Objective Carabid beetles (Coleoptera: Carabidae) are widely distributed and highly sensitive to environmental changes, making them important bioindicators. This study aimed to clarify the faunal composition and large-scale spatial distribution patterns of carabid beetles in typical temperate forests in China, and to provide a scientific basis for developing targeted biodiversity conservation strategies.

Method Study plots were established in nine nature reserves across different latitudinal zones in northern China. Ground-dwelling carabid beetles were collected throughout the growing season using pitfall traps, while vegetation community data were recorded simultaneously. Based on the sampling results, analyses of carabid diversity and faunal composition were conducted. In addition, generalized linear mixed models (GLMMs) were used to examine the relationships between carabid species richness and environmental factors such as elevation, vegetation, and climate.

Result (1) A total of 249 carabid species were collected, of which 190 were identified to species level, belonging to 8 subfamilies, 21 tribes, and 43 genera. At the genus level, monotypic genera (48.83%) and oligotypic genera (39.54%) were overwhelmingly dominant. (2) In terms of global zoogeographical distribution, the identified carabid species in the study area belonged to only six distribution types, dominated by Palaearctic species (61.05%) and species shared by the Palaearctic and Oriental realms (31.05%). Under the zoogeographical regionalization of China, the carabids in the study area were classified into 44 distribution types, among which the Northeast China type accounted for the highest proportion (31.05%). (3) Regarding spatial distribution patterns, carabid species richness was significantly negatively correlated with elevation (P < 0.05). Among the environmental factors examined, species richness was also significantly negatively correlated with herb-layer richness (P < 0.05).

Conclusion The study area harbors rich carabid diversity, and its faunal composition exhibits typical Palaearctic characteristics. Carabid species richness showed a significantly declining pattern with increasing elevation. Among the environmental factors considered, herb-layer richness was the main factor affecting carabid diversity. Therefore, scientific management of understory vegetation should be strengthened to provide suitable microhabitats for small invertebrates such as carabid beetles.