Assessing the status of poorly known species: lessons from partridges and pheasants of Southeast Asia

摘要

There is an urgent need to evaluate the status of groups of species for conservation purposes. A species' status is indicated by both its distribution and abundance, and the rate at which these components are changing. This information is scarce for many tropical forest species. We produced four measures of status based on locality and habitat data for 25 partridges and pheasants of Southeast Asia: (I) change in the number of sites from which a species had been recorded; (2) change in the proportion of localities visited from which a species had been recorded; (3) change in the extent of occurrence; and (4) change in a measure that combined habitat and locality information. Species rankings from the first three measures of status that used locality data alone were significantly correlated with each other. Therefore, differences in sampling do not appear to influence the locality-only assessments. None of the locality-only measures was correlated with the ranking based on both locality and habitat information. The lack of correlation between these assessments and that which included habitat information may result from recent bias in habitats searched. Whereas the paucity of data is acute for some species, we propose that estimating changes in the available habitat within a species' extent of occurrence will provide the best estimate of change of status. Fourteen species show decreases according to all measures.