Recovery of ground-dwelling assemblages during reforestation with native oak depends on the mobility and feeding habits of the species

Abstract

Timber-oriented forest management causes significant changes to the environments, threaten the survival of many native species and it is responsible for the primary forest loss. Recognition of the scale and effects of the primary forest loss has resulted in a considerable degree of interest in the restoration. One of the serious efforts at restoration is the compulsory reforestation of the clear-felled stands of any (native or non-native) forests with native species. To evaluate the success of restoration efforts it is important to answer whether the diversity and composition of indigenous assemblages can recover after reforestation with native trees and to know how long is the recovery time? We studied ground beetles and millipedes from mature (130-year-old) oak forest, and recently established (5-year-old), young (15-year-old), and middle-aged (45-year-old) reforestation with native English oak by pitfall trapping and leaf litter sifting to assess the recovery dynamics of their diversity and composition. The overall number of the ground beetle individuals and species were significantly the highest in the 5-year-old reforestation, while the overall number of millipede individuals and species were significantly the lowest in the recently established reforestation. The elevated overall number of ground beetle individuals and species in the 5-year-old reforestation were due to the colonization of good disperser open-habitat species. The number of forest-associated ground beetle individuals and species were significantly the lowest in the 5-year-old reforestation, whereas from 15years after the reforestation, when the canopy has been closing, there was no significant difference in the number of forest species. The number of forest-associated millipede individuals and species were significantly the lowest in the 5-year-old reforestation; however, they were significantly the highest in the natural mature oak forest. Results of both the ordination and the quantitative character species analysis also confirmed that reforestation with native oak after mechanical soil treatment had detrimental effects on both studied ground-dwelling arthropod groups. The diversity and composition of ground beetles with high dispersal ability and less specific feeding habit recovers after the closure of the canopy, while similar recovery do not occur regarding millipedes with low dispersal ability and specific feeding habit. Our results suggest that soil preparation and light tilling should be omitted during the reforestation and cultivation of the reforested stands.