Pollution, commercial development and modification of natural systems pose a threat, says study

Pollution, commercial development and modification of natural systems are posing serious threats to a large number of freshwater fishes, mollusc and odonates, including dragonflies and damselflies, of the Western Ghats, according to the International Union for Conservation of Nature (IUCN).

It was also found that the highest number of threatened species is located within the southern Western Ghats hotspot in Kerala, Tamil Nadu and southern Karnataka.

The risks faced by these species were highlighted in the assessment of the freshwater biodiversity of the region carried out by the IUCN Global Species Programme's Freshwater Biodiversity Unit, in association with the Zoo Outreach Organisation (ZOO), Coimbatore.

The global conservation status and distribution of 1,146 freshwater species were assessed using the IUCN red list of threatened categories and criteria. Commercial fisheries, aquarium trade, construction of dams and alien invasive species too were found mounting pressure on the species.

It was also found that 180 taxa were threatened with extinction. However, no species was assessed as extinct or extinct in the wild, the report said.

River systems of the Tapi, the Krishna, the Cauvery and the Godavari and species endemic to Gujarat, Maharashtra, Goa, Karnataka, Kerala and Tamil Nadu were reviewed. Andhra Pradesh and western and southern portions of Madhya Pradesh, Orissa and Chhattisgarh were also included in the assessment as the drainages of the rivers originating in the Western Ghats flowed through these States.

The species introduced to the region prior to 1500 AD were assessed and subsequent introductions were treated as non-native ones.

The southern Western Ghats region with catchments, including the Pamba, Meenachil, Muvattupuzha, Periyar, Karuvannur, Bharatapuzha, Chaliyar, Kuttyadi, and Valappattanam of Kerala; the Netravati, upper Kabini and Cauvery of Karnataka; the upper Vaipar, Amaravati, Bhavani and Moyar of Tamil Nadu has the highest richness (260–312 species) and endemism (103–129 species) of freshwater species.

“The analysis informs the status of the freshwater systems in the Western Ghats on which more than 400 million people are dependent across peninsular India,” said Sanjay Molur, Executive Director of ZOO.

A. Gopalakrishnan, scientist in-charge of the National Bureau of Fish Genetic Resources, Kochi, who participated in the evaluation, called for stock-specific rehabilitation of fishes in the river systems to overcome the risks. Protection of key habitats, prevention of flow modifications, and conservation of specialised ecosystems such as Myristica swamps, high altitude peat bogs, and lateritic plateaus and prevention of use of pesticide in upper catchments and regulation of tourism in critical habitats have been suggested by the agency.