2025-01-19

Odonates, including dragonflies and damselflies, are aquatic insects that serve as vital indicators of freshwater ecosystem health. They play a crucial role in controlling insect populations and maintaining ecological balance. The Meenachil River, originating from the Western Ghats in Kerala, flows through Kottayam before emptying into the Vembanad Lake. Known for its biodiversity and cultural significance, the river now faces severe pollution challenges.

Under the aegis of TIES, several pollution studies, research initiatives, and restoration projects are being conducted to rejuvenate the river. As part of these efforts, annual odonate surveys are carried out to assess the population of odonates in the river basin. These surveys involve the participation of experts and an enthusiastic community, including students, academicians, researchers, and employees.

The ninth Meenachil Odonate Survey concluded with remarkable findings. Pollution levels, except in the Meladukkam area where the river originates, have increased alarmingly from the Marmala Waterfalls to Pazhukkanilakayal, the river's endpoint. This pollution has been accompanied by a corresponding and dangerous decline in odonate populations.

The survey, carried out by TIES in partnership with the Kerala Forest Department’s Social Forestry Division, also involved water sample analysis from 16 river locations, with a focus on detecting coliform bacteria. Prior to the survey, a training session was held, inaugurated by K B Subash, ACF of the Social Forestry Division, Kerala Forest and Wildlife Department, Kottayam. The session was led by Ajayakumar MN, an expert on Odonates, and Dr. Punnen Kurian, Secretary of TIES.

As pollution levels rise, many odonate species, which depend solely on clean water for reproduction and growth, have either dwindled or disappeared. Researchers identified 37 species this year, including 18 dragonflies (Odonata) and 19 damselflies (Zygoptera)—a decrease of 10 species compared to previous years.

The diversity of dragonflies, in particular, has suffered significantly compared to damselflies. Notable species like the Pied Reedtail, an indicator of pristine water quality, were observed in locations such as Kidangoor, Thiruvanchur, and Thanaloram. The Malabar Torrent Dart, another rare species, was found only in Meladukkam. However, pollution-tolerant species like the Ditch Jewel were widespread in almost all locations except Meladukkam.

Despite unexpected rain disrupting the survey, experts underscored climate change and pollution as significant threats to odonate diversity.

Assistant Conservator of Forests K.B. Subhash and TIES President Dr. Abraham Samuel K emphasized that the degradation of freshwater ecosystems not only threatens odonates but also poses severe risks to human health, wildlife, and crops.

The survey saw active participation from over 60 students representing 16 institutions. It was led by an expert team, including Dr. Punnen Kurian, M.N. Ajayakumar, Sarath Babu N.B., Tony Antony, Dr. Saritha Ramachandran, Anoopa Mathews, M. Thomas Yakoob, Manju Mary, Amrita V. Raghu, Sujith, and Giri K.M.