Ecological niche modelling for predicting the habitat suitability of endangered tree species Taxus contorta Griff. in Himachal Pradesh (Western Himalayas, India)

The West Himalayan Yew (Taxus contorta Griff.) is an extremely important tree species as its bark and leaves are the source of the anti-cancer medicine Taxol (R) used in chemotherapy for the treatment of a number of different cancers. Unfortunately, the species is endangered because of unsustainable harvesting and over grazing coupled with a very low natural regeneration potential. The Maxent modelling algorithm was used to model the ecological niche and predict the habitat suitability of this species in the Western Himalayas of Himachal Pradesh. The purpose of the modelling was basically to restore the species in its native habitat. The model output had a reasonable area under the receiver operating characteristic curve (AUC) value of 0.905. The jackknife test showed that the land cover and the annual mean temperature were the most important environmental predictors that individually affected the information gain. The results suggested that the Great Himalayan National Park Conservation Area had the highest area (134.14 km(2)) under the very highly suitable category. Being an International Union for Conservation of Nature (IUCN) category II protected area, it would be an ideal place to preserve and reintroduce the species. Among Wildlife Sanctuaries, the Kais Wildlife Sanctuary had the highest proportion of its area (92.46%) under very highly suitable category for T. contorta. Additionally, Churdhar and Tirthan Wildlife Sanctuaries are predicted to have more than 60% of their geographic areas as very highly suitable for the species. Overall, only 6% of the geographic area of Himachal Pradesh was predicted to be very highly suitable.