Kerala, T.N. host most number of butterfly species in Western Ghats

Study highlights conservation gaps and calls for reassessing conservation status of several species

The Western Ghats are home to 337 butterfly species, with Kerala hosting the highest (328), followed by Tamil Nadu (326) and Karnataka (317).

A study published in the Journal of the Bombay Natural History Society on the updated distribution and population status of butterflies reveals that species diversity is highest on the southern Western Ghats and diminishes northward.

Researchers Kalesh Sadasivan of the Travancore Nature History Society and Ashok Sengupta note that these species belong to various families, including Papilionidae (19), Pieridae (34), Nymphalidae (100), Riodinidae (two), Lycaenidae (99), and Hesperiidae (83).

The Western Ghats features 40 species that are strictly endemic. Of these, less than 7% (22 species) figures on the IUCN (International Union for Conservation of Nature) Red List of threatened species, with two classified as ‘near threatened’ and the rest as ‘least concern’.

Around 21% or 71 species are protected under the Wildlife (Protection) Act (WLPA) and amendments up to 2022.

However, the lead author highlights discrepancies in the conservation and legal protection status — some strictly endemic and rare species are not protected under WLPA; and while certain common species are listed on the IUCN Red List, some truly threatened and rare species are not included.

He says the exclusion of endemic species such as Sahyadri green yellow, Nilgiri clouded yellow, red-eye bushbrown, Palni bushbrown, Nilgiri fritillary and cloud-forest silverline from the ambit of the WLPA should be reviewed. Moreover, rare species such as abnormal silverline, yellow-base flitter, Malabar banded swallowtail and Travancore evening brown should be re-evaluated for inclusion on the IUCN Red List. At the same time, common ones such as crimson rose, Indian common rose and Indian tiny grass blue could be excluded from the Red List.

The Western Ghats mountain range, which has been divided into three regions based on the geomorphological, physiographic, climatic floristic and faunistic characteristics, has the highest diversity along the southern and central Western Ghats — with 324 species each. The northern Western Ghats has only 255 species.

Most regions in Kerala and Tamil Nadu have been thoroughly surveyed, but further assessment is required in parts of Karnataka which lie north of Coorg-Kudremukh, Someswara, Sirsi and Kaiga and those north of Satara up to Gujarat, the study recommends.

Published - September 08, 2024 10:22 pm IST