Epsilon Archive for Student Projects

Abstract

Clear-cutting and retention forestry practices have long-lasting ecological impacts, yet their consequences on biodiversity and more specifically on arthropod communities decades after implementation remain poorly understood. This study investigates the differences in ground-dwelling carabid beetle and spider diversity and communities in a Swedish boreal forest, 30 years post-implementation.

Both taxa were sampled using standardized pitfall trapping with an equal division of traps among clear-cuts, retention patches and set asides in the Hälsingland area in central Sweden.

The analysis of alpha-diversity revealed that only abundance patterns and not species richness nor evenness differed significantly with forest treatments. Carabid abundance was highest in set asides, suggesting sensitivity to structural simplification in highly disturbed sites while spider abundance peaked in clear-cuts, likely driven by the dominance of disturbance-tolerant wolf-spiders (Lycosidae).

Beta-diversity analysis showed only minor abundance-based compositional differences and no shift in species presence/absence for carabids, reflecting greater resilience or generalist behaviour. In contrast, spider communities exhibited significant compositional shifts, indicating lasting legacy effects of clear-cutting. Retention patches partially mitigated biodiversity loss, particularly for carabids but failed to restore pre-disturbance community structures when compared to the set asides.

These findings highlight taxon-specific resilience and suggest that while retention forestry offers benefits, it is not a replacement for conservation measures such as set asides. Future research needs to incorporate multi-factorial analysis and long-term monitoring to better inform sustainable forest management strategies.