Dolphins, Whales and Porpoises: 2002-2010 Conservation - IUCN

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Annex 1: Uncertainty The Red List Criteria should be applied to a taxon based on the available evidence concerning its numbers, trend and distribution. In cases where there are evident threats to a taxon through, for example, deterioration of its only known habitat, a threatened listing may be justified, even though there may be little direct information on the biological status of the taxon itself. In all these instances there are uncertainties associated with the available information and how it was obtained. These uncertainties may be categorized as natural variability, semantic uncertainty and measurement error (Akçakaya et al. 2000). This section provides guidance on how to recognize and deal with these uncertainties when using the criteria. Natural variability results from the fact that species’ life histories and the environments in which they live change over time and space. The effect of this variation on the criteria is limited, because each parameter refers to a specific time or spatial scale. Semantic uncertainty arises from vagueness in the definition of terms or lack of consistency in different assessors’ usage of them. Despite attempts to make the definitions of the terms used in the criteria exact, in some cases this is not possible without the loss of generality. Measurement error is often the largest source of uncertainty; it arises from the lack of precise information about the parameters used in the criteria. This may be due to inaccuracies in estimating the values or a lack of knowledge. Measurement error may be reduced or eliminated by acquiring additional data. For further details, see Akçakaya et al. (2000) and Burgman et al. (1999). One of the simplest ways to represent uncertainty is to specify a best estimate and a range of plausible values. The best estimate itself might be a range, but in any case the best estimate should always be included in the range of plausible values. When data are very uncertain, the range for the best estimate might be the range of plausible values. There are various methods that can be used to establish the plausible range. It may be based on confidence intervals, the opinion of a single expert, or the consensus opinion of a group of experts. Whichever method is used should be stated and justified in the documentation. When interpreting and using uncertain data, attitudes toward risk and uncertainty may play an important role. Attitudes have two components. First, assessors need to consider whether they will include the full range of plausible values in assessments, or whether they will exclude extreme values from consideration (known as dispute tolerance). An assessor with a low dispute tolerance would include all values, thereby increasing the uncertainty, whereas an assessor with a high dispute tolerance would exclude extremes, reducing the uncertainty. Second, assessors need to consider whether they have a precautionary or evidentiary attitude to risk (known as risk tolerance). A precautionary attitude will classify a taxon as threatened unless it is certain that it is not threatened, whereas an evidentiary attitude will classify a taxon as threatened only when there is strong evidence to support a threatened classification. Assessors should resist an evidentiary attitude and adopt a precautionary but realistic attitude to uncertainty when applying the criteria, for example, by using plausible lower bounds, rather than best estimates, in determining population size, especially if it is fluctuating. All attitudes should be explicitly documented. An assessment using a point estimate (i.e. single numerical value) will lead to a single Red List Category. However, when a plausible range for each parameter is used to evaluate the criteria, a range of categories may be obtained, reflecting the uncertainties in the data. A single category, based on a specific attitude to uncertainty, should always be listed along with the criteria met, while the range of plausible categories should be indicated in the documentation (see Annex 3). Where data are so uncertain that any category is plausible, the category of ‘Data Deficient’ should be assigned. However, it is important to recognize that this category indicates that the data are inadequate to determine the degree of threat faced by a taxon, not necessarily that the taxon is poorly known or indeed not threatened. Although Data Deficient is not a threatened category, it indicates a need to obtain more information on a taxon to determine the appropriate listing; moreover, it requires documentation with whatever available information there is. 133
Annex 2: Citation of the IUCN Red List Categories and Criteria In order to promote the use of a standard format for citing the Red List Categories and Criteria the following forms of citation are recommended: 1. The Red List Category may be written out in full or abbreviated as follows (when translated into other languages, the abbreviations should follow the English denominations): Extinct, EX Extinct in the Wild, EW Critically Endangered, CR Endangered, EN Vulnerable, VU Near Threatened, NT Least Concern, LC Data Deficient, DD Not Evaluated, NE 2. Under Section V (the criteria for Critically Endangered, Endangered and Vulnerable) there is a hierarchical alphanumeric numbering system of criteria and subcriteria. These criteria and subcriteria (all three levels) form an integral part of the Red List assessment and all those that result in the assignment of a threatened category must be specified after the Category. Under the criteria A to C and D under Vulnerable, the first level of the hierarchy is indicated by the use of numbers (1-4) and if more than one is met, they are separated by means of the ‘+’ symbol. The second level is indicated by the use of the lower-case alphabet characters (a-e). These are listed without any punctuation. A third level of the hierarchy under Criteria B and C involves the use of lower case roman numerals (i-v). These are placed in parentheses (with no space between the preceding alphabet character and start of the parenthesis) and separated by the use of commas if more than one is listed. Where more than one criterion is met, they should be separated by semicolons. The following are examples of such usage: EX CR A1cd VU A2c+3c EN B1ac(i,ii,iii) EN A2c; D VU D1+2 CR A2c+3c; B1ab(iii) CR D VU D2 EN B2ab(i,ii,iii) VU C2a(ii) EN A1c; B1ab(iii); C2a(i) EN B2b(iii)c(ii) EN B1ab(i,ii,v)c(iii,iv)+2b(i)c(ii,v) VU B1ab(iii)+2ab(iii) EN A2abc+3bc+4abc; B1b(iii,iv,v)c(ii,iii,iv)+ 2b(iii,iv,v)c(ii,iii,iv) 134
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2002-2010 Conservation Action Plan
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2002-2010 Conservation Action Plan
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The designation of geographical ent
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False killer whale, Pseudorca crass
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Dedication Steve Leatherwood served
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Acknowledgments We are indebted to
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Introduction Conserving cetaceans (
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Atlantic; bowhead whales in the Ber
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Table 1.1 Classification of the liv
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Table 1.1 ... continued. Classifica
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Figure 1. The hump-backed dolphins
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Chapter 2 Threats Faced by Cetacean
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Figure 4. Risso’s dolphin is one
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dolphins and finless porpoises in H
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Figure 9. Dolphins are attracted to
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Disease and exposure to biotoxins R
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procedure for aboriginal subsistenc
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3.2 Habitat protection and restorat
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Treaty Organization (NATO) caused a
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concerning Specially Protected Area
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Chapter 4 Status of Cetacean Specie
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eeding areas are thought to be rela
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time), they had not yet attained 80
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Long-beaked common dolphin, Delphin
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are taken by driving in some years.
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Irrawaddy dolphin, Orcaella breviro
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may have concentrations of these do
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around the world. There are estimat
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Harbor porpoise, Phocoena phocoena
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For example, in the Mediterranean S
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Franciscana (La Plata dolphin), Pon
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Chapter 5 Recommended Research and
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Figure 25. A sperm whale lifts its
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Figure 27. A male finless porpoise
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side of the Sundarbans, as a result
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16. Assess the impacts of reduced w
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much like those elsewhere in the wo
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Silva 1998; Di Beneditto et al. 199
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stock assessment surveys, and troph
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1996). Even at the bottom end of th
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in some areas urgently needed to be
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vessels are registered in several c
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appears to be limited to dolphins i
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50. Conduct a basin-wide assessment
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Page 91 and 92: Chapter 6 Recommended Conservation
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Page 99 and 100: References Adams, J.E. 1994. Last o
Page 101 and 102: Bearzi, G. 2000. First report of a
Page 103 and 104: Brownell Jr., R.L. and Clapham, P.J
Page 105 and 106: Crespo, E.A., Koen Alonso, M., Dans
Page 107 and 108: Forcada, J. 1995. Abundance of comm
Page 109 and 110: Heyning, J.E. 1989. Cuvier’s beak
Page 111 and 112: Kannan, K., Sinha, R.K., Tanabe, S.
Page 113 and 114: Laist, D.W., Knowlton, A.R., Mead,
Page 115 and 116: document submitted to Workshop on t
Page 117 and 118: Parra, G.J., Azuma, C., Preen, A.R.
Page 119 and 120: Reeves, R.R. 1988. Exploitation of
Page 121 and 122: humpback whale breeding ground in B
Page 123 and 124: cetaceans, 26-28 February 1997, Raj
Page 125 and 126: Van Waerebeek, K. and Reyes, J.C. 1
Page 127 and 128: Zavala-González, A., Urbán-Ramír
Page 129 and 130: Barbara L. Taylor (Chair, CITES/Red
Page 131 and 132: List of Threatened Animals (Baillie
Page 133 and 134: criteria. Mapping at finer scales r
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Dolphins, Whales and Porpoises: 2002-2010 Conservation - IUCN

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