Limits to the use of threatened species lists
TL;DR: This work discusses why threatened species lists are commonly used, and why, if and how they should be used to achieve these purposes; and why some of them perform poorly.
Abstract: Threatened species lists are designed primarily to provide an easily understood qualitative estimate of risk of extinction. Although these estimates of risk can be accurate, the lists have inevitably become linked to several decision-making processes. There are four ways in which such lists are commonly used: to set priorities for resource allocation for species recovery; to inform reserve system design; to constrain development and exploitation; and to report on the state of the environment. The lists were not designed for any one of these purposes, and consequently perform some of them poorly. We discuss why, if and how they should be used to achieve these purposes.
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TL;DR: The process and the technical background to the IUCN Red List system is described, which was designed to measure the symptoms of extinction risk, and uses 5 independent criteria relating to aspects of population loss and decline of range size.
Abstract: The International Union for Conservation of Nature (IUCN) Red List of Threatened Species was increasingly used during the 1980s to assess the conservation status of species for policy and planning purposes. This use stimulated the development of a new set of quantitative criteria for listing species in the categories of threat: critically endangered, endangered, and vulnerable. These criteria, which were intended to be applicable to all species except microorganisms, were part of a broader system for classifying threatened species and were fully implemented by IUCN in 2000. The system and the criteria have been widely used by conservation practitioners and scientists and now underpin one indicator being used to assess the Convention on Biological Diversity 2010 biodiversity target. We describe the process and the technical background to the IUCN Red List system. The criteria refer to fundamental biological processes underlying population decline and extinction. But given major differences between species, the threatening processes affecting them, and the paucity of knowledge relating to most species, the IUCN system had to be both broad and flexible to be applicable to the majority of described species. The system was designed to measure the symptoms of extinction risk, and uses 5 independent criteria relating to aspects of population loss and decline of range size. A species is assigned to a threat category if it meets the quantitative threshold for at least one criterion. The criteria and the accompanying rules and guidelines used by IUCN are intended to increase the consistency, transparency, and validity of its categorization system, but it necessitates some compromises that affect the applicability of the system and the species lists that result. In particular, choices were made over the assessment of uncertainty, poorly known species, depleted species, population decline, restricted ranges, and rarity; all of these affect the way red lists should be viewed and used. Processes related to priority setting and the development of national red lists need to take account of some assumptions in the formulation of the criteria.
1,057 citations
TL;DR: It is highlighted here how the Red List, in conjunction with the comprehensive data compiled to support it and in spite of several important limitations, has become an increasingly powerful tool for conservation planning, management, monitoring and decision making.
Abstract: The IUCN Red List of Threatened Species is the most comprehensive resource detailing the global conservation status of plants and animals. The 2004 edition represents a milestone in the four-decade long history of the Red List, including the first Global Amphibian Assessment and a near doubling in assessed species since 2000. Moreover, the Red List assessment process itself has developed substantially over the past decade, extending the value of the Red List far beyond the assignation of threat status. We highlight here how the Red List, in conjunction with the comprehensive data compiled to support it and in spite of several important limitations, has become an increasingly powerful tool for conservation planning, management, monitoring and decision making.
912 citations
TL;DR: It is argued that the farmland bird indicator is a useful surrogate for trends in other elements of biodiversity in this habitat, and developed statistical methods to calculate supranational, multi-species indices using population data from national annual breeding bird surveys in Europe.
Abstract: The global pledge to deliver ‘a significant reduction in the current rate of biodiversity loss by 2010’ is echoed in a number of regional and national level targets. There is broad consensus, however, that in the absence of conservation action, biodiversity will continue to be lost at a rate unprecedented in the recent era. Remarkably, we lack a basic system to measure progress towards these targets and, in particular, we lack standard measures of biodiversity and procedures to construct and assess summary statistics. Here, we develop a simple classification of biodiversity indicators to assist their development and clarify purpose. We use European birds, as example taxa, to show how robust indicators can be constructed and how they can be interpreted. We have developed statistical methods to calculate supranational, multi-species indices using population data from national annual breeding bird surveys in Europe. Skilled volunteers using standardized field methods undertake data collection where methods and survey designs differ slightly across countries. Survey plots tend to be widely distributed at a national level, covering many bird species and habitats with reasonable representation. National species' indices are calculated using log-linear regression, which allows for plot turnover. Supranational species' indices are constructed by combining the national species' indices weighted by national population sizes of each species. Supranational, multi-species indicators are calculated by averaging the resulting indices. We show that common farmland birds in Europe have declined steeply over the last two decades, whereas woodland birds have not. Evidence elsewhere shows that the main driver of farmland bird declines is increased agricultural intensification. We argue that the farmland bird indicator is a useful surrogate for trends in other elements of biodiversity in this habitat.
847 citations
Cites background from "Limits to the use of threatened spe..."
...Some have suggested that while extinction rate provides an important measure of human impacts over the long term, it is an inherently poor measure of contemporary biodiversity loss (McKinney & Lockwood 1999; Possingham et al. 2002; Royal Society 2003; Jenkins 2003; Balmford et al. 2003)....
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...Change in threat status can also be associated with artefacts such as increased knowledge, increased sampling efforts or changes in taxonomy, or a combination of these factors, rather than genuine population change (Possingham et al. 2002)....
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...Change in threat status can also be associated with artefacts such as increased knowledge, increased sampling efforts or changes in taxonomy, or a combination of these factors, rather than genuine population change ( Possingham et al. 2002 )....
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...Some have suggested that while extinction rate provides an important measure of human impacts over the long term, it is an inherently poor measure of contemporary biodiversity loss (McKinney & Lockwood 1999; Possingham et al. 2002; Royal Society 2003; Jenkins 2003; Balmford et al. 2003)....
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TL;DR: This list includes 700 extant taxa representing 133 genera and 36 families, a 92% increase over the 364 listed in 1989, and reflects the addition of distinct populations, previously non-imperiled fishes, and recently described or discovered taxa.
Abstract: This is the third compilation of imperiled (i.e., endangered, threatened, vulnerable) plus extinct freshwater and diadromous fishes of North America prepared by the American Fisheries Society'S Endangered Species Committee. Since the last revision in 1989, imperilment of inland fishes has increased substantially. This list includes 700 extant taxa representing 133 genera and 36 families, a 92% increase over the 364 listed in 1989. The increase reflects the addition of distinct populations, previously non-imperiled fishes, and recently described or discovered taxa. Approximately 39% of described fish species of the continent are imperiled. There are 230 vulnerable, 190 thretened, and 280 endangered extant taxa, and 61 taxa presumed extinct or extirpated from nature. Of those that were imperiled in 1989, most (89%) are the same or worse in conservation status; only 6% have improved in status, and 5% were delisted for various reasons. Habitat degradation and nonindigenous species are the main threat...
774 citations
Cites background from "Limits to the use of threatened spe..."
...Possingham et al. (2002) discussed the inappropriate uses of conservation lists; although lists have their limitations and critics, they are important tools in the arsenal required for protecting biodiversity in a rapidly changing world....
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TL;DR: Taxonomy and species conservation are often assumed to be completely interdependent activities as mentioned in this paper, however, a shortage of taxonomic information and skills, and confusion over where the limits to'species' should be set, both cause problems for conservationists.
Abstract: Taxonomy and species conservation are often assumed to be completely interdependent activities. However, a shortage of taxonomic information and skills, and confusion over where the limits to 'species' should be set, both cause problems for conservationists. There is no simple solution because species lists used for conservation planning (e.g. threatened species, species richness estimates, species covered by legislation) are often also used to determine which units should be the focus of conservation actions; this despite the fact that the two processes have such different goals and information needs. Species conservation needs two kinds of taxonomic solution: (i) a set of practical rules to standardize the species units included on lists; and (ii) an approach to the units chosen for conservation recovery planning which recognizes the dynamic nature of natural systems and the differences from the units in listing processes that result. These solutions are well within our grasp but require a new kind of collaboration among conservation biologists, taxonomists and legislators, as well as an increased resource of taxonomists with relevant and high-quality skills.
704 citations
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TL;DR: Proposed categories of threat based on the theory of extinction times for single populations and on meaningful time scales for conservation action are presented and suggest are appropriate at least for most large vertebrates.
Abstract: IUCN categories of threat (Endangered Vulnera- ble, Rare, Indeterminate, and others) are widely used in 'Red lists' of endangered species and have become an important tool in conservation action at international, national, re- gional, and thematic levels. The existing definitions are largely subjective, and as a result, categorizations made by different authorities diyfer and my not accurately reflect actual extinction risks. We present proposals to redefine cat- egories in tams of the probability of extinction within a specific time perio4 based on the theory of extinction times for single populations and on meaningful time scales for conservation action. Three categories are proposed (CRITI- CAL, ENDANGE-, VULNERABLE) with decreasing levels of threat over increasing time scales for species estimated to have at least a 10% probability of extinction within 100 years. The process of assigning species to categories may need to vay among different taxonomic groups, but we present some simple qualitative criteria based on population biol- ogy theory, which we suggest are appropriate at least for most large vertebrates. The process of assessing threat is clearly distinguished from that of setting priorities for con- servation action, and only the former is discussed here.
820 citations
01 Jan 2000
TL;DR: This paper focuses on a particular class of reserve design problem where the goal is to achieve some minimum representation of biodiversity features for the smallest possible cost.
Abstract: We focus on a particular class of reserve design problem where the goal is to achieve some minimum representation of biodiversity features for the smallest possible
cost.
739 citations
"Limits to the use of threatened spe..." refers background in this paper
...Reserve selection algorithms seek to conserve biodiversity as efficiently and completely as possible [21, 22 ]....
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TL;DR: It is found that the utility of umbrella and flagship species as surrogates for regional biodiversity may be limited and none of the surrogate schemes evaluated performs significantly better than do a comparable number of species randomly selected from the database.
Abstract: The use of umbrella and flagship species as surrogates for regional biota whose spatial distributions are poorly known is a popular conservation strategy. Yet many assumptions underlying the choice of surrogate species remain untested. By using biodiversity databases containing spatial incidence data for species of concern for (i) the southern California coastal sage scrub habitat, (ii) the Columbia Plateau ecoregion, and (iii) the continental United States, we evaluate the potential effectiveness of a range of conservation surrogate schemes (e.g., big carnivores, charismatic species, keystone species, wide-ranging species), asking how many species potentially are protected by each scheme and at what cost in each habitat area. For all three databases, we find that none of the surrogate schemes we evaluated performs significantly better than do a comparable number of species randomly selected from the database. Although some surrogate species may have considerable publicity value, based on the databases we analyzed, representing diverse taxa on three different geographic scales, we find that the utility of umbrella and flagship species as surrogates for regional biodiversity may be limited.
663 citations
TL;DR: In this article, a simulation method was developed for identifying populations with levels of human-caused mortality that could lead to depletion, taking into account the uncertainty of available information, and a mortality limit was calculated as the product of a minimum population estimate (NMIN), one-half of the maximum net productivity rate (RMAX), and a recovery factor (FR).
Abstract: A simulation method was developed for identifying populations with levels of human-caused mortality that could lead to depletion, taking into account the uncertainty of available information. A mortality limit (termed the Potential Biological Removal, PBR, under the U. S. Marine Mammal Protection Act) was calculated as the product of a minimum population estimate (NMIN), one-half of the maximum net productivity rate (RMAX), and a recovery factor (FR). Mortality limits were evaluated based on whether at least 95% of the simulated populations met two criteria: (1) that populations starting at the maximum net productivity level (MNPL) stayed there or above after 20 yr, and (2) that populations starting at 30% of carrying-capacity (K) recovered to at least MNPL after 100 yr. Simulations of populations that experienced mortality equal to the PBR indicated that using approximately the 20th percentile (the lower 60% log-normal confidence limit) of the abundance estimate for NMIN met the criteria for both cetaceans (assuming RMAX= 0.04) and pinnipeds (assuming RMAX= 0.12). Additional simulations that included plausible levels of bias in the available information indicated that using a value of 0.5 for FR would meet both criteria during these “bias trials.” It is concluded that any marine mammal population with an estimate of human-caused mortality that is greater than its PBR has a level of mortality that could lead to the depletion of the population. The simulation methods were also used to show how mortality limits could be calculated to meet conservation goals other than the U. S. goal of maintaining populations above MNPL.
593 citations
TL;DR: This book discusses the natural heritage of the United States through the lens of species diversity, state diversity, endemism, and Rarity, and the role of government and non-governmental agencies in promoting and protecting these species.
Abstract: Foreword Preface Contributors Participating Institutions Acknowledgements 1. Biodiversity: Our Precious Heritage 2. Discovering Life in America: Tools and Techniques of Biodiversity Inventory 3. A Remarkable Array: Species Diversity in the United States 4. Conservation Status of U.S. Species 5. State of the States: Geographic Patterns of Diversity, Rarity, and Endemism 6. The Geography of Imperilment: Targeting Conservation towards Critical Biodiversity Areas 7. More than the Sum of the Parts: Diversity and Status of Ecological Systems 8. Leading Threats to U.S. Biodiversity: What's Threatening Imperiled Species 9. Strategies for Biodiversity Protection 10. Owning Up to Our Responsibilities: Who Owns Lands Important for Biodiversity? 11. Safeguarding Our Precious Heritage Appendix A: Extinct and missing species of the United States Appendix B: State Diversity, Endemism, and Rarity Appendix C: Kuchler Potential Natural Vegetation Types Appendix D: Principal Sources for the Natural Heritage Central Databases Literature Cited
526 citations