Epsilon Archive for Student Projects

Abstract

Riparian forests serve as critical buffers between terrestrial and aquatic ecosystems, particularly in boreal headwaters where biodiversity is sensitive to land-use disturbances such as forest harvesting. This study investigates the short-term impacts of different riparian buffer designs on the biodiversity and community composition of aquatic macroinvertebrates in seven headwater streams in northern Sweden. Using a Before-After-Control-Impact (BACI) approach, the study compared macroinvertebrate metrics before and after riparian forest harvesting across various treatment and reference sites. Key biodiversity indicators, including total abundance, species richness, and richness and abundance of sensitive EPT taxa (Ephemeroptera, Plecoptera, Trichoptera), were assessed alongside habitat variables such as buffer width, stream substrate composition, and stream size.

The results indicated no statistically significant short-term effects of riparian harvesting on macroinvertebrate community structure across the studied sites, suggesting that the riparian buffer practices – which were distinct in design, exceeding typical standards in terms of width, structural complexity, and were specifically tailored to the characteristics of each site – may be sufficient to maintain ecological integrity in the immediate aftermath of harvesting. Furthermore, buffer width did not significantly correlate with biodiversity metrics, whereas substrate composition, particularly the presence of bryophytes and coarse substrates, showed stronger correlations with macroinvertebrate diversity. Catchment area, as an indicator of stream size, had no significant correlation with biodiversity. These findings highlight the importance of local habitat features over buffer width alone and suggest that ecological responses to forest management may take longer to manifest. Long-term monitoring is recommended to capture delayed or cumulative effects.