Putting the “Beaver” Back in Beverley Brook: Rapid Shifts in Community Composition following the Restoration of a Degraded Urban River

Abstract

Widespread habitat degradation has caused dramatic declines in aquatic biodiversity. Reconfiguring channels and adding physical structures to rivers has become common practice in order to reinstate natural processes and restore biodiversity. However, the effectiveness of such measures is often questioned, especially in urban settings where overriding factors (e.g., water quality) might constrain biotic responses to increased habitat heterogeneity. We monitored invertebrate and fish communities before and up to five years after extensive restoration of Beverley Brook, a small, urban river flowing through a Royal Park in London, UK. Total invertebrate density was 5–148% higher with restoration across the monitoring period, and there was an increase in evenness but not invertebrate richness. Riverflies (Ephmemeroptera and Trichoptera) and crustaceans (Amphipoda, Asellidae) showed marked increases in density with restoration, suggesting improved flow, enhanced water quality, and greater quantity of basal resources. Fish biomass increased by 282% with restoration as did fish richness and the average body mass of three common fish species. Our results provide evidence for the effectiveness of common restoration methods in increasing standing stocks across trophic levels, from basal resources to apex predators. However, we primarily observed changes in the density of existing taxa rather than the development of novel assemblages, suggesting that large-scale factors, such as water quality and the lack of adequate source populations, might be important for understanding changes in biodiversity following river restoration.

Biogeomorphological response to river restoration of a suburban river with large wood: Creating a restoration vision and cost‐effectively monitoring the response trajectory using the citizen science MoRPh survey

“…The gauged records (1935–2022, source: National River Flow Archive, station 39005) show a mean daily flow of 0.539 m 3 .s −1 , median daily flow (Q50) of 0.421 m 3 .s −1 and a 5% exceedance flow (Q5) of 1.266 m 3 .s −1 . The flow regime is affected by runoff from extensive (sub)urban land cover with treated sewage effluent contributing significantly to base flows (Perkins et al, 2021).…”

“…[Color figure can be viewed at wileyonlinelibrary.com] studied reach (and its location adjacent to wooded parts of Wimbledon Common, Figure 1) because all lowland rivers across southern England would have drained wooded catchments prior to landscape development by humans. Indeed, the name of the Beverley Brook originates from 'Beaver Ley' (Perkins et al, 2021), reflecting the Brook's likely wood-influenced historic character. To date, understanding of the likely effects of large wood emplacement in a river has been heavily based on studies of relatively steep, high-energy rivers (Matheson et al, 2017).…”

Research on the Sustainable Development of the Bistrita Ardeleana River in Order to Stop the Erosion of the Riverbanks and the Thalweg

“…In the last two decades, the revitalization of anthropogenic rivers has been established in Europe as a measure to achieve the good ecological status of water bodies, as required by the EU Water Framework Directive (European Commission, 2000), while protecting the objectives downstream of floods. The implementation of the Water Framework Directive in ensuring sustainable water management has been implemented taking into account river basins [1,25,26]. These legislative efforts and necessary actions conclusively aim at increasing the heterogeneity of ecosystems.…”

Research on the Sustainable Development of the Bistrita Ardeleana River through the Resizing of Weirs

“…In the last 20 years in Europe, the restoration of a water course to improve its qualitative or environmental status had to meet the legislative objectives of the European Union such as Directive 2000/60/EC-the framework of the Community policy in the field of water. These legislative efforts and the necessary actions are ultimately aimed at increasing the heterogeneity of ecosystems and the processes of hyporheic exchange [16,17].…”