Species diversity at different spatial scales: Birds in Yushan, Taiwan, and East Asia (China)

Understanding spatial patterns of species diversity is one of the most intriguing questions in ecology. Recently most ecologists have agreed that species diversity is governed by multiple processes and the patterns and processes of species diversity are strongly scale dependent. Nevertheless, few studies have investigated patterns of species diversity across spatial scales or tested multiple processes simultaneously. This dissertation investigated the spatial patterns and tested multiple hypotheses of bird species richness at local (Yushan), regional (Taiwan), and continental (East Asia) scales. Bird species richness showed a plateau-then-decreasing relationship with elevation at the local scale, a hump-shaped relationship with elevation at the regional scale, and an inverse relationship with latitude at the continental scale. The energy limitation theory is strongly supported at all scales, suggesting energy availability is one primary process of species diversity and its effects may be consistent across spatial scales. The spatial heterogeneity theory is evident at the local and continental scales, but its explanatory power is less significant than the energy limitation theory. The evolutionary time theory, area theory, isolation theory, and human disturbance hypothesis are all supportable at certain spatial scales but evidence is not consistent across scales.