Geographic distribution pattern of threatened plants of India and steps taken for their conservation

In spite of its importance in nation-wide conservation planning, comprehensive information on geographic distribution of threatened plants in India is lacking. Even the threat status of these plants is ambiguous and the country's effort to conserve them is not widely known. A critical analysis of these aspects is essential for identifying gaps in threatened plant conservation. Keeping these in view, we present a review of the existing knowledge on geographic distribution pattern of threatened plants of India, their threat status, and conservation action undertaken to recover these species. Using the available data, we unravel patterns of distribution of these threatened plants in different states of India. When ranking of the families was done based on the total number of species under different threat categories, Orchidaceae (644), Fabaceae (185), Poaceae (164), Rubiaceae (103), Asteraceae (88), Euphorbiaceae (72), Asclepiadaceae (62) and Acanthaceae (60) constituted more than half of the total threatened plant species of India. A review on conservation efforts so far undertaken in different parts of the country revealed that the biodiversity-rich phytogeographic regions such as the Himalayas, North East India, and Andaman and Nicobar Islands had lesser conservation efforts in comparison to the Western Ghats, Vindhyas and Peninsular regions of India. The skewed distribution of threatened plants in different states did not truly reflect their absolute presence or absence; rather it is the result of incomplete survey because of the difficult geomorphological and associated geo-climatic conditions, tough terrain and remote locations. In addition, the current data on threatened plants suffer from methodological shortcomings such as classification without using the population data that are so crucial in modern day threat classification, and lack of long-term observational data. The review emphasizes the use of modern tools such as ecological niche modelling for population inventory, area of occupancy and extent of occurrence, and trends in population size and regeneration for precise threat classification conforming to globally accepted methods (e.g. IUCN version 3.1). The works undertaken through the support of Department of Biotechnology, GoI for conservation of 156 threatened plant species under different disciplines of conservation biology during the past three decades have also been compiled and reviewed. A successfully tested protocol following an integrated approach for threatened species conservation is recommended for future conservation action.