Anthropogenic pressures increase extinction risk of an isolated Asian elephant (Elephas maximus) population in southwestern China, as revealed by a combination of molecular‐ and landscape‐scale approaches

Abstract

Identification of the effect of anthropogenic threats on ecosystem is crucial. We used molecular tools and remote sensing to evaluate the population status of an isolated Asian elephant population in southwestern China in response to changes in habitat suitability between 1989 and 2019. A total of 22 unique genotypes were identified from 117 dung samples collected between March and June 2018 using microsatellite DNA analysis, including 13 males and 9 females. Based on the size of fecal boli, 1 animal was a juvenile, 9 were subadults, and 12 were adults, indicating that recruitment was limited. The effective population size was small (15.3) but there was no signature of a recent population bottleneck. We observed a low genetic diversity (H e = 0.46 ± 0.05) and a high level of inbreeding (F is of 0.43 ± 0.11), suggesting low population viability and high risk of extinction. In total, these elephants lost nearly two thirds (62%) of their habitat in 3 decades. The expansion of agriculture and rubber plantations followed by an increase in human settlements after 1989 increased the isolation of this population. We recommend that resettlement of 800 inhabitants of 2 villages and the abandonment of associated farmland and rubber plantations would make an additional 20 km 2 of suitable habitat available. This could allow a population increase of 14 elephants, possibly by translocating individuals from elsewhere in China. Our findings can be applied to the management and conservation of other fragmented populations in China or in other range countries of Asian elephants.

Urban expansion and infrastructure development reduce habitat suitability for Asian elephants in southwestern China

“…There was a 24% decline in suitable habitat within our study area, similar to that affecting the elephant population in Nangunhe, Yunnan (25% between 2004–2019; Chen et al 2022); although, in that case, the loss of suitable habitat mainly occurred beyond the reserve. There had been a 39% decline in the area of suitable habitat within SYR, although there was little change in land‐use and infrastructural development within the reserve over the past 2 decades.…”

Technical Report: Wandering elephants

“…Although 14 per cent of Yunnan province is classified as a nature reserve, the amount of suitable land for elephants is only around 3.3 per cent (Liu and others, 2016;Xinhua Net, 2022). In total, the elephants in southern China lost 62 per cent of their habitat in just three decades (Chen and others, 2021;Liu and others, 2017). As the elephant population grows, the already reduced habitats become less and less capable of supporting them (Chen and others, 2021).…”

“…In total, the elephants in southern China lost 62 per cent of their habitat in just three decades (Chen and others, 2021;Liu and others, 2017). As the elephant population grows, the already reduced habitats become less and less capable of supporting them (Chen and others, 2021). Naturally, as protected habitats become increasingly reduced and fragmented, the home range of elephant populations extends into villages and farmlands, increasing the incidence of crop-raiding and human-elephant conflict (Liu and others, 2017;Li and others, 2018;Stanway, 2021).…”

“…In the last three decades, the elephants of south-east China have lost almost two-thirds of their suitable habitat, which has continuously decreased due to anthropogenic pressures arising from a threefold enlargement of human settlements and agricultural activities (Chen and others, 2021). Human settlements and plantations have replaced the natural forest cover, and the traditional migration corridors for the Asian elephant have been cut off (Su and others, 2020).…”

“…Most instances of HWC can be traced back to anthropogenic drivers, primarily the growth and expansion of human populations, subsequent degradation and fragmentation of natural habitats, and changes in land use (Habib and others, 2015) and anthropogenic climate change (Abrahms, 2021). This is particularly true for the Asian elephant (Elephas maximus) as the species now occupies only 5 per cent of its historical range, becoming increasingly fragmented in small, isolated populations around South-East Asia (Chen and others, 2021). As these drivers continue to increase, HWC is likely to rise in incidence and intensity.…”