Ethnobotany, trade and population dynamics of Cycas circinalis L., and Cycas swamyi Singh & Radha in the Western Ghats of southern India

Abstract

Harvest of Non Timber Forest Products (NTFPs) has been frequently studied as a means to conserve forests and provide income to user communities, often with the assumption that harvest has relatively little ecological impact. Cycas circinalis L. and Cycas swamyi Singh & Radha are such NTFPs extensively harvested from the Western Ghats, South India. They are harvested for bark, leaves, seeds and male cones by indigenous people for medicinal, food and ornamental purposes, while commercially harvested for the medicinal and floricultural industries. Although indigenous people have a long association with Cycas spp, harvest for sale in informal regional markets has been uncontrolled over the past 15years. Cycas circinalis is now regionally listed as 'critically endangered' and internationally listed as an 'endangered' species. In an attempt to understand the uses and responses of these species to harvest pressures, this study aims to document the trade, ethnobotany, life history, and population dynamics of Cycas spp. My study shows there is a large scale trade of leaves and pith and peak leaf sales occurs shortly after new leaf production in cycad habitats. The pith of C. circinalis and C. swamyi are collected for the herbal medicinal industry however, they are adulterants and don't provide the necessary constituents of the herbal drug, vidari. Demographical studies confirm that harvested populations are on a decline as the projected population growth rate over the long term λ, was <1 for all harvested populations. Cycas spp have ancient lineages from the Jurassic age, being long-lived and slow-growing, and this coupled with intensive extraction reduces the chances for populations to rapidly withstand the induced stress of harvest. The effects of harvest can be further compounded by other disturbances such as fire, habitat loss and climate change. Sustainable harvest practices for seed harvested populations and the discontinuation of leaf and pith harvest are imperative to conserve the last few populations of C. circinalis and C. swamyi in the Western Ghats.