Mammalian biogeography of the Alexander Archipelago of Southeast Alaska: a north temperate nested fauna.

Résumé

1. Aim: A large number of studies have analyzed the distribution of mammals within archipelagos, yet few have focused on islands that were heavily glaciated and subsequently colonized following deglaciation. 2. Location: We explored the relative effects of island area and isolation on faunal composition based on 23 mammalian taxa of 24 islands of the Alexander Archipelago, Southeast Alaska. 3. Methods: We used regression of log-transformed variables and several indices of nestedness. 4. Results: These faunas showed significant nested structure using tests of nestedness and regression models. Unlike most landbridge and mainland archipelagos studied previously, isolation appears to be the primary factor determining patterns of species richness. 5. Main conclusions: Colonization ability of particular taxa, rather than extinction, has determined this nested structure. We suggest that other higher latitude archipelagos may show similar historical patterns.