Meera Bhardwaj
The movement of mammals has become highly restricted due to rising construction of linear structures in the Biodiversity hotspot of Western Ghats, says a joint scientific study. In the background of the NDA government aggressively pushing for expansion of the Bharatmala project, expansion of national highways, hydroelectric projects and rail projects in the Western Ghats, this scientific study gains great significance and importance.
In recent years, elephants, leopards, gaurs, sloth bears and sambars are finding it very tough to move from place to place due to rising land use change, linear structures and human settlements in the Western Ghats. Scientists assert an increase in forest connectivity is crucial for movement of mammals in the country. Advocating mitigation measures, they say their open access data portal will help in identifying and prioritizing such areas for restoration and bring back the movement of mammals to ensure gene flow and dispersal.
Researchers used the boundary of the Western Ghats and the region covered an area of 1.2 lakh square kilometers with an elevation range of 300-2700 meters. It comprised the states of Karnataka, Goa, Kerala, Tamil Nadu, Maharashtra and Gujarat. The major forest types comprised evergreen forests and moist and dry deciduous forests. Here, human densities averaged 350 people per sq km. The protected area network in Western Ghats comprises 73 protected areas occupying an area of less than 20,450 sq km.
OVERALL MOVEMENT REDUCED
Scientists from Centre for Wildlife Studies (CWS India), Foundation for Ecological Research, Advocacy and Learning and Columbia University examined the effect of various types of land use, infrastructure, and human population on wildlife movement across two important conservation landscapes – the Western Ghats as also Central India.
Human land use and activity has resulted in the loss of habitat and biodiversity and also altered the movement of these mammals through landscapes. Scientists said natural areas constitute only 20-55 per cent unrestricted, increased and channeled movement areas in the Western Ghats. The study found that the overall movement of four species was reduced in this landscape due to human land-use, human populations, and linear structures. In fact, unrestricted movement was found to be the highest in natural areas and also that occur alongside human populations.
HABITAT FRAGMENTATION
Anisha Jayadevan, CWS and lead author of the study said, “Central India and Western Ghats are witnessing widespread habitat fragmentation. Sustaining the movement of elephants and leopards across such fragmented areas requires planning for landscape permeability to movement. This will ensure continuity of key ecosystem processes such as gene flow and dispersal.”
Studies showed that areas that currently provide unrestricted movement to these animals should be kept protected and free from further land-use change. And wherever movement is hindered – restoration or mitigation measures should be taken up to increase connectivity in the Western Ghat bound states in the country.
LANDSCAPE PERMEABILITY MAPS
Krithi Karanth, Chief Conservation Scientist, CWS, added, “Our research and open access data portal (www.indiaunderconstruction.com) help identify and prioritize areas where restoration or mitigation should be planned to improve permeability to movement for large mammals. These resources will enable informed decision-making environmental impact assessments about the siting of infrastructure.”
The landscape permeability maps generated by this study can be used to identify areas that can improve the freedom of movement for wide-ranging animals.
The research study was published in the journal – Biological Conservation by Anisha Jayadevan, Rajat Nayak, Krithi Karanth, Jagdish Krishnaswamy, Ruth Defries, K Ullas Karanth and Srinivas Vaidyanathan.