Ant utilization of tree trunks in relation to environmental factors in a temperate forest

Forests exhibit complex three-dimensional structures, wherein abiotic factors vary both vertically and horizontally. The interaction between organisms and these factors drives the remarkable biodiversity within forests. Tree trunks serve as vital conduits for organisms moving vertically within the forest, facilitating biodiversity maintenance. Organisms moving vertically through tree trunks in forests face varying abiotic conditions, which may enhance their resilience to long-term environmental changes. Despite numerous studies comparing canopy and ground communities, the distribution of organisms across multiple strata remains poorly understood. Here, we explore the correlation between the horizontal distribution of ants in a forest and environmental factors (topography, tree size, tree species), with a specific focus on their presence on tree trunks. Visual observations were conducted to document ant species richness on tree trunks, supplemented by pitfall traps to quantify soil arthropod biomass, serving as an indicator of protein availability. The results revealed that ant species richness on tree trunks varied based on topography and tree species, showing a positive correlation with tree size. However, no significant relationship emerged between soil arthropod biomass and ant richness on tree trunks. Furthermore, no discernible trend suggesting that certain species were less likely to co-occur was observed; instead, a tendency for some species to co-occur was found. These findings highlight the horizontal heterogeneity in the distribution of ants with respect to topography, tree species, and tree size within the forest.