Patterns of floristic and functional diversity in two treeline ecotone sites of Kashmir Himalaya

Globally, the treelines at higher elevations in mountains are reported to be advancing up-slope in response to recent climate warming. However, little is known about the treeline advancement in the Himalaya due to paucity of baseline vegetation data with which to compare, thus making their assessment and monitoring challenging. To fill this knowledge gap, the present study documented floristic and functional diversity of two treeline ecotone sites in Kashmir Himalaya. At each site, we conducted field sampling by laying five 20-m² plots, with one at the highest limit (T0 plot), two plots below and two above the treeline and two nested subplots of 5-m² for shrubs and five 1-m² for herbs in each plot. We recorded 97 plant species belonging to 33 families from the two sites. We observed a considerable difference in species composition and distribution along the treeline ecotone. Majority of the species reported were perennial herbs. We observed a significant association of growth forms with the particular plots along the treeline ecotone. At both the sites, we recorded highest species richness at the T0 plot which was correlated well with the functional traits, thus indicating convergence of floristic and functional diversity at this transition zone. Interestingly, the T0 plot at both the sites showed maximum overlap of species with the plots above and below the treeline. In an era of climate warming, our study provides crucial baseline data that will facilitate assessment and monitoring of the Himalayan treelines.