Time-Series Analysis of Asian Elephant Habitat Change and Impact on Its Population Dynamic at Regional Scale

摘要

Asian elephant (Elephas Maximus) is not only ingrained in South and Southeast Asia culture, but also environmentally important as a keystone and umbrella species. Nevertheless, its overall population has continued to decline and spatially restrained which resulted in the species being designated as endangered since 1980s. Despite the overall population reduction, the census at country-level showed an increasing trend in some countries, such as in Sri Lanka and India. However, temporal and cross-countries research on elements impacting population dynamic remain limited. This study is aimed at identifying land cover and landscape changes and their relationship to Asian elephant population dynamic across all 13 range states over 1990, 2003. and 2015. The study area is based on confirmed home range of wild Asian elephants from International Union for Conservation of Nature (IUCN). We identified candidate factors potentially impact Asian elephant population which included food and refuge (forest, shrub, grassland, agriculture), physical landscape fragmentation (Patch Density and Largest Patch Index), landscape heterogeneity (Shannon Diversity Index) and human settlement. Integrating of satellite remote sensing and GIS data, we investigated the change of candidate drivers and applied logistic regression to the country-level population data available at each epoch. We identified that forest and largest patch of forest is crucial for large elephant population but should not be singlehandedly used to predict population change. Additionally, we also observed that large elephant population is likely occurs where there are high human presence and activities. This reflects the potential conflict between elephants and human. Through mapping the spatial changes and identifying drivers of Asian elephant population, our study is expected to help regional conservation to understand and incorporate the situation and needs of endangered elephants.