Conservation by Proxy: Indicator, Umbrella, Keystone, Flagship, and Other Surrogate Species - Softcover

Caro, Tim; Girling, Sheila

Softcover

ISBN 10: 1597261939 ISBN 13: 9781597261937

Verlag: Island Press, 2010

Inhaltsangabe

The vast scope of conservation problems has forced biologists and managers to rely on "surrogate" species to serve as shortcuts to guide their decision making. These species-known by a host of different terms, including indicator, umbrella, and flagship species-act as proxies to represent larger conservation issues, such as the location of biodiversity hotspots or general ecosystem health.

 

Synthesizing an immense body of literature, conservation biologist and field researcher Tim Caro offers systematic definitions of surrogate species concepts, explores biological theories that underlie them, considers how surrogate species are chosen, critically examines evidence for and against their utility, and makes recommendations for their continued use. The book

clarifies terminology and contrasts how different terms are used in the real world

considers the ecological, taxonomic, and political underpinnings of these shortcuts

identifies criteria that make for good surrogate species

outlines the circumstances where the application of the surrogate species concept shows promise

Conservation by Proxy is a benchmark reference that provides clear definitions and common understanding of the evidence and theory behind surrogate species. It is the first book to review and bring together literature on more than fifteen types of surrogate species, enabling us to assess their role in conservation and offering guidelines on how they can be used most effectively.

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Tim Caro

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Conservation by Proxy

Indicator, Umbrella, Keystone, Flagship, and Other Surrogate Species

By Tim Caro, Sheila Girling

ISLAND PRESS

Copyright © 2010 Island Press
All rights reserved.

ISBN: 978-1-59726-193-7

Contents

Preface, 
INTRODUCTION, 
Chapter 1 Buzzwords in Conservation Biology, 
DISTRIBUTION OF BIODIVERSITY, 
Chapter 2 Species Indicators of Biodiversity at a Large Scale, 
RESERVE SITE SELECTION, 
Chapter 3 Species Indicators of Biodiversity in Reserve Selection, 
RESERVE DESIGN AND MANAGEMENT, 
Chapter 4 Umbrella Species and Landscape Species, 
Chapter 5 Keystone, Engineering, and Foundation Species, 
SPECIES INDICATORS OF ANTHROPOGENIC CHANGE, 
Chapter 6 Environmental Indicator Species, 
Chapter 7 Ecological-Disturbance Indicator Species, 
Chapter 8 Cross-Taxon-Response Indicator Species, 
PROMOTING CONSERVATION, 
Chapter 9 Flagship Species, 
SUMMARY OF CONCEPT SAND COST-EFFECTIVENESS, 
Chapter 10 Surrogate Species in the Real World, 
References, 
Scientific Names of Species Mentioned in the Text, 
Subject Index, 

CHAPTER 1

Buzzwords in Conservation Biology

Shortcuts

The goal of conservation biology is to stop or delay the extinction of plant and animal populations and to prevent or slow habitat destruction. As populations, species, and habitats are under threat in so many places, we are forced to make difficult decisions about where to focus conservation attention. Ideally, detailed study should precede important decisions, especially those that have long-term ramifications for conservation, but four factors prohibit this: the complexity of nature prevents accurate appraisal of all its aspects, the scale of the biodiversity crisis is vast, political decisions must be made rapidly, and there is a severe shortage of funds. Consequently, conservation scientists are compelled to take shortcuts to identify and solve problems. These involve using satellite imagery to monitor environmental change, modeling population responses to anthropogenic pressure, interviewing people about their activities, garnering expert opinion about species' distributions and the threats they face, and monitoring subsets of species. Subsets may act as proxies for the presence of others, and may help us in deciding where to set up protected areas, in measuring plant and animal community responses to anthropogenic change, and in raising conservation awareness. They are called surrogate species or surrogate taxa, which I define as "species that are used to represent other species or aspects of the environment to attain a conservation objective" (see also Wiens et al. 2008).

Surrogates may be species that represent the whole pool of species, or those that represent subsets of the species pool, or they may be species-groups that represent the species pool (see Fig. 1-1). All of these fall under the rubric of surrogate species in this book. Broadly, surrogates are likely to be most useful when the number of species being protected or monitored is uncertain, or the spatial extent of the task is intermediate in size (Wiens et al. 2008). When the area or number of species is very small, individual species can sometimes be considered one by one, and when the area or number of species is very large, surrogate species may be unable to represent the variety of taxa or habitats present and so may not be helpful. Spatial scale is thus very important in the science of surrogate species.

At its heart, the surrogate species concept relies on extrapolation, from group A to group B, from area A to area B, from subgroup to group, from smaller to larger scale, sample to inventory, habitat to inventory, and so on (Hammond 1995). The key issue is whether such extrapolations are valid. Until we know this, the surrogate species concept is a risky gambit because we may be making unreliable approximations of the larger picture. Nevertheless, perhaps because surrogate terms are catchy shorthand expressions and have now become conservation buzzwords, unreliable and ill-conceived surrogate species continue to be proposed in conservation workshops, in meetings, and in the literature, potentially affecting important management decisions without careful thought as to what such terms really signify in nature and without considering the burden that they carry for conserving species and habitats. Moreover, surrogate concepts are often interchanged, elided, or just used incorrectly, generating a loose terminology that is confusing to laypersons, wildlife managers, and conservation scientists alike. In short, buzzwords in conservation are useful only if they are clearly defined, address clear objectives, and prove themselves to be effective.

I start this chapter by introducing issues of biodiversity and scale, then outline the variety of ways surrogate species are used in conservation, and present five different problems in their application. This chapter provides a sketch of how surrogate concepts are brought into play and misused in conservation science.

Biodiversity

Usage

Biological diversity or biodiversity (Wilson 1992; Harper & Hawksworth 1995) "means the variability among living organisms from all sources including, inter alia, terrestrial, marine, and other aquatic systems, and the ecological complexes of which they are part; this includes diversity within species, between species, and of ecosystems" (Heywood 1995, 8; see also OTA 1987; Hunter 1996; Hubbell 2001; Groves et al. 2002; and Magurran 2004). The concept captures variability in biological systems from genes to communities but in practice centers on species richness (i.e., the number of species present) in an area. Species richness is reasonably precise (at least for animals), relatively easy to measure, and is generally assumed to play a positive role in ecosystem dynamics. Some people erroneously equate species richness with a diversity (i.e., the number of species in a homogeneous habitat), but it can also refer to ß diversity, the difference in composition of species between habitats located in close proximity in the same landscape (also referred to as species turnover or community dissimilarity, Whittaker 1960; Su et al. 2004). Measures of ß diversity can be quantified in several ways, using Jaccard's coefficient or percentage similarity, for example. Alpha diversity increases with the size of the area sampled, whereas ß diversity declines because fewer new species are encountered; γ diversity refers to the total number of species in a given region.

Biodiversity is also measured using combinatorial measures of richness and abundance (Maclaurin & Sterelny 2008), allowing species community structure and composition to be assessed using measures such as the Q statistic, Simpson's index, and Generalized Dissimilarity Modeling (Ferrier et al. 2007).

Biodiversity is used in other senses as well. Endemic species have relatively small geographic ranges (e.g., an average of 64,561 km2 for 147 endemic Mexican mammals versus 427,183 km2 for 314 nonendemics, Ceballos et al. 1998). They may be restricted to an ecoregion, such as mangrove forests, or to a country—bonobos are endemic to the Democratic Republic of Congo, for instance. Species with narrow geographic ranges are especially susceptible to extinction from disease, invasive species, sustained habitat degradation, climate change, or political instability (Usher 1986; Pimmet al. 1995).

Rarity is a...

Details zur Ausgabe

• Verlag: Island Press
• Erscheinungsdatum: 2010
• Sprache: Englisch
• ISBN 10: 1597261939
• ISBN 13: 9781597261937
• Einband: Taschenbuch
• Auflage: 2
• Anzahl der Seiten: 374
• Kontakt zum Hersteller: Nicht verfügbar
• Verantwortliche Person: gpsr@libri.de; gpsr@libri.de; ; Friedensallee 273; Hamburg; 22763; Deutschland