Concern as dragonfly, damselfly species decline in Western Ghats

Mumbai: A landmark two-year survey across the Western Ghats revealed a worrying gap in the region’s biodiversity. 

Researchers documented only about 65% of the dragonfly and damselfly species historically recorded, pointing to a potential shortfall of nearly 35% of these ecologically critical insects.

Conducted between February 2021 and March 2023, the study mapped Odonata populations — an order of insects comprising dragonflies and damselflies — across 144 sites spanning Maharashtra, Goa, Karnataka, Tamil Nadu, and Kerala. The findings were shared on Friday by researchers from MIT World Peace University and the Society for Odonate Studies.

The survey's scale and spread make it one of the most extensive recent efforts to assess freshwater biodiversity in the Western Ghats, a 1,600-km mountain chain along India’s west coast and a globally recognised biodiversity hotspot.

The research team — Dr Pankaj Koparde, Assistant Professor, MIT-WPU Pune, Arajush Payra, PhD scholar, Amey Deshpande, MSc student, and Reji Chandran of the Society for Odonate Studies — undertook rigorous fieldwork across diverse freshwater habitats, including rivers, streams, waterfalls, ponds, lakes, and dams. Many of these sites were remote and difficult to access, posing logistical and regulatory challenges.

Over the course of the study, the team recorded 143 distinct odonate species, including 40 endemic to the Western Ghats. However, this represents only around 65% of the species historically known from the region — an alarming gap that raises concerns about species decline and habitat degradation.

Odonates are highly sensitive to environmental changes as they depend entirely on freshwater ecosystems for reproduction. As a result, they are widely regarded as “indicator taxa,” meaning their presence — or absence — reflects the ecological health of water bodies. The missing species, researchers suggest, could be early indicators of deeper ecological stress.

The study identifies multiple, intensifying threats across the Western Ghats, including linear infrastructure development, hydropower projects, pollution, and large-scale land-use changes. Additional pressures such as unregulated tourism, recurring forest fires, and climate change are further fragmenting and degrading these ecosystems.

The conservation status of recorded species adds to the concern. Three species — Elattoneura souteri, Protosticta sanguinostigma, and Cyclogomphus ypsilon — are currently classified as “Vulnerable” on the IUCN Red List, while many others fall under the “Data Deficient” or “Not Evaluated” categories, highlighting significant knowledge gaps.

The study also highlights regional variations. Maharashtra, where the highest number of sites (105) were surveyed, recorded 100 species, including 12 endemic ones. Kerala, despite fewer sites (14), showed a high concentration of endemic diversity, with 33 endemic species among 83 recorded. Karnataka (17 sites) recorded 64 species with six endemics, Goa (three sites) documented 35 species including four endemics, while Gujarat (five sites) recorded 18 species with no endemic species observed.

Reflecting on the findings, Dr Koparde emphasised the urgency of expanding research efforts.
“This study is one of the most extensive Odonata surveys across the Ghats. We observe a south-to-north compositional turnover that needs further investigation. Our surveys could recover only 65% of the known Odonata fauna, indicating a plausible loss of species and habitats,” he said.

Key findings at a glance:

• Only about 65% of historically recorded odonate species were documented, indicating a potential 35% shortfall and raising concerns about species decline

• A total of 143 species, including 40 endemics, were recorded across 144 sites, making it one of the most extensive recent biodiversity assessments in the region

• As sensitive freshwater bioindicators, odonates reflect ecosystem health; their reduced presence signals emerging ecological stress

• Kerala showed high endemic diversity, while Maharashtra recorded the highest species count due to wider survey coverage

• Multiple threats — including habitat degradation, pollution, infrastructure expansion, hydropower projects, unregulated tourism, forest fires, and climate change — are impacting ecosystems

• Significant knowledge gaps remain, with many species classified as “Data Deficient” or “Not Evaluated”