Compositional change in vascular plant diversity in the alpine mountainous region of Indian north-western Himalaya indicate effects of warming.

Although alpine regions of the Himalaya are characterized by low-temperature and short-growing periods, yet these harbour a high richness of plant species including a greater proportion of partly-endemic flora. Climate warming has drastically influenced the composition of alpine vegetation globally leading to threats of biodiversity loss. Himalaya, a rich biodiversity hotspot, have also been experiencing such warming effects in the recent decades. However, its impact on the Himalayan ecosystem especially on the alpine vegetation is not yet studied in detail. Therefore, we established permanent monitoring plots (PMPs) on three summits of Indian north-western Himalayan region in 2014 at one of the benchmark sites identified and selected under the aegis of Himalayan Alpine Dynamics Research Initiative (HIMADRI) network for long-term monitoring of alpine vegetation following Global Observation Research Initiative in Alpine Environments (GLORIA) multi-summit protocols. These summits are along an elevation gradient from 3600 to 3900 m. Data from PMPs were recorded in the years 2015 and 2020. Over the period of these years, mean annual soil temperature has been found to increase significantly with more increase observed in the summer mean temperature of upper alpine (3900 m) summit. Increase in species richness and plant cover percentage were also observed. The changes in beta and zeta diversity indices revealed Homogenization of biotic communities. Thermophilization was found more pronounced in the lower alpine summits. The study provides the baseline scientific data of alpine communities of the region in response to climate. Thus, this study will serve as an effort towards filling the knowledge gaps in the less explored regions of Indian north-western Himalaya. Continued studies in the present site and further explorations in other parts of alpine eco-regions of Himalaya are necessary, which has greater implications for conservation of vulnerable flora of alpine regions of the Himalaya, in the changing climate scenario. [ABSTRACT FROM AUTHOR]