Response to Comment on "Status and Trends of Amphibian Declines and Extinctions Worldwide"

Abstract

Threatened species lists are often used to evaluate the conservation status of species and habitats. Specialists are always consulted to yield and update lists and, as a rule, their opinions are respected and properly used. The lists produced are, therefore, reliable documents based on all information available. However, lists alone are being used to guide conservation efforts and to assess the health of the environment. One of the most serious problems regarding the misuse of such lists concerns data interpretation (1). Stuart et al. (2) recently reported results from the Global Amphibian Assessment (GAA) (3), which indicate that 1856 species are being threatened worldwide Ealso see (4)^. However, the results published for Brazilian species largely differ from the categorization indicated by specialists (3, 5) EScience Online Material (SOM) Text^. Specialists indicate 24 Brazilian species as threatened, whereas the GAA shows 110 species (3, 5) (Table 1 and SOM Text). This overestimation occurred as a result of the misuse of IUCN–The World Conservation Union Red List criteria (6) during a Breevaluation[ later performed by the GAA coordinating team (3, 5) (SOM Text). The GAA team changed the specialists_ categorization of 95 Brazilian species by using the criteria based on geographic range (3). However, the GAA ignored the IUCN recommendation of using different thresholds for distribution range depending on the taxa in question and used the default values instead (6). These values were set by using taxa with broad and well-known distribution ranges (e.g., mammals and birds) and cannot be applied to animals in general without adjustments. The minimal area for a tiger, for example, is almost an endless space for a tiny leaf-litter frog. Moreover, the current knowledge on species_ distribution hinders this kind of assessment. Brazil houses the richest amphibian fauna of the world, with 776 species (7). Almost half of all species were described in the past 40 years (Fig. 1) (7). Before 1999, 101 species were known only from their type locality (the place where the original specimens were found). From 1999 to 2004, 29 species had their distributions expanded, but the description or revalidation of 86 species increased the number of restricted species to 109 (SOM Text). In just the past 2 years, four species have been rediscovered (8–11). Even in areas that are frequently explored, new species are still being discovered (12–15). If the available data on taxonomy and distribution of Brazilian amphibians are deemed enough for making a detailed assessment of their conservation status, why do wider range extensions and many new species continue to be described?