Associations Between Environmental and Vegetation Factors and Insect Diversity in a Hydropower-Induced Compound Disturbance Landscape: A Case Study of the Three Gorges Dam Area

Insects are sensitive indicators of environmental change, but their responses to large hydropower landscapes remain insufficiently understood because dam areas combine hydrological regulation, shoreline modification, artificial surfaces, vegetation management, and local microclimatic change. This study investigated insect diversity (species richness, inverse Simpson index and exponential Shannon index) across seven survey sites in the Three Gorges Dam area during May, August, and October in 2022 and 2023. Field surveys were combined with environmental, landscape, and vegetation variables to examine associations between compound habitat conditions and insect assemblages. The results showed that insect diversity displayed remarkable seasonal variation, with the highest values (species richness: 16.14, inverse Simpson index: 11.69, exponential Shannon index: 13.57) in August and the lowest values in May (species richness: 5.43, inv Simpson index: 2.35, exponential Shannon index: 3.07), consistent with the plant growing season. Artificial building area proportion was negatively associated with observed species richness across the seven survey sites, whereas no clear association was detected for inverse Simpson or exponential Shannon diversity. Vegetation mixed-effects models indicated positive associations between NDVI and insect diversity after accounting for month, year, and repeated observations within sites. Other site-level environmental correlations were treated as exploratory because of the limited number of independent sites. These findings suggest that insect diversity in dam landscapes is associated with built-surface cover, seasonal vegetation dynamics, and local habitat conditions. Integrating insect surveys with remote-sensing indicators may support biodiversity monitoring and ecological management in large hydropower regions.