Construction and pattern optimization of ecological network in Zhengzhou metropolitan area.

The rapid urbanization process has led to the increasingly prominent problems of ecological environment protection and optimization. The construction of ecological network system, planning to guide ecological values, and efficiently utilizing landscape effects are of great significance for regional regulation of ecological space and promotion of local sustainable development. Taking Zhengzhou metropolitan area as an example, based on land use data at eight time points from 1980 to 2020, using ArcGIS, Guidos Toolbox, Conefor and other tools, we outlined the ecological network with a high structural integrity in the study area. We used future land use simulation to predict future land pattern, morphological spatial pattern analysis to identify landscape elements, minimum cumulative resistance to construct comprehensive resistance surface, gravity model to calculate ecological gravity, hydrologic analysis to create resistance paths, and network structure evaluation, . The results showed that, among the nine source sites in the study area, the ecological sources in the Yellow River Basin connected the large-scale centralized source areas in the east and west of the network. The rest sources were located in the northeast, southeast, and southwest of the study area, which were distributed in a semi-circumferential manner around the main urban area of Zhengzhou. There were a total of 163 minimum cost paths and 58 ecological corridors, of which 10, 19 and 29 were primary, secondary and tertiary corridors, respectively, in the form of "three horizontals and three verticals" and "point-axis" along the Yellow River Basin distribution was dominant. A total of 70 ecological nodes were recored in the study area, which were divided into strategic points (10), natural ecological points (27) and artificial environment points (33). Those ecological nodes were distributed in key nodes such as the core of each source area and the intersection of corridors location. The ecological network included all the landscape elements in the study area and connected the main ecological substrates in a horizontal "C" shape. The overall performance was a semi-enclosed network structure of "one horizontal, two verticals and four groups".