According to a contemporary examination, rising temperatures in the Himalayan region have contributed to an altitude shift among various butterfly and moth species. The Himalayan range, host to over 35% of India’s Lepidoptera order that includes butterflies, moths, and skippers, is grappling with this environmental change.
Understanding Lepidoptera
Lepidoptera, a term originating from Greek language meaning “scaly-winged,” represents an order of insects that comprises different species of butterflies, moths, and skippers. Their wings are covered with microscopic scales which give them their characteristic appearance. Though butterflies, owing to their bright colouring and day-flying habits, are more familiar than moths, the latter are more varied and abundant.
The Crucial Role of Lepidoptera
These species play a pivotal ecological role by converting plant matter into animal matter and serving as food for other animal groups. Furthermore, adult butterflies, skippers and certain moths participate actively in pollination during their nectar-gathering adventures.
About the Study
This enlightening study was conducted by the Zoological Survey of India (ZSI) under the funding of the Ministry of Environment, Forest and Climate Change. Over a span of four years, 1,274 moth species and 484 butterfly species from Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Sikkim, North Bengal, and Arunachal Pradesh were studied. This research led to the discovery of 80 new species of butterflies and moths.
Findings of the Study
The research revealed that at least 49 species of moths and 17 species of butterflies have moved to higher altitudes. This migration indicates a significant change of over 1,000 metres between their current and previously documented mean habitat altitudes. Species like the Common Map butterfly, Tailless Bushblue butterfly, and the Indian Red Admiral butterfly have exhibited changes ranging from 900-1500 metres in their habitats due to global warming.
Climate Change and Lepidoptera
The sensitivity of butterflies and moths to climatic changes makes them potentially insightful indicators of long-term modifications in weather patterns. Notably, certain moth families could experience as much as 91% reduction in suitable habitat areas by 2050 according to ZSI predictions. These findings will be employed as a baseline to monitor the effects of climate change on animal species in future decades.
Biodiversity Richness Hotspots
The study also highlighted two biodiversity richness hotspots. The Darjeeling hills in West Bengal and Kumaon in Uttarakhand have been identified as regions with over 400 and 600 species records respectively. Furthermore, an incremental increase in Lepidoptera biodiversity from Western to Eastern Himalayas was observed.
Reasons for the Altitude Shift
Several factors contribute to the upward movement of these species. The primary driver appears to be receding ice caps and glaciers which subsequently leads to water scarcity. Warmer temperatures have caused an upward shift in vegetation’s altitude as well. Additionally, encroachment of human habitation into previously untouched areas has contributed to the altitude shift. Furthermore, illegal poaching and selling activities have reduced the butterfly population at lower altitudes, pushing these beautiful creatures to seek refuge up the mountains.
