Amphibians, the first vertebrates to inhabit land 360 million years ago, are facing existential threats due to climate change, habitat destruction, and disease.
Postdoctoral researcher Sonali Garg and associate Sathyabhama Das Biju co-authored a new study published in Nature that assesses the global status of amphibians. Garg and Biju are experts in frog biology and have documented more than 100 new frog species across India, Sri Lanka, and other parts of the subcontinent. Garg, currently a postdoc in James Hanken's lab, is a former student of Biju, Hrdy Fellow at Harvard Radcliffe Institute and a professor at the University of Delhi.
The study, featured on the journal's print cover, analyzed more than 8,000 amphibian species worldwide and discovered two out of every five amphibians are threatened with extinction, mainly driven by climate change. More than 100 scientists contributed their data and expertise to the study that found that nearly 41 percent of amphibian species are threatened with extinction, compared with 26.5 percent of mammals, 21.4 percent of reptiles, and 12.9 percent of birds.
According to Biju and Garg, frogs are an excellent model organism to study evolution and biogeography due to their excessive diversity of traits acquired over thousands of years. As well, their sensitivity to abrupt changes in their environment makes them very useful for assessing an ecosystem's health.
Garg has done extensive fieldwork in India, Sri Lanka, the Western Ghats, the Himalayas, and Indo-Burma including recent trips with Professor James Hanken, curator of herpetology at the Museum of Comparative Zoology (MCZ). Garg uses integrative taxonomy to cataloging the diversity of frogs in India and explain their evolutionary histories. She has also added DNA sequencing and CT scanning methods to her research. She and Biju are using the MCZ's herpetological collection in their studies to help provide bench marks for potentially new speciec they discover.
Image: Franky’s narrow-mouthed frog (Mysticellus franki), described by Garg & Biju in 2019, is a Critically Endangered species. This species is endemic to the Western Ghats Biodiversity Hotspot. It is known only from a single locality with an estimated extent of occurrence of less than 2 km2, in threatened habitats rapidly depleting due to expansion of human settlements, agricultural areas, and large-scale tea, coffee and spice plantations. Climate change is a potential future threat insofar as it will cause habitat shifting and the drying of breeding habitats necessary for the survival of this frog. Photo: S. D. Biju.