Asian Elephant (Elephas maximus Linnaeus) Population Status and Demography in Tropical Forest of Southern India

AbstractThe assessment of population dynamics and demography of long-lived species can be challenging due to a longer life span and slow reproduction. The population status and demography of the Asian elephant was studied from Dec 2006 to May 2008 at Mudumalai Tiger Reserves and results were compared with earlier studies carried out in the study area in 1985 and 2000 to understand changes in the population size. The population was estimated using distance sampling and mark-recapture methods during wet and dry seasons. In the line-transect sampling, a total distance of 651.5km was walked. To estimate the population based on the capture-recapture method 17 routes were surveyed consisting of 128.5km surveyed twice per month. The estimated elephant density based on capture-recapture and distance sampling was 3.4/km2and 3.6/km2respectively, which was higher than the earlier estimate (1/km2in 1985 and 2.4/km2in 2000). Thus, the population of elephants increased significantly when compared to the past. The adult male to adult female ratio was 1:20. Tuskless maleMakhnasmake up 20% of the male population. Demography data shows that the male population has increased in the population. But lack of older bulls in the population and mortality of males due to retaliatory killing needs further investigation. The major per cent (61%) of mortality was due to natural causes like disease, injuries, and predation by tigers (two calves). There were sex-biased changes in mortalities that have occurred over time; while adult and sub-adult male mortalities were higher (83%) in the earlier study period, adult female mortalities were higher (54.5%) during the present study. Despite the skewed sex ratio elephant population has increased significantly when compared to the past in the study area.