Climate change could reduce the range of the Malabar tree toad (MTT) in India’s protected areas by as much as 68.7 percent of its current estimated range, according to a study conducted by a group of concerned citizens and scientists.

The currently estimated species distribution in protected areas decreased from 33.5 percent to 68.7 percent in several models between 2061 and 2080 when eight future climate change scenarios, including high emissions, were taken into account.

However, under low-emission scenarios, the species’ range increased from 1.9 percent to 111.3 percent in protected areas, according to the study recently published in the Journal of Environmental Protection. Nature Magazine.

MTT is endemic to the Western Ghats of India and is the only species of the monotypic genus Meaning, It is the only arboreal species in India that, unlike most ground-dwelling toads in the region, has the unique ability to climb and live in trees.

It was first discovered in 1876 and the species was not seen for over 100 years.

It was later rediscovered in 1980 in the Silent Valley National Park in Kerala. Scientists reported On Earth (DTE) Until 2014, very few sightings had been recorded, leading to studies showing that the population and range are distributed “almost throughout the Western Ghats”.

The current study found that adverse climate change has threatened a variety of species in the Western Ghats, a global biodiversity hotspot.

The region is home to about 252 species of the class Amphibia, of which 17 are threatened with extinction and 40 are classified as “data poor”.

Globally, 40.7 percent of amphibians (8,011 species) are the most threatened vertebrate group. This is due to anthropogenic activities such as timber and plant harvesting, agriculture and infrastructure development.

Habitat fragmentation, pollution, diseases and morphological deformations due to climate change have led to the decline of amphibian populations over the last 40 years.

S. Harikrishnan, project director of the Amphibian Recovery Project at the non-profit organisation Wildlife Trust of India, who was involved in the study, noted that the study was a first for India in that distribution modelling of an amphibian-reptile species and an endangered amphibian species was done using citizen science.

“So far, such estimates have only been proven to be made for birds,” he added.

Harikrishnan said that protected areas in the central Western Ghats will lose most of their areas suitable for biodiversity, while habitats in the southern Western Ghats are expected to become more suitable. Species distribution would shift accordingly.

“Restricted and discontinuous distribution, together with climate change, may limit the spread and persistence of MTT populations. Therefore, increased surveys of MTT habitats within and outside the protected areas of the Western Ghats are an important step to ensure the persistence of MTT populations,” the study warned.

Meanwhile, Ravi Chellam, executive director of Metastring Foundation and coordinator of the Biodiversity Collaborative, said climate change is one of the main causes of biodiversity loss. Such distribution models could help understand the distribution of all species and initiate effective measures to protect species.

“Amphibians are one of the groups most sensitive to the impacts of climate change because their unique ecology, habitat requirements and limited heat tolerance mean they have limited dispersal options,” he said.

Unprecedented study of Indian amphibians
The study authors used 655 observations of the toad from various citizen science platforms as well as observations from published scientific papers between 1876 and June 27, 2022.

KV Gururaja, associate professor at Srishti Manipal Institute of Art, Design and Technology and corresponding author of the study, said, “Based on call phenology (the first call of the season), observations of all citizens were divided into northern and southern populations.

“We estimate that in future climate scenarios, populations in Mhadei, Mookambika, Sharavathi Valley and Netravali wildlife sanctuaries may increase. There will also be an increase in Mollem and Kudremukh national parks. In contrast, the number of suitable habitats in Kalakad Mundanthurai Tiger Reserve and Brahmagiri Wildlife Sanctuary would decrease,” he said.

The study found that the future distribution would be 63.6 percent evergreen forests, 14.23 percent some plantation areas, 6.75 percent arable land and 8.41 percent mixed forests.

Grasslands, water bodies and built-up areas experienced losses of 2.97 percent, 2.6 percent and 1.56 percent, respectively, indicating the presence of the species in human-modified habitats.

“Although MTT is a tree toad, it comes to the ground to reproduce, forming pools of water on the edges of streams during the monsoon. Rainfall and moisture therefore provide the necessary conditions for MTT to reproduce,” the study says.

Gururaja explained that studies have shown that amphibians living in forests will lose their much-needed microhabitats due to climate change, unlike those inhabiting open areas, making the study crucial for the conservation and management of MTTs.

Harikrishnan pointed out that the drought experienced by toads and frogs in Karnataka in 2023 affected their breeding and nesting sites. “Such scenarios could become more frequent and force a shift in their range. Our results also show that annual rainfall affects the species populations,” he added.

“Compared to southern populations, northern populations will be most affected by future climate scenarios,” he said.

“Based on these findings on the MTT, a toad endemic to the Western Ghats, from citizen science initiatives, a proposal has been submitted to the Government of Karnataka to declare it the state amphibian,” Gururaja said.