Pacific Northwest Research Station
Pacific Northwest Research Station
Wondzell S.M.,Pacific Northwest Research Station
Water Resources Research | Year: 2017
The spatial and temporal scales of hyporheic exchange within the stream corridor are controlled by stream discharge and groundwater inflow interacting with streambed morphology. While decades of study have resulted in a clear understanding of how morphologic form controls hyporheic exchange at the feature scale, we lack comparable predictive power related to stream discharge and the spatial structure of groundwater inflows at the reach scale, where spatial heterogeneity in both geomorphic setting and hydrologic forcing are present. In this study, we simulated vertical hyporheic exchange along a 600 m mountain stream reach under high, medium, and low stream discharge while considering groundwater inflow as negligible, spatially uniform, or proportional to upslope accumulated area. Most changes to hyporheic flow path residence time or length in response to stream discharge were small (<5%), suggesting that discharge is a secondary control relative to morphologically driven hyporheic exchange. Groundwater inflow was a primary control and mostly caused decreases in hyporheic flow path residence time and length. This finding generally agrees with expectations from the literature; however, flow path response was not consistent across the study reach. Instead, we found that flow paths driven by large hydraulic gradients coinciding with large morphologic features were less sensitive to changes in groundwater inflow than those driven by hydraulic gradients similar to the valley gradient. Our results indicate that consideration of heterogeneous arrangement of morphologic features is necessary to differentiate between hyporheic flow paths that persist in time and those that are sensitive to changing hydrologic conditions. © 2017. American Geophysical Union.
News Article | December 11, 2015
Researchers found evidence that the invasive barred owl is playing a pivotal role in the continued decline of spotted owls, although habitat loss and climate variation were also important in some parts of the species range. Barred owls compete with spotted owls for space, food and habitat. This research indicated that since monitoring began spotted owl populations declined 55-77 percent in Washington, 31-68 percent in Oregon and 32-55 percent in California. In addition, population declines are now occurring on study areas in southern Oregon and northern California that were previously experiencing little to no detectable decline through 2009. Dr. Katie Dugger, a research biologist at the USGS Oregon Cooperative Fish and Wildlife Research Unit, Oregon State University and lead author on the report, said that "This study provides strong evidence that barred owls are negatively affecting spotted owl populations. The presence of barred owls was associated with decreasing spotted owl survival rates in some study areas and spotted owls were disappearing from many of their historical breeding territories as those areas were invaded by barred owls." The exception was a small area in California where barred owl removals began in 2009, and where long-term population declines were only 9 percent. Spotted owl populations and survival rates have increased on the latter area since the removal of barred owls started. However, further research on barred owl removal is required in other parts of the spotted owl's range—especially in Washington, where barred owl numbers have been high for a long time. Additionally, said Dugger, "The amount of suitable habitat required by spotted owls for nesting and roosting is important because spotted owl survival, colonization of empty territories, and number of young produced tends to be higher in areas with larger amounts of suitable habitat, at least on some study areas." Relationships between spotted owl populations and climate was complex and variable, but rangewide, the study results suggested that survival of young spotted owls and their ability to become part of the breeding population increased when winters were drier. This may become a factor in population numbers in the future, given climate change predictions for the Pacific Northwest include warmer, wetter winters. The collaborative team of 37 researchers analyzed data from 11 study areas that represented 9 percent of the spotted owl range. During the study, field crews monitored how many owls inhabited different territories, and the yearly survival and reproductive success of banded spotted owls. "This type of collaborative research focused on specific management and conservation objectives provides important information for resource managers and policy decision-makers who manage public resources," said Eric Forsman, a coauthor on the study at the USDA Forest Service, Pacific Northwest Research Station. The paper, "The effects of habitat, climate and barred owls on long-term demography of northern spotted owls," was published in The Condor: Ornithological Applications and authored by Katie M. Dugger, USGS, Oregon Cooperative Fish and Wildlife Research Unit, Oregon State University Department of Fisheries and Wildlife; Eric D. Forsman, USDA Forest Service, Pacific Northwest Research Station; Alan B. Franklin, USDA APHIS National Wildlife Research Center; Raymond Davis, USDA Forest Service, Pacific Northwest Region, and 33 others. Although they do occur in young forests in some areas, northern spotted owls are strongly associated with old forest in most of their range. The U.S. Fish and Wildlife Service listed the northern spotted owl as threatened in 1990 because of the declines in old-growth forest habitat throughout its range in Washington, Oregon and northern California. Explore further: US advances plan to kill barred owls in Northwest
News Article | April 14, 2016
According to the 2010 United States Census, 51 percent of the people in the U.S. are women. That same year, a study of Ph.D. students in the biological sciences documented that 52 percent of the students pursuing doctorates were women – roughly the same percentage. However, the new study by researchers at Oregon State University and the U.S. Forest Service found that roughly even split soon disappears – in both federal government positions and in academic institutions. The researchers found that 74 percent of federal fisheries scientists or managers are men, as were 73 percent of the university assistant professors, 71 percent of associate professors and 85 percent of full professors. The lack of diversity is even more pronounced when analyzed by race. In 2010, the U.S. population was 64 percent white, and participation in biological sciences Ph.D. programs was 69 percent white. Yet only roughly 10 percent of all fisheries science, manager and faculty positions were occupied by minorities. Results of the study are being published this week in the journal Bioscience. "It is clear that the fisheries science culture is one dominated by white men," said Ivan Arismendi, an Oregon State University research faculty scientist and lead author on the study. "There has been a lot of concern expressed in recent years about diversity, but the numbers don't seem to reflect that concern. It is important to begin turning the process today because the hiring we're doing now will last a generation." Brooke Penaluna, a research fish biologist with the U.S. Forest Service's Pacific Northwest Research Station and co-author on the study, said the reasons for the disparity are not completely clear. "We are graduating women on a 50-50 basis in the biological sciences, but the hiring rate is not keeping pace with the degree rate," Penaluna said. "For some women, it may be the biological clock butting up against the timetable of career advancement. That doesn't explain the disparity among minorities. "We need to look more closely at possible institutional biases. Women, for example, have fewer professional publications and are not asked as often by senior-level scientists to publish. And some federal positions may be in geographic locations that are not attractive to all candidates. We need to create environments that are welcoming so people want to stay – and those conversations can be uncomfortable." The authors suggest diversity training and a diverse composition of search committees at both the federal and academic institution levels, as well as increasing the pool of female and minority candidates, and programs to insure their success and career advancement. Explore further: Study finds shade, cover can reduce predation by birds on trout
Njuguna W.,Oregon State University |
Liston A.,Oregon State University |
Cronn R.,Pacific Northwest Research Station |
Ashman T.-L.,University of Pittsburgh |
Bassil N.,U.S. Department of Agriculture
Molecular Phylogenetics and Evolution | Year: 2013
The cultivated strawberry is one of the youngest domesticated plants, developed in France in the 1700s from chance hybridization between two western hemisphere octoploid species. However, little is known about the evolution of the species that gave rise to this important fruit crop. Phylogenetic analysis of chloroplast genome sequences of 21 Fragaria species and subspecies resolves the western North American diploid F. vesca subsp. bracteata as sister to the clade of octoploid/decaploid species. No extant tetraploids or hexaploids are directly involved in the maternal ancestry of the octoploids. There is strong geographic segregation of chloroplast haplotypes in subsp. bracteata, and the gynodioecious Pacific Coast populations are implicated as both the maternal lineage and the source of male-sterility in the octoploid strawberries. Analysis of sexual system evolution in Fragaria provides evidence that the loss of male and female function can follow polyploidization, but does not seem to be associated with loss of self-incompatibility following genome doubling. Character-state mapping provided insight into sexual system evolution and its association with loss of self-incompatibility and genome doubling/merger. Fragaria attained its circumboreal and amphitropical distribution within the past one to four million years and the rise of the octoploid clade is dated at 0.372-2.05 million years ago. © 2012 Elsevier Inc.
Geiser L.H.,U.S. Forest Service Pacific Northwest Region Air Resource Management Program |
Jovan S.E.,Pacific Northwest Research Station |
Glavich D.A.,U.S. Forest Service Pacific Northwest Region Air Resource Management Program |
Porter M.K.,Washington State University |
Porter M.K.,SLR International Corporation
Environmental Pollution | Year: 2010
Critical loads (CLs) define maximum atmospheric deposition levels apparently preventative of ecosystem harm. We present first nitrogen CLs for northwestern North America's maritime forests. Using multiple linear regression, we related epiphytic-macrolichen community composition to: 1) wet deposition from the National Atmospheric Deposition Program, 2) wet, dry, and total N deposition from the Communities Multi-Scale Air Quality model, and 3) ambient particulate N from Interagency Monitoring of Protected Visual Environments (IMPROVE). Sensitive species declines of 20-40% were associated with CLs of 1-4 and 3-9 kgNha-1 y-1 in wet and total deposition. CLs increased with precipitation across the landscape, presumably from dilution or leaching of depositional N. Tight linear correlation between lichen and IMPROVE data suggests a simple screening tool for CL exceedance in US Class I areas. The total N model replicated several US and European lichen CLs and may therefore be helpful in estimating other temperate-forest lichen CLs. © 2010 Elsevier Ltd.
Holloway G.L.,Fiera Biological Consulting |
Smith W.P.,Pacific Northwest Research Station
Journal of Wildlife Management | Year: 2011
Research on the impact of clearcut logging and partial harvesting practices on northern flying squirrels (Glaucomys sabrinus) has shown inconsistent and contrary results, limiting the use of this species as a management indicator species. Much of this variability in study results is due to the labor intensive nature of studying flying squirrels, resulting in small sampling sizes (average = 5.2 sites, n = 14) and high variation (CV = 0.59) across studies. We conducted a meta-analysis of relevant studies from North America to determine how forestry practices affect flying squirrel abundance. Mean effect size was -1.18 (P<0.001; n = 14) for all studies, indicating a strong difference between control stands and those regenerating postclearcut or following partial harvesting. Our results support the association of northern flying squirrels with mature, uncut forest and their suitability as ecological indicators of these vegetation types. © 2011 The Wildlife Society.
Zarnetske J.P.,Oregon State University |
Zarnetske J.P.,Yale University |
Haggerty R.,Oregon State University |
Wondzell S.M.,Pacific Northwest Research Station |
Baker M.A.,Utah State University
Journal of Geophysical Research: Biogeosciences | Year: 2011
We used an in situ steady state 15N-labeled nitrate ( 15NO3-) and acetate (AcO-) well-to-wells injection experiment to determine how the availability of labile dissolved organic carbon (DOC) as AcO- influences microbial denitrification in the hyporheic zone of an upland (third-order) agricultural stream. The experimental wells receiving conservative (Cl- and Br) and reactive (15NO3-) solute tracers had hyporheic median residence times of 7.0 to 13.1 h, nominal flowpath lengths of 0.7 to 3.7 m, and hypoxic conditions (<1.5 mg O2 L-1). All receiving wells demonstrated 15N2 production during ambient conditions, indicating that the hyporheic zone was an environment with active denitrification. The subsequent addition of AcO- stimulated more denitrification as evidenced by significant δ15N 2 increases by factors of 2.7 to 26.1 in receiving wells and significant decreases of NO3- and DO in the two wells most hydrologically connected to the injection. The rate of nitrate removal in the hyporheic zone increased from 218 kg ha-1 yr-1 to 521 kg ha-1 yr-1 under elevated AcO- conditions. In all receiving wells, increases of bromide and 15N2 occurred without concurrent increases in AcO-, indicating that 100% of AcO- was retained or lost in the hyporheic zone. These results support the hypothesis that denitrification in anaerobic portions of the hyporheic zone is limited by labile DOC supply. Copyright 2011 by the American Geophysical Union.
Pattison R.R.,Pacific Northwest Research Station |
Pattison R.R.,University of Alaska Anchorage |
Welker J.M.,University of Alaska Anchorage
Oecologia | Year: 2014
Changes in winter precipitation that include both decreases and increases in winter snow are underway across the Arctic. In this study, we used a 14-year experiment that has increased and decreased winter snow in the moist acidic tussock tundra of northern Alaska to understand impacts of variation in winter snow depth on summer leaf-level ecophysiology of two deciduous shrubs and a graminoid species, including: instantaneous rates of leaf gas exchange, and δ13C, δ15N, and nitrogen (N) concentrations of Betula nana, Salix pulchra, and Eriophorum vaginatum. Leaf-level measurements were complemented by measurements of canopy leaf area index (LAI) and depth of thaw. Reductions in snow lowered summer leaf photosynthesis, conductance, and transpiration rates by up to 40 % compared to ambient and deep snow conditions for Eriophorum vaginatum, and reduced Salix pulchra conductance and transpiration by up to 49 %. In contrast, Betula nana exhibited no changes in leaf gas exchange in response to lower or deeper snow. Canopy LAI increased with added snow, while reduced winter snow resulted in lower growing season soil temperatures and reduced thaw depths. Our findings indicate that the spatial and temporal variability of future snow depth will have individualistic consequences for leaf-level C fixation and water flux by tundra species, and that these responses will be manifested over the longer term by changes in canopy traits, depth of thaw, soil C and N processes, and trace gas (CO2 and H2O) exchanges between the tundra and the atmosphere. © 2013 Springer-Verlag Berlin Heidelberg (outside the USA).
Flaherty E.A.,University of Wyoming |
Ben-David M.,University of Wyoming |
Smith W.P.,Pacific Northwest Research Station
Journal of Mammalogy | Year: 2010
Where dispersal is energetically expensive, feeding and food availability can influence dispersal success. The endemic Prince of Wales northern flying squirrel (Glaucomys sabrinus griseifrons) inhabits a landscape mosaic of old-growth, 2nd-growth, and clear-cut stands, with the latter 2 representing energetically expensive habitats. We estimated the diet of flying squirrels using stable isotope and fecal analyses, determined whether food availability varies among forest stands, and assessed the likelihood of foraging across a managed landscape given the distribution of foods on Prince of Wales Island (POW), Alaska. Both stable isotope and fecal analyses revealed that conifer seeds, lichens, and fungi were the main dietary items consumed and assimilated by flying squirrels. Similarly, soil macroinvertebrates were consumed by squirrels, whereas berries were not. Nonetheless, although examination of stable isotope data suggested that squirrels assimilated few nutrients from truffles, this food source was among the most frequent diet items in feces, probably because flying squirrels assimilate elements other than nitrogen from fungi. Our surveys showed that conifer seeds, truffles, and lichens were more prevalent in old-growth than 2nd-growth and clear-cut habitats. Thus, our results indicate that diet and availability of food items on POW may influence foraging success and dispersal movements of G. sabrinus across fragmented landscapes because of limited availability of food resources in the managed habitats. © 2010 American Society of Mammalogists.
Donovan G.H.,Pacific Northwest Research Station |
Butry D.T.,U.S. National Institute of Standards and Technology
Landscape and Urban Planning | Year: 2010
We use a hedonic price model to simultaneously estimate the effects of street trees on the sales price and the time-on-market (TOM) of houses in Portland, Oregon. On average, street trees add $8870 to sales price and reduce TOM by 1.7 days. In addition, we found that the benefits of street trees spill over to neighboring houses. Because the provision and maintenance of street trees in Portland is the responsibility of adjacent property owners, our results suggest that if the provision of street trees is left solely to homeowners, then there will be too few street trees from a societal perspective.