1 Sustainable Harvesting and Management of Medicinal Plants in the Nepal Himalaya: Current Issues, Knowledge Gaps and Research Priorities Suresh K. Ghimire Central Department of Botany, Tribhuvan University, Kirtipur, Kathmandu email: sureshkghimire@yahoo.com Abstract Medicinal plants (MPs) form a high percentage of non-timber forest products (NTFPs) collected from the Himalaya. They are the major source of medication for a wide range of ailments for the rural people. Besides their importance in health care, MPs have high socio-cultural, symbolic and economic values, providing income and employment to millions of people living in the region. Unfortunately, in recent decades, the use of many plant-based NTFPs, including MPs, has gone from subsistence collection to large-scale commercial extraction, increasing the probability of over-exploitation. Knowledge of the sustainability of the use of such plant resources is thus urgently needed. Sustainability of the use and management of plant resources can be assured with an understanding of the biological/ecological, economic, socio-cultural and political aspects of resource base; understanding of the complex interactions between many of these factors; and with careful planning and management grounded in ecological principles. Management also requires understanding local perceptions, knowledge and decision making systems relating to the resources. Unfortunately, these aspects of research are greatly lacking from the Himalaya. There is a general lack of precise scientific knowledge regarding both the biological and socio-cultural aspects of the resource base and potential for sustainable harvest. This paper reviews the biological and socio-cultural aspects of research on Himalayan MPs; evaluates current issues and gaps on MP research; and outlines the approaches of ecological research in achieving harvesting sustainability of wild MP resources. 1. Introduction People have used medicinal plants (MPs) in health care since the time of earliest human evolution. In many countries, MPs still remain the major source of medication for a wide range of ailments. Therapeutic effects of MPs are associated with their chemical peculiarities, which are in reality components of the defense strategies of plants. Only 5 to 15% of the approximately 270,000 species of higher plants occurring in the globe have been systematically investigated, and plants remain a rich source of novel bioactive compounds. The potential value of medicinal compounds derived from plants has been proposed as a tangible benefit of biodiversity and therefore a basis for promoting its conservation (Coley et al. 2003). The role of MPs is particularly important in the Himalayan region, where a large proportion of the rural population depends on wild MP resources to meet their health care needs. Besides their importance in health care, MPs have high socio-cultural, symbolic and economic values, providing income and employment to millions of people living in the region. In the Himalaya, MPs are highly valued in different folk healing systems and in scholarly systems of traditional medicine, such as Ayurveda, Unani, Chinese and Tibetan. In addition, Himalayan medicinal plants and their products are also popular in other traditional medical systems (such as Siddha, homoeopathic) as well as in modern allopathic medicines. Plants used in traditional medicine are important sources of novel bio-molecules (Heinrich and Gibbons 2001), with application for the manufacture of pharmaceuticals and cosmeceuticals. Besides, the incorporation of medicinal herbs into health foods, dietary supplements, herbal teas, cosmetics, massage oils, fragrances, and dying and coloring agents has dramatically increased the international demand in medicinal plants. The global market for herbal medicines has been estimated to be worth USD 40-60 billion, annually growing at the rate of 7-10% (for review see Nagpal and Karki 2004; Subrat 2005). The Himalayan region is one of the major repositories of high value MPs in Asia concerned by international trade. India and China alone consume hundreds of MP species from the Himalaya. The annual demand for raw materials of MPs in India, for example, is estimated at 24 million metric tons, which is increasing at the rate of 20% per annum (Karki 2001). Similarly, the traditional Chinese medicine