Amphibian decline in the Mahdei-a cause of concern.
The monsoons have abruptly ended early without a sign off note…and this may sound weird but yes, nature and its varied systems, its unique faunal indicators and floral signs prove that the rains will be back with a bang or rather a torrential shower which would then proceed to begin another spell of rains. Though unconventional in nature, weather forecasts and climate studies show that these patterns are now here to stay and well, we better get used to it as a coastal state to say the least.
And while I am at it, the reasons of my concern as an herpetologist were more so as this is creating an adverse impact on the amphibian populations as well as the densities and I am not talking about the world view in general for now, but our very own species are in decline due this varied pattern of the rains, and the subsequent effects on the niche ecosystem in the forests of the Mahdei region, my area of study and interest.
And while various climatic factors may lead to this decline I have witnessed the failure of specific species like burrowing frogs, tree frogs and bush frog species that have been affected due to non-availability of seasonal pools of water (that either dries up due to the long gaps in rainfall) or the complete wash out of frog spawn (eggs) and even tadpoles due to the incessant heavy spells that occurred in last month. Extremities in rainfall patterns thus have had a drastic effect in certain areas of the Mahdei region, and while these are all on field observations that need to be further analyzed (for which I have collected data and is currently under review), it is the decline of amphibians for other human induced reasons in these parts of the Mahdei that are a cause of concern and need attention.
The most obvious cause is habitat destruction. Like all other lesser forms of flora and fauna, amphibians are threatened and pushed to the brink of local extinction when habitats are altered to practice shifting agriculture or carry monoculture plantations like cashew, areca nut and banana. Clearing of forests for timber and firewood is also an important factor for amphibian decline and life forms like caecilians are the most affected amphibians in these cases.
Likewise mass clearing of forest habitats for development projects like irrigation projects, dam sites and various small and medium clearings for industrial and commercial activity are taking their toll especially in plateaus of the Mahdei region.
It is necessary here to also note that changes in farming practices and the usage of enormously drastic quantities of pesticides, insecticides and fertilizers for ensuring better farm yield have had severe impacts on ground dwelling species of frogs and toads. I have observed many forest species of amphibians, which are found on the fringes of plantations and forest habitats have been affected by use of certain fertilizer usage and have already become locally extinct in such niche habitats.
I am also of the opinion that the introduction of certain species of exotic species of flora including the Australian acacia and the eupatorium weed and their mass propagation have had long term effects on amphibian populations and need to be addressed on a priority by curbing these exotic species in a systematic manner.
New trends in human consumption especially of selective species like the Indian bull frog (locally known as Jumping chicken) and its organized hunting nexus have forced these species into the threatened category not only in the Mahdei region but also in the state as a whole.
Another important factor that I have observed is road kills and this has definitely gone up in the Mahdei region after a criss-cross network of roads, both metal and mud paths have been increasingly upgraded for the use of vehicles, which have taken a toll on selective species of amphibians. The need to monitor ponds, lakes and streams is crucial too and while I have personally not aware of any contamination of water sources, this aspect too can lead to disappearance of certain key species of amphibians from the region.
And while researchers working on the issue of declining amphibian species in the country acknowledge global warming, unknown parasitic infections and increase in ultraviolet-B radiations as important causes of decline in amphibian species on a global scale, we in the state need to realize that our local diversity of amphibians are also on the decline, and the Mahdei forests are just a case study to prove that similar problems exist in other habitats of the state and need urgent attention.
Unless we don’t understand that the survival of lesser known species like amphibians and reptiles are essential for our survival in the long run, we will continue to ignore the problems of local conservation issues and in the end fail to understand the global ones…until the next monsoon fails…and the tap goes dry.
By: - Nirmal Kulkarni