Abstract

Situated in North-Western Himalayas, owing to large variations in the altitude and climatic zones, Pauri Garhwal possesses a rich diversity of flora and fauna. Composition and structure of vegetation of the Garhwal region is being modified due to the invasion ofLantana camara L. Its rapid spreading, entangling nature of canopy of many individuals of a population and allelopathic nature pose serious threat to native forest flora. Beside its natural tendency to invade, the area having sub-tropical climate integrates suitably to its luxurious growth. Z. mauritiana Lam., M. koenigii (L.) Spreng, J. adhatoda L. and C. opacaStapf ex Haines are four native shrub species found abundantly along Nayar river of Garhwal Himalaya. In this study, impact of L. camara invasion on these four major native shrubs was determined. Further, effort was made to correlate it with plant morphology and nutrient status of soil. Although, L. camara upsets importance value indices (IVI) of all four shrubs, its impact on M. koenigii and J. adhatoda was relatively more alarming, later was found to have morphologically weak structure and meager distribution in L. camara invaded localities of study area. It appeared that in comparison to other shrubs, owing to their morphology these two shrubs were subjected to greater competition against L. camara.The decrease in population of these major shrub species will have crucial effect on associated species and consequently on whole ecosystem.

Key words: Competition, Himalaya, invasive, Lantana, shrub.