By Vijay Pinjarkar
NAGPUR: Despite strong global support for tiger conservation, survival of the species continues to be threatened due to habitat loss, poaching and isolation, but a team of global and India scientists have identified several functional corridors through Central India's rugged landscape and have suggested conservation measures, including use of green infrastructure to aid development and granting legal status.
The latest study 'Prioritizing tiger conservation through landscape genetics and habitat linkages' by Bibek Yumnam, YV Jhala, Qamar Qureshi, JE Maldonado, Rajesh Gopal, Swati Saini, Y Srinivas, RC Fleischer from Wildlife Institute of India (WII), Dehradun, Smithsonian Conservation Biology Institute (SCBI), National Museum of Natural History, Washington, and National Tiger Conservation Authority (NTCA), found that independent protected areas (PAs) are too small to fuel tiger population growth.
The study was conducted between 2006 and 2012. It was published last month in Plosone, a paper which highlights only scientifically conducted studies.
The scientists were able to identify individual tigers and their movement patterns through non-invasive genetic analysis of tiger scat. A quantitative assessment of tiger habitats along with detailed modelling and analyses enabled scientists to fashion a plan that could safely and cost-effectively connect isolated tiger populations.
"Our analysis identified 169 individual tigers in the Central Indian region under study, including 17 that had dispersed from one reserve to another," says Fleischer, head of SCBI's Center for Conservation & Evolutionary Genetics.
"Significantly, we found that tiger dispersal is directly related to resistance or cost of moving between populations, a measure based largely on habitat characteristics and the density of human populations. By mapping these tigers' movements, we identified several functional corridors through Central India's rugged landscape that were created through contemporary migration," Fleischer says.
The study proposes that long-term survival is possible only if separate reserves can remain connected to allow for tiger gene flow between them. This connection also reduces inbreeding and loss of genetic variation.
Based on this finding, scientists have proposed conservation measures, including use of green infrastructure to aid development and granting legal status and protection to these specific pathways. "These actions will help restore habitat connectivity and safeguard future of tigers," they say.
Currently there are only about 3,000 tigers left in the wild in 13 Asian countries, occupying just 7% of their historic range. About 60% of these tigers are in India, in a series of widely separated populations.
The study was done by using a panel of 11 microsatellites. It identified 169 individual tigers from 587 scat and 17 tissue samples. It identified 17 tigers as having recent immigrant ancestry. Spatially explicit tiger occupancy was obtained from extensive landscape-scale surveys across 76,913 sqkm. Of this, forest habitat was found to be only 21,290 sqkm.
The results of the study shows that many corridors may still be functional as there is evidence of contemporary migration. Conservation efforts should provide legal status to corridors, use smart green infrastructure to mitigate development impacts, and restore habitats where connectivity has been lost, the experts said.