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• 351. [Article] Stability of gravel at artificially created spawning beds in uncontrolled streams

  Twenty-five gabion-type structures across the main stem and tributaries of the Siuslaw River in the Oregon Coastal Range, installed to expand the available spawning area for fish, were investigated for their ...

  Citation × Citation Citation Abstract Copy Title: Stability of gravel at artificially created spawning beds in uncontrolled streams Author: Helland-Hansen, Erik Andreas Twenty-five gabion-type structures across the main stem and tributaries of the Siuslaw River in the Oregon Coastal Range, installed to expand the available spawning area for fish, were investigated for their ability to perform gravel control functions such as trapping bedload carried by the stream or holding gravel placed behind the structures. The merits of gravel trapping structures in the main stem Siuslaw River were found to depend largely on channel features in the reach at and above the structures. Factors favoring successful developments were: ample gravel supply, high bed roughness, wide straight reaches, and lateral stream bed slopes deflecting flood water from the structure. Among limiting factors were: the existence of pools immediately upstream of structures, deficient gravel supply, curving stream alignment, and unfavorable lateral stream bed slopes. Main stem reaches with an instantaneous peak discharge exceeding 100 cfs per foot width were found questionable for development. The controlling factors in the tributary streams were found to be approach velocities and stream features such as bedrock smoothness, approach slope, channel alignment, constrictions, lateral bed slope, plunge pools, and lengths of gravel beds. Careful placing of gravel to predetermined slopes was found not to be warranted, as the stream would rework the gravel according to local influences. Reaches where the flow was retarded without widening and reaches where high velocities occurred were found especially unfavorable for gravel stability. Flume studies with simulated gabions and full-size gravel were carried out to study incipient motion and scour from a gravel bed behind a gabion. Scour was found to take place from the upstream portion of the gravel bed, resulting in an adversely sloping bed there. Bed forms of standing-wave type, with changing wave location, were encountered when the flow was in the critical region; subsequent scour would wash the bed waves out. Gravel transport from apparently stable beds subjected to very low flow strengths verified that gravel transport is a statistical phenomenon and that the threshold of motion should include time of observation as a variable. Disruption of the gravel imbrication at the bed surface was found to encourage particle movement. The effect of buried perforated pipes o.n reducing bed siltation was investigated at the time of the stability experiments. No beneficial effect on the siltation pattern could be found when well-graded fine material was added to the flume. Title: Stability of gravel at artificially created spawning beds in uncontrolled streams Author: Helland-Hansen, Erik Andreas Twenty-five gabion-type structures across the main stem and tributaries of the Siuslaw River in the Oregon Coastal Range, installed to expand the available spawning area for fish, were investigated for their ability to perform gravel control functions such as trapping bedload carried by the stream or holding gravel placed behind the structures. The merits of gravel trapping structures in the main stem Siuslaw River were found to depend largely on channel features in the reach at and above the structures. Factors favoring successful developments were: ample gravel supply, high bed roughness, wide straight reaches, and lateral stream bed slopes deflecting flood water from the structure. Among limiting factors were: the existence of pools immediately upstream of structures, deficient gravel supply, curving stream alignment, and unfavorable lateral stream bed slopes. Main stem reaches with an instantaneous peak discharge exceeding 100 cfs per foot width were found questionable for development. The controlling factors in the tributary streams were found to be approach velocities and stream features such as bedrock smoothness, approach slope, channel alignment, constrictions, lateral bed slope, plunge pools, and lengths of gravel beds. Careful placing of gravel to predetermined slopes was found not to be warranted, as the stream would rework the gravel according to local influences. Reaches where the flow was retarded without widening and reaches where high velocities occurred were found especially unfavorable for gravel stability. Flume studies with simulated gabions and full-size gravel were carried out to study incipient motion and scour from a gravel bed behind a gabion. Scour was found to take place from the upstream portion of the gravel bed, resulting in an adversely sloping bed there. Bed forms of standing-wave type, with changing wave location, were encountered when the flow was in the critical region; subsequent scour would wash the bed waves out. Gravel transport from apparently stable beds subjected to very low flow strengths verified that gravel transport is a statistical phenomenon and that the threshold of motion should include time of observation as a variable. Disruption of the gravel imbrication at the bed surface was found to encourage particle movement. The effect of buried perforated pipes o.n reducing bed siltation was investigated at the time of the stability experiments. No beneficial effect on the siltation pattern could be found when well-graded fine material was added to the flume. Close

• 352. [Article] Water management in the North Deschutes unit irrigation district : geographic perspectives and remote sensing applications

  The North Unit irrigation District of Central Oregon, a water project developed under the guidelines of the Bureau of Reclamation, is characterized by limited water and the need for efficient utilization ...

  Citation × Citation Citation Abstract Copy Title: Water management in the North Deschutes unit irrigation district : geographic perspectives and remote sensing applications Author: Nellis, M. Duane The North Unit irrigation District of Central Oregon, a water project developed under the guidelines of the Bureau of Reclamation, is characterized by limited water and the need for efficient utilization and control of the irrigation system. To manage the limited water resource, irrigators need a timely and economical method of detecting problems associated with parameters of the irrigation water management system. The primary objective of this research was to determine the practicality of utilizing thermal infrared imagery and color infrared photography for assessing irrigation water management problems. Within this objective the key tasks were to: examine the relationship between the physical and cultural components that play an integral role in irrigation water management; determine the applications of remote sensing for detecting non-uniformity of water distribution over selected fields during three stages of crop growth; determine the applications of remote sensing for detecting crop response in relation to a diversity of field conditions; determine the application of remote sensing for analyzing conveyance system leakage sites; and examine possible techniques for maintaining proper irrigation water management. A field survey of the area covered by the overflights was used to map patterns of fields and irrigation methods. Additionally, maps showing soil series and percent slope were produced of the overflight coverage area. The survey and maps provided a valuable reference during interpretation of the imagery and photography to determine relationships between soils, topography, crop type, size and shape of fields, and irrigation methods employed. Information on cropping history, soil amendments, and irrigation scheduling strategies were obtained from case study farmers. Ground-based measurements were made in conjunction with overflights to determine field characteristics. This involved precise notation of weather conditions, soil parameters and crop characteristics of case study sites. The thermal infrared imagery (flown May 21, May 24, July 7, and September 7, 1979) and color infrared photography (flown May 12, July 9, and September 7, 1979) were analyzed with the aid of a stereomicroscope, film viewing light table, and digital image processor. Data gathered through farm interviews, ground-based measurements, and imagery and aerial photographic interpretation were statistically treated using the Statistical Package for the Social Sciences program at Oregon State University. The results of this research demonstrate the practicality of using thermal infrared imagery and color infrared photography for detecting problems associated with the irrigation water management system. The thermal infrared imagery was useful for detecting canal leakage, non-uniformity of water distribution at all stages of crop growth, and apparent crop canopy temperatures as an indicator of crop stress. The color infrared photography was useful for detecting crop stress resulting from a variety of field conditions. Field conditions detected on the photography and affecting crop health included physical parameters of the land resource base (soils, topography, and climate), the influence of irrigators through tillage practices, the affect of irrigation water applications, and the influence of applications of herbicides, pesticides, and fertilizers. Additionally, color infrared photography was used to determine the extent of unexpected system problems (e.g. flooding caused by a lateral canal plugging). Title: Water management in the North Deschutes unit irrigation district : geographic perspectives and remote sensing applications Author: Nellis, M. Duane The North Unit irrigation District of Central Oregon, a water project developed under the guidelines of the Bureau of Reclamation, is characterized by limited water and the need for efficient utilization and control of the irrigation system. To manage the limited water resource, irrigators need a timely and economical method of detecting problems associated with parameters of the irrigation water management system. The primary objective of this research was to determine the practicality of utilizing thermal infrared imagery and color infrared photography for assessing irrigation water management problems. Within this objective the key tasks were to: examine the relationship between the physical and cultural components that play an integral role in irrigation water management; determine the applications of remote sensing for detecting non-uniformity of water distribution over selected fields during three stages of crop growth; determine the applications of remote sensing for detecting crop response in relation to a diversity of field conditions; determine the application of remote sensing for analyzing conveyance system leakage sites; and examine possible techniques for maintaining proper irrigation water management. A field survey of the area covered by the overflights was used to map patterns of fields and irrigation methods. Additionally, maps showing soil series and percent slope were produced of the overflight coverage area. The survey and maps provided a valuable reference during interpretation of the imagery and photography to determine relationships between soils, topography, crop type, size and shape of fields, and irrigation methods employed. Information on cropping history, soil amendments, and irrigation scheduling strategies were obtained from case study farmers. Ground-based measurements were made in conjunction with overflights to determine field characteristics. This involved precise notation of weather conditions, soil parameters and crop characteristics of case study sites. The thermal infrared imagery (flown May 21, May 24, July 7, and September 7, 1979) and color infrared photography (flown May 12, July 9, and September 7, 1979) were analyzed with the aid of a stereomicroscope, film viewing light table, and digital image processor. Data gathered through farm interviews, ground-based measurements, and imagery and aerial photographic interpretation were statistically treated using the Statistical Package for the Social Sciences program at Oregon State University. The results of this research demonstrate the practicality of using thermal infrared imagery and color infrared photography for detecting problems associated with the irrigation water management system. The thermal infrared imagery was useful for detecting canal leakage, non-uniformity of water distribution at all stages of crop growth, and apparent crop canopy temperatures as an indicator of crop stress. The color infrared photography was useful for detecting crop stress resulting from a variety of field conditions. Field conditions detected on the photography and affecting crop health included physical parameters of the land resource base (soils, topography, and climate), the influence of irrigators through tillage practices, the affect of irrigation water applications, and the influence of applications of herbicides, pesticides, and fertilizers. Additionally, color infrared photography was used to determine the extent of unexpected system problems (e.g. flooding caused by a lateral canal plugging). Close

• 353. [Article] Habitat structure and occupancy patterns of the montane frog, Rana cascadae, in the Cascade Range, Oregon, at multiple scales : implications for population dynamics in patchy landscapes

  Associations between occupancy patterns of a montane anuran species, Rana cascadae, and habitat structure at multiple scales were examined to investigate how population structure may influence persistence ...

  Citation × Citation Citation Abstract Copy Title: Habitat structure and occupancy patterns of the montane frog, Rana cascadae, in the Cascade Range, Oregon, at multiple scales : implications for population dynamics in patchy landscapes Author: Brown, Catherine, 1958- Associations between occupancy patterns of a montane anuran species, Rana cascadae, and habitat structure at multiple scales were examined to investigate how population structure may influence persistence in spatially and temporally heterogeneous environments. Predictions were based on population dynamics suggested by source-sink and metapopulation models. Potential sites in three basins in the central Cascade Range, Oregon, were identified from aerial photos, fieldverified, and surveyed for eggs, tadpoles, and adults. Habitat quality at each site (i.e. vegetation, shoreline topography, area, water retention) and connectivity among sites (i.e. distance, gradient, connecting creeks) were measured to investigate factors that may be associated with distribution patterns at local and regional scales. Habitat structure at the site scale explained many of R. cascadae occupancy patterns. Breeding sites generally were small vegetated ponds with gradual shoreline topography, or flooded meadows. Adults, juveniles, and metamorphs were found in a wider variety of sites including small vegetated ponds, larger deeper lakes, meadows, and creeks. A strong association was found between occupancy and water retention. A large proportion of sites that retained water through the summer were occupied by at least one life history stage. Connectivity metrics were not associated with the distribution of breeding sites; breeding sites generally were dispersed when measured by all metrics. However, the occupancy patterns of adults suggested that frogs moved among sites. In McKenzie Pass, the high density of sites may provide stepping stones, whereas in Three Creeks and Todd Lake, the flowing creeks may provide corridors. Rana cascadae appears to be well adapted to living in a spatially and temporally heterogeneous environment. Breeding was associated with habitat characteristics that may favor rapid development. Habitat and adult occupancy associations suggested that the frog's home range may be larger than a single site. Given the unpredictable environment, use of other habitats such as creeks and large lakes may enable frogs to survive stressful periods. The apparent high mobility may facilitate access to potentially critical alternate habitat, immigration that may "rescue" extant populations, and recolonization of sites where populations have gone extinct. Conservation plans should protect the range of habitats required at multiple spatial scales. Title: Habitat structure and occupancy patterns of the montane frog, Rana cascadae, in the Cascade Range, Oregon, at multiple scales : implications for population dynamics in patchy landscapes Author: Brown, Catherine, 1958- Associations between occupancy patterns of a montane anuran species, Rana cascadae, and habitat structure at multiple scales were examined to investigate how population structure may influence persistence in spatially and temporally heterogeneous environments. Predictions were based on population dynamics suggested by source-sink and metapopulation models. Potential sites in three basins in the central Cascade Range, Oregon, were identified from aerial photos, fieldverified, and surveyed for eggs, tadpoles, and adults. Habitat quality at each site (i.e. vegetation, shoreline topography, area, water retention) and connectivity among sites (i.e. distance, gradient, connecting creeks) were measured to investigate factors that may be associated with distribution patterns at local and regional scales. Habitat structure at the site scale explained many of R. cascadae occupancy patterns. Breeding sites generally were small vegetated ponds with gradual shoreline topography, or flooded meadows. Adults, juveniles, and metamorphs were found in a wider variety of sites including small vegetated ponds, larger deeper lakes, meadows, and creeks. A strong association was found between occupancy and water retention. A large proportion of sites that retained water through the summer were occupied by at least one life history stage. Connectivity metrics were not associated with the distribution of breeding sites; breeding sites generally were dispersed when measured by all metrics. However, the occupancy patterns of adults suggested that frogs moved among sites. In McKenzie Pass, the high density of sites may provide stepping stones, whereas in Three Creeks and Todd Lake, the flowing creeks may provide corridors. Rana cascadae appears to be well adapted to living in a spatially and temporally heterogeneous environment. Breeding was associated with habitat characteristics that may favor rapid development. Habitat and adult occupancy associations suggested that the frog's home range may be larger than a single site. Given the unpredictable environment, use of other habitats such as creeks and large lakes may enable frogs to survive stressful periods. The apparent high mobility may facilitate access to potentially critical alternate habitat, immigration that may "rescue" extant populations, and recolonization of sites where populations have gone extinct. Conservation plans should protect the range of habitats required at multiple spatial scales. Close

• 354. [Article] Stratigraphy, depositional history, and petrology of the Upper Cretaceous(?) to middle Eocene Montgomery Creek Formation, northern California

  The Upper Cretaceous to Eocene Montgomery Creek Formation is exposed between the Klamath and Cascade Mountains in the vicinity of Big Bend and Montgomery Creek, northern California. The formation is divided ...

  Citation × Citation Citation Abstract Copy Title: Stratigraphy, depositional history, and petrology of the Upper Cretaceous(?) to middle Eocene Montgomery Creek Formation, northern California Author: Higinbotham, Larry R. The Upper Cretaceous to Eocene Montgomery Creek Formation is exposed between the Klamath and Cascade Mountains in the vicinity of Big Bend and Montgomery Creek, northern California. The formation is divided into a northern and a southern section. The rocks consist of a basal conglomerate succeeded by feldspathic to lithic graywackes, conglomerates, shales, carbonaceous shales, and minor lignites. The northern section is 3,188 feet thick. Fining upward point bar deposits, abundant foreset- and cross-bedding, and thick flood-basin deposits indicate the northen section strata were deposited by meandering rivers. Carbonaceous shales, lignites and fossil leaves define the swamps that were present in the basins. The southern section is 4,596 feet thick. Thick and laterally extensive sandstone bodies, numerous conglomerate interbeds, and abundant planar cross-bedding suggest that these strata were deposited by braided rivers. A few outcrops low in the section resemble the northern section strata, and are interpreted to be meandering river deposits. A progressive change in composition of the sandstones from the base to the top of the formation occurs in both the northern and southern sections. This reflects the change from metamorphic and plutonic source rocks of the Klamath Mountains to volcanic source rocks of the early Cascade Range. The southern section maintains a more lithic-rich composition, reflecting higher discharge rates and steeper gradients responsible for braided-river deposition. Paleocurrent readings from foreset bedding and imbricated pebbles indicate a north-to-south transport direction in most of both sections. Some westerly transport occurred high in the southern section. Eocene strata four miles north of the northern section reflect a meandering river depositional environment. These strata have a higher shale-to-sandstone ratio, larger proportions of carbonaceous shales and coal, and a different sandstone mineralogy than Eocene rocks to the south. Analysis revealed that the Montgomery Creek Formation carbonaceous shales and coal are sufficiently rich in organic carbon to be hydrocarbon source rocks. Most of the samples are thermally immature, but could produce gas through bacterial-fungal breakdown of organic matter. The Eocene sandstones have adequate porosity and permeability to be petroleum reservoir rocks. The Klamath Mountains acted as a source area for Cretaceous marine deposits in basins north and south of the study area. Either the Cretaceous seas did not transgress into the study area, or such deposits were subsequently removed by erosion. Title: Stratigraphy, depositional history, and petrology of the Upper Cretaceous(?) to middle Eocene Montgomery Creek Formation, northern California Author: Higinbotham, Larry R. The Upper Cretaceous to Eocene Montgomery Creek Formation is exposed between the Klamath and Cascade Mountains in the vicinity of Big Bend and Montgomery Creek, northern California. The formation is divided into a northern and a southern section. The rocks consist of a basal conglomerate succeeded by feldspathic to lithic graywackes, conglomerates, shales, carbonaceous shales, and minor lignites. The northern section is 3,188 feet thick. Fining upward point bar deposits, abundant foreset- and cross-bedding, and thick flood-basin deposits indicate the northen section strata were deposited by meandering rivers. Carbonaceous shales, lignites and fossil leaves define the swamps that were present in the basins. The southern section is 4,596 feet thick. Thick and laterally extensive sandstone bodies, numerous conglomerate interbeds, and abundant planar cross-bedding suggest that these strata were deposited by braided rivers. A few outcrops low in the section resemble the northern section strata, and are interpreted to be meandering river deposits. A progressive change in composition of the sandstones from the base to the top of the formation occurs in both the northern and southern sections. This reflects the change from metamorphic and plutonic source rocks of the Klamath Mountains to volcanic source rocks of the early Cascade Range. The southern section maintains a more lithic-rich composition, reflecting higher discharge rates and steeper gradients responsible for braided-river deposition. Paleocurrent readings from foreset bedding and imbricated pebbles indicate a north-to-south transport direction in most of both sections. Some westerly transport occurred high in the southern section. Eocene strata four miles north of the northern section reflect a meandering river depositional environment. These strata have a higher shale-to-sandstone ratio, larger proportions of carbonaceous shales and coal, and a different sandstone mineralogy than Eocene rocks to the south. Analysis revealed that the Montgomery Creek Formation carbonaceous shales and coal are sufficiently rich in organic carbon to be hydrocarbon source rocks. Most of the samples are thermally immature, but could produce gas through bacterial-fungal breakdown of organic matter. The Eocene sandstones have adequate porosity and permeability to be petroleum reservoir rocks. The Klamath Mountains acted as a source area for Cretaceous marine deposits in basins north and south of the study area. Either the Cretaceous seas did not transgress into the study area, or such deposits were subsequently removed by erosion. Close

• 355. [Article] Denitrification potential in forest riparian soils of the western Oregon Cascades : spatial and temporal variation

  Denitrification, the biological or chemical reduction of ionic nitrogen oxide or dinitrogen, has not been widely studied in forest ecosystems despite widespread interest in other facets of the forest nitrogen ...

  Citation × Citation Citation Abstract Copy Title: Denitrification potential in forest riparian soils of the western Oregon Cascades : spatial and temporal variation Author: McClellan, Michael H. Denitrification, the biological or chemical reduction of ionic nitrogen oxide or dinitrogen, has not been widely studied in forest ecosystems despite widespread interest in other facets of the forest nitrogen economy. This study had three main objectives: to determine whether potential for denitrification exists in forest riparian and hill slope soils in the western Oregon Cascade Mountains; to test the hypothesis that denitrification potential within riparian forests varies with slope position, soil depth, and season; and to contrast denitrification potential in old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco.) and secondary-successional red alder (Alnus rubra Bong.) forests. Denitrification potential was assessed by anaerobically incubating freshly-collected soils in the presence of acetylene and measuring nitrous oxide emission with electron capture gas chromatography. Soils were amended with deionized water, but not with nitrate or carbon sources. Soil moisture, pH, nitrate, ammonium, and total nitrogen, carbon, and phosphorus were measured. Soils were collected during May-June 1984 and August-September 1983 and 1984. After 1 h of incubation, average N-losses from the upper mineral soil (0-15cm) ranged from 0-11.3 ng N g-1 h-1 for the Douglas-fir soils, and from 3.4-24.4 ng N g-1 h-1 for the red alder soils. N-loss was significantly less (p < 0.001) from the lower mineral soil (15-30cm); averages ranged from 0-0.4 ng N g-1 h-1 for the Douglas-fir soils, and from 1.1-16.0 ng N g-1 h-1 for the red alder soils. Flood plain soils usually lost more N (3.6-24.4 ng N g-1 h-1) than did hill slope soils (0-2.3 ng N g-1 h-1); intermediate N losses were measured in toe slope soils (0.8-4.2 ng N g-1 h-1). The effect of slope position was significant (p < 0.001) only in 1983. Seasonal variation was not significant. Multiple regression of N-loss on soil nitrate, total N, and pH accounted for 61% of the N-loss rate variation. Denitrification potential was highly variable, with coefficients of variation ranging between 53 and 281%, and appeared to fit a lognormal distribution. Title: Denitrification potential in forest riparian soils of the western Oregon Cascades : spatial and temporal variation Author: McClellan, Michael H. Denitrification, the biological or chemical reduction of ionic nitrogen oxide or dinitrogen, has not been widely studied in forest ecosystems despite widespread interest in other facets of the forest nitrogen economy. This study had three main objectives: to determine whether potential for denitrification exists in forest riparian and hill slope soils in the western Oregon Cascade Mountains; to test the hypothesis that denitrification potential within riparian forests varies with slope position, soil depth, and season; and to contrast denitrification potential in old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco.) and secondary-successional red alder (Alnus rubra Bong.) forests. Denitrification potential was assessed by anaerobically incubating freshly-collected soils in the presence of acetylene and measuring nitrous oxide emission with electron capture gas chromatography. Soils were amended with deionized water, but not with nitrate or carbon sources. Soil moisture, pH, nitrate, ammonium, and total nitrogen, carbon, and phosphorus were measured. Soils were collected during May-June 1984 and August-September 1983 and 1984. After 1 h of incubation, average N-losses from the upper mineral soil (0-15cm) ranged from 0-11.3 ng N g-1 h-1 for the Douglas-fir soils, and from 3.4-24.4 ng N g-1 h-1 for the red alder soils. N-loss was significantly less (p < 0.001) from the lower mineral soil (15-30cm); averages ranged from 0-0.4 ng N g-1 h-1 for the Douglas-fir soils, and from 1.1-16.0 ng N g-1 h-1 for the red alder soils. Flood plain soils usually lost more N (3.6-24.4 ng N g-1 h-1) than did hill slope soils (0-2.3 ng N g-1 h-1); intermediate N losses were measured in toe slope soils (0.8-4.2 ng N g-1 h-1). The effect of slope position was significant (p < 0.001) only in 1983. Seasonal variation was not significant. Multiple regression of N-loss on soil nitrate, total N, and pH accounted for 61% of the N-loss rate variation. Denitrification potential was highly variable, with coefficients of variation ranging between 53 and 281%, and appeared to fit a lognormal distribution. Close

• 356. [Article] Comparison of stand development of a deciduous-dominated riparian forest and a coniferous-dominated riparian forest in the Oregon Coast Range

  Riparian forests in the central Oregon Coast Range vary along a coniferous-deciduous compositional continuum. Variations in structure and composition affect water quality, fish and wildlife, biodiversity, ...

  Citation × Citation Citation Abstract Copy Title: Comparison of stand development of a deciduous-dominated riparian forest and a coniferous-dominated riparian forest in the Oregon Coast Range Author: Poage, Nathan Jeremy Riparian forests in the central Oregon Coast Range vary along a coniferous-deciduous compositional continuum. Variations in structure and composition affect water quality, fish and wildlife, biodiversity, timber, and aesthetics. A retrospective approach was taken in this study in order to understand and compare the structure, pattern, and history of an unmanaged, mature, deciduous-dominated riparian forest and an unmanaged, mature, coniferous-dominated riparian forest in the central Oregon Coast Range. Information on forest structure and pattern was acquired by mapping locations of all trees and snags (DBH 5cm) within a 2.0 ha and a 2.25 ha reference stand. The history of each stand was reconstructed through analyses of stand structure and composition, tree ages, spatial patterns of trees and snags, as well as detailed field observations. The structure and composition of the two forests is very different. Non-random patterns of trees and snags were observed at multiple scales. Although it is not possible to infer directly the process(es) responsible for observed patterns, point-pattern analysis is a useful tool to detect and describe intra- and interspecific patterns. Neither forest resulted from a single, stand-replacing fire. Instead, both sites were at least partially burned about 145 years ago, possibly in the same fire(s) which spread across an estimated 500,000 acres between the Siuslaw and Siletz Rivers in the mid-1800's (Morris 1934). There is good evidence to suggest that a second fire occurred at the coniferous-dominated site. One or two other fires may have occurred at the deciduous-dominated site. Evidence of wind, herbivory, flooding, pathogens, mass movement events, and non-stand replacing fire was observed at one or both of the sites. Seed source availability as affected by disturbance history may have played a role in forest development at both sites. The seed source availability of red alder relative to Douglas-fir may have increased with successive disturbance events at the deciduous-dominated, riparian forest. A local source of western hemlock seed may have been a key factor in the development of the coniferous-dominated, riparian forest. Title: Comparison of stand development of a deciduous-dominated riparian forest and a coniferous-dominated riparian forest in the Oregon Coast Range Author: Poage, Nathan Jeremy Riparian forests in the central Oregon Coast Range vary along a coniferous-deciduous compositional continuum. Variations in structure and composition affect water quality, fish and wildlife, biodiversity, timber, and aesthetics. A retrospective approach was taken in this study in order to understand and compare the structure, pattern, and history of an unmanaged, mature, deciduous-dominated riparian forest and an unmanaged, mature, coniferous-dominated riparian forest in the central Oregon Coast Range. Information on forest structure and pattern was acquired by mapping locations of all trees and snags (DBH 5cm) within a 2.0 ha and a 2.25 ha reference stand. The history of each stand was reconstructed through analyses of stand structure and composition, tree ages, spatial patterns of trees and snags, as well as detailed field observations. The structure and composition of the two forests is very different. Non-random patterns of trees and snags were observed at multiple scales. Although it is not possible to infer directly the process(es) responsible for observed patterns, point-pattern analysis is a useful tool to detect and describe intra- and interspecific patterns. Neither forest resulted from a single, stand-replacing fire. Instead, both sites were at least partially burned about 145 years ago, possibly in the same fire(s) which spread across an estimated 500,000 acres between the Siuslaw and Siletz Rivers in the mid-1800's (Morris 1934). There is good evidence to suggest that a second fire occurred at the coniferous-dominated site. One or two other fires may have occurred at the deciduous-dominated site. Evidence of wind, herbivory, flooding, pathogens, mass movement events, and non-stand replacing fire was observed at one or both of the sites. Seed source availability as affected by disturbance history may have played a role in forest development at both sites. The seed source availability of red alder relative to Douglas-fir may have increased with successive disturbance events at the deciduous-dominated, riparian forest. A local source of western hemlock seed may have been a key factor in the development of the coniferous-dominated, riparian forest. Close

• 357. [Article] Summary report to assist development of ecosystem flow recommendations for the Coast Fork and Middle Fork of the Willamette River, Oregon

  Prepared for Sustainable Rivers Project of The Nature Conservancy and the U.S. Army Corps of Engineers.

  Citation × Citation Citation Abstract Copy Title: Summary report to assist development of ecosystem flow recommendations for the Coast Fork and Middle Fork of the Willamette River, Oregon Author: Ashkenas, Linda, Nygaard, Chris, Gregory, Stanley V. Prepared for Sustainable Rivers Project of The Nature Conservancy and the U.S. Army Corps of Engineers. Title: Summary report to assist development of ecosystem flow recommendations for the Coast Fork and Middle Fork of the Willamette River, Oregon Author: Ashkenas, Linda, Nygaard, Chris, Gregory, Stanley V. Prepared for Sustainable Rivers Project of The Nature Conservancy and the U.S. Army Corps of Engineers. Close

• 358. [Article] Abundance, habitat association, and foraging ecology of American dippers and other riparian-associated wildlife in the Oregon Coast Range

  To quantify the distribution and abundance of the riparian-associated vertebrate community, I surveyed streams in four basins in the Oregon Coast Range, 1992-1994. I observed mostly birds with fewer observations ...

  Citation × Citation Citation Abstract Copy Title: Abundance, habitat association, and foraging ecology of American dippers and other riparian-associated wildlife in the Oregon Coast Range Author: Loegering, John P., 1964- To quantify the distribution and abundance of the riparian-associated vertebrate community, I surveyed streams in four basins in the Oregon Coast Range, 1992-1994. I observed mostly birds with fewer observations of mammals. Belted Kingfishers (Ceryle alcyon), American Dippers (Cinclus mexicanus), Great Blue Herons (Ardea herodias), and Mallards (Anus plalyrhynchos) comprised >85% of these observations, but no one species was abundant. Abundance of each species was affected by stream order, basin, and season, but to varying degrees. Dippers and kingfishers selected channel unit habitats disproportionately to their availability. Key habitat components that were predictive of use were species specific. Riparian forests and streamside trees were important predictors of use by the three most abundant species; dippers, kingfishers, and herons. Second, I studied nest-site selection of dippers. Dippers selected nest sites based primarily on micro-habitat characteristics. Reproductive success was high and not associated with any habitat or parental foraging behavior. Suitable nest sites provided a physical space to place the nest, were above the upper flood line and inaccessible to ground predators, and were very near or extended over the stream's edge. Within the context of mountain streams, dippers exhibited flexibility in their nest-site selection. Dippers used experimentally-created nest sites, doubling the population on a 10-km reach. Dipper populations appeared to be limited by the availability of suitable nest sites. Third, I studied foraging ecology of dippers by observing prey delivered to nestlings. Dippers fed nestlings a variety of invertebrate and vertebrate prey. Prey was mostly aquatic and composed primarily of mayflies, stoneflies, caddisflies, fish, and adult insects. Younger chicks were fed smaller prey and more mayflies than older chicks. Older chicks were fed larger prey and more caddisflies and fish than younger chicks. Mayflies, stoneflies, and fish were fed more often to nestlings during the first than the second brood-rearing seasons. The caloric content of prey delivered by males and females was similar. However, males delivered more, smaller prey items than females, and this was most pronounced when the females were brooding young chicks. Title: Abundance, habitat association, and foraging ecology of American dippers and other riparian-associated wildlife in the Oregon Coast Range Author: Loegering, John P., 1964- To quantify the distribution and abundance of the riparian-associated vertebrate community, I surveyed streams in four basins in the Oregon Coast Range, 1992-1994. I observed mostly birds with fewer observations of mammals. Belted Kingfishers (Ceryle alcyon), American Dippers (Cinclus mexicanus), Great Blue Herons (Ardea herodias), and Mallards (Anus plalyrhynchos) comprised >85% of these observations, but no one species was abundant. Abundance of each species was affected by stream order, basin, and season, but to varying degrees. Dippers and kingfishers selected channel unit habitats disproportionately to their availability. Key habitat components that were predictive of use were species specific. Riparian forests and streamside trees were important predictors of use by the three most abundant species; dippers, kingfishers, and herons. Second, I studied nest-site selection of dippers. Dippers selected nest sites based primarily on micro-habitat characteristics. Reproductive success was high and not associated with any habitat or parental foraging behavior. Suitable nest sites provided a physical space to place the nest, were above the upper flood line and inaccessible to ground predators, and were very near or extended over the stream's edge. Within the context of mountain streams, dippers exhibited flexibility in their nest-site selection. Dippers used experimentally-created nest sites, doubling the population on a 10-km reach. Dipper populations appeared to be limited by the availability of suitable nest sites. Third, I studied foraging ecology of dippers by observing prey delivered to nestlings. Dippers fed nestlings a variety of invertebrate and vertebrate prey. Prey was mostly aquatic and composed primarily of mayflies, stoneflies, caddisflies, fish, and adult insects. Younger chicks were fed smaller prey and more mayflies than older chicks. Older chicks were fed larger prey and more caddisflies and fish than younger chicks. Mayflies, stoneflies, and fish were fed more often to nestlings during the first than the second brood-rearing seasons. The caloric content of prey delivered by males and females was similar. However, males delivered more, smaller prey items than females, and this was most pronounced when the females were brooding young chicks. Close

• 359. [Article] Input/output energy analysis of regional water pollution control

  Two strategic approaches to water quality control in Oregon's Willamette River are presently being utilized: point source treatment and flow augmentation. Dry weather releases from reservoirs are for authorized ...

  Citation × Citation Citation Abstract Copy Title: Input/output energy analysis of regional water pollution control Author: Heggen, Richard J. Two strategic approaches to water quality control in Oregon's Willamette River are presently being utilized: point source treatment and flow augmentation. Dry weather releases from reservoirs are for authorized purposes other than water quality. Reservoirs can participate in pollution control by summer flow augmentation where authorized water resource objectives (flood control, navigation, etc.) are not sacrificed. It is hypothesized that the differences in total energy impact between treatment and augmentation may be substantial. Of additional interest is the comparison between direct utilization of energy for Willamette Valley pollution control and the indirect energy requirements of such programs. Input/Output analysis (I/O) provides an econometric methodology to study direct and indirect energy response to pollution control alternatives. An energy I/O national model is coupled with a comprehensive Willamette River dissolved oxygen model. Discharge and loadings are empirically related to surveyed direct dollar and energy expenses. These costs are then transformed by I/O to total energy costs. Three approaches to environmental control for the Willamette are examined. One is that of current enforcement coupled with present levels of augmentation. Another consists of less augmentation and increased wastewater treatment. Appropriate tactics involve advanced secondary methods of treatment, regionalization of treatment plants, and yet more stringent effluent requirements for industry. The third approach consists of increased flow augmentation for water quality control. Corresponding treatment is somewhat relaxed. Each alternative of environmental control is evaluated as if it had been practiced in a study year of low natural runoff. The relation of augmentation for water quality to other river uses is used to value flow in a benefits-foregone manner. Independently, reservoir costs are allocated to water quality. An instream unit price is thus assigned to augmentation. For each alternative of treatment and augmentation, the dissolved oxygen quality of the Willamette is simulated and the costs of the environmental strategy estimated. River quality, dollar cost, and energy impact response surfaces are developed. Indirect energy costs, largely expended out of the region, are roughly twice the direct energy use. Because of the predominance of treatment expenses over augmentation cost and the energy-intensive nature of treatment, energy impact is substantially a reflection of treatment degree. Because augmentation reduces treatment environmentally required, energy and dollar efficient management calls for the full role of augmentation in water quality control. To a reasonable degree this has in fact been carried out. Policies of the region are compared; the present commitments to environmental improvement and economic development are found to contradict the area's energy objectives. Title: Input/output energy analysis of regional water pollution control Author: Heggen, Richard J. Two strategic approaches to water quality control in Oregon's Willamette River are presently being utilized: point source treatment and flow augmentation. Dry weather releases from reservoirs are for authorized purposes other than water quality. Reservoirs can participate in pollution control by summer flow augmentation where authorized water resource objectives (flood control, navigation, etc.) are not sacrificed. It is hypothesized that the differences in total energy impact between treatment and augmentation may be substantial. Of additional interest is the comparison between direct utilization of energy for Willamette Valley pollution control and the indirect energy requirements of such programs. Input/Output analysis (I/O) provides an econometric methodology to study direct and indirect energy response to pollution control alternatives. An energy I/O national model is coupled with a comprehensive Willamette River dissolved oxygen model. Discharge and loadings are empirically related to surveyed direct dollar and energy expenses. These costs are then transformed by I/O to total energy costs. Three approaches to environmental control for the Willamette are examined. One is that of current enforcement coupled with present levels of augmentation. Another consists of less augmentation and increased wastewater treatment. Appropriate tactics involve advanced secondary methods of treatment, regionalization of treatment plants, and yet more stringent effluent requirements for industry. The third approach consists of increased flow augmentation for water quality control. Corresponding treatment is somewhat relaxed. Each alternative of environmental control is evaluated as if it had been practiced in a study year of low natural runoff. The relation of augmentation for water quality to other river uses is used to value flow in a benefits-foregone manner. Independently, reservoir costs are allocated to water quality. An instream unit price is thus assigned to augmentation. For each alternative of treatment and augmentation, the dissolved oxygen quality of the Willamette is simulated and the costs of the environmental strategy estimated. River quality, dollar cost, and energy impact response surfaces are developed. Indirect energy costs, largely expended out of the region, are roughly twice the direct energy use. Because of the predominance of treatment expenses over augmentation cost and the energy-intensive nature of treatment, energy impact is substantially a reflection of treatment degree. Because augmentation reduces treatment environmentally required, energy and dollar efficient management calls for the full role of augmentation in water quality control. To a reasonable degree this has in fact been carried out. Policies of the region are compared; the present commitments to environmental improvement and economic development are found to contradict the area's energy objectives. Close

• 360. [Article] Colonization patterns of stream benthos on artificial substrates in Taiwan

  Experiments on the colonization of artificial substrates by stream benthos were conducted in upper Chingmei Stream, Taiwan. The artificial substrates were colonized by stream benthos for periods of 3, ...

  Citation × Citation Citation Abstract Copy Title: Colonization patterns of stream benthos on artificial substrates in Taiwan Author: Shieh, Sen-her Experiments on the colonization of artificial substrates by stream benthos were conducted in upper Chingmei Stream, Taiwan. The artificial substrates were colonized by stream benthos for periods of 3, 6 12, 21, 30 and 42 days.The two experiments were designed for different purposes. Experiment I from December 15, 1990 to January 29, 1991 investigated the colonization patterns of stream benthos at two sites: a polluted site caused by coal mining activities (Site 1) and a recovery site further downstream of the polluted site (Site 2). Experiment II from March 14, 1991 to April 28, 1991 tested the effect of two different sizes of substrate (cobble and gravel) on the colonization patterns of stream benthos at Site 2. In Experiment I, the total number of individuals and taxa were significantly affected by exposure period of experimental substrates and sites which indicate the occurrence of succession and the detrimental effect of coal mining activities on the benthic community. At Site 1, only Caenis sp., Euphaea sp. and Chironomidae occurred on all sampling dates and were abundant. The other taxa may just continue to drift away from the site. The chironomid larvae were most abundant. They accounted for over 90% of the colonizing individuals from day 12 to day 42. At Site 2, Baetis spA and Chironomidae were most abundant. They accounted for over 80% during the experiment, except on day 21. The relative abundance shifted from Baetis sp.A to Chironomidae with an increase in colonization time. Association analysis was performed on the abundance of taxa pairs within the same functional feeding group at Site 2. The results suggest that filter-feeders and predators have concordant colonization patterns. The relationship between taxa and abundance at the two sites also was tested by lognormal distribution to determine the degree of equilibrium of the community. In Experiment II, the substratum types influenced only the total number of individuals colonizing baskets. The gravel substrate provides more surface area for stream benthos and supports more individuals. Baetis sp.A and chironomid larvae were abundant; they accounted for over 84% of the individuals from day 6 to 42 on both gravel and cobble. The chironomid larvae comprised 36% of the fauna on the gravel substrate and 35 - 79% of the fauna on the cobble substrate. The results of association analysis on the abundance of taxa pairs within the same functional feeding group showed that there were more taxa pairs with significant associations on cobble than on gravel. The negatively significant associations also occurred more on the cobble substrate. This indicates that biological interactions may be important in determining the development of community on the cobble substrate. Disturbance caused by floods influenced the colonization patterns, especially on the gravel substrate. It reset the artificial substrates back to earlier conditions. This study only suggests that competition may occur in the subtropical Taiwanese stream and further experimentation is needed to demonstrate whether competition occurs. Title: Colonization patterns of stream benthos on artificial substrates in Taiwan Author: Shieh, Sen-her Experiments on the colonization of artificial substrates by stream benthos were conducted in upper Chingmei Stream, Taiwan. The artificial substrates were colonized by stream benthos for periods of 3, 6 12, 21, 30 and 42 days.The two experiments were designed for different purposes. Experiment I from December 15, 1990 to January 29, 1991 investigated the colonization patterns of stream benthos at two sites: a polluted site caused by coal mining activities (Site 1) and a recovery site further downstream of the polluted site (Site 2). Experiment II from March 14, 1991 to April 28, 1991 tested the effect of two different sizes of substrate (cobble and gravel) on the colonization patterns of stream benthos at Site 2. In Experiment I, the total number of individuals and taxa were significantly affected by exposure period of experimental substrates and sites which indicate the occurrence of succession and the detrimental effect of coal mining activities on the benthic community. At Site 1, only Caenis sp., Euphaea sp. and Chironomidae occurred on all sampling dates and were abundant. The other taxa may just continue to drift away from the site. The chironomid larvae were most abundant. They accounted for over 90% of the colonizing individuals from day 12 to day 42. At Site 2, Baetis spA and Chironomidae were most abundant. They accounted for over 80% during the experiment, except on day 21. The relative abundance shifted from Baetis sp.A to Chironomidae with an increase in colonization time. Association analysis was performed on the abundance of taxa pairs within the same functional feeding group at Site 2. The results suggest that filter-feeders and predators have concordant colonization patterns. The relationship between taxa and abundance at the two sites also was tested by lognormal distribution to determine the degree of equilibrium of the community. In Experiment II, the substratum types influenced only the total number of individuals colonizing baskets. The gravel substrate provides more surface area for stream benthos and supports more individuals. Baetis sp.A and chironomid larvae were abundant; they accounted for over 84% of the individuals from day 6 to 42 on both gravel and cobble. The chironomid larvae comprised 36% of the fauna on the gravel substrate and 35 - 79% of the fauna on the cobble substrate. The results of association analysis on the abundance of taxa pairs within the same functional feeding group showed that there were more taxa pairs with significant associations on cobble than on gravel. The negatively significant associations also occurred more on the cobble substrate. This indicates that biological interactions may be important in determining the development of community on the cobble substrate. Disturbance caused by floods influenced the colonization patterns, especially on the gravel substrate. It reset the artificial substrates back to earlier conditions. This study only suggests that competition may occur in the subtropical Taiwanese stream and further experimentation is needed to demonstrate whether competition occurs. Close