Geographic distribution patterns, population dynamics, and habitat vulnerability of endangered and endemic Trillium...

Mountain ecosystems are essential for understanding species distribution and adaptation. Anthropogenic pressure and global change threaten high-altitude medicinal plants. This study evaluates the ecology and biogeography of the endemic Trillium govanianum (Melanthiaceae), focusing on its response to disturbance gradients, spatial distribution, and community structure in the Kashmir Himalayas. Field surveys across 18 sites recorded 113 plant species associated with T. govanianum populations, predominantly herbs (82.3%), perennials (80.5%), and hemicryptophytes (52.2%), with microphyllous leaf forms (59.3%). Species richness was highest in the Asteraceae, Polygonaceae, and Lamiaceae families. Digital elevation model (DEM) analysis revealed that 50% of T. govanianum populations were found between 2800 and 3050 m, primarily on north-facing slopes. Floristic dissimilarity between temperate and subalpine communities was significant, with a dissimilarity of 77.8% (PERMANOVA: F = 9.146, p < 0.0001; NMDS stress = 0.093), demonstrating clear ecological segregation. Indicator species analysis identified 56 taxa with strong zonal fidelity, with T. govanianum as a typical subalpine indicator species. Co-occurrence analysis indicated positive relationships with Rumex nepalensis, Taxus wallichiana, and Geum elatum, and negative relationships with Morina longifolia and Micromeria biflora, suggesting both facilitative and competitive interactions. Canonical correspondence analysis (CCA) identified nomadic settlements (10.7%, p = 0.018) and non-timber forest product extraction (10.6%, p = 0.022) as significant threats, explaining 57.6% of the variation in species composition among sites. These threats reduce the abundance of T. govanianum and disrupt its population distribution. The findings emphasize the need for conservation strategies, monitoring, habitat protection, and sustainable livelihood interventions.