干旱区生态环境知识资源中心

The changes in land use/land cover (LULC) play a major role in the study of various aspects of environmental issues. Land use is the results of various socioeconomic activities taking place at various urban and regional setups. In this paper, landscape dynamic characteristics are investigated by using remote sensing and geographic information system in mountainous watershed of Abha, Saudi Arabia. Land use classes were mapped and assessed from a time series of maps of year 2000-2010. The LULC transformations were also analyzed according to elevation and slope. Assessment of the data shows that LULC had undergone substantial changes in this semi-arid mountainous watershed from 2000 to 2010. During this period, the sparse vegetation and water bodies decreased from 48.47 to 39.31 km(2) and 0.30 to 0.11 km(2), respectively, whereas build-up area increased from 17.02 to 36.36 km(2). The area under water bodies has reduced due to construction activities, disturbance in drainage network, and sedimentation in the watershed. The areas having high altitudes were exposed to changes in landscape characteristic. In the regions having lower altitude (1,950-2,350), an agricultural land has decreased, whereas build-up land has increased. As a result of rough structure, only small flat areas, located in this sections and valley channels, may be used as build-up land. Slope gradient had also an influence on the distribution of LULC. The assessment of land use and land cover type distribution by slope category provided the baseline for the implementation of the nationwide land conservation policy of conversion of agricultural land to forestland in order to control high soil erosion risk. The changes in land use and land cover in the studied watershed were mainly controlled by human factors (land management, construction, and population pressure) rather than natural factors.