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Accumulation of Knowledge and Changes in Red List Classifications within the Family Galliformes1980–2004

Lee, David C., Marsden, Stuart J.
Biodiversity and conservation 2006 v.15 no.6 pp. 1887-1902
decision support systems, extinction, grouse, partridges, pheasants, population dynamics, risk, threatened species
The IUCN Red List classification scheme has, for many years, aided the prioritisation of conservation action by identifying taxa most at risk of extinction. This is a study of the accumulation of knowledge concerning extinction risk in gamebirds over the last 25 years (the Red Lists published in 1981, 1988, 1994, 2000 and 2004). The change from the rather subjective assessment criteria of the 1980s to the more quantitative scheme of 1994 was marked by a sharp increase in the proportion of species classed as threatened. Between 1994 and 2000, 17% of threatened species moved threat category (21 upgraded and 28 downgraded) while between 2000 and 2004 just 7% of species shifted category. The main threat criteria (those associated with ‘declining population’, ‘small range’ and ‘small population’) were used in similar proportions in 1994 and 2000, suggesting no real change in the ways that classifications are arrived at. Decision tree analysis showed that species moving between threat categories between 1994 and 2004 tended to be polytypic and have large global ranges, suggesting that such species are amongst those most difficult to classify. Considering actual direction of change between 1994 and 2004, geographic region and taxonomic group were important, with pheasants, and partridges and their allies (species of the Palearctic and Oriental regions), tending to be downgraded, and the grouse, megapodes and cracids of the New World and Australasia tending to be upgraded. While there are now few movements in threat category between assessments, we caution that this certainly does not mean that we have accumulated adequate knowledge to properly support the classifications for most species.