One of the most important regions of the world for wild tigers is the Satpura–Maikal landscape in India. It is classed as a global-priority Tiger Conservation Landscape (TCL) because it has sufficient tiger habitat to support a long-term sustainable tiger population. A recent gene survey of tigers in the region shows how important the landscape is to the big cat.
The survey published in Ecology and Evolution examined the diversity of genetic material between tigers to examine the flow of genes between individuals and the extent of inter-breeding. 273 tigers were surveyed.
The wide diversity of genetic material was good news as it shows that tigers can roam freely and mate over a wide area. This was put down to the connectivity of forests and tiger habitats across on the landscape level of the region.
The tiger population of the Satpura–Maikal TCL is predominantly found in the alluvial flood plains of the Himalayan foothills, the Central Indian highlands, and the forests of Western Ghats. This particular TCL is home to 12% of India’s tiger population and comprises 13% of suitable tiger habitat in the country.
It’s important for tigers to be able to roam freely in order to mate to prevent ‘bottlenecks’ in the gene flow which can make them more susceptible to disease and genetic mutations. This can easily happen when small populations of tigers become isolated from their neighbours.
While the researchers found that there had been no bottleneck affecting the regions tigers in the past and all tigers had a wide genetic diversity there was a significant difference between tigers in unconnected reserves and tigers living in reserves that were connected with forest corridors. The connecting wildlife and tiger corridors helped tigers to maintain the genetic diversity.
While the gene survey seems to indicate that there was no bottleneck in recent times the researchers have highlighted that the region benefited from little human activity until fairly recent times. It has only been in the last 150 years or so that agriculture and forest fragmentation have taken place. As it can take 200 generations for a bottleneck to become evident in a genetic survey it may be that insufficient time has passed for the full impact of human activity to be seen.
The study was undertaken by:
- Sandeep Sharma and John Seidensticker of the Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia
- Trishna Dutta and Thomas C. Wood from Environmental Science & Policy Department, George Mason University, Fairfax, Virginia
- Jesús E. Maldonado of Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia
- Hemendra Singh Panwar from Peace Institute Charitable Trust, Delhi, India.
The researchers concluded that, “We found that the tiger meta-population in the Satpura–Maikal landscape has low levels of genetic structure. Genetic subdivision was low between tiger reserves that were connected with forest corridors, thus lending support toward the functionality of this connectivity. The future of this tiger meta-population relies on implementing an effective policy that includes further protecting the tiger populations and their habitat in the tiger reserves and forested corridors that connect them.”