Western Ghats shelter highest number of endemic orchids in Peninsular India

According to a recent research review published in the Journal of Threatened Taxa, Western Ghats, one of the eight hottest biodiversity hotspots in the world, harbours highest number of endemic orchid species found in Peninsular India. 123 species among the 130 endemic orchid species of peninsular India are found in different parts of Western Ghats, says the study. Among them, 95 species are strictly restricted to Western Ghats.

A terrestrial orchid species found in Western Ghats

Flowers of a terrestrial orchid in Western Ghats

Peninsular India is the region is bordered by Vindhyan mountain range in the north, Arabian Sea in the west, Indian Ocean in the south and Bay of Bengal in the east and comprises of seven Indian states – Andhra Pradesh, Goa, Karnataka, Kerala, Maharashtra, Odisha and Tamil Nadu and union territory - Pondicherry. Geographically, peninsular India is divided into Western Ghats, Eastern Ghats and Deccan Plateau. 

 Kerala shelters maximum number of endemic orchids in Western Ghats

According to the study, Kerala part of Western Ghats has maximum number of endemic orchid species. Agasthyamalai-hills, Anamalai-High Ranges, Nilgiri-Silent Valley-Kodagu region are some of the important regions here which support high endemism, says the paper. 

State-wise distribution of endemic orchids in Western Ghats

The present study also points out the high endemism among orchids found in Western Ghats. Of the 123 endemic orchids found in Western Ghats, 95 are strictly restricted to these mountain ranges. At the same time, among the 22 species of endemic orchids found in Eastern Ghats, only 5 species are strictly endemic. None among the 29 endemic orchids reported from Deccan Plateau are restricted to the plateau. 

Endemic orchid fauna of Peninsular India

According to a study, the family of orchid like plants have 22500 different species across the world. Among them, 1331 species are reported from India. 404 species among them are endemic to India. 

The present study claims that the actual number of endemic orchid species at peninsular region is 130 which are distributed into 38 genera. Among them, 43 are ground orchids, 85 are epiphytic or grow on trees and two are holomycotrophic (grows on dead or decaying matter). 

In the past, different studies have come out with different figures about the endemism among orchids in the region. However, the authors of the present study claims that they have updated the list by including latest changes in the taxonomy and updated distribution data for many orchid species. 

According to the paper, many species which were earlier considered as endemic were later reported from other regions also. “A total of 27 orchid species earlier considered as endemic to the peninsular region are excluded from the list owing to their extended distribution in the neighbouring countries”, says the paper.

Threats to endemic orchid fauna in peninsular India

According to the study, different forms of human intervention like cattle grazing, mining, construction activities and forest fires are the major threats to these endemic orchids in the peninsular region.