Bangalore: What do Indian species such as blackbucks and chinkara have in common? Human cultural tolerance, which has allowed them to survive, and thrive, in the regions where they are currently found, and which has helped them outsmart other large mammalian species that have moved to extinction faster.
Click here to view a slideshow about the mammals study, narrated by tiger expert Ullas Karanth
Human population density, extent of protected areas, forest cover and habitat elevation are other factors that have played a role in the dramatic decline of 25 large mammals in India over the past century, a population slide that has become steeper over historical time.
Using 30,000 historic records spanning 150 years, researchers report in the 10 March issue of the Proceedings of the Royal Society, UK, that there is a definite pattern in the way large mammal species in India are becoming extinct. So, if measures are taken, these large bodied mammals can be saved, despite the high probability of extinction, say the authors.
“This is certainly a very novel study in terms of its historical analysis of mammalian disappearance or persistence at local scales in India,” said R. Sukumar, professor at the Centre for Ecological Sciences, Indian Institute of Science in Bangalore. This provides a firmer basis for us to understand how mammals with different ecological needs respond to human-induced changes in the environment or how human-animal cultural relationship contributes to its persistence, he added.
Human-led global extinction of large terrestrial animals is occurring at an alarming rate, but these species are the most threatened in South Asia where 25% of species are facing extinction, and 50% face declining populations.
Dividing the Indian geographical area into a grid with 1,326 cells—the average cell size is 2,818 sq. km—the authors found that protected areas facilitated lower extinction in at least 18 species, especially carnivores and forest-dwelling mammals. On other hand, forest cover, normally considered important for wildlife survival, was shown to play a role in protecting only seven species including sambar, blackbuck, chinkara and sloth bear.
Human population density, notorious for harming the ecology, is shown to have facilitated extinction of at least 12 species; though some herbivores have persisted despite high density. Referring to the scale of the study, over geographical area and time, lead author Krithi Karanth of Columbia University, New York, said: “This has not been done in India before, either on the temporal or spatial scale. Thanks to excellent record keeping by the British, we (India) actually are one of the few countries where it is possible to go back in time.”
Historian of ecological change Mahesh Rangarajan, from the Jawaharlal Nehru University in New Delhi said the paper telescopes with information a very important feature: that while our ecosystems are stretched and highly damaged, they are not beyond repair.
An interesting finding of the study is the role of “human cultural tolerance”—a feature unique to southern Asia—in affecting extinction probabilities. This is particularly evident in Gujarat and Rajasthan. Encouraging local communities’ tolerance of species and enforcing existing laws, along with improving protection in parks, will go a long way in saving species, said Karanth.
Social activists and wildlife biologists in India have been at loggerheads over the importance of protected areas in conservation. Activists contend that protected areas are an imposition, but we show that “effective parks”, not just those on the map, are indeed important, particularly for these species, said co-author Ullas Karanth of the Wildlife Conservation Society, India, who is also a noted tiger conservationist. The authors used a new approach, so-called “occupancy modelling”, one that integrates historical records with current data. Both Sukumar and Karanth say this method, so far not used in India, will help experts understand the present-day distribution of species and identify habitats and landscapes for focusing conservation efforts.
While Karanth thinks large infrastructure projects, including that of the National Highways Authority of India, coming up in the country could benefit from such studies, Rangarajan is rather sceptical. Scientists are still a friendly outside presence, sometimes treated as adversaries and less often as partners, he argued. “But like all good research, it will instil caution in respect to accommodating human demands for biomass in the small refuge that remain intact.”