Herbaceous Flora in High Altitude of Imja Valley, Sagarmatha National Park Nepal Himalaya

Abstract

This study has been carried out in the Imja valley, north-east part of the Sagarmatha National Park. The present study starts from Phungitanga (3400m asl) to Chhukung (4,650m asl) between 27º49’58.08”N to 27º54’18.48”N and 86º30’57.06”E to 86º99’15.96”E. This research work aims to study the floristic composition, altitudespecies

richness relationship and disturbance-species richness relationship of herbaceous flora. The sampling was conducted at 60 sites in varying altitudes (3600-4100m) to cover all types of forest and different aspects. Total number of species and sign of human impacts were recorded in each sampling plots. Species were observed and collected enroute as well as with

in the sampling plots.The Generalized Linear Models (GLM) was used to elucidate the relationship of species richness with elevation as well as disturbance. Analysis of Covariance (ANCOVA) was also used to evaluate the effect of categorical variables like grass cutting, litter fodder collection along with altitude on species richness. Altogether 180 species of herbaceous angiosperms under 93 genera and 35 families were recorded. Asteraceae is observed as the largest family with 26 species. Similarly, Saxifraga is the largest genus comprising 9 species. 20 species are added as with new locality in Eastern Nepal and 43 species with different altitudinal ranges than recorded in Press et al. (2000). Monotonic decrease in herbaceous species richness with increasing altitude is found between 3600-4100m and with generating a high-elevation plateau between 3600-4000m as observed by Grytnes and Vetaas (2002). Only grass cutting and litter/fodder collection are found to be significant to the species richness supporting the “Intermediate Disturbance Hypothesis-IDH”.