the planet's biotic impoverishment are needs for food and shelter, the challenge is all
intertwined with the causes of poverty and the more daunting. But biotic impoverishment
population growth, and they are linked to the now is less advanced than it would have been
inequitable distribution of resources, land, and had no action been taken in past decades to
wealth. Nations are suffering serious economic stem these losses, and a tremendous untapped
losses, individual well-being is declining, and potential for further conservation exists. Many
future generations are losing invaluable assets genes and species are sure to be lost in the
as a result of legal and economic incentive coming decades, but which and how many are
structures that favor unsustainable patterns of matters within humanity's control.
II. Why is Biological Diversity Important?
B
iodiversity is the variety of the world's various plant and animal species remove pollu-
organisms, including their genetic tants from the water and provide the spawning
diversity and the assemblages they and rearing habitat for commercially important
form. It is the blanket term for the natural bio- fish and crustaceans. Similarly, forest ecosys-
logical wealth that undergirds human life and tems help regulate water discharge into rivers,
well-being. The breadth of the concept reflects which affects the frequency of floods and the
the interrelatedness of genes, species, and availability of water during dry seasons. These
ecosystems. Because genes are the components and other ecosystems also influence local cli-
of species, and species are the components of matic conditions or, in the case of a forested
ecosystems, altering the make-up of any level area as large as Amazonia, even global climate.
of this hierarchy can change the others. There- In a sense, species and ecosystems are inte-
fore, whether the goal is to obtain products grated service networks and the parts need to
from individual species, services from eco- be conserved to conserve the whole. Just as
systems, or to keep ecosystems in a natural habitats and ecosystems must be maintained
state for future generations, these linkages to conserve species, species must be conserved
must be taken into account in management to maintain habitats and various ecological
policies. How biodiversity contributes to vari- services.
ous products and ecological services and
figures in the dynamics of ecological systems Each species' characteristics are determined
and how the biological sciences can help by genetic make-up. Management of this
policy-makers set priorities for conserving bio- genetic diversity is particularly important in
logical diversity are questions of growing small populations and in domestic species.
importance as threats to biodiversity mount. Humanity has long recognized and utilized
genetic diversity in the development of varie-
Species are central to the concept of biodiver- ties of domesticated plants and animals for use
sity. Individual species—Earth's various plants, in agriculture, forestry, animal husbandry, and
animals, and microorganisms—provide the rice aquaculture. In U.S. agriculture alone, crop-
and fish we eat, the penicillin doctors use to breeding programs drawing on genetic diver-
save lives, and other natural products. They sity add an estimated $1 billion annually to the
also provide options for addressing future value of production (OTA 1987). Another way
human needs, and invaluable aesthetic, spirit- farmers take advantage of genetic diversity is
ual, and educational benefits. Just as important, by planting numerous varieties of crops as a
species provide more subtle benefits in the hedge against total crop failure. By planting
form of wide-ranging ecological services. several varieties of potatoes, for example,
Coastal wetland ecosystems formed from Andean farmers can count on a successful