Survey of the effects of land cover changes on rangelands of Ghoorichay chatchment using remote sensing technique

In the present time, land use changes are being conducted without clear and logical programming or regarding the environmental effects of the changes. Because land use changes occur in a large scale, remote sensing technique is a useful and valuable tool for monitoring the changes. The aim of this research is investigation of the effects of land cover changes on rangelands of Ghoorichay chatchment located in the north of Ardabil province using remote sensing technique.

In this investigation, TM images for year 1987, ETM images for year 2001 and OLI-TIRS images for year 2015 were collected and analyzed. After image pre-processing enhancements and corrections, the images were classified using maximum likelihood supervised classification method. Then, considering study area features, the images were classified into four land cover classes: dry land, range land, bare land and village. Moreover, NDVI index and slope layer were used to increase classification accuracy. At last, land cover changes and their effects on the range lands were detected. Overall accuracies and kappa coefficient were evaluated.

According to the results, during the studied period, 5885 hectare (49.7%) of study area had changed. The most land cover changes were related to range land with intensive decrease of 2540 hectares (21.4%) which was changed into bare land and dry land.

Additional information such as slope layer and NDVI index in assistant with supervised classification of satellite images can increase the accuracy of image classification to provide land cover maps.