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Summary: The climate scenarios of the IPCC suggest that adaptation to future climate change will be required. The North Sea Region, a marginal sea of the Atlantic Ocean between Great Britain, Scandinavia, Germany, the Netherlands and Belgium, is particularly affected due to rising sea level and a changing water balance. Water management plays a key role in sustainable management of natural and societal resources. This paper presents a participatory study of community approaches to regional adaptation to climate change. Water management adaptation options to regional climate induced changes until 2050 were developed together with stakeholders for the Wesermarsch County (Northern Germany). Available information on expected regional climate change and a modelling study on hydrological change suggested that adaptation of water management will be required until 2050. A regional stakeholder forum formulated a vision on how the Wesermarsch should look like in 2050. Following the holistic approach of collaborative planning, two stakeholder groups developed an adaptation portfolio on how urban and rural areas could adapt their water management to cope with the expected changes. Since most of the stakeholders do not want the county to undergo significant changes in terms of landscape and land use, they proposed technical measures to enforce flood protection and enhance the performance of the existing water management system. Adaptation in terms of land use change was not proposed although information on comparable examples from similar regions was available. To justify the proposed adaptation options, available information on expected climate change impacts was used selectively. Uncertainty in model projections was partly ignored to legitimate suggesting inflexible (technical) adaptation measures. However, collaborative planning proved to be helpful for a joint adaptation to climate change at the regional scale. Stakeholders as well as scientists took active part in the participatory learning process as required by EU directives. [Copyright &y& Elsevier]

Changes in climate and water management are expected to result in increased stream drying (i.e., intermittency) in many regions, and these changes could affect ecological processes. Aquatic detritivores process organic matter that supports C cycling. Crayfish can contribute substantially to detrital processing; however, intermittency and biological communities interact to alter detrital pathways and processing rates. Our goals were to evaluate the effect of intermittency on leaf breakdown and to provide empirical evidence regarding whether the role of shredders, including crayfish, changes with intermittency. We hypothesized that different factors would control leaf breakdown in intermittent and perennial stream segments because stream flow and duration affect heterotrophic microbes and macroinvertebrate shredders. We predicted: 1) faster leaf breakdown in perennial segments compared to intermittent segments because of greater processing by microbes and shredders and more physical abrasion from increased discharge; 2) crayfish with access to both detritus and macroinvertebrate prey would function primarily as predators in perennial segments, potentially slowing decomposition; and 3) intermittent segments would have fewer macroinvertebrate shredders and, therefore, crayfish would function as shredders and promote leaf breakdown. To investigate how intermittency and macroinvertebrate assemblages interact to affect leaf breakdown, we used a 53-d experiment with 3 treatments: 1) open bags allowing crayfish and macroinvertebrates access, 2) closed bags with an added crayfish and allowing all macroinvertebrates access, and 3) closed bags allowing only non-crayfish macroinvertebrates access. Leaf breakdown was faster in perennial stream segments likely because of greater macroinvertebrate processing. Because breakdown rates did not differ substantially across treatments, there was no evidence that crayfish suppressed macroinvertebrate shredder processing. However, breakdown rates tended to be higher when crayfish had access to leaf litter, even in intermittent segments where crayfish densities were low. Our results suggest that crayfish were more important than other macroinvertebrates to leaf breakdown in intermittent segments. As hydrologic regimes of perennially flowing streams are modified, increased intermittency could slow decomposition by changing crayfish density and macroinvertebrate assemblages. [ABSTRACT FROM AUTHOR]