Comparison of Ecological Patches' Potentials and Functions in Rangeland Ecosystems (Case Study: Qahavand Rangelands, Hamedan Province, Iran)

Interrupting the processes which control ecosystem resources has dramatic impacts on the rangeland conditions. To protect ecosystems and landscape, it needs to understand the ecosystem processes which regulate the ecosystem resources. As main components of ecosystems, patches and inter-patches play important roles in energy and materials cascade. Ecologically, functional parameters such as stability, infiltration and nutrient cycling serve as key factors determining the movement of sediments, nutrients and organic matter as well. The present research aims to evaluate and compare the ecological patches of grasses, shrubs and mixed grasses- shrub using indices of stability, infiltration and nutrient cycling. Therefore, sampling was carried out in Qahavand rangelands located in the south east of Hamadan province, Iran on three patches of grass (Cynodon dactylon), shrub (Camphorosma monspeliaca L. and Astragalus microcephalus) and mixed grasses-shrub (Camphorosma monspeliaca + Cynodon dactylon) to evaluate the aforementioned parameters. Samples were taken along three 50 m transects using LFA (Landscape Function Analysis) method. Three indices of stability, infiltration and nutrient cycling and their individual contributions on the whole ecosystems' functions were determined. Results showed that all three patches vary significantly in function so that the mixed patch (Camphorosma monspeliaca + Cynodon dactylon) may be accounted for the highest values among the others. The study area had a good level of stability and nutrient cycling while infiltration rate was moderate mainly due to much proportion of clay in soil texture. Somehow, results of soil profile study in the area imply good stability and moderate infiltration.