Altitudinal diversity patterns of ground beetles (Coleoptera: Carabidae) in the forests of Changbai Mountain, Northeast China

Little is currently known about the biodiversity harboured by China's last remaining pristine temperate forests. Especially, studies into the diversity patterns of highly diverse insect taxa are very rare, while such studies are highly valuable, for example, as baseline to evaluate the effectiveness of China's ongoing large-scale reforestation efforts in restoring forest biodiversity. We sampled ground beetles (Coleoptera: Carabidae) on 33 plots distributed across five distinct mature forest ecosystems occurring at altitudes between 700 and 2000 m on Changbai Mountain to address these prevailing knowledge gaps. Pitfall trapping yielded a total of 4834 ground beetles representing 47 species. Carabid abundance increased while α-diversity decreased with increasing elevation. No significant correlation was observed between the abundance of common species and their elevational distribution. Beetle assemblages originating from the high-elevation forest types formed a partly overlapping cluster, while beetle assemblages at lower elevations were more strongly differentiated according to forest type. Our results support the assumption that carabids are highly sensitive to climate change. The Korean pine-dominated forest, which has not previously been distinguished as a discrete forest type, showed a distinct carabid beetle composition, indicating its requirement of specific conservation attention. The carabid diversity in high-elevation birch forest and low-elevation mixed broad-leaved and conifer forests is particularly threatened by climate change, and long-term future monitoring of ground beetle diversity on Changbai Mountain is expected to provide extremely valuable insights into climate change-effects on insect communities in China's pristine temperate forests.