Study flags threat to frogs from agroforestry

Agroforestry practices may be harmful to some species of endemic frogs while a few are less affected by modified habitats, a new study by researchers from the Mysuru-based Nature Conservation Foundation (NCF-India) and the Bombay Environmental Action Group (BEAG) said.

The findings by Vijayan Jithin and Rohit Naniwadekar of the NCF and Manali Rane and Aparna Watve of the BEAG were published in Ecological Applications, a journal of the Ecological Society of America.

They studied the amphibian diversity and abundance in the low-elevation lateritic plateau of Maharashtra’s northern Western Ghats across orchards, paddy fields, and unmodified stretches during the monsoon season between June and September 2022. Four geographically separated plateaus – Devi Hasol, Devache Gothane, Gaonkhadi, and Bakale – were sampled to capture the spatial variability.

The research team found amphibian diversity was lowest in paddy and abundance was the least in orchards compared to the relatively undisturbed plateaus. Endemic species, including the CEPF burrowing frog (Minervarya cepfi) and Goan fejervarya (Minervarya gomantaki) were less abundant in modified habitats, indicating that agroforestry practices may be particularly detrimental to these vulnerable amphibians.

“The conversion of plateaus into agricultural lands is a significant threat to these habitats and the species they support,” Mr Jithin, the lead author of the study said.

“Given the expansion of orchards, we recommend adapting agroforestry practices to be more frog-friendly. Retaining natural water bodies and adding water sources in orchards, combined with sensitisation and incentives for landowners, could help mitigate habitat loss,” he said.

On the other hand, species such as the Minervarya syhadrensis commonly found across South Asia, were more prevalent in paddy fields, suggesting shifts in community composition due to habitat changes.

“We cannot say the more generalist species are adapting (to modified habitats) since adaptation needs a longer period in the time scale of evolution. They are spreading into such habitats,” Mr. Jithin, the lead author, told The Hindu.

Landscape transformation

The lateritic plateaus, formed through volcanic activity millions of years ago, are rich in endemic biodiversity but largely unprotected. Traditional conversion of these plateaus into paddy fields has now given way to blasting and transforming the landscape into mango and cashew orchards.

A view of expanding mango orchards in the Ratnagiri lateritic plateaus of Maharashtra. | Photo Credit: Special arrangement

The study highlights how these conversions reduce critical habitats for frogs, such as rock pools that protect tadpoles and eggs during monsoon dry spells.

“Low-elevation plateaus are home to endemic and threatened species of plants and animals that rely on clean water sources. Their presence indicates the health of aquatic resources which are the lifeline of local communities. It is necessary to conserve and restore the freshwater habitats to ensure the well-being of all life forms,” Dr Watve, also the coordinator of the IUCN SSC Western Ghats Plant Specialist Group, said.

IUCN SSC stands for ‘International Union for Conservation of Nature Species Survival Commission’.

Underscoring the need to check the “alarming rate” of modification of the lateritic plateaus of the Western Ghats, Dr Naniwadekar said: “Our studies show the critical role of water resources and climate in supporting amphibian persistence. It is essential to identify and conserve key amphibian habitats in collaboration with local communities to protect these unique ecosystems, particularly in light of climate change.”

The study was funded by the United Kingdom-based On the Edge Conservation, BEAG, The Habitat Trust, and NCF-India.