Climate change threatens amphibians worldwide; 136 Indian species at risk: Study

Climate change is deteriorating amphibian species around the world and the species continue to be the most threatened class of vertebrates, new research in Nature journal reports.

In India, 136 of the 426 species evaluated in the study were found to be threatened, an international team of researchers, including those from Council of Scientific & Industrial Research-Centre for Cellular and Molecular Biology (CSIR-CCMB), Hyderabad, and other Indian institutes, said in their study.

"Among the states with high amphibian diversity, Kerala has 178 species of which 84 are threatened, Tamil Nadu is next with 128 species of which 54 are threatened and Karnataka is in third place with 100 species of which 30 are threatened," said study author Gururaja K. V. and faculty at Srishti Manipal Institute of Art, Design and Technology, Manipal Academy of Higher Education (MAHE), Bengaluru campus.

Current and projected climate change effects are estimated to be responsible for 39 per cent of status deteriorations since 2004, followed by habitat loss, which has affected around 37 per cent of species in the same period, the researchers said in their study.

India's Western Ghats were among the regions which recorded the greatest concentrations of threatened species, according to the study. Other regions included the Caribbean islands, Mesoamerica, the tropical Andes, the mountains and forests of western Cameroon and eastern Nigeria, Madagascar and Sri Lanka.

In 2004, the Global Amphibian Assessment demonstrated that amphibians were the most threatened class of vertebrates worldwide, and it has since been used to guide amphibian conservation efforts.

In this study, the researchers analysed the second Global Amphibian Assessment, completed in June 2022, which re-evaluates the species from the first assessment and increases the number of species evaluated.

They found that the status of amphibians continues to deteriorate, with around 40 per cent of the species studied being categorised as threatened.

The primary driver of these declines has shifted from disease to climate change, the authors suggest.

"The results will strongly highlight how the national level priorities for species conservation need to be aligned to the change in the status of amphibians and the threats that impact amphibians. It should trigger consultations within countries on priorities and fundraising for amphibian conservation efforts," said Karthikeyan Vasudevan, paper co-author and chief scientist at CSIR-CCMB.

Documented amphibian extinctions continue to increase: there were 23 by 1980, an additional 10 by 2004, and 4 more by 2022, for a total of 37, the study said.

The findings, part of the second Global Amphibian Assessment, are based on the evaluation of 8,011 species for the International Union for Conservation of Nature (IUCN) Red List. The IUCN is an international organisation working in the field of nature conservation and sustainable use of natural resources.

The authors call for urgent scaled-up investment and policy responses to support the survival and recovery of amphibians