Assessing elephant dung decay rate in a forest-plantation mosaic in the Valparai plateau, Anamalai hills, southern India
Student name: Ms Sushma Sharma B S
Guide: Dr Neeti
Year of completion: 2017
Host Organisation: Nature Conservation Foundation, Mysore
Supervisor (Host Organisation): Dr M. Ananda Kumar
Abstract: Population estimation is important to understand the ecological role of a species in its habitat.
Over the decades, various species-specific direct and indirect techniques have been formulated
to estimate population. Indirect sign survey using faecal count is one such method widely used
for elusive or wide ranging species living in dense vegetation. This study focused on Asian
elephant (Elephas maximus) in the Anamalai landscape. Elephant population across its range in
Asia has been facing elevated threats due to habitat loss by developmental activities. A sound
baseline ecological data including population estimates is essential to draw appropriate
conservation strategies and management. Dung count survey is one of the popular methods
widely employed to assess elephant populations for which estimation of defecation rate and
decay rate parameters are of paramount importance. The study aimed at estimating dry season
dung decay rate and identify environmental and habitat factors influencing dung decay process,
on the Valparai plateau in the Anamalai hills. The 220 km² of Valparai plateau is landscape
matrix of tea, coffee plantations interspersing with Eucalyptus and rainforest fragments. Forty-
six fresh dung samples were marked covering four major habitat types on the Valparai plateau,
and samples were monitoring every alternate day and environmental variables including
temperature, relative humidity, canopy density, boli size and rainfall were also recorded. The
dung decay estimates obtained from the study was 0.015piles/day derived as a reciprocal of
mean days to decay (65 days (±4.05)). This rate was higher than estimates previous studies done
in this landscape (Baskaran et al. 2007). Though, mean number of days to decay varied across
habitats no significant difference was noticed in decay rates between habitats. Among the
covariates, only rainfall had significant effect on dung decay. Survival curve plotted using Cox
regression showed that decay process did not start until the 39
th
day and variably dropped
thereafter under the influence of rainfall. The decay rate estimated will be helpful to estimate
elephant populations in the Anamalai landscape.
Keywords: elephant, dung count, dung decay rate, Valparai, Anamalai hills
