Demographic and genetic structure of a severely fragmented population of the endangered hog deer (Axis porcinus) in the Indo- Burma biodiversity hotspot

Abstract

The population of the globally endangered hog deer (Axis porcinus) has declined severely across its geographic range. Intensive monitoring of its demographic and genetic status is necessary. Northeast India is a stronghold of the species; however, in recent years the population has been getting fragmented, and it is vulnerable to extinction. We examined the demographic and genetic structure of a small hog deer population in the floating meadows of Keibul Lamjao National Park (KLNP), located on the western fringe of the Indo-Burma biodiversity hotspot for conservation planning. We used a double-observer distance sampling method to derive the hog deer abundance and population structure. We also derived the genetic diversity of the population through microsatellite screening and bottleneck detection. Our study revealed that the abundance of the deer in the park was 1.82-4.32 individuals/km2. The adult male to female ratio and fawn to doe ratio were 36.2 {+/-} 1.9 males/100 females and 16.5 {+/-} 0.4 fawns/100 females, respectively. The mean number of alleles at 23 loci was 2.70 {+/-} 0.18, the observed heterozygosity (HO) ranged from 0.26 to 0.63 (mean 0.42 {+/-} 0.02), the expected heterozygosity (HE) ranged from 0.23 to 0.73 ({chi} = 0.51 {+/-} 0.03), and the polymorphic information content (PIC) ranged from 0.2 to 0.67 ({chi} = 0.43 {+/-} 0.03). The observed allelic distribution reveals that the population has not encountered any genetic bottleneck in the recent past. Although the population is declining, it still retains some rare alleles, and the genetic diversity is 50%. This diversity will probably not affect the short-term population growth but may affect the evolutionary potential by limiting the selection flexibility. Conservation measures coupled with a scientifically sound management regime may help the persistence of the population in the region at a time when the population still retains rare alleles and maintains reproductive fitness.