BENGALURU: A cave in Kolar, around 63 km from Bengaluru, is the only known home of a specific species of bats. Called the Kolar Leaf Nosed bats (KLNB), a small colony of this highly endangered species has somehow managed to survive in the Hanumanahalli cave amid various challenges of urbanisation and concretisation.
While its habitat has been declared a conservation reserve, researchers from the Bat Conservation India Trust are looking at ways to expand its ambit to the nearby hills that are possibly foraging grounds for the KLNB.
According to the researchers, KLNB is found nowhere else. The Hanumanahalli cave is both their roosting and breeding site. To protect their habitat, the state government based on the report from researchers and the Karnataka Forest Department, in July 2019, declared it as a conservation reserve. Yet, their habitat is not fully safe.
Rajesh Puttaswamaiah, Citizen Scientist and Trustee of the Trust, told The New Indian Express that the cave is surrounded by agricultural land and fields. These bats feed on insects found in these lands. But with changing agricultural activities, increased use of pesticides, changing cropping patterns and farmers selling their land, these endemic bat species are getting affected. Studies have shown that these bats feed on insects found on tamarind and pongamia pinnata trees.
A team of five researchers has been studying the region around the cave and different patches of Kolar and the species since the last five years. Their study starts from 6 pm and continues till 6 am. They are undertaking telemetry and acoustic study on the species, studying the distance they travel, types of feed, foraging area - agricultural crops or fruits - and their flying pattern.
In one instance, they noted that a farmer chopped off around 50 trees in his land to arrange for money for a wedding in the family. The loss of trees affected the flying of the KLNBs. They noted that they fly making a bush line - tree to tree, but since the trees in the avenue were axed and had become an open field, it made their flying difficult.
During the research they also noted that KLNBs were last seen in the hills near Antargange, located around 80 km from Bengaluru. Antargange is well known for its natural volcanic rock formation and is around 4 km from Kolar. After 2014, bats have not been sighted in this region, the researchers said. They are found only in the Hanumanahalli cave. “This clearly indicates that the cave is the last location of the critically endangered species, making it also a location that needs very critical protection,” the researchers pointed out.
The cave is a very narrow subterranean crevice and measures about 40ft deep, 2 ft height and around 80-90 ft width based on visibility.
The cave also houses other bat species, including the Hipposideros durgadasi (found in Jabalpur, Madhya Pradesh and in Kolar), which is also an endemic species.
Puttaswamaiah said they are also studying the breeding pattern of the KLNB in collaboration with researchers from Indian Institute of Science. Different studies have also been undertaken to study their genetic variations and mortality.
The study team in 2020 gave two reports to the forest department with the recommendation for urgent protection of two hills in the vicinity - Devarayasamudra and Avani. The two faced the threat of quarrying as three quarry sites were operating on Devarayasamudra hills, a monolithic rock, which is the habitat to various wildlife species, including leopard, sloth bear and others.
The issue was picked up by the National Green Tribunal and quarrying was stayed. The government, too, ordered protection to the hills. Now the teams are checking for evidence of the presence of the KLNBs there. It has been reported that the bats visit the hills for foraging. At present the hills and the surrounding region is not part of the conservation reserve but efforts are on to include it. A detailed flora and fauna report has also been prepared, he added.
About KLNB
They derive the name from the region where they are found - Kolar (the district is famous for the gold mines and milk production. It is also famous for the Someshwara and Kolaramma temples). These bats have yellowish fur and their underbelly shades between light gray to brown. They have pointed ears and are one of the smallest of Leafnosed bat species. Their weight ranges from 6-9 gms. The call frequency of the Kolar Leafnosed bats ranges from 102 kHz to 107 kHz.