治沟造地背景下延安市生境质量时空演变特征

Spatial and temporal variations of habitat quality under the background of gully control and land consolidation in Yan′an, China

研究治沟造地工程背景下延安市土地利用及生境质量的变化,对黄土高原生态保护和高质量发展具有重要意义。基于延安市遥感影像数据,运用ArcGIS和InVEST模型定量分析了2010—2018年延安市土地利用和生境质量的时空变化特征,并结合各区县治沟造地工程实施情况,剖析其与区域生境质量的关系。结果表明:(1)延安市主要土地利用类型为草地、林地和耕地,2010—2018年土地利用类型变化主要为三者互相转化;(2)延安市生境质量处于中等水平,高和较高等级生境质量面积占50%以上,呈现东南和西南高,北部较低的分布格局;2010—2018年间,延安市生境质量指数下降了1.4%,宝塔区中部由于城市扩张指数下降最为显著;(3)延安市生境质量具有一定的空间聚集性,“H-H”集聚区主要位于西南部林区,“L-L”集聚区主要位于西北部的吴起县以及东部的延长、宜川两县;2010—2018年间生境质量的空间集聚程度有分散的趋势,中部呈现较大的点状退化;(4)治沟造地工程对延安市生境质量有一定的负面影响。通过因地制宜的生态保护模式,延安市在维持生境质量较为稳定的同时,保证了耕地红线和粮食安全,实现了高质量发展和生态保护之间的平衡关系。

Studying variations in land use and habitat quality in Yan′an City under the background of the gully control and land consolidation project(GCLC) has significant implications for ecological protection and quality development of the Loess Plateau. Therefore, this study quantitatively analyzed the temporal and spatial variations of land use and habitat quality in Yan′an City from 2010 to 2018 using the ArcGIS and InVEST models. The relationship between the status of implementation of the GCLC project in various districts in Yan′an City and regional habitat quality was also analyzed. The results showed that:(1) The land use types in Yan′an City mainly consisted of grassland, forest land, and cultivated land. From 2010 to 2018, the land use types remained relatively stable with limited interchangeable transformation among cultivated land, forest land, and grassland.(2) The habitat quality of Yan′an City was at the medium level, and the area of higher habitat quality levels accounted for more than 50% of the total area. The distribution pattern of habitat quality was higher in the southeast and southwest, and lower in the north. During the study period, the habitat quality index of Yan′an City decreased by 1.4%, and this trend was the most evident in central Baota District due to urbanization.(3) The habitat quality of Yan′an City had a certain degree of spatial aggregation. The “H-H” cluster is mainly located in the southwest forest region, while the “L-L” cluster is mainly located in Wuqi County in the northwest and Yanchang and Yichuan counties in the east. From 2010 to 2018, the spatial agglomeration of habitat quality tended to be scattered, and a large point degradation was observed in the central part.(4) The GCLC project had negative impact on the habitat quality of Yan′an City to a certain degree. Yan′an City maintained a relatively stable habitat quality and fulfilled the red line for cultivated land and food security concomitantly through ecological protection modes adapted to local conditions, resulting in a balance between quality development and ecological protection.