The rate of grassland depletion in India caused by development projects is blamed for endangering fauna such as the Great Indian Bustard. Another key species feared to face a similar fate is the blackbuck (Antilope cervicapra), endemic to the Indian subcontinent.
Scientists from the Indian Institute of Science (IISc) in Bengaluru studying genetic diversity of the blackbuck population in three main clusters across India, however, reveal that these animals are resilient and adjust well to human-induced changes to habitats1.
The scientists studying the antelopes in the northern, southern, and eastern regions of India expected the geographic separation of clusters with dense human habitation between them to be an impediment for the animals’ movement from one location to another.
“We had the idea that these populations might be genetically constricted, and going forward, they may be in danger of incurring inbreeding depression (decreased biological fitness because of inbreeding),” says one of the scientists Ananya Jana.
The locations selected for the study were mostly grasslands and scrublands in eight states — from Bhetanai in Odisha, Velavadar in Gujarat, Nannaj in Maharashtra to Tal Chhapar in Rajasthan, Haliya in Uttar Pradesh, Rollapadu and Ananthapur in Andhra Pradesh, Point Calimere in Tamil Nadu, and Kolar, Challakere, Jayamangali and Ranebennur in Karnataka.
The scientists supposed that the blackbuck population was fragmented and restricted to smaller pockets, affecting genetic diversity — an element key for survival in changing environments. But to their surprise, they found that blackbucks have beaten the odds to thrive. A 2017 IUCN report puts the population of blackbucks at 35000 which, Jana believes, has now increased. The next step, the scientists say, would be to understand the traits of the species that helped them survive by studying changes in their DNA and gut microbiome.
Praveen Karanth, Professor at the Centre for Ecological Sciences (CES), IISc and co-author of the study says they want to radio collar some of the males to see how far they can travel since they have dispersed well, maintaining the gene flow. “From what we know, their adaptability is a key factor that helped them survive and maintain the genetic diversity,” he says.
Most blackbucks were seen outside protected areas and in agricultural fields and farms. Like many wild herbivores, blackbucks are also attracted to human-dominated landscapes presumably due to the easy availability of food. The study findings are also an indicator of how well certain wild species coexist with humans. Jana said that in certain locations in the east, including Bhetanai, blackbucks occupied farmlands to forage on crops, but farmers were very tolerant of their presence. This coupled with stringent laws protecting these animals could have also contributed to their survival.
Karanth and Jana collected faecal samples of blackbucks, extracted and sequenced the DNA, and deployed computational tools to map the geographic locations with the genetic data.
The team also used simulations to trace how the three present-day clusters may have evolved from their common ancestor. They found that an ancestral blackbuck population first split into two groups: the northern and the southern cluster. The eastern cluster – even though geographically closer to the northern cluster – seems to have emerged from the southern cluster.
Karanth says geographical barriers like the Satpura hill range and rivers may have prevented the northern cluster from moving to the east, while a fairly smooth coastal route along the south would have enabled the southern cluster to move to the east. He also suspects isolated populations of blackbucks exist across peninsular India.
The most important finding from the study, says Jana, is the resilience of this species.
