Hotspot analysis of Taiwanese breeding birds to determine gaps in the protected area network

Background: Although Taiwan is an important hotspot of avian endemism, efforts to use available distributional information for conservation analyses are so far incomplete. For the first time, we present a hotspot analysis of Taiwanese breeding birds with sufficient sampling coverage for distribution modeling. Furthermore, we improved previous modeling efforts by combining several of the most reliable modeling techniques to build an ensemble model for each species. These species maps were added together to generate hotspot maps using the following criteria: total species richness, endemic species richness, threatened species richness, and rare species richness. We then proceeded to use these hotspot maps to determine the 5% most species-rich grid cells (1) within the entire island of Taiwan and (2) within the entire island of Taiwan but outside of protected areas. Results: Almost all of the species richness and hotspot analyses revealed that mountainous regions of Taiwan hold most of Taiwan's avian biodiversity. The only substantial unprotected region which was consistently highlighted as an important avian hotspot is a large area of unprotected mountains in Taiwan's northeast (mountain regions around Nan-ao) which should become a high priority for future fieldwork and conservation efforts. In contrast, other unprotected areas of high conservation value were just spatial extensions of areas already protected in the central and southern mountains. To combine the results of our four hotspot criteria, we assessed which grid cells were the most valuable according to all four criteria. Again, we found the Nan-ao mountain regions to be important. We also showed that different hotspot criteria only partially overlapped and sometimes barely at all. Conclusions: Therefore, to protect areas based on only one hotspot criterion (total species richness) would not protect areas based on other hotspot criteria (endemic species richness, threatened species richness, or rare species richness) in Taiwan.