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• 21. [Article] A comparison of nest site selection and reproductive effort by reticulate sculpin (Cottus perplexus) in two streams of different geologies in the central Coast Range of Oregon

  Nest sites of reticulate sculpin (Cottus perplexus) were located in two stream reaches, one from a basalt basin and one from a sandstone basin. Stream reaches were similar in gradient, basin area, elevation, ...

  Citation × Citation Citation Abstract Copy Title: A comparison of nest site selection and reproductive effort by reticulate sculpin (Cottus perplexus) in two streams of different geologies in the central Coast Range of Oregon Author: Bateman, Douglas S. Nest sites of reticulate sculpin (Cottus perplexus) were located in two stream reaches, one from a basalt basin and one from a sandstone basin. Stream reaches were similar in gradient, basin area, elevation, climate, and riparian vegetation but differed in biologic community structure and substrate characteristics. An electivity index was used to determine if selection for nest sites occurred and also to compare patterns of selection between habitat types and stream reaches. Eggs from nests were collected so comparisons in reproductive effort could be made between streams and habitat types. Cobble sized substrate was positively elected in all habitat units examined and moderate embeddedness (6-25%) was positively elected in all units but one. No nests were found on bedrock, wood, or fine sediment substrate. A small number of nests were found on both larger gravel and boulder size particles. Only two out of 471 nests located were associated with rocks which were embedded 51% or more. Reproductive effort on a per nest basis was greater in the basalt stream. Nest weights in the basalt stream exceeded nest weights in the sandstone stream by 90% (95% confidence interval 52-152%) on average and the number of eggs per nest was 39% (95% confidence interval 8-79%)greater in the basalt stream. Differences in reproductive effort per nest within an individual stream were not detected in comparisons among scour pools, riffles, high cobble density and low cobble density habitat units. Reproductive effort per nest varied through the sampling period with intermediate effort early, low effort in the mid portion and the highest effort late. This pattern was apparent in both streams but statistically significant in the sandstone stream only. Nest densities were similar at 0.16 nest/m² and 0.17 nest/m² for the basalt and sandstone streams respectively. Differences in nest densities within streams were not detected between scour pools and riffles in either stream or between high and low cobble density units in the basalt stream. A difference was detected between high and low cobble density units in the sandstone stream (p=0.02). Nest densities were greater on average in the tailout portions of pools as opposed to the head and body portions in both streams but statistically significant in the sandstone stream only (p=0.04). We speculate that because patterns of electivity were similar between streams and between different habitat types within a stream, all with different levels of habitat availability, that male fitness is tightly linked with habitat selection for nest sites. Our results would suggest that reticulate sculpin nest site selection and reproductive effort are not strongly influenced by habitat on a geomorphic channel unit scale. It may be more appropriate to delineate sculpin habitat by substrate patches within geomorphic habitat units. Title: A comparison of nest site selection and reproductive effort by reticulate sculpin (Cottus perplexus) in two streams of different geologies in the central Coast Range of Oregon Author: Bateman, Douglas S. Nest sites of reticulate sculpin (Cottus perplexus) were located in two stream reaches, one from a basalt basin and one from a sandstone basin. Stream reaches were similar in gradient, basin area, elevation, climate, and riparian vegetation but differed in biologic community structure and substrate characteristics. An electivity index was used to determine if selection for nest sites occurred and also to compare patterns of selection between habitat types and stream reaches. Eggs from nests were collected so comparisons in reproductive effort could be made between streams and habitat types. Cobble sized substrate was positively elected in all habitat units examined and moderate embeddedness (6-25%) was positively elected in all units but one. No nests were found on bedrock, wood, or fine sediment substrate. A small number of nests were found on both larger gravel and boulder size particles. Only two out of 471 nests located were associated with rocks which were embedded 51% or more. Reproductive effort on a per nest basis was greater in the basalt stream. Nest weights in the basalt stream exceeded nest weights in the sandstone stream by 90% (95% confidence interval 52-152%) on average and the number of eggs per nest was 39% (95% confidence interval 8-79%)greater in the basalt stream. Differences in reproductive effort per nest within an individual stream were not detected in comparisons among scour pools, riffles, high cobble density and low cobble density habitat units. Reproductive effort per nest varied through the sampling period with intermediate effort early, low effort in the mid portion and the highest effort late. This pattern was apparent in both streams but statistically significant in the sandstone stream only. Nest densities were similar at 0.16 nest/m² and 0.17 nest/m² for the basalt and sandstone streams respectively. Differences in nest densities within streams were not detected between scour pools and riffles in either stream or between high and low cobble density units in the basalt stream. A difference was detected between high and low cobble density units in the sandstone stream (p=0.02). Nest densities were greater on average in the tailout portions of pools as opposed to the head and body portions in both streams but statistically significant in the sandstone stream only (p=0.04). We speculate that because patterns of electivity were similar between streams and between different habitat types within a stream, all with different levels of habitat availability, that male fitness is tightly linked with habitat selection for nest sites. Our results would suggest that reticulate sculpin nest site selection and reproductive effort are not strongly influenced by habitat on a geomorphic channel unit scale. It may be more appropriate to delineate sculpin habitat by substrate patches within geomorphic habitat units. Close

• 22. [Article] Comparing streambed light availability and canopy cover in streams with old-growth versus early-mature riparian forests in western Oregon

  This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Springer and can be found at: http://www.springer.com/life+sciences/ecology/jou...

  Citation × Citation Citation Abstract Copy Title: Comparing streambed light availability and canopy cover in streams with old-growth versus early-mature riparian forests in western Oregon Author: Bechtold, Heather A., Warren, Dana R., Keeton, William S., Rosi-Marshall, Emma J. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Springer and can be found at: http://www.springer.com/life+sciences/ecology/journal/27. Title: Comparing streambed light availability and canopy cover in streams with old-growth versus early-mature riparian forests in western Oregon Author: Bechtold, Heather A., Warren, Dana R., Keeton, William S., Rosi-Marshall, Emma J. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Springer and can be found at: http://www.springer.com/life+sciences/ecology/journal/27. Close

• 23. [Article] Structure and composition of unmanaged riparian forests in the coastal mountains of Oregon, U.S.A.

  We characterized the structure and composition of unmanaged riparian forests in three river basins in Oregon’s coastal mountains. Our objective was to evaluate stand attributes at three spatial scales: ...

  Citation × Citation Citation Abstract Copy Title: Structure and composition of unmanaged riparian forests in the coastal mountains of Oregon, U.S.A. Author: Pabst, Robert J., Spies, Thomas A. We characterized the structure and composition of unmanaged riparian forests in three river basins in Oregon’s coastal mountains. Our objective was to evaluate stand attributes at three spatial scales: streamside (site), drainage network (stream order), and basin (subregion). Data on basal area, species composition, snag density, canopy cover, and tree regeneration were collected along transects at 124 sites. Conifer basal area increased with distance from stream, a trend similar among subregions, and was highest at sites along first-order streams. Hardwood basal area was relatively constant with distance from stream and was proportionally higher at sites along second- and third-order streams than at sites along first-order streams. Conifer and hardwood tree regeneration occurred infrequently and varied by topographic position, stream order, and subregion. Conifer regeneration was associated with basal area of shadetolerant conifers and appeared to be limited by shrub competition. The unmanaged forests we studied were characterized by a patchy mosaic of structure and composition. Hardwoods and shrubs were major components of the near-stream environment in these forests, whereas dominance of conifers was limited to hillslopes. It appears that finescale patterns associated with proximity to the stream are influenced by coarser scale factors such as valley-floor width and climate. Title: Structure and composition of unmanaged riparian forests in the coastal mountains of Oregon, U.S.A. Author: Pabst, Robert J., Spies, Thomas A. We characterized the structure and composition of unmanaged riparian forests in three river basins in Oregon’s coastal mountains. Our objective was to evaluate stand attributes at three spatial scales: streamside (site), drainage network (stream order), and basin (subregion). Data on basal area, species composition, snag density, canopy cover, and tree regeneration were collected along transects at 124 sites. Conifer basal area increased with distance from stream, a trend similar among subregions, and was highest at sites along first-order streams. Hardwood basal area was relatively constant with distance from stream and was proportionally higher at sites along second- and third-order streams than at sites along first-order streams. Conifer and hardwood tree regeneration occurred infrequently and varied by topographic position, stream order, and subregion. Conifer regeneration was associated with basal area of shadetolerant conifers and appeared to be limited by shrub competition. The unmanaged forests we studied were characterized by a patchy mosaic of structure and composition. Hardwoods and shrubs were major components of the near-stream environment in these forests, whereas dominance of conifers was limited to hillslopes. It appears that finescale patterns associated with proximity to the stream are influenced by coarser scale factors such as valley-floor width and climate. Close

• 24. [Article] Influences of Human Activity on Stream Temperatures and Existence of Cold-Water Fish in Streams with Elevated Temperature: Report of a Workshop

  This report was prepared by the Independent Multidisciplinary Science Team of the Oregon Plan for Salmon and Watersheds

  Citation × Citation Citation Abstract Copy Title: Influences of Human Activity on Stream Temperatures and Existence of Cold-Water Fish in Streams with Elevated Temperature: Report of a Workshop Author: Independent Multidisciplinary Science Team (Or.) This report was prepared by the Independent Multidisciplinary Science Team of the Oregon Plan for Salmon and Watersheds Title: Influences of Human Activity on Stream Temperatures and Existence of Cold-Water Fish in Streams with Elevated Temperature: Report of a Workshop Author: Independent Multidisciplinary Science Team (Or.) This report was prepared by the Independent Multidisciplinary Science Team of the Oregon Plan for Salmon and Watersheds Close

• 25. [Article] Results and review of a riparian survey method used in eastern Oregon

  In the late 1970s, approximately 400 miles of streams were inventoried by the Prineville District of the Bureau of Land Management for in-stream and riparian condition. During the summer of 1994, the riparian ...

  Citation × Citation Citation Abstract Copy Title: Results and review of a riparian survey method used in eastern Oregon Author: Rasmussen, Christine G. In the late 1970s, approximately 400 miles of streams were inventoried by the Prineville District of the Bureau of Land Management for in-stream and riparian condition. During the summer of 1994, the riparian portion of the survey was repeated on 17 of the original streams miles, contained within 11 stream sections where grazing strategies had been altered. This project was a case study designed to evaluate efficiency of the original methods and identify factors involved in individual stream responses. The streams selected to be resurveyed varied in community types present, gradient, elevation, grazing system, disturbance history, influence of beaver, and restoration efforts. Community types were identified by their major components (grass-shrub, sedge-rush) and measured for length and width. Length of stream bank damage was estimated and causes noted. Stream sections were surveyed between matching points for the 1976-78 and 1994 surveys. Most streams had increases in riparian area and decreases in bank damage and lengths of cutbanks, suggesting an upward trend in condition. The bank damage, riparian area, and community identification portions of the survey were identified as useful though composition measurements were determined to be less dependable and repeatable. Title: Results and review of a riparian survey method used in eastern Oregon Author: Rasmussen, Christine G. In the late 1970s, approximately 400 miles of streams were inventoried by the Prineville District of the Bureau of Land Management for in-stream and riparian condition. During the summer of 1994, the riparian portion of the survey was repeated on 17 of the original streams miles, contained within 11 stream sections where grazing strategies had been altered. This project was a case study designed to evaluate efficiency of the original methods and identify factors involved in individual stream responses. The streams selected to be resurveyed varied in community types present, gradient, elevation, grazing system, disturbance history, influence of beaver, and restoration efforts. Community types were identified by their major components (grass-shrub, sedge-rush) and measured for length and width. Length of stream bank damage was estimated and causes noted. Stream sections were surveyed between matching points for the 1976-78 and 1994 surveys. Most streams had increases in riparian area and decreases in bank damage and lengths of cutbanks, suggesting an upward trend in condition. The bank damage, riparian area, and community identification portions of the survey were identified as useful though composition measurements were determined to be less dependable and repeatable. Close

• 26. [Article] Patterns in stream geomorphology and implications for hyporheic exchange flow

  Longitudinal water surface profiles from high-gradient mountain streams provide useful indicators of the relative potential for hyporheic exchange flow in stream reaches with varying morphology. The spacing ...

  Citation × Citation Citation Abstract Copy Title: Patterns in stream geomorphology and implications for hyporheic exchange flow Author: Anderson, Justin K. Longitudinal water surface profiles from high-gradient mountain streams provide useful indicators of the relative potential for hyporheic exchange flow in stream reaches with varying morphology. The spacing between slope breaks in step-pool and pool-riffle streams provides a geomorphic scaling metric that indicates how the length of average hyporheic flow paths change throughout the river continuum. Twelve stream reaches were randomly selected and surveyed in the Lookout Creek basin at the H.J. Andrews Experimental Forest in the western Cascades Mountains of Oregon. Stream reach morphology was examined for patterns that are expressed over a continuum ranging from headwater to mid-order streams that can be predicted from easily measured drainage basin characteristics. Simple and multiple linear regression models were used to predict changes in lateral complexity in stream reaches, and to predict how the general shape of the water surface profile changes as drainage basin area increases from 0.6 km² to 62.3 km². Patterns in the lateral complexity of stream reaches were associated with the degree of channel confinement in valley segments, and longitudinal patterns in bed configuration were strongly associated with the position of a stream reach within the river continuum. Stream reach longitudinal profiles were evaluated to determine how patterns in slope breaks change throughout the portion of the river continuum represented by the study area. Channel units were defined according to slope categories for flat water, steep water, and step units (FLATs, STEEPs and STEPs). A set of regression models was used to predict how slope break spacing and the general shape of the water surface profile change as drainage basin area increases from 0.6 km² to 62.3 km². Output from these regression equations was tested against independent field data to evaluate model performance. The models generally performed well. Longitudinal transects of piezometers were installed along the thalweg of a second order, and a third order stream reach. Longitudinal profiles in the piezometer transects were surveyed, and piezometers were used to measure hydraulic head in stream beds. Data were used to test a theoretical model that predicts downwelling where stream profiles are convex, and upwelling where stream profiles are concave. Overall, the shape of the water surface profile explained 38% of the variation in the distribution of hydraulic pressure head in the streambed. Results demonstrated the usefulness of quantifying the magnitude of concavities and convexities in stream profiles. A metric for expressing the average water surface concavity (AWSC) is proposed. I demonstrated that this metric could be useful for comparing the potential for hyporheic exchange in stream reaches with varying degrees of stream profile roughness. Results showed a decreasing trend in AWSC as drainage basin area increased. Upwelling and downwelling zones were identified in piezometer transects, and their longitudinal lengths were measured. The lengths of downwelling zones were compared to the spacing between slope breaks in the water surface profile. Average lengths of downwelling zones and FLAT channel slope units increased with increasing basin area at a similar rate, indicating that slope break spacing was a useful indicator for average downwelling zone length. My results demonstrate that patterns in stream morphology are useful for predicting patterns in hyporheic exchange flow throughout the river continuum. I suggest that the potential for gravity driven exchange flow decreases along the river continuum as AWSC decreases. I also suggest that the frequency of hydrologic exchange between the stream and the hyporheic zone decreases, and that the average length of hyporheic flow paths increase, across the river continuum. Title: Patterns in stream geomorphology and implications for hyporheic exchange flow Author: Anderson, Justin K. Longitudinal water surface profiles from high-gradient mountain streams provide useful indicators of the relative potential for hyporheic exchange flow in stream reaches with varying morphology. The spacing between slope breaks in step-pool and pool-riffle streams provides a geomorphic scaling metric that indicates how the length of average hyporheic flow paths change throughout the river continuum. Twelve stream reaches were randomly selected and surveyed in the Lookout Creek basin at the H.J. Andrews Experimental Forest in the western Cascades Mountains of Oregon. Stream reach morphology was examined for patterns that are expressed over a continuum ranging from headwater to mid-order streams that can be predicted from easily measured drainage basin characteristics. Simple and multiple linear regression models were used to predict changes in lateral complexity in stream reaches, and to predict how the general shape of the water surface profile changes as drainage basin area increases from 0.6 km² to 62.3 km². Patterns in the lateral complexity of stream reaches were associated with the degree of channel confinement in valley segments, and longitudinal patterns in bed configuration were strongly associated with the position of a stream reach within the river continuum. Stream reach longitudinal profiles were evaluated to determine how patterns in slope breaks change throughout the portion of the river continuum represented by the study area. Channel units were defined according to slope categories for flat water, steep water, and step units (FLATs, STEEPs and STEPs). A set of regression models was used to predict how slope break spacing and the general shape of the water surface profile change as drainage basin area increases from 0.6 km² to 62.3 km². Output from these regression equations was tested against independent field data to evaluate model performance. The models generally performed well. Longitudinal transects of piezometers were installed along the thalweg of a second order, and a third order stream reach. Longitudinal profiles in the piezometer transects were surveyed, and piezometers were used to measure hydraulic head in stream beds. Data were used to test a theoretical model that predicts downwelling where stream profiles are convex, and upwelling where stream profiles are concave. Overall, the shape of the water surface profile explained 38% of the variation in the distribution of hydraulic pressure head in the streambed. Results demonstrated the usefulness of quantifying the magnitude of concavities and convexities in stream profiles. A metric for expressing the average water surface concavity (AWSC) is proposed. I demonstrated that this metric could be useful for comparing the potential for hyporheic exchange in stream reaches with varying degrees of stream profile roughness. Results showed a decreasing trend in AWSC as drainage basin area increased. Upwelling and downwelling zones were identified in piezometer transects, and their longitudinal lengths were measured. The lengths of downwelling zones were compared to the spacing between slope breaks in the water surface profile. Average lengths of downwelling zones and FLAT channel slope units increased with increasing basin area at a similar rate, indicating that slope break spacing was a useful indicator for average downwelling zone length. My results demonstrate that patterns in stream morphology are useful for predicting patterns in hyporheic exchange flow throughout the river continuum. I suggest that the potential for gravity driven exchange flow decreases along the river continuum as AWSC decreases. I also suggest that the frequency of hydrologic exchange between the stream and the hyporheic zone decreases, and that the average length of hyporheic flow paths increase, across the river continuum. Close

• 27. [Article] The development and maintenance of stream community structure and organization

  The goal of this study was to better understand stream communities through a perspective that might make their structure, organization, and development more understandable. This goal was approached through ...

  Citation × Citation Citation Abstract Copy Title: The development and maintenance of stream community structure and organization Author: Wevers, Mary Jo The goal of this study was to better understand stream communities through a perspective that might make their structure, organization, and development more understandable. This goal was approached through the following objectives: 1. To determine the assemblages of stream organisms and define subsystems within a stream community. 2. To explain the structure and organization of the subsystems by means of habitat, life history, trophic, and environmental relationships. 3. To explain how the community as a whole and the subsystems develop and persist through immigration, colonization, and subsystem interactions. An organismic perspective of stream communities is utilized in addressing the development and maintenance of stream community structure and organization. The conceptual framework of Warren et al. (1979) provides a perspective which emphasizes the importance of species interrelationships and interdspendencies within a community. This perspective is organismic in that it takes the view that communities exhibit organismic properties. It is hot organismic in the Clementsian sense that communities are metaphorical organisms. A hierarchical scheme of stream community subsystems is presented. Habitat organization is used to define 2° and 3° subsystems. Trophic organization defines 4° subsystems, and other aspects of life history organization define 5° subsystems. Two model streams were employed in this study of stream community structure and organization. The 2° subsystems, shallow riffles, deep riffles, and pools, were sampled for one year following initiation of the experiment. Community organization and development are described in terms of biomass and taxa numbers. Macroinvertebrate biomass and taxa number tended to be greater in riffle habitats than in pool habitats. Biomass in 2° and 3° subsystems generally in creased with time. Taxa number increased until early winter when it declined slightly. Changes in biomass and taxa number in 4° trophic subsystems and 5° species population subsystems are also discussed. Species pool, life history, and colonization determination of stream community structure and organization are addressed. The potential capacity of the stream community resides in the species pool. The pattern of kinds and abundances of species in space and time is partially determined by the life history patterns of the species. Colonizing ability of species populations affects the development and organization of stream communities. Downstream drift and aerial sources of colonists contributed to the colonization of the experimental streams in this study, although the relative importance of the two sources changed through time. Stream habitat and environment play important roles in stream community development and organization by providing shelter or cover and supplying needed resources. As the environment provided by a stream system impinges upon the stream community, there must be concordance between the community and its environment. The climatic parameters light and temperature and autochthonous and allochthonous inputs such as litter fall are discussed as environmental parameters that impinge on the model stream communities. Title: The development and maintenance of stream community structure and organization Author: Wevers, Mary Jo The goal of this study was to better understand stream communities through a perspective that might make their structure, organization, and development more understandable. This goal was approached through the following objectives: 1. To determine the assemblages of stream organisms and define subsystems within a stream community. 2. To explain the structure and organization of the subsystems by means of habitat, life history, trophic, and environmental relationships. 3. To explain how the community as a whole and the subsystems develop and persist through immigration, colonization, and subsystem interactions. An organismic perspective of stream communities is utilized in addressing the development and maintenance of stream community structure and organization. The conceptual framework of Warren et al. (1979) provides a perspective which emphasizes the importance of species interrelationships and interdspendencies within a community. This perspective is organismic in that it takes the view that communities exhibit organismic properties. It is hot organismic in the Clementsian sense that communities are metaphorical organisms. A hierarchical scheme of stream community subsystems is presented. Habitat organization is used to define 2° and 3° subsystems. Trophic organization defines 4° subsystems, and other aspects of life history organization define 5° subsystems. Two model streams were employed in this study of stream community structure and organization. The 2° subsystems, shallow riffles, deep riffles, and pools, were sampled for one year following initiation of the experiment. Community organization and development are described in terms of biomass and taxa numbers. Macroinvertebrate biomass and taxa number tended to be greater in riffle habitats than in pool habitats. Biomass in 2° and 3° subsystems generally in creased with time. Taxa number increased until early winter when it declined slightly. Changes in biomass and taxa number in 4° trophic subsystems and 5° species population subsystems are also discussed. Species pool, life history, and colonization determination of stream community structure and organization are addressed. The potential capacity of the stream community resides in the species pool. The pattern of kinds and abundances of species in space and time is partially determined by the life history patterns of the species. Colonizing ability of species populations affects the development and organization of stream communities. Downstream drift and aerial sources of colonists contributed to the colonization of the experimental streams in this study, although the relative importance of the two sources changed through time. Stream habitat and environment play important roles in stream community development and organization by providing shelter or cover and supplying needed resources. As the environment provided by a stream system impinges upon the stream community, there must be concordance between the community and its environment. The climatic parameters light and temperature and autochthonous and allochthonous inputs such as litter fall are discussed as environmental parameters that impinge on the model stream communities. Close

• 28. [Article] Stream-Associated Amphibian Habitat Assessment in the Portland-Vancouver Metropolitan Region

  This study assessed the influence of landscape development on stream-associated amphibians in forested riparian areas within the Portland-Vancouver metropolitan region. Human alteration of landscapes may ...

  Citation × Citation Citation Abstract Copy Title: Stream-Associated Amphibian Habitat Assessment in the Portland-Vancouver Metropolitan Region Author: Dietrich, Andrew Evans Year: 2012 This study assessed the influence of landscape development on stream-associated amphibians in forested riparian areas within the Portland-Vancouver metropolitan region. Human alteration of landscapes may dramatically affect the ecology of neighboring aquatic systems. It was hypothesized that lotic amphibians would be negatively associated with greater amounts of landscape development and positively associated with forested area within the surrounding watershed. Thirty-seven 1st-3rd order streams were sampled between June 21st and September 21st in 2011. Streams potentially providing adequate habitat for stream-obligate amphibians were randomly selected. Amphibians were surveyed along 30-meter stream transects using an active-cover search (ACS). Environmental variables associated with development in surrounding landscapes were measured in situ. GIS delineation was conducted to define landscape-scale variables at stratified distances from riparian networks up-stream of each site via the utilization of the 2006 NLCD dataset and a finer-scale, regional dataset compiled by the Institute for Natural Resources (INR). Amphibians were detected at seventeen of the thirty-seven sampled streams. The most commonly detected species were Dicamptadon tenebrosus, Plethadon vehiculum and Plethadon dunni. Streams where amphibians were observed had lower average water temperature and conductivity, coarser stream substrate and were located on public property more often than streams where no amphibians were detected. Landscape variables were most significant to amphibians within 100 and 200 meters of the upstream stream network. Occupancy of a site by facultative species was best explained by the proportion of mixed forest in the surrounding watershed (R2=0.343, p<0.001). Occupancy of a stream by obligate species was best predicted by measurements of water quality and in-stream cover (Water Temperature: R2=0.275, p<0.001; Water Conductivity: R2=0.248, p<0.001; Cover: R2=0.323, p<0.001). Occupancy of stream refugia by all observed amphibians was positively influenced by higher percentages of forest cover and lower percentages of urban development and herbaceous vegetation in the surrounding watershed. Results of this study indicate that urban refugia must contain adequate riparian forest area, coarse stream substrate and clean, cool water to sustain stream-amphibian communities. Protection of remnant forested headwater stream networks is essential to the conservation of lotic amphibians in this urbanized region. Title: Stream-Associated Amphibian Habitat Assessment in the Portland-Vancouver Metropolitan Region Author: Dietrich, Andrew Evans Year: 2012 This study assessed the influence of landscape development on stream-associated amphibians in forested riparian areas within the Portland-Vancouver metropolitan region. Human alteration of landscapes may dramatically affect the ecology of neighboring aquatic systems. It was hypothesized that lotic amphibians would be negatively associated with greater amounts of landscape development and positively associated with forested area within the surrounding watershed. Thirty-seven 1st-3rd order streams were sampled between June 21st and September 21st in 2011. Streams potentially providing adequate habitat for stream-obligate amphibians were randomly selected. Amphibians were surveyed along 30-meter stream transects using an active-cover search (ACS). Environmental variables associated with development in surrounding landscapes were measured in situ. GIS delineation was conducted to define landscape-scale variables at stratified distances from riparian networks up-stream of each site via the utilization of the 2006 NLCD dataset and a finer-scale, regional dataset compiled by the Institute for Natural Resources (INR). Amphibians were detected at seventeen of the thirty-seven sampled streams. The most commonly detected species were Dicamptadon tenebrosus, Plethadon vehiculum and Plethadon dunni. Streams where amphibians were observed had lower average water temperature and conductivity, coarser stream substrate and were located on public property more often than streams where no amphibians were detected. Landscape variables were most significant to amphibians within 100 and 200 meters of the upstream stream network. Occupancy of a site by facultative species was best explained by the proportion of mixed forest in the surrounding watershed (R2=0.343, p<0.001). Occupancy of a stream by obligate species was best predicted by measurements of water quality and in-stream cover (Water Temperature: R2=0.275, p<0.001; Water Conductivity: R2=0.248, p<0.001; Cover: R2=0.323, p<0.001). Occupancy of stream refugia by all observed amphibians was positively influenced by higher percentages of forest cover and lower percentages of urban development and herbaceous vegetation in the surrounding watershed. Results of this study indicate that urban refugia must contain adequate riparian forest area, coarse stream substrate and clean, cool water to sustain stream-amphibian communities. Protection of remnant forested headwater stream networks is essential to the conservation of lotic amphibians in this urbanized region. Close

• 29. [Article] Window Queries Over Data Streams

  Evaluating queries over data streams has become an appealing way to support various stream-processing applications. Window queries are commonly used in many stream applications. In a window query, certain ...

  Citation × Citation Citation Abstract Copy Title: Window Queries Over Data Streams Author: Li, Jin Year: 2008 Evaluating queries over data streams has become an appealing way to support various stream-processing applications. Window queries are commonly used in many stream applications. In a window query, certain query operators, especially blocking operators and stateful operators, appear in their windowed versions. Previous research work in evaluating window queries typically requires ordered streams and this order requirement limits the implementations of window operators and also carries performance penalties. This thesis presents efficient and flexible algorithms for evaluating window queries. We first present a new data model for streams, progressing streams, that separates stream progress from physical-arrival order. Then, we present our window semantic definitions for the most commonly used window operators—window aggregation and window join. Unlike previous research that often requires ordered streams when describing window semantics, our window semantic definitions do not rely on physical-stream arrival properties. Based on the window semantic definitions, we present new implementations of window aggregation and window join, WID and OA-Join. Compared to the existing implementations of stream query operators, our implementations do not require special stream-arrival properties, particularly stream order. In addition, for window aggregation, we present two other implementations extended from WID, Paned-WID and AdaptWID, to improve excution time by sharing sub-aggregates and to improve memory usage for input with data distribution skew, respectively. Leveraging our order-insenstive implementations of window operators, we present a new architecture for stream systems, OOP (Out-of- Order Processing). Instead of relying on ordered streams to indicate stream progress, OOP explicitly communicates stream progress to query operators, and thus is more flexible than the previous in-order processing (IOP) approach, which requires maintaining stream order. We implemented our order-insensitive window query operators and the OOP architecture in NiagaraST and Gigascope. Our performance study in both systems confirms the benefits of our window operator implementations and the OOP architecture compared to the commonly used approaches in terms of memory usage, execution time and latency. Title: Window Queries Over Data Streams Author: Li, Jin Year: 2008 Evaluating queries over data streams has become an appealing way to support various stream-processing applications. Window queries are commonly used in many stream applications. In a window query, certain query operators, especially blocking operators and stateful operators, appear in their windowed versions. Previous research work in evaluating window queries typically requires ordered streams and this order requirement limits the implementations of window operators and also carries performance penalties. This thesis presents efficient and flexible algorithms for evaluating window queries. We first present a new data model for streams, progressing streams, that separates stream progress from physical-arrival order. Then, we present our window semantic definitions for the most commonly used window operators—window aggregation and window join. Unlike previous research that often requires ordered streams when describing window semantics, our window semantic definitions do not rely on physical-stream arrival properties. Based on the window semantic definitions, we present new implementations of window aggregation and window join, WID and OA-Join. Compared to the existing implementations of stream query operators, our implementations do not require special stream-arrival properties, particularly stream order. In addition, for window aggregation, we present two other implementations extended from WID, Paned-WID and AdaptWID, to improve excution time by sharing sub-aggregates and to improve memory usage for input with data distribution skew, respectively. Leveraging our order-insenstive implementations of window operators, we present a new architecture for stream systems, OOP (Out-of- Order Processing). Instead of relying on ordered streams to indicate stream progress, OOP explicitly communicates stream progress to query operators, and thus is more flexible than the previous in-order processing (IOP) approach, which requires maintaining stream order. We implemented our order-insensitive window query operators and the OOP architecture in NiagaraST and Gigascope. Our performance study in both systems confirms the benefits of our window operator implementations and the OOP architecture compared to the commonly used approaches in terms of memory usage, execution time and latency. Close

• 30. [Article] Subsurface flow of a forested riparian area in the Oregon coast range

  This study was undertaken to gain further understanding of the subsurface hydrology for a stream-adjacent riparian area in Western Oregon's Coast Range. Spatial and temporal fluctuations of the free water surface ...

  Citation × Citation Citation Abstract Copy Title: Subsurface flow of a forested riparian area in the Oregon coast range Author: Reiter, Maryanne This study was undertaken to gain further understanding of the subsurface hydrology for a stream-adjacent riparian area in Western Oregon's Coast Range. Spatial and temporal fluctuations of the free water surface of a toeslope, adjacent riparian area, and stream channel in a forested terrace reach were monitored over a period of one year. A total of 27 piezometers were installed (nine in each of three transects established perpendicular to the stream) in a stream-adjacent terrace and hillslope. These piezometers were monitored from September 26, 1989 to July 25, 1990. Results indicate that the direction of flow within a forested terrace can vary throughout the year. During the drier months of September and October, flow direction was generally towards the stream. However, by November the direction of flow for those areas closest to the stream had begun to change. In some cases the direction of flow changed up to 180° from the September direction. The location of influent/effluent zones along the stream (i.e., zones along the stream where the terrace has a lower or higher hydraulic head than the stream, respectively) also varied throughout the year. During October, 1989 the furthest upvalley stream-adjacent piezometer had hydraulic heads greater than the stream for the entire month, while two other stream adjacent piezometers did not. During normal precipitation in January, 1990 both furthest upvalley and the middle stream-adjacent piezometers had hydraulic heads greater than the stream for the entire month. By July, 1990 only the middle stream-adjacent piezometer had a hydraulic head greater than the stream for the entire month, while the furthest upvalley piezometer had a higher head for 33% of the month and the hydraulic head of furthest downvalley piezometer never exceeded that of the stream. For the Deer Creek study site, subsurface velocities were estimated to be in the range of 10-8 to 10-11 m/s resulting in a 3.8 year minimum travel time for storm water to reach the stream. Thus, soil matrix velocities using the Darcy equation were not sufficient to generate stormflow. However, no overland flow was observed during storm events, indicating that alternative subsurface flow pathways, such as macrochannels, are being utilized. Previous research has suggested that the release of water from terrace storage in small headwater streams is no.t sufficient to maintain baseflow. The results of the Deer Creek study support this conclusion. Furthermore, the results of this study indicate that forested riparian areas are hydrologically complex with respect to both space and time and that oversimplification of these systems may lead to misinterpretation of other processes associated with subsurface water dynamics. Title: Subsurface flow of a forested riparian area in the Oregon coast range Author: Reiter, Maryanne This study was undertaken to gain further understanding of the subsurface hydrology for a stream-adjacent riparian area in Western Oregon's Coast Range. Spatial and temporal fluctuations of the free water surface of a toeslope, adjacent riparian area, and stream channel in a forested terrace reach were monitored over a period of one year. A total of 27 piezometers were installed (nine in each of three transects established perpendicular to the stream) in a stream-adjacent terrace and hillslope. These piezometers were monitored from September 26, 1989 to July 25, 1990. Results indicate that the direction of flow within a forested terrace can vary throughout the year. During the drier months of September and October, flow direction was generally towards the stream. However, by November the direction of flow for those areas closest to the stream had begun to change. In some cases the direction of flow changed up to 180° from the September direction. The location of influent/effluent zones along the stream (i.e., zones along the stream where the terrace has a lower or higher hydraulic head than the stream, respectively) also varied throughout the year. During October, 1989 the furthest upvalley stream-adjacent piezometer had hydraulic heads greater than the stream for the entire month, while two other stream adjacent piezometers did not. During normal precipitation in January, 1990 both furthest upvalley and the middle stream-adjacent piezometers had hydraulic heads greater than the stream for the entire month. By July, 1990 only the middle stream-adjacent piezometer had a hydraulic head greater than the stream for the entire month, while the furthest upvalley piezometer had a higher head for 33% of the month and the hydraulic head of furthest downvalley piezometer never exceeded that of the stream. For the Deer Creek study site, subsurface velocities were estimated to be in the range of 10-8 to 10-11 m/s resulting in a 3.8 year minimum travel time for storm water to reach the stream. Thus, soil matrix velocities using the Darcy equation were not sufficient to generate stormflow. However, no overland flow was observed during storm events, indicating that alternative subsurface flow pathways, such as macrochannels, are being utilized. Previous research has suggested that the release of water from terrace storage in small headwater streams is no.t sufficient to maintain baseflow. The results of the Deer Creek study support this conclusion. Furthermore, the results of this study indicate that forested riparian areas are hydrologically complex with respect to both space and time and that oversimplification of these systems may lead to misinterpretation of other processes associated with subsurface water dynamics. Close