Blogs > Environment Awareness > Invasive species in Western Ghats Rivers threatens the endemic aquatic fauna

Posted by Harikrishnanbhaskaran on July 19, 2012

Western Ghats, the ancient mountain range in the southern India which is older than Himalayas is a new entrant to the league of Word Heritage sites for its rich biodiversity. However, new studies show that incidence of foreign type of organisms in these riverine environments is a main hazard for this World Heritage site. These non-native organisms introduced in the rivers of Western Ghats for agricultural purposes or as biological controllers, are gradually wiping away organisms found in these rivers, according to certain research outcomes.

Plants like Eichhornia crassipes and Pistia stratiotes serve as good examples of alien plants in these rivers. Similarly, Salvinia molesta, Hydrilla and Ipomea fistulosa were first introduced as ornamental plants in aquariums but later became major weeds in these rivers. They cover the water surface, often increasing the rate of sedimentation. They also hinder the daylight which is essential for the underwater plants for photosynthesis. Mikania macarantha, is a similar plant now threatening biodiversity in the area. It forms a thick layer over the river surface and the connected riparian forest, blocking the sunlight. 

Exotic fishes add one more name to the list of foreign organisms causing threat to innate organisms in the Western Ghats Rivers. Introduced to control mosquito and diseases caused by them, these aquatic organisms have turned out to be enemies in course of time. Gambusia affinis, was widely introduced as a biological agent to control mosquitos. But now they have entered Western Ghats streams, raising stiff competition for resources with native species, wiping away them locally. This is dangerous when for the endemic fishes in Western Ghats Rivers

Clarias gariepinus, was brought in by farmers who wanted a fast growing fish which eats up everything including waste from slaughter houses, to increase fish production. But the fish known for its ability to survive in drastic conditions has turned out to be a serious threat to native species of fishes and other organisms when invaded main stream rivers.

Unlike other threats which destruct a river ecosystem, foreign species and the extent of the damage caused by them are often invisible for the naked eye for a long time if detailed research is not being carried out.  So the current studies show that there is a need to conduct more in-depth studies and take up conservation efforts to help the world heritage site from degrading further.there is also an urgent need for the government to formulate and implement a policy for the management of the invasive species in India. 

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