Relationship of topography and soil chemistry with species composition in Chandragiri hill, central Nepal

Abstract

The present study aims at finding the effects of topography and soil chemistry with species richness and species composition in Chandragiri hill, central Nepal. Environmental variables like topography, soil, climate affect the distribution of species. Most of the literature reported a hump-shaped pattern between species richness and environmental variables. The study was carried out in the community forest of Chandragiri hill, central Nepal. Altogether, 35 plots of 10 × 10 m 2 were established between 1500-2500 m. Quadrats of 10 × 10 m 2 , 5 × 5 m 2 and 1 × 1 m 2

were established for the assessment of trees, shrubs and herbs respectively. Soil was collected from the four corners of the plot and further analysis was carried out in the lab. Soil chemical properties i.e. pH, total nitrogen (TN), soil organic matter (SOM), available phosphorous (AP) and available potassium (AK) were determined in the laboratory. Altogether, 180 species were recorded from the study site. Data analysis was carried out using correlation, ANOVA, regression and ordination. Among the various variables studied, only soil pH showed a significant negative relationship with total species richness. Shrubs, herbs and climbers also showed the same pattern to soil pH as found between total species richness and soil pH. However, the tree showed no significant trend with soil pH. Herb and shrub showed significant relation with SOM and TN respectively. Species composition in the site was strongly influenced by altitude, pH, TN and AK. At the local level, soil heterogeneity was the factor determining species richness. On the other hand, species composition was influenced by the interaction of various environmental variables. Such studies provide information about species richness in the study site and hence can be precious for the formulation of conservation strategies. In addition, it also helps in prioritizing the site on the basis of biodiversity.