THE SPATIAL-DISTRIBUTION OF THREATENED SPECIES - MACROSCALES AND NEW-WORLD BIRDS

Despite the urgent need to understand how threatened species are distr ibuted across the globe, empirical analyses of geographical patterns o f threat at large scales across physic ally, rather than politically, defined areas are scarce. Here, we examine the geographical distributi on of threatened species in the avifauna of the New World, across an a rea spanning the tropics and two temperate regions. Both the absolute number and the proportion of threatened species in an area are highest in the tropics; the latter is especially high in the Caribbean and Br azilian coastal forest areas. Areas in the southern hemisphere, areas with high levels of endemism, and areas rich in species and higher tax a have high numbers of threatened species. Tropical areas may contain more threatened bird species either because these areas suffer higher levels of threatening processes, or because they are inhabited by spec ies which, on average, are more vulnerable to given levels of threaten ing processes. We present evidence that both of these mechanisms may c ause the patterns of threat observed in this avifauna. Whereas the gen eral coincidence between areas rich in species, higher taxa and threat ened species could give cause for optimism that strategies aimed at pr otecting one aspect of biodiversity might also protect others, we put forward reasons why such optimism may be premature, and urge caution w hen interpreting the consequences of these patterns for conservation.