Shortcomings of Threatened Species Categorization Systems: Reply to Soberón and Medellín

We evaluated threatened species categorization systems (hereafter, systems) in use on the American continent (de Grammont & Cuaron 2006). In all we assessed 25 systems used by international agencies and most systems used by countries on the continent or proposed by academics, corresponding to 36 threatened species lists in 20 countries. We concluded that most systems, but especially national systems (i.e., those particular to a given country), have serious deficiencies and that the current World Conservation Union system (IUCN 2001) is at present the most appropriate. Soberon and Medelĺin (2007) argue that these conclusions are not supported by our arguments. They miss, however, some of the main points we made in our paper and do not present arguments or solid evidence to support most of their criticisms. None of their opinions invalidate our conclusions. The main purpose of our analysis was to identify whether or not categorization systems comply with the 15 characteristics that any system should have in order to provide an objective, scientifically based evaluation of species’ conservation status. We assessed how systems are used to categorize species’ extinction risk. Because we did not evaluate systems or lists as normative tools, conservation priority lists, or other uses and misuses of threatened species lists (Cuaron 1993; Possingham et al. 2002; Lamoreux et al. 2003), there was no need to use different measures of success in our analysis. The method we used to evaluate threatened species categorization systems, a single weight for the 15 desirable characteristics, helps in assessments of systems and identifies which systems are better. The main point is that we identified the areas in which the systems are inadequate for evaluation of species’ conservation status so that the relevant parties could use that information to improve their system or choose a more adequate one. Soberon and Medelĺin object to our use of binary scores, even though most of the desirable characteristics