Taking a leap forward to save frogs
Frogs and toads, together with salamanders and caecilians, are called amphibians. They are called so because they go through two stages in their lives and not because they live in both water and on land. The first stage is the tadpole stage, also called larvae or pollywog, when they are fish-like and generally live in water. Over a period, tadpoles metamorphose to the second stage of adults and live on varied habitats. The tadpoles feed on algae, zooplankton and sometimes on other tadpoles, while the adults prefer insects as food.
Globally, there are about 7,551 species of amphibians, which is the fourth largest category among vertebrates. In India, there are 412 species of amphibians, of which 370 are frogs and toads, 40 caecilians and 2 salamanders. The Western Ghats alone harbours about 225 species of amphibians, of which 200 are endemic. In the last 17 years, nearly 170 species have been discovered in India, indicating the enormous species diversity that still exists in our country.
Marvellous as they may be, unfortunately nearly one-third of the global amphibian species are on the verge of extinction. It is estimated that as many as 200 amphibian species may have been wiped out of this planet in the last three decades. Amphibians require a suitable habitat, both in water and land, for their survival and are very sensitive to changes in their environment.
Rapid urbanisation, degradation of habitats, climate change, usage of chemical pesticides and fertilisers, invasive species and infectious diseases are some of the prominent reasons for global amphibian decline. In some cases, the decline can be pointed to a single reason, whereas in some enigmatic declines, the drivers of decline act synergistically. Scientists all over the world are now working towards conservation of amphibians and to check and/or reverse the global decline of amphibians. This scenario is no different in the Western Ghats.
Take a look at some of the many frog species endemic to this biodiverse region.
n Ponmudi Bush frog (Raorchestes ponmudi): It is an arboreal frog that inhabits high evergreen tree canopies and is endemic to the Western Ghats. It is a critically endangered species and has direct development, which means that there is very little difference between larval and adult forms. The tadpoles develop into tiny frogs within the egg.
n Waynad Bush frog (Psuedophilautus wynaadensis): It is an arboreal frog, endemic to the Western Ghats and is generally found in the bushes. It is an endangered species too.
n Coorg Yellow Bush frog (Raorchestes luteolus): It is an arboreal frog, endemic to the Western Ghats and found in the bushes.
n Ochlandra Reed-bush frog (Raorchestes ochlandrae): It is an arboreal frog, endemic to the Western Ghats and found inside Ochlandra reed bushes. It also has a direct development in its life stage.
n Kottigehara Dancing frog (Micrixalus kottigeharensis): It is an aquatic frog endemic to the Western Ghats and found along the torrential streams. A diurnal species with unique foot flagging behaviour, it lays eggs inside streams and has sand-burrowing tadpoles. It is a critically endangered species.
n Gundia Leaping frog (Indirana gundia): It is a semi-aquatic frog, endemic to the Western Ghats and found along streams and stream edges. It has a unique, semi-aquatic tadpole stage and primitive inguinal amplexus. It is a critically endangered species.
n Small Tree frog (Rhacophorus lateralis): It is an arboreal frog endemic to the Western Ghats. It has a unique breeding behaviour wherein individuals build purse nests to protect eggs from desiccation. It is an endangered species.
n Sholiga’s Narrow-Mouthed frog (Microhyla sholigari): It is a small, semi-aquatic frog endemic to the Western Ghats. It is an endangered species.
In last few decades, problems seem to plague this region and its amphibian inhabitants. Due to the perceived concept of perennial river systems, dams are proposed and constructed. This has resulted in the submergence of vast tracts of pristine forest habitats and reduction of habitats for the amphibians. In addition, new developmental projects like expanding existing road and railway networks, thermal power plants and others are underway which are detrimental to the Kermits and their habitats in the Western Ghats. If this pace of destruction continues, the croaks may be silenced very soon.
The Western Ghats has been facing severe pressures of development. On one hand, the land cover changes with expanding plantations and crop lands are posing a threat to these habitats. On the other hand, intensive farming practices with the usage of fertilisers and other inputs are also posing severe challenges to aquatic beings. For the frogs and toads, any disturbance on land and/or water is difficult. But since they have two life stages, they make for good bio-indicators to ascertain the ecological status of the habitat.
Yet, the current trends with respect to their populations are not very encouraging. As per the IUCN (International Union for Conservation of Nature) Red List assessment, among the amphibians of the Western Ghats, 17 are critically endangered, 31 are endangered, 17 are vulnerable, 5 are near threatened and 33 are least concern species. It is a matter of grave concern that the status of the remaining 122 species, forming about 55%, is still unknown either due to deficient data or the data has not been evaluated yet.
But, there is hope. It has been proved time and again that people’s participation is the best solution to the conservation of endangered species and the same works wonders for amphibians too. For example, an initiative called ‘Citizen Science’ (CS) trains citizens and helps them understand and report the amphibians found in their place. Community-focused conservation initiatives in the Western Ghats have already started showing results.
Bisle Frog Watch, started in 2012, is one such example. Every year, a team of 20 enthusiastic and passionate conservationists from all over India gather at Bisle near Sakleshpur for a two-day training in basic taxonomy and ecology of amphibians. They use ‘Frog Find’, a free android app that helps in identifying frogs and toads. After the training, they start reporting species from their region. They post their finding on Frog Watch India, an online user group under the India Biodiversity Portal. This curated information will help scientists understand the distribution and ecology of the species, ultimately leading to the conservation of amphibians. Efforts such as these and others all around the world are the only hope to get these magnificent frogs jump back from the brink of extinction and leap with life again.
(The author is with Gubbi Labs, a Bengaluru-based research collective)