Effects of a hydropower project on a high‐value Asian elephant population

Abstract

Habitat loss and fragmentation are leading contributors to the endangered status of species. In 2006, the Nakai Plateau contained the largest known Asian elephant (Elephas maximus) population in the Lao People's Democratic Republic (Lao PDR), and the population was among those with the highest genetic diversity reported for Asian elephants. In 2008, completion of the Nam Theun 2 hydroelectric dam inundated much of the Plateau, resulting in the loss of 40% of elephant habitat. We studied elephant presence, movements, and the incidence of human–elephant conflict (HEC) on the Nakai Plateau and surrounding areas from 2004 to 2020, before and for 12 years after dam completion. To examine contemporary population dynamics in the Nakai elephants, we used genetic sampling to compare minimum population numbers, demography, and levels of genetic diversity from the wet and dry seasons in 2018/2019, 10 years after dam completion, with those reported in a pre‐dam‐completion genetic survey. After dam completion, we found a major increase in HEC locally and the creation of new, serious, and persistent HEC problems as far as 100 km away. While we were unable to compare estimated population sizes before and after dam completion, our data revealed a decrease in genetic diversity, a male‐biased sex ratio, and evidence of dispersal from the Plateau by breeding‐age females. Our results raise concerns about the long‐term viability of this important population as well as that of other species in this region. Given that hydropower projects are of economic importance throughout Laos and elsewhere in southeast Asia, this study has important implications for understanding and mitigating their impact.

Carrying capacity estimation and habitat suitability of Sumatran elephant in Datuk Gedang Wildlife Corridor, Bukit Tigapuluh Landscape, Jambi, Indonesia

“…The conservation of Sumatran elephants is increasingly threatened when they are outside the conservation area. Several studies mentioned that the highest level of conflict between elephants and humans is found in spaces that were shared by humans and elephants (Sitompul et al 2013b;de Mel et al 2022;Rahman et al 2022;Budd et al 2023). Currently, 85% of the Sumatran elephants' habitat is outside the conservation area (Gopala et al 2011).…”