Variation in Plant Functional Traits along altitudinal gradient and land-use types in Sagarmatha National Park and Buffer zone

Abstract

Plant traits are the charactersistics of a plant species which act as useful predictors of the response to the environmental stimuli. They represent specific functional adaptations to various environmental stresses. This study deals with the variation in plant functional traits along elevation gradient and landuse types in Sagarmatha National Park and Buffer Zone, Solukhumbu district, Nepal. Two

field investigations at different seasons (April and September) were made for collecting samples. A relatively large samples was used (involving 60 genera, belonging to 31 families). The land-use types selected included disturbed (cultivated land, exploited forest, and meadow) and less disturbed (natural forest) categories. Altogether, 11 different traits of plants, which included life form, growth form, plant height, clonality, spinescence, leaf dry matter content, stem specific density, bark thickness, twig dry matter content, twig drying time, and specific root length were examined. The selected dominant species have been divided into three different categories of growth form (herb, shrub and tree). It was found that plants adapt in various ways to deal with the changing environmental conditions for which they shows different traits. The application of plant functional traits is very useful to understand vegetation-environment relationships. Statistical analyses showed significant differences between traits along both the elevation gradient and land-use types. In the disturbed land-use categories, we found high variation in a particular trait. Correlation analyses revealed that most of the traits were interrelated. Herbs and shrubs were found to be dominant in the higher elevation and in disturbed landuse categories.

Species recorded at high altitude were mostly short basal herbs, while spinesescense and tall trees were observed at the lower altitude. Species recorded in meadows and exploited forests showed high variation in traits due to disturbance mainly grazing, fire, trampling, litter collection, etc. Altitudinal variation, climatic condition and disturbance most strongly influence trait expressions of the study site. Plants show these traits for their defense against the adverse conditions.

Keywords: functional traits, altitudinal gradient, land-use types, disturbances.