Effects of forest disturbance on diversity of deadwood–associated beetles in the Green Zone of Ulaanbaatar, Mongolia

Forest disturbance alters habitat structure and strongly influences saproxylic beetle communities in boreal forests. We investigated how disturbance type and severity shape beetle diversity and community composition in the boreal forests of the Green Zone surrounding Ulaanbaatar, Mongolia. Using a fully factorial design (three forest types × four disturbance severity levels) sampled over three years, we quantified species richness, Shannon diversity, total abundance, and the abundance of fire-favoured beetles. Disturbance type, severity, and their interaction significantly influenced all response variables. Burnt forests supported higher diversity, richness, and abundance—particularly of fire-favoured taxa—than insect-damaged forests. Abundance of fire-favoured beetles declined from high-severity to control conditions, whereas Shannon diversity peaked at moderate disturbance, consistent with increased habitat heterogeneity. Differences in species richness were comparatively modest. Indicator species analyses highlighted the prominence of xylophagous taxa, particularly Buprestidae and Cerambycidae, under higher disturbance severity. Community composition differed markedly among disturbance types, with both disturbance-related variables and stand structural attributes jointly shaping assemblages. Our results highlight the importance of disturbance-generated post-disturbance habitat structures, particularly deadwood, in maintaining saproxylic biodiversity. Conservation-oriented forest management should prioritize the retention of post-disturbance substrates, especially following moderate to high-severity disturbances, to sustain biodiversity under increasing natural and anthropogenic impacts.