Landscape Function Analysis to Assess the Grazing Effect on Some Soil Features in Arid Ecosystem

Sustainable rangelands management continues to be one of the main challenges facing arid ecosystem. The function of a rangeland ecosystem depends on the conservation of resources within the ecosystem. Finding the rangeland ecosystem functions requires the knowledge of soil and vegetation characteristics to understand the ecosystem's capabilities. In this research, in order to identify the damaged areas in arid regions, the effect of grazing on the ecosystem function was investigated using the distance from the water resources. Thus, in the present study, around 3 water resources in 4 principal geographical directions and 172 plots with 4 m2 were installed. In each plot, 11-soil surface indexes were estimated by the landscape function analysis (LFA) method. Then, using 11 soil surface indexes, three soil functional properties include stability; permeability and nutrient cycle were calculated. In order to determine the sensitivity of the LFA method and separate the functional and structural characteristics SPSS software V.19 were used  and the analysis of variance and comparing the mean of common features conducted by Duncan's method. Multivariate analysis of variance and correlation showed that the three functional features had no significant relationship with the four geographical directions (P <0.01) but had a significant relationship with the distance from the water resources (P <0.01). These results indicated that the ecosystem functions increases with distance from the water resources. Also, the results of Duncan's test showed that the high grazing intensity near the water resources caused a critical range of 150m from the water resources.