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Weekly Highlights for 12-1-2017


Physical Processes Dominate Channel Evolution in Olympic National Park Rivers – A Reply

A team of federal scientists address comments from researchers who disagree with the conclusions of the East et al. paper that river channel evolution is driven primarily by physical factors rather than an overabundance of elk due to wolf eradication. The team does not dismiss the influence of elk on riparian vegetation, but contend the weight of evidence indicate floods and other physical drivers have dominated the change in river channels during the last 70 years while biological drivers are secondary. The disagreement highlights the difficulties of determining the causes of ecological change in a complex world, and misinterpretations that are possible when viewing change through a narrow lens.

East, A.E., Jenkins, K.J., Happe, P.J., Bountry, J.A., Beechie, T.J., Mastin, M.C., Sankey, J.B., Randle, T.J., 2017, Reply to “Wolf-triggered trophic cascades and stream channel dynamics in Olympic National Park- a comment on East et al. (2016)” by Beschta and Ripple: Earth Surface Processes and Landforms, p. online. [Details]

Contact: Kurt Jenkins, FRESC, 360-565-3041, Profile

Scale, Climate Change, and Thermal Heterogeneity in PNW Rivers

Climate-driven increases in water temperature may affect aquatic organisms, yet patches of cooler water could serve as refuges for anadromous species like salmon. It is unclear if the frequency, size, and spacing of cold-water patches in rivers are adequate for salmonids during the warmest time of year. Researchers used high-resolution remotely sensed water temperature data and created models to characterize current and future summer thermal heterogeneity patterns for 11,308 kilometers of rivers throughout the Pacific Northwest and northern California. Present thermal heterogeneity varied among rivers; some had long uninterrupted stretches of warm water, while others had many smaller cool patches. Water temperature data examined at fine resolutions - below 1 kilometer - showed thermal heterogeneity at scales that may be important for salmonids. Models predicted minor changes in spacing, length, and density of cool patches in a warmer climate, but cool patches moved locations within a river, and changes were greater in certain rivers. These results can highlight areas of potential management concern and identify specific strategies for improving the availability and quality of refuges through targeted restoration activities.

Fullerton, A.H., Torgersen, C.E., Lawler, J.J., Steel, E.A., Ebersole, J.L., Lee, S.Y., 2018, Longitudinal thermal heterogeneity in rivers and refugia for coldwater species- effects of scale and climate change: Aquatic Sciences, p. online,[Details]

Contact: Christian Torgersen, FRESC, 206-616-1874, Profile

Beaver-related Restoration Practices in Rangeland Streams of the Western USA

North American beavers (Castor canadensis) are ecosystem engineers whose activities impact hydrologic functions well beyond their immediate activity area. Translocation of beavers into formerly occupied habitats is a restoration strategy aimed at accelerating recovery of degraded streams and increasing water resources in arid and semi-arid environments. Because beaver restoration may also create social conflict, USGS scientists and collaborators identified a need to assess the efficacy and impacts of restoration projects. In an inventory of 97 projects, authors found that relocation of nuisance beavers was the most common reason for projects. Goals included increasing available surface water, improving fish and wildlife habitat, controlling sediment, and rehabilitating riparian vegetation. Beavers were often moved without regard to genetics, disease, or potential conflicts with nearby landowners. Long-term planning and monitoring schemes were mostly absent, and water rights issues were often unaddressed. The authors conclude that beaver-related restoration activities would benefit from further research to inform development of clear guidelines for best practices.

Pilliod, D.S., Rohde, A.T., Charnley, S., Davee, R.R., Dunham, J.B., Gosnell, H., Grant, G.E., Hausner, M.B., Huntington, J.L., Nash, C., 2017, Survey of beaver-related restoration practices in rangeland streams of the western USA: Environmental Management, p. online,[Details]

Contact: David Pilliod, FRESC, 208-426-5202, Profile

Conservation Efforts Database Presented to GBLCC

USGS ecologist Justin Welty and U.S. Fish and Wildlife Service collaborators presented highlights and updates to the Conservation Efforts Database 2.0 to the Great Basin Landscape Conservation Cooperative in a webinar on November 30. The Conservation Efforts Database is an innovative planning tool designed to quantify sagebrush conservation efforts in 11 Greater Sage-grouse states in the western United States.

Contact: Justin Welty, FRESC, 208-426-5212, Profile

Molybdenum isotope fractionation during adsorption to organic matter

Molybdenum is a micronutrient required by all living organisms that regulates many other biogeochemical cycles. Most studies emphasize how molybdenum adheres to inorganic compounds in soils and sediments, but interactions with organic matter can also affect molybdenum cycling in terrestrial, riverine, and marine environments. Scientists from USGS and Oregon State University assessed molybdenum adherence to organic matter by measuring molybdenum isotope fractionation on both a laboratory proxy for natural organic matter and on field samples from Oregon forests. They found that molybdenum entering from rainfall forms a complex with organic matter, where the lighter isotope of molybdenum is preferentially adsorbed and the heavier isotope is transported through the environment. Additionally, less molybdenum is adsorbed as pH rises, leading to a larger isotope shifts. Molybdenum isotope adsorption to organic matter was similar to prior results observed with inorganic compounds, which may alter how molybdenum preserved in marine sediments is used to interpret historic patterns of ocean oxygenation and global bedrock weathering.

King, E.K., Perakis, S.S., Pett-Ridge, J.C., 2017, Molybdenum isotope fractionation during adsorption to organic matter: Geochimica et Cosmochimica Acta, v. 222, p. 584–598,[Details]

Contact: Steven Perakis, FRESC, 541-750-0991, Profile

Press Inquiries/Media

USFWS Taps USGS Scientist for Input on Exotic Annual Grass Control

Sarah Levy of the U.S. Fish and Wildlife Service, Pacific Region, contacted USGS ecologist Matthew Germino on November 22 asking for comments regarding what is and is not known regarding the status of weed-suppressive bacteria used to control exotic annual grass in the Great Basin. Ms. Levy is preparing an informational public relations product for USFWS.

Contact: Matthew Germino, FRESC, 208-426-3353, Profile

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