Urban ecosystems are characterized by human disturbance and changes in the amount, types, and spatial arrangement of wildlife habitat. The relative importance of habitat and human associated variables to urban birds is unknown. In 1999, I surveyed spring bird and plant communities along 54 perennial streams
in the Portland, Oregon...
The structure and components of riparian areas influence the rate, amount, and timing of water, nutrients, organic debris, and inorganic materials that enter streams and rivers. The energy of floodwaters and their ultimate volume, timing and erosive power is influenced by the soils, vegetation and geomorphology of fluvial surfaces within...
This study examined the occurrence of coarse woody debris (i.e., pieces greater than 0.15 m in diameter and 2.0 m in length) in first- through fifth-order streams located within the Drift Creek Basin of the Oregon Coast
Range. Nine "tributary reaches" were surveyed to determine how three land management treatments...
Organic matter dynamics in riparian ecosystems are largely driven by interactions among hydrology, soil, and vegetation. In two riparian meadows, northeast Oregon, I examined the hypothesis that vegetation and soil characteristics in three plant communities - defined as wet, moist, and dry meadow - were strongly influenced by hydrological and...
Riparian areas that can be used as reference sites on which to base goals of vegetation restoration have not been documented in the Oregon Coast Range. I examined the composition and distribution of unmanaged riparian overstories in the central Oregon Coast Range along nine streams which have experienced minimal disturbance...
As a key factor contributing to slope stability, in-stream habitat for aquatic species (e.g., salmonids), nutrient cycling, and corridors for upland species, riparian vegetation and its maintenance is of critical conservation importance. Subsequently, the chronic degradation of aquatic and riparian ecosystems in the semi-arid and arid landscapes of the western...
Managing riparian buffer zones is a potentially important approach to protecting streams from agricultural pollution. This study was conducted to determine if a pasture, a hybrid poplar (Populus trichocarpa x deltoides) stand, or a native oak (Quercus garryana) forest, had the greatest potential to serve as a nutrient buffer zone....
Little research has been directed toward determining the status and ecological role of riparian areas in agricultural landscapes of the Willamette Valley, Oregon. A research project has been designed to contribute to the development and evaluation of alternative future scenarios and to improve the basic understanding of the role of...
This study was conducted to describe variation of riparian vegetation in an Oregon Coast Range system according to geomorphic characteristics and in relation to streamflow. Specific objectives of this study were to: I) examine if the vegetation composition and structure of the riparian forest varied among channel-reach morphologies, 2) examine...
The purposes of this study were:1) to review the land use history of Oak Creek watershed since European settlement. And 2) to consider the human-caused impacts and their effects associated with different land uses. The study area was classified into three land use patterns: residential,agricultural, and forested areas.Since the European...
Riparian vegetation (trees > 10 cm dbh), woody debris (> 10 cm diam, > 1 m long), channel, and landform characteristics were inventoried in mature (80-150 yrs) and old-growth riparian areas (>250 yrs) selected from small tributaries of the Coos and Coquille River basins in southwestern Oregon. Basal area of...
I studied riparian forests of four western Oregon watersheds (dry south to wet north) to determine the multiscale controls on woody riparian vegetation. I conducted separate analyses of controls on plant distribution, diversity, and tree regeneration using vegetation and environmental data collected in two related field studies: (1) a multiscale...
A multitude of biotic and physical factors, many of them unique to riparian environments, interacted to form an extremely complex ecosystem along Catherine Creek in the Wallowa Mountains. A total of 258 stands of vegetation representing 60 communities was identified. At least 20 species of mammals and 81 species of...
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...
I examined the abundance and habitat associations of terrestrial amphibian species and the species richness of terrestrial amphibian communities in riparian buffer strips, clearcuts, and unmanaged riparian forests. The study was conducted in the western hemlock (Tsuga heteropliylla) vegetation zone of the northern and central Oregon Coast Range. Data were...
Riparian zone vegetation can influence terrestrial and aquatic food webs through variations in the amounts, timing, and nutritional content of leaf and other litter inputs. Differences in vegetation composition and density, as well as riparian topography, may modulate the strength and quality of these inputs. Changes in inputs to small...
This publication is aimed at watershed councils, government agencies, and specialists (foresters, wildlife and fisheries biologists) interested in riparian area silviculture or watershed restoration. It contains information on the ecology of riparian forests and a checklist of recommended practices and common mistakes made in restoring conifers to hardwood-dominated riparian forests....
Published January 1995. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Discusses what land use practices can impact riparian areas and the techniques landowners, volunteers, and professional resource managers can use to improve and protect riparian function.
This classification describes common streamside plant communities and the typical riparian settings in which they are found. The purpose of the guide is to allow an observer to interpret site factors from the vegetation, or to project potential plant community development from
key site factors. It should be useful in...
Two trials were conducted to evaluate changes in the quantity, quality, and moisture of available forage in the pasture, and shrub utilization by cattle during a 30-d late summer grazing period (Trial 1) and the effect of cow age (experience) on grazing distribution and diet composition (Trial 2) in mountain...
Riparian areas in the Pacific Northwest provide important biotic and abiotic
features, such as down wood, moist microsites, and abundant invertebrate prey that
benefit aquatic and terrestrial amphibians. Reported high densities of amphibians from
streams and riparian areas in the Pacific Northwest highlight their importance in riparian
food webs. Amphibians...
Seasonal trends in forage production and environmental parameters
for five plant community types within a northeastern Oregon riparian zone
were described and modeled using correlation and path analysis. Wet
meadows produced the greatest amount of herbage biomass, followed by moist
bluegrass meadows, gravel bars, forests and dry bluegrass meadows. Trends...
Streams make up only one percent of the watershed. Nonetheless, they are an essential component to watershed health. Streams are home to wildlife and fish. Well-functioning streams contribute to water quantity and quality. And streams play an important role in flood and erosion control.
Riparian communities dominated by members of the
Salicaceae (Salix lasiandra, S. lutea, S. lemmonii,
Populus trichocarpa, P. tremuloides and S. exiqua) were
studied at the Crooked River National Grassland in central
Oregon. The objectives of this study were to examine the
relationships between the Salix and Populus species and
microsite...
During 1988-1989, stream habitat variables were compared between beaver-dam sites and unoccupied-stream sites to identify variables that may have been important for beaver (Castor canadensis) in selecting dam sites in the streams of the Drift Creek basin, Lincoln County, Oregon. Increasing valley floor width and grass/sedge cover and decreasing stream...
Vegetation provides food for many insects, and many insects serve as food for bats. We investigated the linkages among these three trophic levels in riparian areas throughout the Oregon Coast Range by examining the influence of vegetation cover, composition, and structure on the activity of nocturnal insects and bats, the...
Grazing of riparian forage by livestock may alter stream channel morphology in ways that impact nearby aquatic habitat, bank stability, vegetative cover and water quality. A number of grazing management practices have been proposed as a means to reduce the amount of time cattle spend in the riparian zone. The...
This study was designed and implemented to observe
the spatial and temporal dynamics of groundwater levels
and temperatures adjacent to a beaver pond in semi-arid
central Oregon. The study site was located on the eastern
boundary of Painted Hills National Monument along Bridge
Creek, a tributary to the John Day...
In the Coast Range of western Oregon, some natural resource managers are converting red alder-dominated riparian areas to conifers to increase the future source of in-stream large wood for salmonid habitat. However, studies in Alaska have shown red alder-dominated riparian areas support greater invertebrate biomass compared to conifer-dominated areas. In...
Riparian ecosystems play numerous and essential roles related to the quality and
flow of water, and food/habitat for fish, and varieties of wildlife. Due to lateral and linear linkages throughout the landscape, these zones influence the integrity of the terrestrial as well as the entire aquatic-riverine ecosystem. Since Euro-American settlement...
Fire is the dominant disturbance process in western U.S. forests, and although effects of fire in upland forests are relatively well-studied, there is little information about fire effects on riparian forests, critical areas of the landscape for both habitat and water quality. This dissertation examines different aspects of fire effects...
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CHAPTER 2 - FIRE SEVERITY IN RIPARIAN AREAS OF THE BISCUIT AND
B&B COMPLEX FIRES, OREGON
Relatively little is known about wintering bird communities in lowlands of the Pacific Northwest, yet, the condition of winter habitats potentially can pose a major constraint on bird populations. I initiated a study to determine: (1) Which avian species use lowland riparian and wetland habitats in the Willamette Valley during...
Most recent research on stream amphibians in the Pacific Northwest has focused on associations with reach-level or stand-level environmental features. Little is known about landscape-level distributions of these species or landscape-level aspects of their life-histories. I used a watershed-wide sample and logistic regression to develop models and maps of probability...
Because riparian canopy controls most energy inputs to stream
ecosystems, it directly affects the structure of aquatic food webs and the
ecological processes that govern interactions among trophic levels. This
study addresses the interdependence among riparian canopy, benthic
community structure, and the carrying capacity of high desert streams for
salmonid...
Recognizing the importance of native black cottonwood-dominated riparian
forests is especially important to preserve, protect, and manage for biodiversity in
the Willamette River Valley. Species composition, structure, and biomass along a
successional gradient from stand initiation to late succession of black cottonwood
(Populus balsamfera L. subsp. trichocarpa (T. & G.)...
Elk River is a sixth order stream, draining a 200 square
kilometer basin in the Klainath Mountain province of
southwestern Oregon. Timber harvesting began in the basin
during the 1950's, with peak removal of wood occurring in the
mid to late 1960's. This activity lead to an increase in the...
The objective of my study was to examine differences in riparian tree and shrub composition associated with adult aquatic emergence and implications for terrestrial spiders in these sites. Seasonal abundance and biomass of adult emergent aquatic insects, riparian arthropod abundances and spider densities were compared between conifer- and hardwood-dominated sites...
This report discusses major characteristics of western Oregon’s lowland rivers, streams, and estuaries that the IMST finds to be important to wild salmonids. IMST describes how landscape scale factors (landscape structure, landscape function, disturbance regimes, and landscape scale biological processes) historically supported salmonid populations in western Oregon lowlands. The report...
Woody riparian vegetation is an essential component of riparian ecosystems, responsible in part for the maintenance of functional ecological processes. The plant community composition and distribution provide an indication of the underlying mosaic of environmental attributes and processes. Restoration and management of riparian communities have been hindered by the lack...
Streamside buffer strips provide numerous benefits to stream ecosystems. The buffer strips create shade, provide shelter for wildlife, act as barriers to logging debris during and after timber harvest, and serve as a continued source of large woody debris. Quantifying woody inputs resulting from windthrow provides managers with estimates for...
This study was undertaken to evaluate the spatial and temporal characteristics
of riparian groundwater tables adjacent to beaver ponds. The research was
conducted in two parts; in the first portion a two-dimensional, finite-difference
computer model was developed and utilized to simulate groundwater elevations
through time in pond-adjacent aquifers. Two types...
Twelve stream segments in the Silvies River drainage system were classified in
the fall of 1993 and again in 1994, using a morphological classification of natural
rivers (Rosgen 1994). Bankfull flow of stream channels is the key feature of this
system. Measurement of bankfull is used in the calculation of...
Properly functioning riparian systems are vital to the health of watersheds and provide an important forage and habitat resource for livestock and wildlife. Riparian grazing management strategies that are economically feasible and achieve environmental goals are needed by resource managers and livestock producers. The objective of this thesis was to...
The nature and extent of niparian vegetation change from 1972 to
1981 in the Willamette River Greenway in Benton and Linn Counties,
Oregon was quantitatively investigated. The study was primarily by
aerial imagery analysis and associated field verification. A classification
of vegetation and land cover within the study area was...
Current riparian management objectives in the Pacific Northwest promote both retention of existing conifers and conversion of hardwood-dominated areas to conifers. Although understanding of relationships between riparian vegetation and salmonid prey availability is growing, temporal variation in these relationships is poorly understood. Seasonal fluxes in availability of aquatic and terrestrial...
Remote sensing techniques have long been useful in quantifying changes in ecosystems and the field of remote sensing is constantly evolving to better assess and describe changes, both spatially and temporally. In this thesis I explored the novel use of two remote sensing methods to quantify ecosystems; repeat photograph to...
I compared species composition and relative abundance of'small
mammals and herpetofauna between riparian and upslope habitats among 5
forest types. Riparian- and upslope- associated species were identified
based on capture frequency. Small mammal species richness was similar
between stream and upslope habitats and among the 5 forest types. There
were...
Riparian zones provide habitat for breeding birds in the semiarid western United States; however, there are few data available that address the effects of livestock grazing strategies on riparian habitats and avian communities. Documenting avian community composition in different riparian vegetation communities and relating vegetation communities to livestock grazing strategies...
Fish assemblage structure was determined along a longitudinal
gradient for three drainages in the upper John Day basin: Middle
Fork, South Fork, and upper Mainstem proper. One or two tributaries
in each drainage were included. Where possible, sites were paired:
those with good versus those with poor riparian habitat. Detrended...
The Tualatin Basin landscape has undergone extensive change since the initiation of Euro-American settlement, with important consequences for basin hydrology and water quality. Changes that include the isolation of the Tualatin River from its floodplain areas, losses of important wetlands and riparian areas, and urbanization associated with population growth in...
Management practices and options to provide habitat for wildlife in the Great Basin of southeastern Oregon deal with both vegetation treatment and protection, livestock management, maintenance or distribution of water developments, protection of wildlife areas through road closures or fencing, and direct manipulation of wildlife through hunting, trapping, or other...
This study describes streams in the Blue Mountains and Wallowa Mountains of Northeastern Oregon in order to characterize the interactions between the terrestrial and aquatic ecosystems and to determine how logging affects those relationships. Five stream reach pairs, each consisting of an undisturbed reach and a similar reach flowing through...
Riparian areas are eco-tones where aquatically- and terrestrially-derived insect biomass is exchanged between habitats, presenting consumers with new sources of energy, and resulting in a reciprocal subsidy. The relative contribution of energy exchange and the
resulting impacts on vertebrate riparian consumers, such as fish or birds, remains poorly understood. We...
Land use alters the physical and biological structure of stream ecosystems and potentially alters their capacity to process nitrogen (N), an essential nutrient that has nearly doubled in abundance on the biosphere
during the past century from human activities. In this dissertation, I quantified uptake and transformation of nitrate (NO₃⁻)...
I studied small-mammal communities and their response to grazing in mixed-conifer forests and oak woodlands in the Cascade-Siskiyou National Monument in southern Oregon. My objectives were to (1) compare small-mammal communities among forest types and grazing intensities, (2) identify riparian affiliated species, and (3) describe microhabitat associations. Over two years,...
Three studies were conducted to evaluate different grazing systems on mixed conifer rangelands in eastern Oregon, and photo points and aerial photography was used to determine effects of 25 years of cattle grazing on stream channel changes and vegetation responses. The first study was designed to determine if grazing treatment...
The Tualatin River in northwest Oregon has been designated as water quality limited by the Oregon Department of Environmental Quality. Restoration and enhancement of riparian areas to improve water quality is one task to be pursued by management agencies. This paper examines some of the potential costs and benefits of...