Impacts of forestry on ant species richness and composition in warm-temperate forests of Japan

Abstract

To understand the long-term impacts of forestry, i.e., the conversion of old-growth native forests to second-growth native forests or conifer plantations, on ant species richness (i.e., the number of species) and species composition, ant assemblages from five old-growth forests (more than 120 years), four second-growth forests (30–70 years) and three conifer plantations (30–40 years) were compared in the Shimanto River Basin, Shikoku, southwest Japan. The number of ant species collected totaled 39. The number of ant species from the old-growth native forests, second-growth native forests and conifer plantations was 10–20, 15–20 and 11–15, respectively. The overall ant species richness had not been affected by forest conversion. However, correspondence analysis (CA) showed that the ant species composition was markedly different between old-growth forests and converted forests (second-growth forests and conifer plantations). The species richness of woodland specialists was greater in the old-growth forests, and open-habitat specialists and habitat generalists dominated the converted forests. The impacts of forestry on ant assemblages were of a long duration. Ant assemblages of the second-growth forests under regeneration for 40–70 years after logging were still distinct from those of old-growth forests. Careful management of second-growth forests bordering old-growth remnants would be essential to prevent the invasion of open-habitat species of ants into the interior of old-growth forests.