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Seeing the landscape for the trees: Metrics to guide riparian shade management in river catchments
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Rising water temperature (Tw) due to anthropogenic climate change may have serious conse- quences for river ecosystems. Conservation and/or expansion of riparian shade could counter warming and buy time for ecosystems to adapt. However, sensitivity of river reaches to direct solar radiation is highly het- erogeneous in space and time, so benefits of shading are also expected to be site specific. We use a network of high-resolution temperature measurements from two upland rivers in the UK, in conjunction with topo- graphic shade modeling, to assess the relative significance of landscape and riparian shade to the thermal behavior of river reaches. Trees occupy 7% of the study catchments (comparable with the UK national aver- age) yet shade covers 52% of the area and is concentrated along river corridors. Riparian shade is most ben- eficial for managing Tw at distances 5–20 km downstream from the source of the rivers where discharge is modest, flow is dominated by near-surface hydrological pathways, there is a wide floodplain with little land- scape shade, and where cumulative solar exposure times are sufficient to affect Tw. For the rivers studied, we find that approximately 0.5 km of complete shade is necessary to off-set Tw by 18C during July (the month with peak Tw) at a headwater site; whereas 1.1 km of shade is required 25 km downstream. Further research is needed to assess the integrated effect of future changes in air temperature, sunshine duration, direct solar radiation, and downward diffuse radiation on Tw to help tree planting schemes achieve
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Effect of fine wood on juvenile brown trout behaviour in experimental stream channels
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In-stream wood can increase shelter availability and prey abundance for stream-living fish such as brown trout, Salmo trutta, but the input of wood to streams has decreased in recent years due to harvesting of riparian vegetation. During the last decades, fine wood (FW) has been increasingly used for biofuel, and the input of FW to streams may therefore decrease. Although effects of in-stream FW have not been studied as extensively as those of large wood (LW), it is probably important as shelter for small-sized trout. In a laboratory stream experiment, we tested the behavioural response of young-of-the-year wild brown trout to three densities of FW, with trout tested alone and in groups of four. Video recordings were used to measure the proportion of time allocated to sheltering, cruising and foraging, as well as the number of aggressive interactions and prey attacks. Cruising activity increased with decreasing FW density and was higher in the four-fish groups than when fish were alone. Foraging decreased and time spent sheltering in FW increased with increasing FW density. Our study shows that juvenile trout activity is higher in higher fish densities and that trout response to FW is related to FW density and differs from the response to LW as reported by others.
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Report: Riparian Prioritization and Status Assessment for Climate Change Resilience of Coldwater Stream Habitats within the Appalachian and Northeastern Regions
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Among a host of other critical ecosystem functions, intact riparian forests can help to reduce vulnerability of coldwater stream habitats to warming regional temperatures. Restoring and conserving these forests can therefore be an important part of regional and landscape-scale conservation plans, but managers need science and decision-support tools to help determine when these actions will be most effective. To help fill this need, we developed the Riparian Prioritization for Climate Change Resilience (RPCCR) web-based decision support tool to quickly and easily identify, based on current riparian cover and predicted vulnerability to air temperature warming, sites that are priority candidates for riparian restoration and conservation.
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Tools & Resources
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Riparian Restoration Decision Support Tool
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Riparian Prioritization and Status Assessment for Climate Change Resilience of Coldwater Stream Habitats within the Appalachian and Northeastern Regions
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Among a host of other critical ecosystem functions, intact riparian forests can help to reduce vulnerability of coldwater stream habitats to warming regional temperatures. Restoring and conserving these forests can therefore be an important part of regional and landscape-scale conservation plans, but managers need science and decision-support tools to help determine when these actions will be most effective. To help fill this need, we developed the Riparian Prioritization for Climate Change Resilience (RPCCR) web-based decision support tool to quickly and easily identify, based on current riparian cover and predicted vulnerability to air temperature warming, sites that are priority candidates for riparian restoration and conservation.
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Riparian Restoration
