Species-specific habitat fragmentation assessment, considering the ecological niche requirements and dispersal capability

Abstract

Habitat fragmentation assessment is quite important for the endangered risk assessing and conservation management for threatened animals. Note that even sympatric species may differ in habitat fragmentation, due to the various ecological niche requirements and dispersal capabilities. We therefore develop an integrated method for assessing the habitat fragmentation that combines habitat suitability with dispersal distance data to assess the patch isolation, within-patch fragmentation and identify the functional habitat fragmentation categories. Specifically, the ecological niche modeling enables us to identify the species-specific suitable areas through connecting the niche requirements and distribution, which indirectly includes the effects of habitat loss and degradation. The integrated fragmentation assessments enable the conservation planners to consider not only the population isolation level in large scale, but also the spatial connectivity within-patch and different fragmentation categories for landscape conservation that would otherwise appear cryptic under more typical habitat suitability or fragmentation assessing approaches. Furthermore, these assessments cal also be applied in the quantitatively endangered status ranking.We applied this method in two sympatric montane Galliform birds in China, Chinese Grouse (Bonasa sewerzowi) and Blood Pheasant (Ithaginis cruentus) for comparison and illustration purpose. Generally, the suitable areas of Chinese Grouse were predicted to be significantly smaller than that of Blood Pheasant. The habitat of Chinese Grouse was also more severely fragmented than the Blood Pheasant through both scales of patch isolation and within-patch fragmentation. We therefore suggest that the Chinese Grouse should be even more threatened than previously considered.