Journal of Forestry Research (2009) 20(3): 223-228 DOI 10.1007/s11676-009-0041-z Regeneration ecology and population status of a critically endangered and endemic tree species (Ilex khasiana Purk.) in north-eastern India Upadhaya Krishna 1 , Barik Saroj Kanta 2 , Adhikari Dibyendu 2 , Baishya Ratul 2 , Lakadong Nigyal John 2 1 Division of Environmental Science, Department of Basic Sciences and Social Sciences, School of Technology, North - Eastern Hill University, Shillong 793 022, India 2 Centre for Advanced Studies in Botany, School of Life Sciences, North - Eastern Hill University, Shillong 793 022, India Abstract: Detailed studies on population structure and regeneration ecology of Ilex khasiana were carried out at five representative natural populations i.e. Mylliem (Population – I), Upper Shillong (Population – II), Shillong Peak (Population – III), Laitkor (Population – IV) and Nongpiyur (Population – V) to probe into the responsible affecting factors for its population structure and regeneration ability in these populations. Experimental observation under three controlled light conditions (full sunlight (100%), intermediate sunlight (50%) and low sunlight (30%)) showed that the growth status and survival rates of seedlings under intermediate and low light were better than those under the high light condition. The density-diameter distribution in population of adult trees (≥5cm dbh) exhibited a typical character of a regen- erating population. A higher seedling mortality rate in natural populations of I. khasiana was most probably due to increase in light intensity following vegetation destruction and other anthropogenic disturbances that cause opening of forest canopy. The findings of the present study would be of immense value in formulating appropriate conservation measures for the species. Keywords: Ilex khasiana; endangered species; population status; regeneration; north-eastern India Introduction About half of the world's vascular plants are highly restricted in their distribution region. The areas of their occurrence have con- tinuously decreased during the last few decades due to various anthropogenic activities (Vega et al. 2004). Ilex khasiana is one of the 48 critically endangered species identified world-wide by World Conservation Monitoring Centre (Walter and Gillett 1998) and also is endemic species to East Khasi Hills of Meghalaya in north-eastern India. Williams (1998) and IUCN (2007) reported that the Ilex khasiana was confined only to Meghalaya with a total population size of three to four individuals only. The species was listed under very rare category by Rao and Haridasan (1983) and Haridasan and Rao (1982, 1985). Due to very small population size and its threatened habitats, the species is facing to the risk of extinction. An understanding of the population status and regeneration behavior is a pre-requisite for developing conservation strategies Received: 2008-12-20; Accepted: 2009-01-20 © Northeast Forestry University and Springer-Verlag 2009 The online version is available at http://www.springerlink.com Biography: Upadhaya Krishna (1973-), Male, Lecturer in Division of Environmental Science, Department of Basic Sciences and Social Sciences, School of Technology, North - Eastern Hill University, Shil- long 793 022, India. (E-mail: upkri@yanhoo.com) Responsible editor: Zhu Hong for the threatened species. Studies on population status and re- generation behavior, which provide vital data on critical stages of the lifecycle of a species, are essential for formulating appropriate conservation strategies (Krenova and Leps 1996). Successful regeneration of a species in nature depends on its ability to with- stand disturbance stress that plays a key role in seedling survival and establishment (Rao et al. 1990). This is often achieved through differences in life history strategies and segregation of regeneration niches (Barik et al. 1992). Coppicing is another effective mechanism of tree regeneration following clear-felling and is viewed as an active strategy to withstand dry environment and disturbance of mild intensity (Rundel 1991). Results of our field survey in north-eastern India revealed that population size of Ilex khasiana was much larger than that re- ported by earlier researcher (Williams 1998). It is necessary to investigate the causes of poor regeneration in nature. Therefore, the present study was undertaken to: (1) assess the current status of natural population and its regeneration mechanism in nature and (2 identify responsible affecting factors for constraining the natural regeneration ability, resulting in species decline and (3) develop a strategy for conservation of the species. Materials and methods Study area The study was conducted in and around Shillong Peak extending up to Mylliem covering an area of about 220 km 2 with an eleva- tion range of 1340-1990 m a.s.l. The study area experiences a RESEARCH PAPER