Identifying the potential global distribution and conservation areas for Terminalia chebula, an important medicinal tree species under changing climate scenario

Terminalia chebula Retz. (Combretaceae), commonly-known as chebulic myrobalan is one of the important Non-Timber Forest Product (NTFP) species which is harvested for its fruits and galls. The species known as the "King of medicines" is used widely in Ayurveda, Sidda, Unani, and traditional Chinese medicines for curing a wide variety of diseases in Asia and Africa. Terminalia chebula is an important ingredient of Triphala (Ayurvedic medicine) along with Terminalia bellirica and Phyllanthus emblica. The fruits of the tree also yields a dye which is used as an organic dye in the textile industries. In recent years, there is an increasing demand for herbal remedies and organic dyes, resulting in extensive extraction of fruits and galls from T. chebula. In this study, the major objective was to identify sites for the conservation of T. chebula and to identify important environmental variables determining its distribution. Based on the existing species distribution records (primary and secondary), along with a suite of climatic variables, the present and future distribution of the species were predicted. The study identified ecological niches that are suitable for the cultivation of the species; the species occurs in India, Pakistan, Sri Lanka, Cambodia, Myanmar, Vietnam, China, Laos, Thailand, Bhutan, Taiwan, Nepal and Bangladesh under the current climatic scenario. Within India, our results suggest that the central and south India are highly suitable in the current scenario. The mean annual temperature, temperature seasonality and isothermality seem to be the most important variables determining the distribution of the species which is directly influenced by climate change. Overall, the study indicated that under the future climate change scenarios the distribution of T. chebula is likely to decrease. The results indicate that T. chebula is highly vulnerable to climate change. Considering the economic importance of the species, it is important to understand how the species distribution will alter in the wake of climate change to develop effective conservation strategies. The study also provides important environment variables that determine the species distribution which could aid in identifying areas where the species could be cultivated.