The recovery of ant communities in regenerating temperate conifer forests

Although ants perform many critical functions in forested ecosystems, little is known about how they respond to timber harvesting, especially in temperate systems. We examined ground-foraging ant communities and 11 forest characteristics in temperate conifer forests of southwestern Oregon, USA that ranged in age from 5 to 427 years. Seven forest characteristics were related to stand age and were summarized using principal components analysis (PCA). In this case study, species richness was nearly three times higher in young clearcuts compared to closed-canopy and old stands, and worker number was highest in young stands, lowest in closed-canopy stands, and intermediate in old stands. Using stepwise multiple regression, we found that both species richness and worker number were significantly related to PCA axis 1, which represented the environmental changes that accompany stand development, and canopy variability. Though species richness was high in recently logged stands, our study suggests that, in this system, the ant community does not resemble those found in mature forests until over 100 years following disturbance. Because ants modify their environment and perform ecosystem functions like seed dispersal, the alteration of ant communities may cascade through other parts of ecosystems.