Individual movement of large carabids as a link for activity density patterns in various forestry treatments

Abstract

Activity density is one of the most common measures for ground-dwelling arthropods including carabids. The term refers to the empirical fact that pitfall trap catches depend on the individuals’ activity; the higher activity of the individuals, the more catches in the traps. Although the movement at the individual level is widely studied, there is no available evidence whether the individual movement can be a good proxy for activity density. In our study, we aimed to explore this link in two ground beetle species, Carabus scheidleri and C. coriaceus, in oak-hornbeam forest in Hungary. We used pitfall traps for activity density and capture-mark-recapture and radio telemetry to record individual movement patterns in different forestry treatments, preparation cuttings and clear-cuttings, and their control plots. We identified an indirect link between activity density and movement of individuals via treatment types. Although activity density, mean walking speed, and the proportion of active time were significantly higher in both treatments than in control plots, individual movement reveals only temporal use of these habitats. Beetles left treatments within a few days. We concluded that the high turnover of individuals in treatments might indirectly suggest that these habitats likely act as temporary foraging sites for both species.