مشخصات پژوهش

Vegetation is one of the most important factors in assessing land degradation. On the other hand, remote sensing of vegetation changes can provide useful information for ecosystem management. Therefore, this study sought to investigate the trend of changes in vegetation and its correlation with land-use and climate change in northeastern Iran. To this end, the data regarding the NDVI and EVI which were extracted from the MODIS satellite and MOD13A2 product from 2000 to 2017 were used to study vegetation changes, and data obtained from the MODIS MCD12Q1 product from 2001 to 2017 were used to investigate the land-use changes. Moreover, the meteorological stations' data were examined to evaluate the trend of climate factors in the region. The study's results showed that the trend of changes in both NDVI and EVI was significantly negative. Furthermore, the land-use analysis showed that the agricultural and rangeland area decreased and the urban and barren land area increased significantly. The temperature also increased significantly during the period while the precipitation decreased slightly. Moreover, it was found that there was a significant correlation between land-use classes, NDVI, and EVI and that the correlation between precipitation and NDVI was significant at 95% (R=0.53). on the other hand, the investigation of the relationship between climatic factors, land use, and vegetation indices based on the Pearson correlation coefficient indicated that the land-use had a higher correlation with vegetation indices compared with that of the climatic factors. Therefore, it could be argued that degradation can be affected by human activities which in turn leads to land-use changes and the overuse of water and soil resources. The degradation can also be influenced by climate change, leading to a decrease in the available water supply to be used by natural vegetation. However, land-use and human activities were found to have more influence on NDVI, EVI, and land degradation.