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.

Cover crop in orchards is recognized as a sustainable practice that enhances multiple ecosystem services, yet systematic evaluations of different cover crop management models in citrus orchards remain limited. This study investigated the effects of cover crop management models (natural cover crop: T1, Lolium perenne L.: T2, Trifolium repens L.: T3, Vicia villosa Roth: T4, and mixed cover crops: T5) on soil properties, soil CO₂ flux, leaf physiological traits, fruit quality, and yield in a citrus orchard, using clean tillage as a control. Results showed that cover crop management models significantly influenced soil water content, available nitrogen (AN), available phosphorus (AP), and available potassium (AK). The V. villosa model (T4) reduced AN and AP but enhanced leaf chlorophyll (Cl) and nitrogen (N) content. Soil CO₂ flux was significantly higher under T4, and it showed the lowest soil moisture. The results of mantel tests revealed that AP and soil moisture were key drivers of leaf traits, though no significant treatment effects on fruit quality or yield were detected within the two-year experimental period. These findings indicate that cover crop management models rapidly alter soil properties and CO₂ emissions, but longer-term observations are needed to evaluate cascading effects on fruit. This study offers evidence-based soil management solutions and a framework for enhancing multiple ecosystem services in orchards worldwide.