Using Landscape Metrics to Assess the Structure Changes of the Landscape of Gharasou Watershed in Kermanshah

Sustainability of natural resources is directly or indirectly related to surface cover of the region. Therefore, the maintenance of coordination between sustainable resources and socioeconomic needs and the increasing environmental awareness and efforts to manage sustainable natural resources require studying land use monitoring and land cover and its changes for time scales and in different locations. Land cover and its changes are important variables which have significant effects on the environment and its processes. The increase in population and the development of human activities over the last few decades have significantly affected the earth's surface. The change in land use and non-use of land has increased the suitability of the destruction process. Therefore, it is necessary to investigate the relationship between changes made in different uses and each of its consequences for their correct and optimal management. Attention to the development of remote sensing science in the past years along with these changes, various methods, and algorithms have been developed to investigate the changes in applications. One of these methods, which focuses on the quantization of the spatial structure of the terrestrial landscape (In fact, it means the surface of the earth, where there are different spots that set up a particular arrangement of topography, vegetation, and land use and in which a combination of local ecosystems or land uses have been replicated in a similar form) is the landscape metrics. These metrics are able to provide a great deal of information about the structure and modifications of the constituent parts of the land in a patches space of time. Landscape metrics are in three levels, including the entire area of the landscape (the integrated and various types of classes and patches in the landscape), the level of user classes and land cover (all patches representing a type of user or a type of cover), and the surface of the patch (defined as single patches and spatial properties, the type of content, and the texture of the patches) are measurable. In this research, by studying and reviewing scientific sources and obtaining expert knowledge of the bachelor, regarding the suitability of the measures with the purpose of the research and considering the correlation between their concept, set of measures of composition and distribution of facial features were selected for the present study. The assessment of the number of patch on the class level showed that the greatest change during this period was in the number of patches pertaining to the agricultural and human-made class, which indicates the fragmentation and the disturbance in the land reated as a result of the expansion of agricultural land and human beings. The comparison of patch density at the level of the class show that the expansion of human land and increasing agricultural use, the development of activities, and user changes have caused the density of rangeland patches to be reduced and have a greater fragmentation than other classes. The results of the increase in the number of patch from 67291 to 112382 at the surface of the landscape indicate the decomposition and reduction of continuity with the help of which it is possible to detect the processes involved in the decomposition and fragmentation of the landscape surface. In addition, the results of the increase in the patch density on the surface of the landscape from 34.28 to 57.25 per 100 hectares indicates the fragmentation of the landscape during the studied period. The results of the surface of the landscape for a Contag metric indicate a decrease in integrity and an increase in fragmentation, and for Shannon diversity metric, an increase in diversity in land use change. Generally, in order to understand the changes in the landscape structure areas, changes in natural environments should all be assessed on a time basis. Therefore, in this research, it was necessary to analyze landscape in the time frame of the study in order to evaluate the changes in the applications. The determination of the uses indicates that the watersheds have created patches in the region over the past years (various agricultural and human resources). Using the metrics at the level of the class and landscape, the results of the study indicate that the shape of the land is generally fragmentary in terms of the integrity of the structural elements.