Browsing by Author "Wilby, Robert L."

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    Extreme low flow effects on riverine fauna: a perspective on methodological assessments
    (Wiley, 2022-03-29) White, James C.; Aspin, Thomas; Picken, Jessica Louise; Ledger, Mark E.; Wilby, Robert L.; Wood, Paul J.
    River flow regimes face increasing pressure from human activities including water resource management operations and climate change. Consequently, extreme hydrological events are becoming more severe and commonplace, and there is a pressing need to understand and manage their ecological effects. Extreme low-flows (ELFs) – those displaying significantly greater magnitudes and durations than typical low-flow conditions – are being increasingly experienced globally. Fish and macroinvertebrate responses to ELFs have been more widely researched relative to other organism groups in riverine environments, although such studies have employed variable methodological techniques. In this perspective piece, we identify field-based assessments and controlled experiments as two key research paradigms used to examine riverine faunal responses to ELFs. Field-based assessments are often explorative and can benefit from utilising large-scale and long-term datasets. Alternatively, controlled experiments typically employ more hypothesis-driven approaches and can establish strong cause and effect linkages through high replication and control over potentially confounding parameters. Each paradigm clearly possesses their respective strengths, which we highlight and discuss how these could be better harnessed to optimise scientific advancements. To date, studies examining faunal responses to ELFs in these two research paradigms have largely been undertaken in parallel. Here, we argue that future research should seek to develop closer synergies to optimise the quality and quantity of evidence to better understand riverine faunal responses to ELFs. Such scientific advances are of paramount importance given the vulnerability of riverine fauna, and the ecosystems they comprise, as they face a new era of ELFs in many global regions.
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    Small Water Bodies in Great Britain and Ireland: Ecosystem function, human-generated degradation, and options for restorative action
    (Elsevier, 2018-07-26) Riley, William D.; Potter, Edward C. E.; Biggs, Jeremy; Collins, Adrian L.; Jarvie, Helen P.; Jones, J. Iwan; Kelly-Quinn, Mary; Ormerod, Steve J.; Sear, David A.; Wilby, Robert L.; Broadmeadow, Samantha; Brown, Colin D.; Chanin, Paul; Copp, Gordon H.; Cowx, Ian G.; Grogan, Adam; Hornby, Duncan D.; Huggett, Duncan; Kelly, Martyn G.; Naura, Marc; Newman, Jonathan R.; Siriwardena, Gavin M.
    Small, 1st and 2nd-order, headwater streams and ponds play essential roles in providing natural flood control, trapping sediments and contaminants, retaining nutrients, and maintaining biological diversity, which extend into downstream reaches, lakes and estuaries. However, the large geographic extent and high connectivity of these small water bodies with the surrounding terrestrial ecosystem makes them particularly vulnerable to growing land-use pressures and environmental change. The greatest pressure on the physical processes in these waters has been their extension and modification for agricultural and forestry drainage, resulting in highly modified discharge and temperature regimes that have implications for flood and drought control further downstream. The extensive length of the small stream network exposes rivers to a wide range of inputs, including nutrients, pesticides, heavy metals, sediment and emerging contaminants. Small water bodies have also been affected by invasions of non-native species, which along with the physical and chemical pressures, have affected most groups of organisms with consequent implications for the wider biodiversity within the catchment. Reducing the impacts and restoring the natural ecosystem function of these water bodies requires a three-tiered approach based on: restoration of channel hydromorphological dynamics; restoration and management of the riparian zone; and management of activities in the wider catchment that have both point-source and diffuse impacts. Such activities are expensive and so emphasis must be placed on integrated programmes that provide multiple benefits. Practical options need to be promoted through legislative regulation, financial incentives, markets for resource services and voluntary codes and actions.