Temperate Terrestrial Vertebrate Faunas in North and South America: Interplay of Ecology, Evolution, and Geography with Biodiversity

Abstract

Abstract: To help identify the factors that govern species richness in biological preserves, we performed a comparative study of terrestrial vertebrate species richness for two analogous montane areas critical for biodiversity conservation: the Greater Yellowstone region of the Rocky Mountains, United States, and the Nahuel Huapi region, Patagonia, around Bariloche, Argentina. We explored the ecological interactions of such factors as latitude, habitat heterogeneity, inferred productivity, geographic context, history of lineage, and history of environment in generating and maintaining species richness. Overall species richness of terrestrial vertebrates was higher in the Yellowstone area, but patterns were not uniform across vertebrate classes. Ectotherms (reptiles and amphibians) were more diverse in the Patagonian site, whereas endotherms (birds and mammals) were more diverse in the Yellowstone site. The higher diversity of Patagonian ectotherms is a result of abnormally high numbers of species within two specialized taxa: frogs and the lizard genus Liolaemus. There were high percentages of endemic species (68% of amphibians, 35% of reptiles, 15% of mammals) and feral, non‐native mammals (19%) in Patagonia. These results imply that (1) biodiversity is generated and maintained by a combination of local phenomena and by continental area and related historical constraints; (2) the relative weight of the various influences may differ for ectotherms ( fit latitudinal and related models) and endotherms ( fit history‐based models); and (3) because larger‐scale processes are so important for the maintenance of natural biological diversity, it is crucial that biological reserves be selected and managed with an understanding of the geographical and geological context of the continents on which they are located. Reserves located on large continents with connections to other continents preserve large numbers of species per given unit of geographic area and protect critical habitat for species such as migrants that require large areas for maintenance of persistent populations. In contrast, reserves located on relatively isolated continents protect a high number of evolutionarily unique species per given unit of geographic area and have a high potential for colonization by exotic species.