217 Vascular epiphytic community along elevational zone in sub-tropical forest ecosystem.

Vascular epiphytes contribute substantially to floral diversity, species richness, productivity, nutrient storage and complex arboreal communities in forest ecosystems. However, they have received insufficient attention due to accessibility limitations. In this communication, we analysed the vascular epiphytic species richness and composition in sub-tropical forests (from 400 to 1300 m) of Darjeeling eastern Himalaya. The study area was classified into three elevations (low, mid and high). We studied the correlation between vascular epiphytic richness and host tree traits such as circumference at breast height (CBH), bark texture and bark pH. Additionally, we applied Canonical Correspondence Analysis (CCA) to explain epiphyte diversity with respect to climatic variables (mean annual temperature, mean annual precipitation and mean annual relative humidity). In total, 942 individuals of vascular epiphytes belonging to 71 species under 46 genera and 21 families were recorded. Orchidaceae was by far the most species-rich family followed by the fern family Polypodiaceae. The results showed the species richness in mid elevations was comparatively lower than in the low and high elevations. Our study suggests that climatic variables and host tree traits such as CBH and bark texture were closely associated with epiphytic richness and diversity. These findings could be seminal in understanding the distribution pattern of vascular epiphytes and community composition with their relation to host tree traits. Nevertheless, effective and strategic conservation of vascular epiphytes must be considered in Darjeeling Himalaya. [ABSTRACT FROM AUTHOR]