Physical Sciences and Mathematics Commons^™

Evidence For Accelerated Weathering And Sulfate Export In High Alpine Environments, John T. Crawford, Eve-Lyn S. Hinckley, M. Iggy Litaor, Janice Brahney, Jason C. Neff

Watershed Sciences Faculty Publications

High elevation alpine ecosystems—the 'water towers of the world'—provide water for human populations around the globe. Active geomorphic features such as glaciers and permafrost leave alpine ecosystems susceptible to changes in climate which could also lead to changing biogeochemistry and water quality. Here, we synthesize recent changes in high-elevation stream chemistry from multiple sites that demonstrate a consistent and widespread pattern of increasing sulfate and base cation concentrations or fluxes. This trend has occurred over the past 30 years and is consistent across multiple sites in the Rocky Mountains of the United States, western Canada, the European Alps, the Icelandic …

Resurgence Of An Apex Marine Predator And The Decline In Prey Body Size, Jan Ohlberger, Daniel E. Schindler, Eric J. Ward, Timothy E. Walsworth, Timothy E. Essington

Watershed Sciences Faculty Publications

In light of recent recoveries of marine mammal populations worldwide and heightened concern about their impacts on marine food webs and global fisheries, it has become increasingly important to understand the potential impacts of large marine mammal predators on prey populations and their life-history traits. In coastal waters of the northeast Pacific Ocean, marine mammals have increased in abundance over the past 40 to 50 y, including fish-eating killer whales that feed primarily on Chinook salmon. Chinook salmon, a species of high cultural and economic value, have exhibited marked declines in average size and age throughout most of their North …

Beavers Alter Stream Macroinvertebrate Communities In Northeastern Utah, Susan E. Washko, Brett B. Roper, Trisha Brooke Atwood

Watershed Sciences Faculty Publications

1. Understanding changes in macroinvertebrate communities is important because they play a large role in stream ecosystem functioning, and they are an important food resource for fish. Beaver‐induced changes to stream morphology could alter macroinvertebrate communities, which in turn could affect food webs and ecosystem function. However, studies investigating the effects of North American beaver activities on macroinvertebrates are rare in the inter‐mountain west, an area with high potential for beaver‐assisted restoration.
2. The aim of this study was to quantify differences in the macroinvertebrate community between unaltered segments of streams and within beaver ponds in north‐eastern Utah, U.S.A. We assessed macroinvertebrate …

Evidence For Large Holocene Earthquakes Along The Denali Fault In Southwest Yukon, Canada, Andrée Blais-Stevens, John J. Clague, Janice Brahney, Panya Lipovsky, Peter J. Haeussler, Brian Menounos

Watershed Sciences Faculty Publications

The Yukon–Alaska Highway corridor in southern Yukon is subject to geohazards ranging from landslides to floods and earthquakes on faults in the St. Elias Mountains and Shakwak Valley. Here we discuss the late Holocene seismic history of the Denali fault, located at the eastern front of the St. Elias Mountains and one of only a few known seismically active terrestrial faults in Canada. Holocene faulting is indicated by scarps and mounds on late Pleistocene drift and by tectonically deformed Pleistocene and Holocene sediments. Previous work on trenches excavated against the fault scarp near the Duke River reveals paleoseismic sediment disturbance …

Marine Reserves Shape Seascapes On Scales Visible From Space, Elizabeth M. P. Madin, Alastair R. Harborne, Aaron M. T. Harmer, Osmar J. Luiz, Trisha Brooke Atwood, Brian J. Sullivan, Joshua S. Madin

Watershed Sciences Faculty Publications

Marine reserves can effectively restore harvested populations, and ‘mega-reserves’ increasingly protect large tracts of ocean. However, no method exists of monitoring ecological responses at this large scale. Herbivory is a key mechanism structuring ecosystems, and this consumer–resource interaction's strength on coral reefs can indicate ecosystem health. We screened 1372, and measured features of 214, reefs throughout Australia's Great Barrier Reef using high-resolution satellite imagery, combined with remote underwater videography and assays on a subset, to quantify the prevalence, size and potential causes of ‘grazing halos’. Halos are known to be seascape-scale footprints of herbivory and other ecological interactions. Here we …

Mapping Valley Bottom Confinement At The Network Scale, Gary R. O'Brien, Joseph Michael Wheaton, Kirstie Fryirs, William W. Macfarlane, Gary Brierley, Kelly Whitehead, Jordan T. Gilbert, Carol Volk

Watershed Sciences Faculty Publications

In this article, we demonstrate the application of a continuous confinement metric across entire river networks. Confinement is a useful metric for characterizing and discriminating valley setting. At the reach scale, valley bottom confinement is measured and quantified as the ratio of the length of channel confined on either bank by a confining margin divided by the reach length. The valley bottom is occupied by the contemporary floodplain and/or its channel(s); confining margins can be any landform or feature that makes up the valley bottom margin, such as bedrock hillslopes, terraces, fans, or anthropogenic features such as stopbanks or constructed …