ABSTRACT Aim Forests across Central Europe are undergoing rapid changes driven by disturbance and climate variability, with uncertain consequences for insect biodiversity. Lepidoptera, being sensitive to habitat structure and microclimatic conditions, are ideal model organisms to study these dynamics. We assessed how forest disturbances, temperature variability, and tree cover shape the species richness of butterflies, moths, and macro‐moths. Location Germany. Taxon Lepidoptera (butterflies, moths, macro‐moths). Methods We combined nationwide unstructured citizen science data with species distribution modelling and sampling‐bias correction to estimate temporal species richness. Mixed‐effects models were used to relate species richness to forest disturbance, thermal variability and tree cover. Results Butterfly richness remained relatively stable between 2015 and 2019, whereas moth richness initially increased before declining in later years. Young forest disturbances (< 5 years) were positively associated with species‐rich communities in both butterflies and moths, whereas richness declined with increasing time since forest disturbance. Temperature variability, measured as the standard deviation of summer daily mean temperatures, was positively related to moth richness but negatively related to butterfly richness, suggesting contrasting sensitivity related to diel activity patterns. Tree cover showed weakly positive associations with butterfly richness but negative associations with moth richness. Main Conclusions Disturbance and temperature variability jointly structure Lepidoptera communities. Young canopy gaps enhance habitat heterogeneity and resource availability, while moderate temperature variability may expand microclimatic niches for moths but impose stress on diurnal butterflies. Our nationwide analysis highlights the importance of conserving a fine‐scale mosaic of successional forest stages and structural heterogeneity to sustain Lepidoptera biodiversity and promote resilient forests under accelerating climate change.
Khaliq et al. (Sun,) studied this question.