Facilitation is a global phenomenon that occurs when one species promotes the growth, survival, and reproduction of another species, mostly in harsh environments like alpine and arid zones. It is a well-studied subject in plant ecology, however, the importance of nurse shrubs in maintaining plant community diversity is not well studied in the Himalayas. This research aimed to assess the facilitative role of an endemic shrub, Berberis mucrifolia, in maintaining plant community diversity and composition, and richness of medicinal and useful herbs in the Langtang valley of Nepal’s Himalayas. We conducted field sampling during monsoon and post-monsoon seasons on transects at three elevations. Seven shrub patches (pure stands of Berberis) were selected randomly in each elevation, and three 1×1 m plots sampled in a patch, each with an adjacent open plot. Altogether 256 one square meter plots (21 patches x 3 plots x 2 locations x 2 seasons) were sampled, recording species growing within Berberis and adjacent open areas.
Results/Conclusions
Plant species richness and richness of useful species were significantly higher inside Berberis canopy. Significantly greater Relative Interaction Index for both overall plant species and useful species during the dry season indicated increased facilitation during stressful conditions. Species assemblages in plots within and outside the canopy of Berberis were distinct, with some shared species, and unique species present within the shrub canopy in both seasons. Increment in Species Richness Index showed that 19% (total=105) species, combining both seasons, were added to the community because of the presence of the micro-habitat patches created by Berberis. Notably, facilitation by Berberis increased the richness of useful species by 16.07% (total=56). The findings of this study demonstrated the importance of facilitation in the Himalayas and need to incorporate facilitation into management strategies for effective biodiversity conservation and sustainability.