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Elizabeth A Kramer - One of the best experts on this subject based on the ideXlab platform.
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quantifying expected ecological response to natural resource legislation a case study of riparian buffers Aquatic Habitat and trout populations
Ecology and Society, 2006Co-Authors: Krista L Jones, Geoffrey C Poole, Judy L Meyer, William Bumback, Elizabeth A KramerAbstract:Regulations governing the management of streamside vegetation (riparian buffers) lie at a nexus between environmental, social, and land development interests, and can yield especially contentious debates among stakeholders. In 2001, the State Legislature of Georgia, USA, took up this debate; the Legislature reduced the minimum width of mandatory-forested riparian buffers along designated trout streams from ~30 m (100 ft) to ~15 m (50 ft), and commissioned this study to assess the expected response of existing trout populations. Because our research was designed to provide rigorous and accessible data for informing this management debate, this research may serve as a general template for other studies designed to inform regulatory and management decisions. We established and quantified relationships among riparian forests, Aquatic Habitat (stream temperature and riffle embeddedness), and trout reproductive success (biomass of young trout). We used these relationships to determine the expected impacts of the buffer width reduction on Aquatic Habitat and trout reproductive success at the stream segment and stream network scales, and assessed associated uncertainty. When compared with stream segments having 30-m wide buffers, our analysis indicated that individual stream segments with 15-m wide buffers have: 1) higher peak temperatures (average peak stream temperatures during the warmest week of the year increase by ~2.0 ± 0.3°C, depending on summertime climate conditions); and 2) more fine sediments (fines in riffle Habitats increase by approximately 25% of the observed inter-study-site range). The data show that trout populations will respond markedly to these Habitat changes. Linear regression models and an associated Monte Carlo uncertainty assessment document an expected 87% reduction in young trout biomass, with a 95% confidence interval ranging from a 66% reduction to a 97% reduction. A landscape assessment showed that 63% of Georgia's 2nd- to 5th-order trout stream segments could maintain stream temperatures likely (>50% probability) to support young trout in streams bordered by 30-m wide forested riparian buffers. Less than 9% of those streams (only those at the highest elevations) would maintain such temperatures with 15-m wide riparian buffers. As young trout are indicative of trout reproductive success, our results portend substantial reductions or elimination of trout populations in northern Georgia streams where vegetated riparian buffer widths are reduced to 15 m.
Krista L Jones - One of the best experts on this subject based on the ideXlab platform.
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quantifying expected ecological response to natural resource legislation a case study of riparian buffers Aquatic Habitat and trout populations
Ecology and Society, 2006Co-Authors: Krista L Jones, Geoffrey C Poole, Judy L Meyer, William Bumback, Elizabeth A KramerAbstract:Regulations governing the management of streamside vegetation (riparian buffers) lie at a nexus between environmental, social, and land development interests, and can yield especially contentious debates among stakeholders. In 2001, the State Legislature of Georgia, USA, took up this debate; the Legislature reduced the minimum width of mandatory-forested riparian buffers along designated trout streams from ~30 m (100 ft) to ~15 m (50 ft), and commissioned this study to assess the expected response of existing trout populations. Because our research was designed to provide rigorous and accessible data for informing this management debate, this research may serve as a general template for other studies designed to inform regulatory and management decisions. We established and quantified relationships among riparian forests, Aquatic Habitat (stream temperature and riffle embeddedness), and trout reproductive success (biomass of young trout). We used these relationships to determine the expected impacts of the buffer width reduction on Aquatic Habitat and trout reproductive success at the stream segment and stream network scales, and assessed associated uncertainty. When compared with stream segments having 30-m wide buffers, our analysis indicated that individual stream segments with 15-m wide buffers have: 1) higher peak temperatures (average peak stream temperatures during the warmest week of the year increase by ~2.0 ± 0.3°C, depending on summertime climate conditions); and 2) more fine sediments (fines in riffle Habitats increase by approximately 25% of the observed inter-study-site range). The data show that trout populations will respond markedly to these Habitat changes. Linear regression models and an associated Monte Carlo uncertainty assessment document an expected 87% reduction in young trout biomass, with a 95% confidence interval ranging from a 66% reduction to a 97% reduction. A landscape assessment showed that 63% of Georgia's 2nd- to 5th-order trout stream segments could maintain stream temperatures likely (>50% probability) to support young trout in streams bordered by 30-m wide forested riparian buffers. Less than 9% of those streams (only those at the highest elevations) would maintain such temperatures with 15-m wide riparian buffers. As young trout are indicative of trout reproductive success, our results portend substantial reductions or elimination of trout populations in northern Georgia streams where vegetated riparian buffer widths are reduced to 15 m.
G M Kondolf - One of the best experts on this subject based on the ideXlab platform.
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large woody debris in urban stream channels redefining the problem
River Research and Applications, 2012Co-Authors: N S Lassettre, G M KondolfAbstract:Large woody debris (LWD) is an important ecological element in rivers and streams. Despite its importance, LWD is often removed from urban stream channels for flood control or road maintenance purposes, an approach with high economic and ecological costs and one that is largely unsuccessful. We propose an approach to conserve LWD in channels by modifying infrastructure (culverts and bridges) to allow LWD passage, maintaining Aquatic Habitat and reducing flooding and road maintenance costs. In Soquel Creek (California, USA), which has a history of LWD-related flooding, we compared long-term LWD management costs of historical, current and a LWD-passing approach whereby infrastructure is enlarged to accommodate LWD passage downstream. We estimated costs of infrastructure replacement, programmatic flood control (LWD removal), LWD-related flood damage and lost Aquatic Habitat. The amount of lost Aquatic Habitat was determined by comparing LWD loading (pieces m−1) in Soquel Creek (0.007 pieces m−1) to nearby unmanaged streams (0.054 to 0.106 pieces m−1). Estimated costs of infrastructure able to pass LWD were nearly double that of historical costs but comparable to current costs. The LWD-passing approach was comparable to removal approaches in the short term (1 to 50 years) but much less in the long term (51 to 100 years), as expenditures in infrastructure replacement to accommodate LWD yielded reductions in flooding costs and Habitat loss. Given the urgency to maintain and restore Aquatic Habitat, the proposed approach may be broadly applicable. Copyright © 2011 John Wiley & Sons, Ltd.
J V Ward - One of the best experts on this subject based on the ideXlab platform.
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Aquatic Habitat dynamics along a braided alpine river ecosystem tagliamento river northeast italy
Ecosystems, 2002Co-Authors: Dave B Arscott, Klement Tockner, Dimitry Van Der Nat, J V WardAbstract:Aquatic Habitat change caused by flooding was quantified along the Fiume Tagliamento, a morphologically intact gravel-bed river ecosystem in northeast Italy. Five different geomorphic reaches (each around 1.5 km), ranging from near the headwaters at 800 m above sea level (a.s.l.) to near the mouth at 5 m a.s.l., were studied over a 1-year period. All floodplain water bodies in each reach were delineated in August 1999 using a differential global positioning system. Each reach was remapped twice (in December 1999 and August 2000) to investigate the impact of autumn and spring flood seasons on Aquatic Habitat composition and configuration. A high degree (nearly 62%) of Aquatic Habitat turnover was documented in a braided headwater floodplain. The degree of Aquatic Habitat turnover decreased with decreasing elevation to approximately 20% turnover in a meandering reach at 5 m a.s.l. In contrast to turnover, braiding, sinuosity, and Aquatic Habitat composition changed little in response to flooding in all reaches. Location of Aquatic Habitats in floodplains changed considerably (turnover), whereas Habitat configuration and composition remained relatively stable. These results support the applicability of the shifting mosaic steady-state model to riverine floodplain environments.
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Aquatic Habitat diversity along the corridor of an alpine flood plain river fiume tagliamento italy n
Archiv Fur Hydrobiologie, 2000Co-Authors: Dave B Arscott, Klement Tockner, J V WardAbstract:Habitat structure and diversity were investigated at multiple scales along the Tagliamento River (NE Italy) to analyze the spatial and temporal configuration of the Aquatic Habitat templet in a complex alluvial river corridor in the European Alps. A geomorphic approach was employed to determine floodplain structure and channel configuration using aerial photographs and digitized maps. Structural, thermal, and chemical variables were sampled monthly for one year in 3-km long study sections within six distinct geomorphic reaches along the longitudinal continuum. Aquatic Habitat heterogeneity and complexity was quantified along the longitudinal dimension (corridor scale), within geomorphic reaches (floodplain scale) and within floodplain water bodies (within-Habitat scale). Four major types of Aquatic Habitats were distinguished: surface-connected channels (SC), alluvial channels (AC), tributary channels (TC), and isolated standing water bodies (ISO). The first 3 types included primary, secondary, and tertiary branches plus backwaters. Active floodplain width was greatest in the island-braided lower floodplain (reach IV), which also exhibited the highest values for Aquatic Habitat area per river km, Aquatic-terrestrial ecotone length per river km, within-floodplain thermal heterogeneity, and Aquatic Habitat diversity. Principal component analysis (PCA) clearly distinguished lotic from standing waters along the primary axis and substrate gradients (both longitudinally between floodplains and laterally within floodplains) on the secondary axis. PCA applied to 21 chemical variables illustrated a downstream increase in floodplain-scale spatio-temporal heterogeneity along the river corridor. Total environmental variance is considerably enhanced by the superimposition of longitudinal changes (corridor scale) on lateral changes within geomorphic reaches (floodplain scale). This study clearly demonstrated the high levels of structural complexity and Habitat diversity that are possible in Alpine rivers, with implications for the important role of environmental heterogeneity in sustaining functional integrity.
Mathias G Kondolf - One of the best experts on this subject based on the ideXlab platform.
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geomorphological stream channel classification in Aquatic Habitat restoration uses and limitations
Aquatic Conservation-marine and Freshwater Ecosystems, 1995Co-Authors: Mathias G KondolfAbstract:1Land managers in western North America have embraced classification of stream channels based on geomorphological characteristics as the importance of channel stability in successful restoration of Aquatic and riparian Habitat has become widely recognized. 2Classification can permit rapid inventory of large regions, provide a stratified geomorphological framework within which more detailed observations can be organized, and provide an initial basis for selecting restoration strategies. 3Existing classifications are arbitrary, developed by creating classes out of a continuum of channel form. Moreover, stream channels are dynamic, and the existing condition does not necessarily reflect former, long-term, or future conditions. 4The user should not confuse the classification exercise with a complete understanding of the channel. Before any channel works are actually undertaken, site-specific studies are essential, including historical studies to determine former channel conditions and to shed light on underlying causes for degradation of Aquatic or riparian resources. 5When applying a classification system, the raw data collected should be reported, not simply the resultant channel classes. Channels that do not fit neatly within pre-existing classes should be reported as such and not lumped in classes where they ‚should’ be.
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historical channel analysis and its application to riparian and Aquatic Habitat restoration
Aquatic Conservation-marine and Freshwater Ecosystems, 1995Co-Authors: Mathias G Kondolf, Marit LarsonAbstract:1The planning, design and evaluation of a restoration project should be guided largely by an understanding of past channel changes. 2A historical analysis can sometimes reveal underlying causes of channel change and document prior Habitat conditions, both useful in setting appropriate objectives for restoration. 3Restoration planning should address the historical causes and patterns of channel degradation that cannot be detected by examining current conditions alone. Moreover, ongoing adjustments in the channel and changes in the catchment must be understood when interpreting channel changes following construction of restoration projects. 4Changes in channel form (and the independent geomorphological variables of run-off and sediment load from the catchment) can be documented from a variety of sources, including historical maps, boundary lines, aerial photography, bridge and pipeline surveys, gauging records, field evidence and archival sources. Historical riparian vegetation, and use by fish and wildlife, may also be documented from early survey records, photographs and written accounts. 5Historical analysis should cover an area large enough to capture all events potentially influencing the project reach. The entire catchment upstream should be examined to identify events affecting the flow regime and sediment load, such as deforestation or dam construction. For channels in erodible alluvium, the study should include the channel downstream to the first stable grade control to capture events whose effects may propagate upstream, such as channelization or base lowering. 6Application of historical channel analysis to the San Luis Rey River in California served as a basis for evaluating the potential for (and hydrological constraints upon) riparian restoration.