Blue consequences of the green bioeconomy: Clear‐cutting intensifies the harmful impacts of land drainage on stream invertebrate biodiversity

Abstract

1. Growing bioeconomy is increasing the pressure to clear-cut drained peatland forests. Yet, the cumulative effects of peatland drainage and clear-cutting on the biodiversity of recipient freshwater ecosystems are largely unknown.2. We studied the isolated and combined effects of peatland drainage and clearcutting on stream macroinvertebrate communities. We further explored whether the impact of these forestry-driven catchment alterations to benthic invertebrates is related to stream size. We quantified the impact on invertebrate biodiversity by comparing communities in forestry-impacted streams to expected communities modelled with a multi-taxon niche model.3. The impact of clear-cutting of drained peatland forests exceeded the sum of the independent effects of drainage and clear-cutting, indicating a synergistic interaction between the two disturbances in small streams. Peatland drainage reduced benthic biodiversity in both small and large streams, whereas clear-cutting did the same only in small streams. Small headwater streams were more sensitive to forestry impacts than the larger downstream sites. 4. We found 11 taxa (out of 25 modelled) to respond to forestry disturbances. These taxa were mainly different from those previously reported as sensitive to forestry-driven alterations, indicating the context dependence of taxonomic responses to forestry. In contrast, most of the functional traits previously identified as responsive to agricultural sedimentation also responded to forestry pressures.In particular, taxa that live temporarily in hyporheic habitats, move by crawling, disperse actively in water, live longer than 1 year, use eggs as resistance form and obtain their food by scraping became less abundant than expected, particularly in streams impacted by both drainage and clear-cutting.5. Synthesis and applications. Drained peatland forests in boreal areas are reaching maturity and will soon be harvested. Clear-cutting of these forests incurs multiple environmental hazards but previous studies have focused on terrestrial ecosystems. Our results show that the combined impacts of peatland drainage and clearcutting may extend across ecosystem boundaries and cause significant biodiversityThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Drainage‐induced browning causes both loss and change of benthic biodiversity in headwater streams

“…The few previous studies that have addressed the impacts of peatland management on benthic biodiversity have generally shown that drainage-induced changes to stream habitat and/or water quality reduce invertebrate diversity in recipient streams (Ramchunder et al 2012;Brown et al 2019;Rajakallio et al 2021). Similarly, in a study of 18 streams in northern Sweden, Jonsson et al (2017) concluded that DOC and pH were the main drivers of benthic invertebrate richness and community composition.…”

Protecting our streams by defining measurable targets for riparian management in a forestry context

“…We draw on our experience working on riparian buffers with other researchers, managers, practitioners and policymakers in Canada (the province of British Columbia—BC), Finland and Sweden (e.g. Hasselquist et al., 2021; Jyväsjärvi et al., 2020; Kuglerová et al., 2020; Rajakallio et al., 2021; Richardson et al., 2012; Richardson & Béraud, 2014), but our conclusions are likely applicable to other forestry jurisdictions. We write this perspective to highlight that a dialogue among policymakers, managers and scientists is urgent to identify key priorities and actions aimed at improving local best‐management‐practices for freshwater and riparian protection.…”