The biogeographic history of small mammals in the Great basin: observations on the last 20,000 years [Histoire biogéographique des petits mammifères du Great basin : observations sur les 20.000 dernières années].

Résumé

The extirpation of a yellow-bellied marmot in western Nevada that occured within the past 1500 years was not related to climatic events nor human activities. Evidence from archaeological and paleontological sites meets key predictions drawn from J. H. Brown's argument that boreal mammals colonized the Great Basin during the Pleistocene, only to become isolated on, and differentially extinct across, Great Basin mountains during the Holocene. Sylvilagus idahoensis decreased in abundance here at about 7,000 years ago, apparently at about the same time that Ochotona princeps became extinct in the lowlands of the northern half of the Great Basin. These shifts seem correlated with a decrease in effective precipitation inferred from paleobotanical data. Hares (Lepus sp.) appear to have been more abundant during the earlier Holocene than during later times in many more northerly parts of the Great Basin, while several sites suggest survival of the extinct noble marten (Martes nobilis) until a few thousand years ago. The fact that boreal mammals are isolated on Great Basin mountains has important implications for the management of high altitude habitats in this region.