干旱区绿洲城镇景观生态风险时空变化分析——以张掖绿洲乡镇为例

Spatio-temporal evolution of landscape ecological risk in oasis cities and towns of arid area:A case study of Zhangye Oasis Township

科学评估与分析干旱区绿洲乡镇景观生态风险,对优化绿洲土地资源管控和维护干旱区绿洲生态系统稳定性具有重要现实意义。以张掖市绿洲乡镇为对象,基于土地利用数据和景观格局指数,结合ArcGIS空间分析功能,研究其景观生态风险时空特征及影响因素。结果表明:1987—2018年,耕地和建设用地变化明显,分别增加429.03 km^(2)和236.26 km^(2);整体景观生态风险呈下降趋势,并呈“南北高、中间低”格局特征;各乡镇风险水平在空间上正向聚集,位于绿洲边缘地区的乡镇风险变化明显;人为活动干扰是近年风险水平变化的主要因素。研究成果可为西北干旱区绿洲生态保护与治理提供决策参考。

The scientific assessment and analysis of landscape ecological risks in oasis towns is of great practical significance for optimizing management and control of oasis land resources and maintaining the stability of oasis ecosystem in arid areas. Based on land use data and landscape pattern index, combined with ArcGIS spatial analysis function, this paper studied the temporal and spatial characteristics and influencing factors of landscape ecological risk in oasis towns in Zhangye City. The results showed that the cultivated land and construction land have changed significantly from 1987 to 2018, with an increase of 429.03 km^(2) and 236.26 km^(2), respectively. The overall landscape ecological risk level showed a downward trend and the pattern of high in the north and south while low in the middle. The risk level of each township is positively aggregated in space, and the dramatic change of the estimated risk was also found on the edge of the oasis. Human disturbance is the main factor of risk level change in recent years. The research results can provide decision-making reference for ecological protection and management of oases in arid areas of northwestern China.