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Preparing for Climate Change Impacts on Freshwater Ecosystems (PRINCE): Literature Review and Proposal Methodology

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Preparing for Climate Change Impacts on Freshwater Ecosystems (PRINCE): Literature Review and Proposal Methodology Preparing for climate change impacts on freshwater ecosystems (PRINCE): literature review and proposal methodology Science Report: SC030300/PR SCHO0805BJJF-E-E The Environment Agency is the leading public body protecting and improving the environment in England and Wales. It’s our job to make sure that air, land and water are looked after by everyone in today’s society, so that tomorrow’s generations inherit a cleaner, healthier world. Our work includes tackling flooding and pollution incidents, reducing industry’s impacts on the environment, cleaning up rivers, coastal waters and contaminated land, and improving wildlife habitats. This report is the result of research commissioned and funded by the Environment Agency’s Science Programme. Published by: Authors: Environment Agency, Rio House, Waterside Drive, Aztec West, Dr Kieran Conlan1 Almondsbury, Bristol, BS32 4UD Professor Stuart Lane2 Tel: 01454 624400 Fax: 01454 624409 Professor Steve Ormerod3 www.environment-agency.gov.uk Trevor Wade1 ISBN: ISBN 1844324729 Dissemination Status: Publicly available © Environment AgencyggggggggggggggggggggNovember 2005 Keywords: Climate change, freshwater ecosystems, modelling, This report is the result of work by the Environment Agency with management implications contributions from the Countryside Council for Wales (CCW) and English Nature Research Contractor: All rights reserved. This document may be reproduced with prior 1 Cascade Consulting permission of the Environment Agency. Enterprise House, Manchester Science Park, Lloyd Street North, Manchester M15 6SE. Tel: 0161 227 9777 The views expressed in this document are not necessarily those of the Environment Agency. Environment Agency’s Project Manager: This report is printed on Cyclus Print; a 100% recycled stock, Dr Harriet Orr, Environment Agency Research Fellow (Climate which is 100% post consumer waste and is totally chlorine free. Change), Hysed, Geography Department, Lancaster University, Water used is treated and in most cases returned to source in Lancaster LA1 4YB better condition than removed. Collaborator(s): Further copies of this report are available from: 3 The Environment Agency’s National Customer Contact Centre by Cardiff University, Department of Biology, Ecological Processes 2 emailing [email protected] or by Durham University, Department of Geography telephoning 08708 506506. Science Project Number: SC030300 (X1-045/3) Product Code: SCHO0805BJJF-E-P Project record Preparing for climate change impacts on freshwater ecosystems (PRINCE): Literature review and proposal methodology Science at the Environment Agency Science underpins the work of the Environment Agency. It provides an up-to-date understanding of the world about us and helps us to develop monitoring tools and techniques to manage our environment as efficiently and effectively as possible. The work of the Environment Agency’s Science Group is a key ingredient in the partnership between research, policy and operations that enables the Environment Agency to protect and restore our environment. The science programme focuses on five main areas of activity: • Setting the agenda, by identifying where strategic science can inform our evidence- based policies, advisory and regulatory roles; • Funding science, by supporting programmes, projects and people in response to long-term strategic needs, medium-term policy priorities and shorter-term operational requirements; • Managing science, by ensuring that our programmes and projects are fit for purpose and executed according to international scientific standards; • Carrying out science, by undertaking research – either by contracting it out to research organisations and consultancies or by doing it ourselves; • Delivering information, advice, tools and techniques, by making appropriate products available to our policy and operations staff. Steve Killeen Head of Science Executive Summary Introduction Preparing for Climate Change Impacts on Freshwater Ecosystems (PRINCE) was commissioned by a consortium led by the Environment Agency in partnership with English Nature and the Countryside Council for Wales. The key objectives of the project are to: i) review information and understanding of the implications of climate change for freshwater ecosystems; ii) inform a wide range of policies about ecosystem management implications; iii) communicate an improved understanding of climate change effects; iv) apply this to predictions of consequences in selected ecosystems. The fundamental approach is to determine potential climate change impacts on freshwaters, from the perspective of both the physico-chemical (abiotic) drivers of ecosystem function together with the process-based ecosystem (biotic) interactions that influence habitat, assemblage and/or species functioning and dynamic evolution. PRINCE addresses climate impacts on freshwater ecosystems and will provide information for UK Agencies on the likely future impacts and implications for the management of freshwaters. The approach incorporates responses to changes in the mean and variability of the future climate (both high and low rainfall, river flows, etc.). Climate change scenarios A number of general circulation models (GCMs) are currently available to simulate future climate, each of which gives differing results, particularly at regional scales. To date, the UK Climate Impacts Programme (UKCIP) 2002 scenarios have been applied most widely, and for consistency form the basis of the current analysis. It is acknowledged, however, that these scenarios tend towards drier future predictions relative to other GCMs. With this in mind, data provided by UKCIP demonstrate that under medium–high emissions there will be more hot and dry summers, with over half of the summers by the 2080s similar to the hot, dry summer of 1995. The significance of this for freshwater ecosystems is that drought conditions would be far more prevalent, particularly in south-east England. There would also be a shift to a greater proportion of wetter winters such as that experienced in 1994/1995, particularly in the north and west, although the shift is less pronounced than the projected increase in summer drought. Groundwater recharge would also be reduced and flows in groundwater-dominated rivers are projected to decrease throughout the year. The proposed research will use downscaled scenarios projected for the 2020s and 2050s to explore impacts on selected ecosystems. Project record Preparing for climate change impacts on freshwater ecosystems (PRINCE): Literature review and proposal methodology Ecosystem typology A freshwater ecosystem typology was developed for the PRINCE project to group freshwater environments that may have similar climate sensitivities. The typology drew on international and national regulations and typologies where relevant. Three classes were identified: • rivers and streams: upland and lowland headwaters, middle and lower river reaches, and predominantly groundwater-fed rivers (chalk or sandstone); • standing open waters and canals: lakes (eutrophic to dystrophic), ditches, ponds, canals and reservoirs; • wetlands and washlands: grazing marsh and improved grasslands on floodplain, lowland raised bog, fens, reedbeds and wet woodlands. Key non-biological factors that influence ecosystem dynamics • Potential changes in climate are likely to influence the aquatic ecosystem in two ways, by episodic pulsed effects (i.e., changes in the frequency, duration and magnitude of extreme events) and by progressive change in average conditions. Thermal effects Many freshwater species are sensitive to the water thermal regime and often have a limited range of temperature tolerance. Thermal regime is also critical to the life cycle of a wide range of aquatic organisms, and often creates the spatial separation of closely related species. Along with features such as velocity or depth preference, thermal regime has been a major influence on the evolved traits of organisms. Thermal regime may also influence: • biotic vital rates (metabolism, respiration and/or production), often in conjunction with water velocity and temperature-dependent concentrations of dissolved oxygen; • life cycles and inter-relationship of a wide range of organisms from the invertebrates, amphibians, fish and birds that are controlled by temperature and/or by the seasonal hydrograph; • linkages, dispersal or migrations across ecosystems, for example between marine systems and freshwaters by long-distance migrants (Atlantic salmon, eel, shad), or across watersheds during inter-basin dispersal flights by invertebrates; • introduction, survival and population dynamics of exotic organisms, such as non- native species. Water quantity effects As well as effects on annual flow regimes and individual event hydrographs, changed water quantity will also modify velocity profiles, hydraulic character, water levels, inundation patterns, the cyclical changes in the amount of available water and changes in wetted perimeter. All of these can influence local habitat conditions, availability and Project record Preparing for climate change impacts on freshwater ecosystems (PRINCE): Literature review and proposal methodology connectivity. In addition, the frequency, timing and magnitude of extreme events of both low and high discharge will change markedly in future climates. The consequences for habitat configuration, availability and quality will depend both on local conditions and on the habitat distribution or adaptability of affected organisms. Water-quality
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