Impact of Altitude on Population Structure and Distribution of Assamese Macaque (Macaca assamensis Mc’clelland, 1840) in Dampa Tiger Reserve in Mizoram, India

Abstract

A study on population status and distribution of Assamese macaque ( Macaca assamensis ) across altitudinal gradients in Dampa Tiger Reserve (DTR), Mizoram, India was conducted. Six species of diurnal primates inhabits in DTR and a study on Assamese macaque is reported here. Line transact method was adopted for population sampling. Total distance covered was 293.5 km. Data on group locations, demography and site covariates including trail length, duration of walk, forest type were recorded. Nine groups of Assamese macaque comprising of 123 individuals were recorded mostly at an altitude between 250 m to 856 m. The smallest group was consisted of 7 individuals, and the largest was of 21 individuals. An average group size calculated was 13.6 (±4.32) individuals. The population comprised of 36.59% male, 53.66% female, and 9.76% immature. All the groups were comprised of multi-males and multi-females. The population encounter rate was 0.42 individual/km and the group encounter rate was 0.03group/ km. Total male to female ratio was 1:1.46, adult adult male to female ratio was 1:1.53. All female to immature ratio was 1:0.18 and an adult female to immature ratio was 1:0.26. Maximum sighting were at the distance between 30-50 m. Area of occupancy of groups was about 26 km 2 and ecological density was 4.7/ km 2 . Among primates in DTR, wild population of Assamese macaques were found to occupy altitudinal range between 250 to 856 m. 67% individuals were distributed at the altitude between 400 to 600 m. Presence of other primate species in DTR restricted the occurrence of this species.