Investigation of Rangeland Changes Based on Landscape Metrics Analysis (Case Study: Kezab Rangelands, Yazd Province, Iran)

Abstract

Adverse changes in rangeland vegetation can be considered as one of the criteria for land degradation. Some of these changes can be evaluated through monitoring the spatial changes of landscape parameters. This study aimed to investigate the landscape changes in Kezab rangelands of Yazd province, central Iran. Landsat satellite images of 1990, 2002, and 2013, and landscape metrics including Total Edge, Edge Density, Mean Shape Index, Number of Patches, Mean Patch Size, and Median Patch Size were used in this study. Landscape fragmentation was analyzed through calculating various metrics of landscape patterns using the FRAGSTATS software. This study was performed with a focus on landscape elements in poor and very poor rangelands. Results indicated a reduction in the area of rangelands with poor conditions and an increase in the size of rangelands with very poor conditions. The results showed that perimeter sum of spots in rangelands increased From 51.6 km in 1990 to 62 km in 2013. This increase in the perimeter showed further destruction of poor rangelands. This process was considerably seen in very poor rangelands and increased from 48.9 km in 1990 to 56 km in 2013. The process of Edge Density index changes confirmed the intensification of desertification in the region. Also, the number of patches in poor and very poor rangelands increased from 23 to 11 and from 4 to 10, respectively. The intensification of destruction has been shown in very poor rangelands. Rangelands were also changed in terms of other landscape parameters, eventually leading to the deformation of rangeland patches and the degradation process has been intensified in this region. According to the results of these studies, landscape changes of rangelands could be assessed at various time intervals to detect the factors affecting rangelands.