IISc research finds blackbucks adapted to human-altered landscapes, says their population is growing

Praveen Karanth, Professor at the Centre for Ecological Sciences (CES), IISc and senior author of the study, explained, “Increased human activities like indiscriminate cutting of trees and building dams across rivers have sliced up natural landscapes. These changing landscapes are restricting animal species to smaller areas and preventing them from moving to farther regions in order to find new mates, a factor that is crucial for maintaining their genetic diversity. We need genetic diversity to sustain a population because if you have genetic diversity, the population is more adaptable to changing environments.”

The study is published in the scientific journal Conservation Genetics.

Blackbucks are found only in the Indian subcontinent. Males have corkscrew-shaped horns and black-to-dark brown coats, while the females are fawn-coloured. The animals are mainly seen in three broad clusters across India-northern, southern, and eastern regions.

“This geographic separation as well as dense human habitation between the clusters would be expected to make it difficult for them to move from one location to another. We went in with the idea that these populations might be genetically constricted, and going forward, they may be in danger of getting incurring inbreeding depression (decreased biological fitness because of inbreeding),” said Ananya Jana, a former PhD student from Centre for Ecological Sciences, IISc and the first author of the study.

Karanth and Jana collected faecal samples of blackbucks from 12 different locations spread across the country. The researchers tracked the animals on foot and in vehicles to collect the samples. In the lab they extracted and sequenced the DNA from the faecal samples to study the genetic makeup of blackbucks 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 in northern, southern and eastern regions may have evolved from their common ancestor.

The researchers found that an ancestral blackbuck population first split into two groups: the northern and the southern cluster. Next, the team found that despite all odds, male blackbucks appear to disperse more than expected, thus contributing to geneflow (gene flow is the transfer of genetic material from one population to another) in this species. Females, on the other hand, appear to stay largely within their native population ranges. The data also showed an increasing trend in blackbuck population numbers as compared to the recent past, according to the note shared by the IISc.

“So, (it) looks like this species has managed to survive in a human-dominated landscape,” noted Karanth.