Thrissur: In a first, College of Forestry, Thrissur, in coordination with the Centre for Climate Change Research, has conducted a dragonfly-survey in five identified wetland zones of Thrissur. Thirty one species of dragonflies, including some rare species like Platylestes Platystylus and large migratory groups of Wandering gliders were found during the survey.
Absence of some common endemic species like Damselflies aka 'Soochithumbi' is considered to be an indicator of widespread loss of habitat and massive elimination of larvae and pupae during the catastrophic floods that ravaged Kerala recently. The first ever dragonfly survey in the Thrissur-Ponnani region was led by acclaimed odonatist Dr Francy Kakkassery. Around 70 odonate watchers participated in the survey which followed a seminar held at the Climate Change Research Centre,Vellanikkara, on October 21.
Fresh water contamination
Rapid increase in the number of Common dragonflies, locally known as 'Changathi thumbi' (Brachythemis contaminata), around fresh-water springs is a pointer to water pollution, the experts said. “Common dragonflies breed in contaminated stagnant water. Their large-scale presence around fresh-water springs denotes water contamination, mixing up of water bodies and cessation of springs,” Rison Thumpur, an odonate enthusiast who participated in the survey, said.
Considerable fall in the number of damselflies in the region also pointed to changes in the ecosystem triggered by the unprecedented floods. According to Muhammed Sherrif, a lepidopterist, the floods have caused massive elimination of dragonfly larvae that are aquatic. Dragonflies pupate in shrubs, low, hydrated twigs and on the banks of water bodies. Floodwater has carried away a large number of pupae and larvae eliminating an entire batch of dragonfly nymphs, he said.
However, the environmental changes have paved way for certain remarkable findings in the field of dragonfly research. Platylestes platystylus or 'Pachakkannan Cherachirakan’ has been spotted in the subcontinent after almost eighty-five years at Ponnani wetlands during the latest survey. Originally found in Thailand and some parts of Myanmar, the presence of Platylestes platystylus had been recorded in West Bengal in 1933 by British odonatist Fraser.
Sensitization, the need of the hour
Addressing the odonata experts and civilian fly-watching groups that participated in the seminar held at the Climate Change Research Centre, Dr Francy Kakkassery elaborated on the need of popularising basic fly-watching and identification techniques among the general public. Flies and insects reflect environmental changes minutely. Even the slight changes in the ecology could be identified by analysing the number, behaviour and pattern of flies, he said.
Manoj Karingamadathil, an active member of 'Kole Birders,' a bird and fly-watching collective based in Thrissur, opined that dragonfly and butterfly watching is less popular among nature lovers when compared to bird-watching and wildlife survey. “There isn't yet a reliable source of consolidated data about the population of flies and insects in Kerala. The biggest hurdle that we encounter while assessing the impact of the recent floods on insect population is that we don't possess a comprehensive data on previous status of these species. Let us see this disaster as an opportunity to make collective efforts to record, conserve and study flies and insects,” he added.
The 70 fly-watchers who participated in the survey split themselves into 10 teams and surveyed five ecological zones of Thrissur and Ponnani namely Thommana, Enammavu, Palakkal, Ponnani and Biyyam Lake.
Dr Nameer P O, head of the Department of Wildlife Sciences and Centre for Wildlife Studies, College of Forestry, presided over the academic sessions at the seminar.