Construction of an urban ecological network and landscape optimization in Xi'an based on bird habitats.

By comprehensively revealing species habitat quality, spatial distribution characteristics and landscape structure information, the construction of refined urban biotope mapping can provide scientific support for optimizing the urban ecological pattern. As a key indicator species in urban ecosystems, bird habitat changes reflect environmental quality, making bird habitat optimization crucial for urban ecological planning and restoration. Based on Fragstats 4.2 software, we analyzed the biotope of the landscape pattern of Xi'an City by combining the factors of horizontal structure, vertical structure and forest type, and carried out cluster analysis based on the distribution data of birds to identify their habitat preference. We further combined the maximum entropy model and morphological spatial pattern analysis model to identify the ecological sources suitable for bird habitats and construct an urban ecological network with bird habitats as the core. The results showed that in the biotopes delineated in the study area, the grey biotope had the highest area share (87.8%), followed by the green biotope (5.5%), the farmland biotope (4.7%), and the blue biotope (2.0%). The results of landscape fragmentation analysis showed that the green biotope had the highest degree of fragmentation, followed by the blue biotope, farmland biotope, and grey biotope. The distribution frequency of birds in each biotope was in the order of grey biotope (63.2%) > green biotope (24.5%) > blue biotope (8.6%) > farmland biotope (3.4%). The results of cluster analysis showed that birds preferred to inhabit biotopes such as farmland, grassland, and semi-closed/semi-open mixed multi-storey forest. The ecological network constructed based on bird habitats identified 38 ecological sources, 69 ecological corridors, 40 ecological pinch points, and 54 ecological barriers. The construction of the urban ecological network centered on bird habitats could provide an important reference for urban habitat quality improvement, biodiversity conservation, and regional ecological planning.