Impact of landscape pattern on habitat quality in typical karst areas and analysis of its driving factors

The heterogeneity of karst landforms is strong. The superimposition of natural fragmentation and human activities further divides the habitats. The mechanism by which the fragmentation of the landscape pattern affects species migration, gene flow, and ecosystem functions remains unclear. This study is based on land use data and natural geographic data (DEM, karst landforms, soil types, slope, soil layer thickness, comprehensive vegetation coverage, bare rock exposure rate, and rocky desertification degree) of Guizhou Province from 2000 to 2020, this study analyzed various landscape pattern indices and habitat quality during the 20-year period, by exploring the effects of different landscape pattern indices on habitat quality at global and local scales. The results showed that the level of land use in Guizhou Province increased and the structure stabilized during the 20-year period (LPI: 58.3044→66.9573), and landscape fragmentation decreased (AI: 88.3015→88.7391) and connectivity weakened (CONTAG: 56.5393→55.9076). Habitat quality had large spatial distribution differences, with an overall annual average decline rate of 5.59% from 2000 to 2020. There was a strong local spatial autocorrelation between landscape pattern index and habitat quality. Globally, AI, COHESION, CONTAG and LPI were positively correlated with HQ (AI: r = 0.45; COHESION: r = 0.34; CONTAG: r = 0.39; LPI: r = 0.42), while LSI, PD, SHDI and SPLIT were negatively correlated with HQ (LSI: r=-0.45; PD: r=-0.44; SHDI: r=-0.52; SPLIT: r=-0.28). From a local perspective, “H-H” and “H-L” types are interspersed in non-karst areas and karst trough valleys, “L-H” and “L-L” types are interspersed in karst trough valleys and karst plateaus, and “H-L” and “L-H” types are interspersed in karst canyons, peak-tufted depressions, and faulted basin areas. Habitat quality degradation is the result of the nonlinear superposition of natural vulnerability (bedrock exposure rate, soil thickness) and human activities (land expansion for construction, agricultural intensification). After 2010, the driving mechanism in Guizhou Province shifted from “nature-led” to “human-land interaction”. The results of this study can help to further understand the ecological environmental problems in Guizhou Province, and provide theoretical references for the formulation of ecological environmental protection policies and ecological functional zoning in Guizhou Province.