Abstract
<title>Abstract</title> <p>Ground-active arthropods are sensitive to forest-floor habitat structure, but their responses to recreational use may not appear as simple declines in total captures. We examined ground-active arthropod assemblages along a recreational-use gradient in Zijin Mountain, Nanjing, eastern China, where nine observation sites were classified into high-use (HRD), moderate-use (MRD) and low-use (LRD) categories using a visual interpretation disturbance score. Arthropods were repeatedly sampled with pitfall traps from July to December, and vegetation cover, litter cover and litter thickness were measured to characterize habitat structure. Recreational-use categories differed mainly in litter-layer structure rather than broad vegetation cover: HRD sites had thinner litter and lower litter cover, whereas tree, shrub and herb cover did not differ significantly among categories. HRD sites showed the highest activity density, but lower rarefied taxon richness, Shannon diversity and Pielou’s evenness, together with higher Berger–Parker dominance. Rank–abundance patterns and dominance metrics indicated that this high activity density reflected dominance concentration rather than a broad increase across taxa, with Formicidae accounting for nearly half of total abundance in HRD. By contrast, LRD had a more distributed abundance structure, with greater contributions from Blattodea, Gryllidae, Araneae and other intermediate-abundance taxa. Community composition differed among recreational-use categories, but sampling date explained a larger fraction of compositional variation, indicating strong seasonal turnover. HRD also had higher proportions of omnivorous and high-dispersal taxa and lower community-weighted body length, whereas LRD had higher proportions of detritivore-associated, predator-associated and low-dispersal taxa. These results suggest that ground-active arthropod assemblages along this recreational-use gradient differed mainly through dominance concentration, dominant-taxon composition, litter-associated habitat context, functional-composition shifts and seasonal turnover, rather than through a simple reduction in total activity density. Maintaining litter cover and ground-layer heterogeneity may help sustain more even forest-floor arthropod assemblages in heavily visited forest patches.</p>