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Displaying 4,191 - 4,200 of 65,126 Publications- The frequency of dissolved oxygen depletion events (hypoxia) in coastal aquatic ecosystems has risen dramatically since the late 20th century, yet the causes and consequences of hypoxia for some culturally and economically important species remain poorly understood. In rivers, oxygen depletion can be caused by high densities of spawning Pacific salmon (Oncorhynchus spp.) consuming oxygen faster than can be replaced by reaeration. This process may be exacerbated when salmon densities are artificially inflated, such as when hatchery-origin salmon stray into rivers instead of returning to...AuthorsChristopher J. Sergeant, J. Ryan Bellmore, J. Ryan Bellmore, Jeffrey A. Falke, Franz J. Mueter, Peter A.H. WestleyKeywordsSourceScience of The Total Environment. 896: 165247.Year2023
- Soil erosion and sedimentation problems remain a major water quality concern for making watershed management policies in the Mississippi River Basin (MRB). It is unclear whether the observed decreasing trend of stream suspended sediment loading to the mouth of the MRB over the last eight decades truly reflects a decline in upland soil erosion in this large basin. Here, we improved a distributed regional land surface model, the Dynamic Land Ecosystem Model, to evaluate how climate and land use changes have impacted soil erosion and sediment yield over the entire MRB during the past century....AuthorsZihao Bian, Ge Sun, Steve McNulty, Shufen Pan, Hanqin TianSourceWater Resources ResearchYear2023
- Invasive annual grasses have long been known to increase wildfire danger in shrublands and woodlands of the American West. Ventenata (Ventenata dubia) is one such grass. First reported in North America in 1952 in Washington state, it is now expanding into previously invasion- resistant forest landscapes. Unlike cheatgrass, another invasive grass, ventenata can grow in sparsely vegetated rocky meadows. These forest scablands, often embedded within a forested landscape, have historically served as natural fire breaks. Lacking sufficient fuels, the scablands usually stopped fire from spreading...AuthorsJohn Kirkland, Becky K. KernsKeywordsSourceScience Findings 260. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 6 p.Year2023
- Oak (Quercus) are a dominant and important tree genus in the Central Hardwood Region (USA) due to their commercial timber value, and food value of their protein-rich seed – acorns – to wildlife. Acorn production is characteristic of masting, with highly variable crop sizes that are synchronized within populations, but with consideration variation among individual trees. Critical to acorn masting studies are longitudinal datasets, which are often difficult to maintain due to a host of constraints. One possible approach to extending mast datasets involves the use of dendrochronology, where...AuthorsThomas W. Patterson, Katie H. Greenberg, Andrew Hacket-PainKeywordsSourceForest Ecology and ManagementYear2023
- Each year, agricultural residues such as stalks, husks, and pits/nutshells from food crop harvesting are available on a gigatonne scale worldwide. While biorefinery routes have been used convert agricultural residue carbohydrates into value-added products (e.g., bioethanol, biochemicals), the lignin, comprising 20–50% of the dry mass of agricultural residues, remains largely underutilized. Therefore, there is an urgent need to explore the utilization of agricultural biorefinery lignins for value-added products. In this review, we briefly introduce the origins of agricultural lignins,...AuthorsXiang Wang, Weiqi Leng, R.M. Oshani Nayanathara, David Milsted, Thomas L. Eberhardt, Zhao Zhang, Xuefeng ZhangSourceJournal of Agriculture and Food ResearchYear2023
- While climate change will have significant impacts on terrestrial organisms, microclimates offer potential refugia for vulnerable species when regional conditions become unsuitable and temperatures exceed physiological limits. The efficacy of microclimates as buffers to extreme events is determined not only by their availability, but also by the behavioral flexibility of individuals to access these unique environments during stressful periods. We characterized (i) how forest structure and topography shaped microclimates at roost sites used by California spotted owls (Strix occidentalis...AuthorsKate A. McGinn, M. Zachariah Peery, Ceeanna J. Zulla, William J. Berigan, Zachary A. Wilkinson, Josh M. Barry, John J. Keane, Benjamin ZuckerbergKeywordsSourceBiological Conservation. 283(12): 110132Year2023
- Many models are designed to generate future predictions under climate-change scenarios. Such models are typically calibrated for a study area with climate data that represent historical conditions. However, future projections of the model may include outputs for which the model has not been calibrated. Ideally, a climate-change-impacts model would be calibrated for recent conditions and also for possible future climate conditions. We demonstrate an approach, where a vegetation model is subjected to two calibrations: conventionally to the study area and separately to the study area plus...AuthorsEllynne Kutschera, John B. Kim, G. Stephen Pitts, Ray DrapekSourceLand. 12(6): 1121.Year2023
- Classification of remotely sensed imagery for reliable land use and land cover (LULC) remains a challenge in areas where spectrally similar LULC features occur. For example, bare soils of harvested crop fields in agricultural watersheds exhibit spectral characteristics similar to high intensity developed regions and impede an accurate classification. The goal of this study is to improve the accuracy of LULC classification of satellite imagery for the Big Sunflower River Watershed, Mississippi using ancillary data, multiple classification methods, and a post-classification correction (PCC)....AuthorsPadmanava Dash, Scott L. Sanders, Prem Parajuli, Ying OuyangKeywordsSourceRemote SensingYear2023
- Color variation is a frequent evolutionary substrate for camouflage in small mammals, but the underlying genetics and evolutionary forces that drive color variation in natural populations of large mammals are mostly unexplained. The American black bear, Ursus americanus (U. americanus), exhibits a range of colors including the cinnamon morph, which has a similar color to the brown bear, U. arctos, and is found at high frequency in the American southwest. Reflectance and chemical melanin measurements showed little distinction between U. arctos and cinnamon U. americanus individuals. We...AuthorsEmily E. Puckett, Isis S. Davis, Dawn C. Harper, Kazumasa Wakamatsu, Gopal Battu, Jerrold L. Belant, Dean E. Beyer, Colin Carpenter, Anthony P. Crupi, Maria Davidson, Christopher S. DePerno, Nicholas Forman, Nicholas L. Fowler, David L. Garshelis, Nicholas Gould, Kerry Gunther, Mark Haroldson, Shosuke Ito, David Kocka, Carl Lackey, Ryan Leahy, Caitlin Lee-Roney, Tania Lewis, Ashley Lutto, Kelly McGowan, Colleen Olfenbuttel, Mike Orlando, Alexander Platt, Matthew D. Pollard, Megan Ramaker, Heather Reich, Jaime L. Sajecki, Stephanie K. Sell, Jennifer Strules, Seth Thompson, Frank van Manen, Craig Whitman, Ryan Williamson, Frederic Winslow, Christopher B. Kaelin, Michael S. Marks, Gregory S. BarshSourceCurrent BiologyYear2023
- Understanding prey consumption patterns is critical to understanding the ways in which seabirds cope with a changing ocean. However, characterizing the dietary habitats of seabirds can be challenging. In this study, we investigated the diet of the Marbled Murrelet Brachyramphus marmoratus population that lives in waters off California, Oregon, and Washington, USA, using fecal DNA, custom metabarcoding, and high-throughput sequencing. Murrelets were captured at sea by dip-netting at night. Across this region, murrelets consumed highly diverse prey types including 17 fish species and 10...AuthorsEmily D. Fountain, Paige J. Kulzer, Richard T. Golightly, James W. Rivers, Scott F. Pearson, Martin G. Raphael, Matthew G. Betts, S. Kim Nelson, Daniel Roby, Nicholas F. Kryshak, Stephanie Schneider, M. Zachariah. PeeryKeywordsSourceMarine Ornithology. 51(2): 145–155.Year2023