Dragonfly, damselfly count dips in Delhi biodiversity parks this year, survey finds

A survey of dragonflies and damselflies across seven biodiversity parks in Delhi this year has shown that the density of individuals as well as diversity has seen marginal dip compared to last year’s counts owing to the erratic rains, said senior officials

A survey of dragonflies and damselflies across seven biodiversity parks in Delhi this year has shown that the density of individuals as well as diversity has seen marginal dip compared to last year’s counts owing to the erratic rains, said senior officials. Additionally, a new species, the Yellow-tailed Ashy Skimmer, has been observed in the DDA Aravalli Biodiversity Park this year, while Blue Grass Dart (Pseudagrion microcephalum) has been spotted for the first time at the Yamuna Biodiversity Park. Scientists said a total of 11,154 individuals were recorded this year, compared to last year’s mark of 13,253.

The Blue Grass Dart has been spotted for the first time at Yamuna Biodiversity Park. (Photo sourced)

The three-day dragonfly and damselfly survey was conducted across seven Delhi Development Authority (DDA) Biodiversity Parks of Yamuna, Aravalli, Neela Hauz, Tilpath Valley, Kamla Nehru Ridge, Tughlaqabad and Kalindi, from September 17 to 19 with the help of experts and students from colleges of University of Delhi.

Speaking on the dip in the number of individuals spotted this year, entomologist Mohd (CHECK) Faisal said that there has been a minor dip in diversity as well as density of dragonfly due to increase in dry areas and climatic conditions.

“Delhi has seen erratic rains and adverse weather conditions with increase in dry areas and lack of formation of water pools in biodiversity parks. This year a new species seen in DDA Aravalli Biodiversity Park was Yellow-tailed Ashy Skimmer (Potamarcha congener). Last year it was observed for the first time in Yamuna biodiversity park so its range has increased.”

Yellow-tailed Ashy Skimmer are found perching on dry twigs near ephemeral ponds, marshes, while Blue grass dart is seen perching on water plants in lakes and in marshes with a well-developed vegetation at the banks. The presence of these dragonflies indicate a healthy ecosystem. These insects form a part of the “odonata” family. Odonatas are characterised by large round heads, compound eyes, two pairs of long, transparent wings and elongated abdomens.

Faiyaz Khudsar, scientist in-charge, DDA Biodiversity programme, said, “Dragonflies have complex life cycles and highly specific habitat needs that make them difficult to raise and release on any meaningful scale. Most of their life is spent as aquatic nymphs, living in ponds or wetlands for months or even years. These nymphs are territorial, predatory, and require clean, stable aquatic environments. Therefore, only clean and functioning wetland ecosystems can sustain their population which in turn help in mosquito control in surrounding areas and restored DDA Biodiversity Parks provide such pristine ecosystems.”

When the data related to diversity of species is compared, the maximum of 23 species were spotted at the Yamuna Diversity Park — up from last year’s 21 mark. However, diversity declined from 26 to 22 species in Kamla Nehru Ridge; 14 to 12 in Tughlaqabad Biodiversity Park; and 20 to 15 species in Kalindi Biodiversity Park. A dip was also seen in Neela Hauz and Tilpath Valley parks.

Kalindi Biodiversity Park recorded a maximum of 4,234 individuals with Ditch Jewel being the most seen species followed by 2520 individuals across 22 species in the Kamla Nehru Ridge where the most common species was Wandering Glider. Some of the most observed species at the Yamuna Diversity Park include Rudy Marsh Skimmer and Dart Jewel.

Some of the most seen species across the seven biodiversity parks also include the Scarlet Skimmer, Ditch Jewel, Wandering Glider, Coromandel Marsh Dart and Rudy Marsh Skimmer.

The dragonfly count was first done in 2018 across three biodiversity parks. It has been conducted annually for the past five years now since 2022. The census covers seven biodiversity parks developed by the DDA — two floodplain ecosystems, the 457-acre Yamuna Biodiversity Park and 400-acre Kalindi Biodiversity Park, and five patches of the Aravalli hill ranges, including the 692-acre Aravalli Biodiversity Park, 175-acre Tilpath Valley, 320-acre Tughlaqabad, 215-acre Kamla Nehru Ridge, and the 10-acre Neela Hauz.