Vanishing Taxus baccata L. Due to Unsustainable Exploitation and Climate Change in West Kameng and Tawang Districts of Arunachal Pradesh

Abstract

Taxus baccata, a small to medium sized tree is valuable for extraction of taxol which is used in preparation of anti-cancer drugs (breast and ovarian cancer), kaposi’s sarcoma (an AIDS related cancer) and over 20 such other indications. The plant is rare, endangered and listed in Appendix II of Convention on International Trade in Endangered Species of wild Fauna and Flora (CITES) showing widespread decline in population and increasing fragmentation worldwide. Around 2 to 3 million kg of biomass is harvested annually where as the sustainable rate of harvesting is estimated to be 0.6 million kg per year. It grows at an altitudinal range of 1500 to 3000 m throughout Arunachal Pradesh in Bomdila, Shergaon, Eagle Nest, Dirang, Thungri, Tawang, Mago and Zemithang in West Kameng and Tawang Districts, Tale Valley (few trees only) of Lower Subansiri, Anini, Mayodiya in Dibang Valley district, Mechuka in West Siang and Melinja and Hot spring areas of Lohit District. Random linear transacts in West Kameng and Tawang districts of Arunachal Pradesh recorded a total of 265 Taxus plants. Out of which, 130 are live trees and 135 are dead plants. In the absence of standard lopping technique and non-existence of any regulatory mechanisms for sustainable harvest, the leaves were pruned mercilessly to the extent that plant could not withstand to survive. Moreover, the pressing demands and associated lucrative price lured middlemen and villagers to plunder this scarce resource pushing it to the extreme limits of disappearance. The interaction with the villagers revealed that about 100 trucks of Taxus leaves were supplied each from villages of the area. Thus, around 1000 full grown trees have been completely pruned from the area before the ban imposed by the Supreme Court of India in 1996. The results point towards unsustainable and unorganized way of exploitation of the plant in the eastern Himalayas during the recent past. Although Taxus baccata is known to be tolerant to shade, high temperature and low moisture stress but the sudden and unlikely changes in climatic variables may cause both positive and negative impacts on the future of the plant. Hence, the paper attempts to discuss the impact of unsustainable exploitation as well as climate change and suggest suitable strategies for conservation and modeling of this rare and endangered medicinal plant in the study area.