Huntingdon, United Kingdom
Huntingdon, United Kingdom

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Vieira C.,University of Porto | Vieira C.,University of Lisbon | Aguiar F.C.,University of Lisbon | Portela A.P.,University of Porto | And 18 more authors.
Hydrobiologia | Year: 2016

Mediterranean watercourses are among the most threatened ecosystems worldwide, being increasingly important to understand environmental drivers of biotic assemblages. Our aim was to provide a comprehensive picture of bryophyte communities in Mediterranean rivers and to determine the environmental factors that influence their distribution. We used floristic data collected for inter-calibration purposes under the European Water Framework Directive and River Habitat Survey, from 474 river reaches in six countries of the European Mediterranean basin. We analysed data through classification, ordination and environmental niche modelling techniques, and classified taxa according to biogeographic and aquatic habitat frameworks developed specifically for bryophytes. These analyses revealed four types of communities influenced by spatio-temporal precipitation patterns, altitude and water chemistry factors, most notably calcium and manganese. Community types are compositionally differentiated, although they share some core taxa and show an overall tendency to have several temperate and exclusively aquatic taxa despite the intermittent nature of water flow in highly seasonal Mediterranean rivers. The modelling approach can be improved at a more local scale when more bryological data and higher-resolution environmental information become available. Given future scenarios of climate change and human alteration of hydrological regimes, broader scales studies are needed to monitor shifts in bryophyte communities. © 2016 Springer International Publishing Switzerland


Wilby R.L.,Loughborough University | Orr H.,UK Environment Agency | Watts G.,UK Environment Agency | Battarbee R.W.,University College London | And 16 more authors.
Science of the Total Environment | Year: 2010

It is widely accepted that climate change poses severe threats to freshwater ecosystems. Here we examine the scientific basis for adaptively managing vulnerable habitats and species. Our views are shaped by a literature survey of adaptation in practice, and by expert opinion. We assert that adaptation planning is constrained by uncertainty about evolving climatic and non-climatic pressures, by difficulties in predicting species- and ecosystem-level responses to these forces, and by the plasticity of management goals. This implies that adaptation measures will have greatest acceptance when they deliver multiple benefits, including, but not limited to, the amelioration of climate impacts. We suggest that many principles for biodiversity management under climate change are intuitively correct but hard to apply in practice. This view is tested using two commonly assumed doctrines: "increase shading of vulnerable reaches through tree planting" (to reduce water temperatures); and "set hands off flows" (to halt potentially harmful abstractions during low flow episodes). We show that the value of riparian trees for shading, water cooling and other functions is partially understood, but extension of this knowledge to water temperature management is so far lacking. Likewise, there is a long history of environmental flow assessment for allocating water to competing uses, but more research is needed into the effectiveness of ecological objectives based on target flows. We therefore advocate more multi-disciplinary field and model experimentation to test the cost-effectiveness and efficacy of adaptation measures applied at different scales. In particular, there is a need for a major collaborative programme to: examine natural adaptation to climatic variation in freshwater species; identify where existing environmental practice may be insufficient; review the fitness of monitoring networks to detect change; translate existing knowledge into guidance; and implement best practice within existing regulatory frameworks. © 2010 Elsevier B.V.


Boon P.J.,Scottish Natural Heritage | Holmes N.T.,Alconbury Environmental Consultants | Raven P.J.,UK Environment Agency
Aquatic Conservation: Marine and Freshwater Ecosystems | Year: 2010

Over the last 20 years the concept of 'freshwater quality' has expanded to incorporate a range of physical, chemical, hydromorphological and biological characteristics. In Europe, this process has been given greater impetus by the EC Water Framework Directive (WFD) and the requirement for Member States to assess and monitor a comprehensive suite of freshwater features. Assessments of river hydromorphology are needed not only for implementing the WFD but also for nature conservation purposes, such as monitoring the condition of Special Areas of Conservation under the EC Habitats Directive and helping in the management and restoration of rivers. At present there are few detailed methods available in Europe for assessing river hydromorphology, and standard approaches are urgently required. The European Committee for Standardization (CEN) works to promote voluntary technical harmonization in Europe in conjunction with worldwide bodies and its European partners. The production of a CEN standard for assessing the hydromorphological features of rivers began in September 1999 and culminated in the production of EN 14614 in November 2004. EN 14614 is a 'guidance standard' that provides a framework of general principles and sets out which aspects of river hydromorphology should be assessed, how to plan and conduct field surveys, how results should be interpreted and presented, and ways of applying quality assurance procedures. A second CEN standard on river hydromorphology has recently been published. Using simple scoring systems, this will enable the extent of hydromorphological modification to river channels, banks, riparian zones and floodplains to be recorded and assessed consistently. CEN standards encourage European collaboration and provide a framework which other countries can use to develop their own assessment methods. However, ways need to be found to streamline the process of standardization and to ensure that published standards influence the work of researchers, environmental regulators and policy makers. Copyright © 2010 John Wiley & Sons, Ltd.


Ferreira J.,Instituto Da A Gua Ip | Padua J.,Instituto Da A Gua Ip | Padua J.,EDP Energias de Portugal | Hughes S.J.,University of Trás os Montes e Alto Douro | And 5 more authors.
Limnetica | Year: 2011

The Water Framework Directive (WFD), which established the use of hydromorphological quality elements to assess the ecological status of water bodies, has influenced the purpose and content of several European methods for characterizing physical structure and assessing habitat quality in rivers. The River Habitat Survey (RHS) is a WFD compliant method developed in the UK and follows rapid and simple survey procedures using a standardised approach to characterize the physical habitat and evaluate hydromorphological quality. In Portugal, RHS was adopted for WFD purposes due to its successful long term application across the UK and other European countries. Even so, an effort was made to adapt the RHS to Portuguese regional and river characteristics, in order to accurately record habitat features, assess habitat quality and comply with legal requirements. This paper describes the constraints, adaptations, state of the art and way forward for a successful RHS implementation in Portugal. Constraints concerning the application of RHS to Mediterranean rivers are strongly related to natural hydromorphological processes, namely annual and inter-annual flow variability, which is a potential source of covariance with anthropogenic pressures. This leads to difficulties in recognizing and accurately recording some RHS features. Adaptations to RHS were introduced for survey guidelines, recording procedures and improved definitions of habitat features. Additional modifications were prepared in different sections of RHS field form to reflect Portuguese river features and incorporate components required by the WFD. © Asociación Ibérica de Limnología, Madrid. Spain.


Raven P.J.,Aztec | Holmes N.T.,Alconbury Environmental Consultants | Vaughan I.P.,University of Cardiff | Dawson F.H.,UK Center for Ecology and Hydrology | Scarlett P.,UK Center for Ecology and Hydrology
Aquatic Conservation: Marine and Freshwater Ecosystems | Year: 2010

Some ecological effects of physically modifying rivers are still unclear, partly due to scale factors, but also because the character of high quality habitat is poorly understood. Surveys at 278 sites on 141 near-natural streams and rivers in northern and western Europe were carried out between 1994 and 2009 to benchmark the habitat quality assessment system used for River Habitat Survey (RHS). The objectives were to establish if RHS was suitable outside the UK, investigate if 500 m was still valid as the survey length, suggest a benchmarking strategy and recommend improvements to habitat quality assessment protocols. Some modifications to RHS are needed to take account of differences in hydrological conditions, land-use and, most importantly, riparian habitat structure found in mainland Europe. On average, 82-87% of channel attributes and 87-98% of channel and bank features were recorded within the first of consecutive RHS sites, confirming that 500 m is an effective sample length for characterizing small rivers. Stream-flow character appeared to influence the distribution of several in-channel features, with greater diversity and between-site variation associated with rivers of mixed flow-types. To account for local variation and for effective use of survey time, it is recommended that two or more consecutive RHS sites are used for benchmarking purposes. A suite of assessment protocols with agreed criteria and analytical rules, linked to specific objectives (e.g. nature conservation, geomorphic condition), is needed to establish the character and habitat quality of rivers in a consistent fashion.8.A multi-discipline benchmarking programme using hydro-ecological regions in Europe would build on existing knowledge and help to improve both the inter-calibration and local application of quality assessment protocols. Data-sharing by hydrologists, river ecologists and fluvial geomorphologists would improve the basis for managing rivers in support of the European Water Framework Directive and Habitats Directive. Copyright © 2010 John Wiley & Sons, Ltd.


Mainstone C.P.,Natural England | Holmes N.T.H.,Alconbury Environmental Consultants
Aquatic Conservation: Marine and Freshwater Ecosystems | Year: 2010

The restoration of riverine habitats that have been physically modified by man has gained momentum over the past two decades, driven by a number of objectives. Formalizing the planning and implementation of such activity, however, so that it demonstrably meets national and local environmental objectives without compromising essential societal needs such as flood risk management, has proved problematic. This paper addresses the operational realities of river restoration in the UK as experienced in England by the authors, and in doing so attempts to provide a vision for how strategic planning and implementation of restoration measures sensitive to these realities might be introduced. Specifically, the paper explores:the prevailing perspectives on river restoration, shaped by both legislative drivers for ecosystem and biodiversity protection and the multiple uses made of rivers, their floodplains and catchments;how decisions have tended to be made to date and how the government agencies for environmental protection and biodiversity conservation in England are planning to make decisions in the future;the key obstacles to putting in place scientifically and technically robust, large-scale, long-term, economically viable plans for river restoration;the potential for using rivers with special conservation designations for wildlife as a springboard for a strategic approach to river restoration more widely. The issues hindering a strategic operational approach to river restoration in England are common to the rest of the UK and other developed countries grappling with the enormity of the river restoration challenge. To make real progress with river restoration, an operational decision-making framework is needed that promotes progressive and strategic action but at the same time gives everyone confidence that such action is realistic and worthwhile. Copyright © 2010 John Wiley & Sons, Ltd.

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