Assessing the vulnerability of grasslands in Gannan of China under the dual effects of climate change and human activities

Climate change and human activities are two major drivers of grasslands degradation. Understanding the vulnerability of grasslands to both drives is of great importance for grassland conservation. This research established a vulnerability assessment model with historical and future the Normalized Difference Vegetation Index (NDVI), which was predicted by an optimized spatiotemporal NDVI prediction model, and then examined the vulnerability of grasslands under climate change and human activities in Gannan Prefecture on the north-eastern Qinghai-Tibet Plateau. Our results show that Gannan grasslands would show a vulnerability pattern of higher in the west and lower in the east under climate change and human activities. More than 46 % and 17 % of the region will become highly and medium vulnerable areas in the future, mainly concentrated in Maqu, Luqu and Xiahe counties in the west, southwest and northwest of Gannan. Specifically, the vulnerability is the lowest under the future climate scenario of moderate carbon emissions (i.e. RCP 4.5). Land use types such as forest land, unutilized land and cultivated land conversion to grassland could partially offset the vulnerability mainly caused climate change, while the conversion of grassland to unutilized land, forest land and cultivated land would increase the vulnerability of grassland. Our results would help to deepen the understanding of the patterns and main drivers of Gannan grasslands vulnerability under the impacts of climate change and human activities, and provide theoretical basis for the development of corresponding grassland management policies.