Prey animals of different body size, and the habitats that support such types of prey are crucial for co-existence of large carnivores like tiger and leopard in a landscape.
Tigers and leopards consume prey animals that vary in body sizes and weight.
The weight often varies in the range of 10-250 kg.
Seven ungulate (hoofed mammals) prey species are found in Manas National Park.
This study highlighted the population density of the prey species and how human disturbances affect them. The study was facilitated by Directorate of Manas Tiger Reserve and the Forest Department (Bodoland Territorial Council and Assam Government) and supported by Panthera, IUCN-KFW, Assam Government and NTCA.
The study was limited to the Bansbari and Bhuyanpara ranges of the park only (total area of 398 km2), as these areas have remained largely conflict-free since 2003.
In Manas National Park, there are small prey like barking deer, medium prey like hog deer and large prey like sambar.
However, all these species are threatened by habitat loss and hunting throughout their ranges that increase the challenges of recovering tiger population.
Therefore, understanding the determinants of their occurrence and abundance is critical to initiate sustained efforts for recovery of both prey and large carnivore populations in any landscape.
Here, the study area falls under the TraMCA (Transboundary Manas Conservation Area) Landscape, a large forested India-Bhutan landscape spread across Assam, West Bengal and Arunachal Pradesh States of India.
The study area is also a biodiversity-rich region that was devastated by armed conflict during the late 1980’s to 2003.
The conflict had caused loss of animal population in the area.
Over 80 per cent of armed conflicts between 1950 and 2000 occurred in the world’s Biodiversity Hotspots where post-conflicts the species required recovery support.
It is worth mentioning that the park’s natural resources also meet the livelihood requirement of local communities residing around park boundaries.
The communities collect fuelwood, food (e.g. vegetables and fish), building materials (such as thatch) and graze their livestock.
A socio-economic study conducted by Aaranyak in 2015 estimated that 78% of local communities are unable to fulfil their annual requirements from agriculture and thus access the park natural resources for their subsistence.
Therefore, the current study expected that anthropogenic use of the park affected animal behaviour over space and time.
Surveys were conducted on 66 line transects with a total effort of 317 km of survey walk.
During the survey, 509 independent observations of seven ungulate species were recorded, of which 417 were in grasslands versus 92 in the woodlands.
People in wildlife habitat are a known source of disturbance.
In Manas, people who collect natural resources in the park have not only impacted presence of species in areas but also their behaviour if compared to species from a habitat that is mostly undisturbed (e.g. Kaziranga National Park).
To understand this better, the study used 9,209 independent photographs of the seven prey species from Manas and Kaziranga taken by camera traps.
The results show that species like barking deer, hog deer, wild pig, sambar and wild buffalo that are mostly active during day hours in Kaziranga were found to be mostly active at night in Manas. This is how species have responded to human disturbances within the park.
This has serious implications on health and population growth of prey species that directly impacts the population of tigers and other large carnivores of Manas.