深入探究半干旱区景观格局变化规律,明确其生态风险时空演变特征与影响因素,对优化半干旱区景观格局、防范和治理生态风险、促进区域可持续高质量发展具有重要意义。以宁夏回族自治区盐池县为例,基于2000—2020年土地利用数据,通过景观格局指数构建生态风险模型,结合地统计分析和地理探测器模型,对其景观格局变化及生态风险时空演变与影响因素进行综合研究。结果表明：（1） 2000—2020年盐池县耕地和未利用地面积下降,其余地类均呈增加趋势,其中建设用地扩张速度最快,年均增长率为6.90%。（2） 2000—2020年盐池县景观斑块数、斑块密度、景观形状指数和香浓多样性指数上升,最大斑块指数和蔓延度指数下降,表明景观格局呈破碎化、复杂化和分散化的发展态势。（3） 2000—2020年盐池县生态风险指数由0.1465下降至0.1312,其中高、较高和中等风险区面积占比分别下降5.25%、24.21%和5.44%,而低和较低风险区面积占比分别增加14.11%和20.79%,空间上呈现出北高南低的分布格局。（4） 随着社会需求的日益增长和人类活动的加剧,自然因素对生态风险空间分异格局的影响逐渐弱化,而社会经济因素作用不断增强。

As well as being one of the most sensitive regions to global changes induced by human activities, semiarid regions are characterized by drought and low rainfall, sparse vegetation, and extremely fragile ecological environments. It is therefore of great theoretical and practical significance to optimize the landscape pattern of semiarid regions, prevent and manage ecological risks, and promote sustainable and high-quality development via in-depth exploration of the changing laws of landscape patterns in semiarid regions, and clarifying the temporal and spatial evolution characteristics and influencing factors of ecological risks. This study considers Yanchi County in Ningxia, China based on the land use data taken from 2000 to 2020, and uses the landscape pattern index to construct an ecological risk assessment model. Comprehensive research is undertaken on the temporal and spatial evolution of ecological risks and the factors that influence such risks. The results show that: (1) From 2000 to 2020, the area of cultivated land and unused land in Yanchi County decreased; all other land use types showed an increase over this time period. The construction land was seen to have increased the fastest, with an average annual growth rate of 6.90%. The overall land use data shows a rapid expansion in the proportion of construction land, a reduction in the area of cultivated land, an increase in forest and grassland, and an increase in the land area covered by water. (2) From 2000 to 2020, affected by the disturbances to the natural environment and human activities, the number of landscape patches, patch density, landscape shape index and Shannon’s diversity index in Yanchi County increased; in the same period, the largest patch index and spread index decreased, indicating that the landscape became increasingly fragmented and an increase in the complexity and decentralization of land use occurred. (3) From 2000 to 2020, the ecological risk index of Yanchi County decreased from 0.1465 to 0.1312, in which the proportion of higher, high and moderate risk areas decreased by 5.25%, 24.21% and 5.44%, respectively, while the proportion of lower and low risk areas increased by 14.11% and 20.79%, respectively. The distribution pattern of the ecological risk index is high in the north and low in the south. (4) With increasing social demand and the intensification of human activities, the influence of natural factors on the spatial pattern of ecological risks has gradually weakened, whereas the influence of social and economic factors has continued to increase.