Biogeography and composition of dry forest bird communities in Bolivia

摘要: In Bolivia dry forests are distributed extensively in the southeastern lowlands and extend into country's northern southern Andes rain-shadowed intermontane valleys, where they often form habitat islands. We examined biogeography composition of bird communities at 14 Andean seven lowland forest localities Bolivia. To minimise biases, analyses considered only core speciessensu Remsen (1994) zonal vegetation types. Of a total 608 recorded species, 454 were species 99 (22 %) typical species. Core richness varied from 65 to 156 individual sites. One occurred all sites 154 (34 single locality each; this tendency was most evident Bolivian 46 % once. Comparisons showed that valleys heterogeneous distinct. Localities homogeneous with affinities forests; latter separated Velasco Chaco woodland sites, respectively. A continuous ordination revealed steep gradient large areas small, relatively humid islands northwest. Typical prevalent south, whereas predominated Frugi-granivores nectarivores such as pigeons doves, hummingbirds, emberizid finches insectivores made greater contributions communities. The biogeographical birds varied. Overall, gradually decreased increased elevation, which pronounced Andes; we found no elevational threshold avifaunal turnover. An examination range limits northwestward reduction avifauna isolated Andes. With restricted Bolivia, area has considerably higher level endemism than Chaco. colonised by two different ways. upper ascended directly adjacent lower probably during drier cooler periods Pleistocene resulted expansions seasonally tropical Amazonia.