Reversing net loss but aggravating fragmentation of habitat in the global Asian elephant range in the mid-2010s

Abstract

Megafauna, such as elephants, are flagship species and play keystone roles in maintaining ecosystem function. Human-induced deforestation has considerably reduced the global geographic range and population size of Asian elephants (Elephas maximus) in recent decades, yet some reports suggest a possible recent recovery of some of their habitats. The long-term global dynamics of these habitats, however, remain largely unknown. In this study, we compiled environmental covariates from 39 published papers that assessed habitat suitability for Asian elephants. Using these covariates and a habitat suitability index model, we investigated the interannual dynamics of habitat suitability across the species' range from 2000 to 2020. Additionally, we analyzed trends in habitat fragmentation during the same period. Our findings revealed a significant 4.36 % decline in suitable habitat areas over two decades. Interestingly, a tipping point occurred around 2014, when habitat suitability stabilized and began to show slight improvement. However, habitat fragmentation continued to worsen throughout the study period. Notably, habitat suitability was higher in transboundary regions, where degradation was less severe than within protected areas. After 2018, habitat suitability in transboundary regions surpassed that of the protected areas. These findings emphasize the need to prioritize the protection of remaining Asian elephant populations and address the challenges of habitat fragmentation and connectivity across the species' range. Our study highlights the conservation potential often-overlooked transboundary regions and underscores the importance of leveraging geospatial data spanning long time periods and large spatial scales for comprehensive habitat evaluations.