Preliminary Analysis of the Ecology and Geography of the Asian Nuthatches (Aves: Sittidae)
We explored distributions of Asian nuthatch species in ecological and geographic space using ecological niche modeling based on occurrence data associated with specimens and observations. Nuthatches represent a well-defined clade occurring throughout the Northern Hemisphere, but are most diverse in southern Asia where 15 of the 24 species occur and where the lineage is believed to have evolved. Species richness was focused in a narrow east-west band corresponding to the forested parts of the Himalayas with a maximum number of nine species predicted present in these foci. The distributional predictions have a mid-elevation focus with highest species diversity between 1,000 and 2,000 m. Niche breadth and volume were positively related, but accumulation of distributional area (niche volume) decreased with additional environmental combinations (niche breadth). The extent of potential range filling, a measure of distributional disequilibrium, was connected with montane habit ([R2] = 0.422) indicating that montane situations limit the distributional potential of species.
Shaily Menon, Zafar-Ul Islam, Jorge Soberon, and A. Townsend Peterson. "Preliminary Analysis of the Ecology and Geography of the Asian Nuthatches (Aves: Sittidae)" Wilson Journal of Ornithology 120.4 (2008): 692-699.
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