Rarities pattern of vascular plants in the high-altitude forests of Indian western Himalaya: Conservation implications

Abstract

The assessment of plant rarity patterns and mapping of endemic species is a challenging task, however, this kind of assessment having great conservation significance. In the present study, a classification system of rarity, considering biogeographical, ecological and abundance of species was developed along with assessing the vegetation composition. Following systematic random approach of vegetation sampling, three altitude transects were sampled within each 100 m interval in three possible aspects (North-West, North-East and South-West) in the high-altitude forested zone (2000–3300 m asl) of Kedarnath Wildlife Sanctuary (KWS). The study identified a total of 295 plant species (191 genera and 70 families) in the studied region. Considering different attributes of rarity, 8- rarity groups were used for identification of rare and endemic plants. Altogether, most of the species exhibited wide geographical distribution an attribute of commonness, and few of these have narrow distributions due to habitat specificity. The lower altitudinal zone exhibited the maximum floristic diversity (184 spp.; 62.4 %), and minimum in the higher zone (134 spp.; 45.4 %). Tree species richness decreases, and its endemic subset increased along the altitudinal gradient due to remoteness, habitat heterogeneity, isolation of the areas and other environmental factors. A sharp decline was observed in the tree species richness from lower (33 spp.; 84.6 %) to higher altitude (8 spp.; 20.51 %). The species to genera ratio in the entire altitudinal range was 1.2 for trees and 1.6 for shrubs and herbs. Rarity analysis of these native and endemic species has highlighted conservation priorities at local and regional scale.