Temperate terrestrial vertebrate faunas in North and South America: Interplay of ecology, evolution, and geography with biodiversity

To help identify the factors that govern species richness in biological pre serves, we performed a comparative study of terrestrial vertebrate species richness for two analogous montane areas critical for biodiversity conserva tion: the Greater Yellowstone region of the Rocky Mountains United States a nd the Nahuel Huapi region, Patagonia, around Bariloche, Argentina. We expl ored the ecological interactions of such factors ns latitude, habitat heter ogeneity, inferred productivity, geographic context history of lineage and history of environment in generating and maintaining species richness. Over all species richness of terrestrial vertebrates was higher in the Yellowsto ne area, but patterns were not uniform across vertebrate classes Ectotherms (reptiles and amphibians) were more diverse in the Patagonian site, wherea s endotherms (birds and mammals) were more diverse in the Yellowstone site. The higher diversity of Patagonian ectotherms is a result of abnormally hi gh numbers of species within two specialized taxa: frogs and the lizard gen us Liolaemus. There were high percentages of endemic species (68% of amphib ians 35% of reptiles 15% of mammals) and feral, non-native mammals (19%) in Patagonia. These results imply that (1) biodiversity is generated and main tained by a combination of local phenomena and by continental area and rela ted historical constraints; (2) the relative weight of the various influenc es may differ for ectotherms (fit latitudinal and related models) and endot herms (fit history-based models); and (3) because larger-scale processes ar e so important for the maintenance of natural biological diversity, it is c rucial that biological reserves be selected and managed with nn understandi ng of the geographical and geological context of the continents on which th ey are located. Reserves located on large continents with connections to ot her. continents preserve large numbers of species per given unit of geograp hic area and protect critical habitat for species such as migrants that req uire large areas for maintenance of persistent populations. In contrast, re serves located on relatively isolated continents protect a high number of e volutionarily unique species per given unit of geographic area and have a h igh potential for colonization by exotic species.