Population density, habitat use and activity patterns of endangered hog deer in Cambodia

Hog deer (Axis porcinus) were once widespread throughout much of lowland Southern Asia, but numbers rapidly declined during the last two decades. In Cambodia, the species was considered extinct until 2006 when a small number of individuals (presumedly spp. annamiticus) was rediscovered along the western bank of the Mekong River, near Kratie. Since reliable data on this population are lacking, we conducted two camera trap surveys to investigate hog deer habitat use, activity patterns and density. In the first survey, camera traps were placed in a random regular grid covering all main habitat types in the region, enabling us to verify hog deer presence/absence and identify habitat use. We found that hog deer were confined to a remnant patch of tall moist grassland of approximately 2 km2, at least in the dry season. The follow-up survey was conducted exclusively in this tall grassland patch, in which we estimated hog deer activity patterns and density using kernel density estimation and a simplified version of the random encounter model (REM). Cameras were active for a total of 1770 camera trap days, during which 609 independent hog deer encounters were recorded. Density was estimated to be 41.8 (CI: 37.93–45.72) individuals km−2, equating to an estimated abundance of 84 individuals. Hog deer activity was mainly crepuscular and nocturnal. We conclude that the recently rediscovered hog deer population in Kratie province is extremely vulnerable to extinction due to its small size and its complete dependency on a tiny remnant patch of core habitat. Conservation and restoration actions to preserve and restore prime habitat are urgently required to prevent local extinction.

https://doi.org/10.1007/s13364-022-00619-5