How land use and roads affect herbivore habitats

Herbivores, animals that eat plants, play a crucial role in the health of a forest by maintaining the diversity of plant life. They shape the ecosystem by controlling fires, cycling nutrients, and maintaining vegetation dynamics. Unfortunately, they are often left behind by large carnivores when it comes to targeted conservation efforts. But increasingly, human activities in landscape modification for development are impacting herbivore habitats and require urgent attention.

In a first-of-its-kind study, the National Centre for Biological Sciences (NCBS) Bengaluru, a centre of the Tata Institute of Fundamental Research, has shown how changes in land-use patterns and roads in the central Indian landscape are disrupting the genetic connectivity of two large herbivores: Gaur and Sambar.

Gaur and sambar are endemic to South and Southeast Asia and are among the most important prey species for large carnivores such as tigers.

For the study published in the international journal for research, Molecular EcologyThe research team comprising lead author Abhinav Tyagi, Uma Ramakrishnan, Nidhi Yadav and Awadhesh Pandit collected hundreds of fecal samples of gaur and sambar from the tiger reserves of Kanha, Pench, Nagzira-Nawagaon, Bor and Tadoba-Andhari, besides the Umred Karhandla Wildlife Sanctuary and the wildlife corridor between Kanha and Pench Tiger Reserve. They found that both species face threats such as habitat fragmentation, habitat loss, illegal poaching and other human-induced impacts that are responsible for population declines and local extirpations.

Increasing threats

Central India, like other areas of conservation concern, is threatened by growing linear infrastructure such as highways, railways and changes in land use patterns, expanding road networks, mining activities and other development projects. Such infrastructures impede the movement of animals and create fragmented populations confined to small, disconnected habitats. Maintaining movement between habitats usually results in mating and genetic exchange, the loss of which can increase the chances of species extinction.

Researchers stress that the Umred Karhandla Wildlife Sanctuary, with a small population, is the most genetically diverse sanctuary and there is a need for conservation measures.

Urban areas and road networks are expected to grow significantly by 2030, and human populations are also expected to increase, especially in biodiversity hotspots. The combined effects of human demographic growth, land-use change and climate change pose serious threats to wildlife connectivity. Despite the need for development to meet India’s economic goals, it is critical to align development with conservation objectives, the study said.