Abandonment of salvage logging in windthrown stands is key to protection of late-succession carabid assemblages

Abstract

The usual practice in forest stands following a windthrow event is to perform salvage logging of all broken trees with their crowns before seedlings are planted. Does leaving broken tree crowns on the ground afford shelter for forest species? Epigeic carabids (Coleoptera) were the test taxon. The following hypotheses were put forward: (1) the more severe the disturbance, the higher the abundance and species richness, and the lower the proportion of late successional fauna in carabid assemblages, (2) crowns of pine trees lying on the ground support a higher proportion of late-successional carabid species, which effect should be more pronounced in more severely disturbed stands, but will decrease as needles fall off over the next 3 years. In order to verify the first hypothesis, 3 variants of stand disturbance (severely, moderately and least disturbed stands) were distinguished. The second hypothesis was verified by distinguishing additional variants at locations under and between tree crowns in the severely and moderately disturbed stands. Hypothesis 1 was proved correct and hypothesis 2 was proved partially correct. Simultaneously, it was demonstrated that the importance of the leaf area index for carabids decreased over the 3 years, while the significance of environmental indices, such as soil respiration rate and soil humidity, increased. This study indicates that there is a rationale for leaving in place at least some crowns lying on the ground in windthrown forest stands to provide shelter for forest species.