Biodiversity and biogeography of birds in Pacific Mexico along an isolation gradient from mainland Chamela via coastal Marias to oceanic Revillagigedo Islands

A study of bird biodiversity along an isolation gradient from mainland Chamela to the oceanic Revillagigedo Islands reveals that island avifaunas exhibit reduced taxonomic diversity and relatedness compared to mainland areas. The research, conducted across three sites—Chamela (262 species), coastal Marias (191 species), and remote Revillagigedos (148 species)—demonstrates a clear pattern: as isolation increases, the number of breeding species declines, and generalist species replace specialists. This supports the hypothesis that closely related taxa exclude each other on islands, leaving small ecological niches unoccupied by specialists. The findings highlight the impact of geographic isolation on avian biodiversity and community structure in Pacific Mexico.

Hahn, I., Hogeback, S., Römer, U., & Vergara, P. M. (2012). Biodiversity and biogeography of birds in Pacific Mexico along an isolation gradient from mainland Chamela via coastal Marias to oceanic Revillagigedo Islands. Vertebrate Zoology, 62(1), 123–144. https://doi.org/10.3897/vz.62.e31373