Taxonomic and functional plant diversity patterns along an elevational gradient through treeline ecotone in Kashmir

Species distribution and community assembly patterns along elevation gradients have been studied world over but not much information in this regard is available about the Indian Himalayan region, including the Kashmir Himalaya. It is in this context that we studied elevational (2200-3800 m) patterns in plant species richness, and functional and taxonomic group diversity with particular reference to treeline ecotone (3200-3700 m). Present study revealed that the patterns of species richness were not consistent across taxonomic or functional groups of plants. Four patterns of species richness in relation to elevation were observed: low-elevation plateau with a mid-peak in bryophytes and lichens, mid-peak pattern in pteridophytes and inverted hump-shaped pattern in monocots. During the present investigation, rapid changes in species composition and physiognomy were recorded in the treeline ecotone over small elevational increases. Number of tree species in this zone declined rapidly from four species at an elevation of 3200 m to one at 3700 m. While from 2200 m to 3200 m the vegetation was predominated by fir (Abies pindrow) forming a closed canopy forest, but beyond 3200 m its density decreased rapidly with concomitant increase in the density of birch (Betula utilis). Ultimately birch was the dominant treeline species and grew in association with Rhododendron campanulatum up to 3700 m, beyond which treeless alpine meadow existed. The present study is first of its kind carried out in Kashmir Himalaya and would hence serve an important baseline for similar such studies that would pave way for better understanding and conservation of plant communities in such mountainous regions.