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Chinese Farming-pastoral Ecotones (CFPE) is the largest ecologically fragile zone in China. The dynamic prediction and impact factors analysis of landscape ecological risk based on LUCC have an important significance for effectively resolving ecological and environmental risk. In this paper, CA-Markov and BRT models were used to quantitatively analyze dynamic change, evolution characteristics, and influencing factors of landscape ecological risk.The results showed that: (1) LUCC types significantly changed from 2000 to 2040, especially in the bareland regions, which decreased by 1.64 times from 2000 to 2020, mainly transferred out to grassland and farmland. (2) The overall ecological risk showed a trend of increasing first and then decreasing. The highest ecological risk regions reached an area of 192,000 km2 in 2020 and decreased by 1.78 times from 2020 to 2040, these areas showed high spatial correlation and aggregation. (3) Topographical, climate, and socioeconomic factors had certain impacts on landscape ecological risk. Elevation (24.4%) was the most important factor affecting ecological risk, followed by temperature (19.1%), precipitation (15.7%), slope (13.6%) and GDP (8.4%). The study not only proposes a novel method regarding prediction and quantitative assessment of ecological risk based on influencing factors, but also provides a more precise and specific decision-making basis for sustainable development of ecological safety and social economic in the CFPE. [ABSTRACT FROM AUTHOR]

Farming-pastoral Ecotones in China (FPEC) is one of the most fragile ecological area in China. Landscape ecological risk assessment of FPEC based on terrain gradients has important strategic significance for ensuring national ecological security and the sustainable development of social economy. Based on the 30 × 30 m land use data and DEM data of FPEC in 1980, 1990, 2000, 2010 and 2020, this paper constructs a landscape ecological risk assessment model, and uses the methods of spatial autocorrelation analysis and terrain distribution index to appraise the dynamic change law and influential factors of FPEC landscape ecological risk on various terrain gradients. The results showed that: (1) In recent 40 years, land use/land cover changes (LUCC) has significantly changed, and the farmland area has increased continuously, mainly transferred from grassland, forest and bare land, particularly the bare land converted into grassland in recent 10 years, which leads to substantial increase in grassland area. (2) The overall ecological risk of the study area showed an upward trend, and the area of highest risk regions has increased more than twice during the study period, mainly distributed in the regions of "interference of human activities in low terrain" and "change of natural high terrain environment," these regions showed a high spatial concentration. (3) Ecological risk along with terrain gradient distribution is mainly limited by climate and terrain factors, the interference of human activities and natural environment change are the main influential factors of ecological risk increase in low and high terrain, respectively. Therefore, it is necessary to adapt to local conditions, and low terrain should rationally develop and utilize natural resources to reduce the interference of unreasonable production and human activities. In order to promote the sustainable and healthy development of FPEC, the policy of closing hillsides to facilitate afforestation should be adopted in the high terrain to reduce the impact of natural environment changes. [ABSTRACT FROM AUTHOR]