Assessment of orchid diversity in the sacred groves of Kodagu, India’s Central Western Ghats Biodiversity Hotspot: implications for bio-cultural diversity management

Biodiversity is the buzzword of the day when it comes to addressing environmental issues, and India’s Western Ghats are a goldmine of amazing beauty and biodiversity. Orchids, known as jewels of the plant kingdom, are “Keystone resources’’ that play a significant role in maintaining the forest canopies. The indigenous Kodava culture of nature worship and the beautiful alpine landscape provide an idyllic area, which is a perfect habitat for wild orchids. Unfortunately, there is little available data and less investigation on this aspect. The aim of this study was to evaluate the diversity and host taxa preference of orchid species found in sacred groves of two different vegetation types in the Central Western Ghats Biodiversity Hotspot of India, specifically in the Kodagu District.

In this study, the orchid diversity was analyzed using the stratified random sampling technique. A 100-meter-long and 5-meter-wide belt transect was laid, with a sampling intensity of 1% of total area. A complete enumeration of both epiphytic and terrestrial orchid was done in each sampling plot. Using Johansson’s five zone classification, the distribution of orchids on each tree was assessed. The diversity indicators were calculated and the number of orchids on the host tree was correlated with its girth.

Based on the results of the various diversity indices, semi-evergreen types of sacred groves had higher host tree and orchid diversity. There were 54 orchid species identified from the two types of vegetation namely semi-evergreen (42 species), and moist deciduous (34 species); 45 of them were epiphytes and 9 were terrestrial. The most dominant orchid species in semi evergreen groves were Dendrobium herbaceum and Pholidota pallida, while Pholidota pallida and Malaxis rheedi were dominated in moist deciduous groves. Artocarpus hirsute, Canarium strictum, Mangifera indica, and Vitex altisima were the most dominant host tree species in both vegetation types. Among the Johansson’s five zone classifications, Zone 3 was found to be the best. The highest numbers of orchids were found in the host trees with lower girth class (50 cm to 100 cm).

Orchid diversity is higher in sacred groves of both vegetation types, highlighting the importance of managing biocultural diversity. There is a long history of this small patchy forest, reserved for the worship of deities or ancestors, protecting the surrounding natural vegetation, which includes some very old trees.

Diversity of orchids in sacred groves of Kodagu