VASCULAR PLANT SPECIES RICHNESS ALONG ELEVATION GRADIENT OF THE KARNALI RIVER VALLEY, NEPAL HIMALAYA

Abstract

In the present study, primarily we aim to check the prediction of species richness pattern with elevation gradient and compare the empirical study with regional pattern and regressed it with different environmental parameter as well. The sampling method was designed to include all the habitat types and vegetation. Latitude, longitude, altitude, and aspect were recorded for each plot. The total vascular plants along with the life forms were regressed against the altitude. The regression was also done between species richness and different environmental parameters. A Generalized Linear Model (GLM) with a quasi-poisson error of distribution was used to elucidate the pattern of species richness. A total of 199 vascular plant species were recorded of which 145 species were herbs, 21 trees and 33 shrubs. Species richness of total vascular plants and all life forms showed a unimodal pattern with altitude. An empirical study coincides with the regional study forming a peak at mid altitude but no plateau was observed in our study. Despite the pattern, regional studies showed a mid altitude peak at 1500 m asl but our study had a peak at an altitude of 3500 m asl. This study clearly shows the differences in pattern of species richness between the regional scale and local scale which is due to the differences in sampling strategy and data gathering methods.