<scp>InVEST</scp> Model and Landscape Indices Reveal Habitat Quality Degradation From Land Use Changes in South China

The intensification of human activities has degraded the ecological environment of Hunan Province in South China. Existing studies on the province's habitat quality (HQ) primarily focus on specific landscapes or geomorphic zones, lacking quantitative analysis of the contribution of land use and land cover change (LULC) to HQ changes, as well as the application of landscape indices to characterize HQ dynamics. This study evaluated HQ changes in Hunan Province from 2000 to 2023, landscape indices, and spatial autocorrelation analysis. The results indicate that LULC was dominated by forestland (62.16%-62.6%) and cultivated land (27.82%-28.83%), and HQ was mainly categorized as high-quality (40.73%-42.23%) and medium-quality (24.14%-25.1%), with them concentrated in the mountainous regions, central plains, and lakeshores of western, southern, and eastern Hunan. For both LULC and HQ, landscape fragmentation, instability, and heterogeneity increased over the study period. LULC changes were primarily driven by the mutual conversion between cultivated land and forestland (-30.26% to +29.86%) and the expansion of built-up land (mainly converted from other land types); HQ degradation (high to low-quality) was most frequent during the 2015-2020 period. Specifically, the conversion of cultivated land to forestland had a positive effect on the total HQ (+29.86%), whereas the conversion of forestland to cultivated land reduced HQ (-30.26%); the conversion between built-up land and other land types exerted the most significant effect on the average HQ (> 4.93%). A strong positive spatial autocorrelation was observed between LULC and HQ indices, with significant clustering in mountainous and urban regions. This study demonstrates that LULC changes, particularly irreversible urbanization, drive HQ degradation by increasing landscape fragmentation and heterogeneity. To mitigate ecological fragmentation, sustainable land-use planning must prioritize forestland conservation, cultivated land protection, and rational urban expansion. Additionally, integrating LULC monitoring with HQ assessments is critical for balancing socioeconomic development and ecological integrity in South China.