Central Oregon Research Articles

Effects of springtime sodium selenate foliar application and NPKS fertilization on selenium concentrations and selenium species in forages across Oregon

Selenium (Se) concentrations in soils and plants are low in the Pacific Northwest, and consequently, in livestock consuming locally-grown forages. Applying sodium selenate with traditional nitrogen-phosphorus-potassium-sulfur (NPKS) fertilizers provides a cost-effective Se agronomic biofortification method for increasing forage Se concentrations and maintaining optimum health and productivity of livestock. This 2-year study was conducted across Oregon on four representative forage fields: orchardgrass (Dactylis glomerata L.) in Terrebonne (central Oregon), grass-clover mixture in Roseburg (southwestern Oregon), and both grass mixture and alfalfa (Medicago sativa L.) fields in Union (eastern Oregon). Using a split plot design with double-repeated measures (2017 and 2018 with first, second, third, and residual harvest cuts each year), we determined the effect of springtime Se foliar application rate (0, 45, or 90 g Se ha−1 from sodium selenate; whole plot) and NPKS fertilization (none, NPK/PK fertilization, or NPKS/PKS fertilization; subplot; NPKS amounts adapted to meet forage and soil requirements) on total Se concentration and beneficial Se species in forages. Forage Se concentrations increased linearly with foliar sodium selenate application, doubling with each additional 45 g Se ha−1 application (first cut median: 0.11, 2.06, and 4.15 mg kg−1 dry matter, respectively). Nearly all incorporated Se was contained in the first two cuts (87 % and 9 % in first and second cuts, respectively) and most applied selenate was metabolized to selenomethionine. NPK/PK fertilization decreased Se concentrations in second and latter cut forages from Se-amended fields, whereas sulfur fertilization decreased forage Se concentrations from non-Se amended fields. Among forages, alfalfa had greater Se concentrations under low soil Se conditions, whereas grass-dominated forages had higher Se concentrations after Se-amendment. In conclusion, springtime sodium selenate foliar application is an effective management strategy to increase forage total Se concentrations and highly bioavailable selenomethionine concentrations across Oregon, and should be implemented to meet local forage and livestock requirements.

Trading off retained daily catch for longer seasons to maximize angler benefits in recreational fisheries management

Abstract Recreational fishing benefits associated with angling opportunity, such as fishing season duration and certainty of season duration, may outweigh trip-based benefits, such as retained catch, in measures of angler utility. We developed an age-structured population dynamics model to predict how these three beneficial attributes are affected by four recreational management parameters: minimum size limit; bag limit; inter-season quota transfer limits; and in-season adjustment of season duration. We incorporated results of stated-preference angler surveys to produce a bioeconomic model for two case studies: Atlantic Florida red snapper, and central Oregon Pacific halibut. In maximizing long-term total utility, a strong trade-off between season length and retained daily catch was observed in both fisheries, arising from increased minimum size limits which lengthened fishing seasons but reduced daily retained catch. The optimal management policy across the combination of beneficial attributes was sensitive to assumptions of the curvature of utility functions, i.e. to the degree to which anglers value those attributes with diminishing marginal returns, but generally involved satisfying the strong stated preferences for increased angling opportunity.

Effects of initial spacing and species mix on stand developmental patterns in two field trials in central Oregon

Productivity, stand dynamics, and ecosystem processes characterizing mixed-species forests have been inferred from a mix of inventory data, observational studies, and designed experiments. Designed experiments are expensive to implement and maintain for a sufficiently long time in most temperate species, but associated treatment replication and randomization lower the risk of confounding from spatial correlations among species composition, environmental conditions, and productivity. Results from replicated mixed-species spacing trials in 45-yr-old Pinus ponderosa/Abies grandis plots and 53-yr-old P. ponderosa/P. contorta plots demonstrated main and interaction effects of spacing and species composition on growth and stand structure, as well as the change in these effects over time. Initial spacing ranged from 1.8 m to 5.5 m on a square grid. Mixtures of P. ponderosa and A. grandis at wide spacings offered A. grandis the opportunity to achieve cumulative height growth nearly equal to P. ponderosa and thereby form a uniform mixed canopy but lower cumulative stem volume growth. The same initial species mixture at closer spacing resulted in increasingly stratified mixtures with P. ponderosa dominating the overstory due largely to its more rapid juvenile height growth and wider crown, relegating shade tolerant A. grandis to the understory. A similar pattern emerged in the mixtures of P. ponderosa and P. contorta, but with more subtle gradients in vertical structure attributable to less extreme differences in juvenile height growth and shade tolerance. By the end of 2019 (plantation age 53), no significant overyielding or underyielding occurred in the mixed-species plots of P. ponderosa/P. contorta. In contrast, by the end of 2018 the mixed-species plots of P. ponderosa/A. grandis (plantation age 45 years) achieved some overyielding that was marginally significant (net volume production) or very significant (gross volume production) only at the narrowest (1.8-m) spacing. The timing and intensity of mortality shifted mixing effects on periodic annual increment slightly over time. Evidence for consistent overyielding among spacings was weak in these P. ponderosa/P. contorta and P. ponderosa/A. grandis spacing trials at total plantation age of 53 and 45 years, respectively. However, statistical power for detecting mixing effects was limited by the relatively small number of replications, and size differentiation continues to emerge at successively wider spacings on mixed-species plots.

Reconstructing Extreme Precipitation in the Sacramento River Watershed Using Tree‐Ring Based Proxies of Cold‐Season Precipitation

AbstractExtreme precipitation and consequent floods are some of California's most damaging natural disasters, but they are also critical to the state's water supply. This motivates the need to better understand the long‐term variability of these events across the region. This study examines the possibility of reconstructing extreme precipitation occurrences in the Sacramento River Watershed (SRW) of Northern California using a network of tree‐ring based moisture proxies across the Western US. We first develop a gridded reconstruction of the cold‐season standardized precipitation index (SPI) west of 100°W. We then develop an annual index of regional extreme precipitation occurrences in the SRW and use elastic net regression to relate that index to the gridded, tree‐ring based SPI. These regressions, built using SPI data across the SRW only and again across a broader region of the Western US, are used to develop reconstructions of interannual variability in extreme precipitation frequency back to 1400 CE. The SPI reconstruction is skillful across much of the West, including the Sacramento Valley and Central Oregon. The reconstructed SPI also captures historical interannual variations in extreme SRW precipitation, although individual events may be under‐ or over‐estimated. The reconstructions show more SRW extremes from 1580 to 1700 and 1850 to 1915, a dearth of extremes prior to 1550, and a 2–8 year oscillation after 1550. Using tree‐ring proxies beyond the SRW often dampens the reconstructed extremes, but these data occasionally help to identify known extreme events. Overall, reconstructions of SRW extreme precipitation can help to understand better the historic variability of these events.

Quantifying sedimentation patterns of small landslide‐dammed lakes in the central Oregon Coast Range

AbstractUnderstanding sedimentation patterns in small coastal watersheds due to landscape perturbations is critical for connecting hillslope and fluvial processes, in addition to managing aquatic habitats for anadromous fish and other aquatic species in the Oregon Coast Range (OCR). Changes in sedimentation patterns spanning the last 250 years are preserved in two landslide‐dammed lakes in small watersheds (< 10 km2) underlain by the Tyee Formation in the central OCR. Dendrochronology of drowned Douglas‐fir stumps in both lakes provided precise timing of the damming and formation of the lakes, with Klickitat Lake forming in winter ad 1751/52 and Wasson Lake in winter ad 1819/20. Perturbations from wildfires, logging and road development, and previously underappreciated snow events affect sedimentation rates in the lakes to different degrees, and are identified in the sediment record using cesium‐137 (137Cs), high‐resolution charcoal stratigraphy, local fire records, and aerial photography. Each lake has variable sedimentation accumulation rates (0.05–4.4 cm yr−1) and mass accumulation rates (0.02–1.42 g cm−2 yr−1). Sedimentation rates remained low from the landslide‐damming events until the mid‐19th century, when they increased following stand‐replacing wildfires. Aside from a sediment remobilization triggered by human modification of the landslide dam at Klickitat Lake around 1960, the largest peaks in mass accumulation rates in the mid‐20th century at both lakes in the early 1950s precede major road construction and logging activity in the watersheds. Subsequent sedimentation rates are lower, but variable, and possible effects of logging and road development might be exacerbated by abnormal precipitation and heavy snow events. A comparison of previous studies of landslide‐dammed lakes in larger watershed of the OCR are consistent with our findings of increased sedimentation in the mid‐20th century, as well as higher sedimentation rates in the debris‐flow dominated southern Tyee Formation than in the lower‐relief northern Tyee Formation.

Molecules to Mountains: A Multi-Proxy Investigation Into Ancient Climate and Topography of the Pacific Northwest, USA

We characterize the topographic evolution of the Pacific Northwest, United States, during the Cenozoic. New paleosol carbonate stable isotope (δ18O) results from central Oregon are presented, along with published proxy data, including fossil teeth, smectites, and carbonate concretions. We interpret a polygenetic history of Cascade Mountain topographic uplift along-strike, characterized by: 1) Steady uplift of the Washington Cascades through the Cenozoic due long-term arc rotation and shortening against a Canadian buttress, and 2) Uplift of the Oregon Cascades to similar-to-modern elevations by the late Oligocene, followed by topographic stagnation as extension developed into the Neogene. Since the Miocene, meteoric water δ18O values have decreased in Oregon, possibly due to emergence of the Coast Range and westward migration of the coastline. Spatial variability in isotopic change throughout the Pacific Northwest suggests that secular global climate change is not the primary forcing mechanism behind isotopic trends, though Milankovitch cycles may be partly responsible for relatively short-term variation.

Estimation of Surface Canopy Water in Pacific Northwest Forests by Fusing Radar, Lidar, and Meteorological Data

Surface Canopy Water (SCW) is the intercepted rain water that resides within the tree canopy and plays a significant role in the hydrological cycle. Challenges arise in measuring SCW in remote areas using traditional ground-based techniques. Remote sensing in the radio spectrum has the potential to overcome the challenges where traditional modelling approaches face difficulties. In this study, we aim at estimating the SCW by fusing information extracted from the radar imagery acquired with the Sentinel-1 constellation, aerial laser scanning, and meteorological data. To describe the change of radar backscatter with moisture, we focused on six forest stands in the H.J. Andrews experimental forest in central Oregon, as well as four clear cut areas and one golf course, over the summers of 2015–2017. We found significant relationships when we executed the analysis on radar images in which individual tree crowns were delineated from lidar, as opposed to SCW estimated from individual pixel backscatter. Significant differences occur in the mean backscatter between radar images taken during rain vs. dry periods (no rain for >1 h), but these effects only last for roughly 30 min after the end of a rain event. We developed a predictive model for SCW using the radar images acquired at dawn, and proved the capability of space-based radar systems to provide information for estimation of the canopy moisture under conditions of fresh rainfall during the dry season.

Staring at the Sun during Wildfire Season: Knowledge, Uncertainty, and Front-Line Resistance in Disaster Preparation.

As climate change increases the frequency and severity of disasters, and population and social changes raise the public’s vulnerability to disaster events, societies face additional risk of multiple disaster events or other hazards occurring simultaneously. Such hazards involve significant uncertainty, which must be translated into concrete plans able to be implemented by disaster workers. Little research has explored how disaster managers incorporate different forms of knowledge and uncertainty into preparations for simultaneous hazards or disaster events, or how front-line disaster workers respond to and implement these plans. In this paper I draw on ethnographic research working as a wildland firefighter, interviews with firefighters and fire managers, and state and agency planning documents to examine preparations for two events occurring in Central Oregon in August 2017: (1) the height of wildfire season and (2) hundreds of thousands of anticipated visitors for a total solar eclipse. I find that different qualities of risk, hazard, and uncertainty across these two events were central to the development and implementation of disaster plans. Agency leaders devised worst-case scenario plans for the eclipse based on uncertain predictions regarding hazards from the eclipse and the occurrence of severe wildfires, aiming to eliminate the potential for unknown hazards. These plans were generally met with skepticism by front-line disaster workers. Despite the uncertainties that dominated eclipse-planning rhetoric, firefighters largely identified risks from the eclipse that were risks they dealt with in their daily work as firefighters. I conclude by discussing implications of these findings for conceptual understandings of disaster planning as well as contemporary concerns about skepticism and conspiracy theories directed at government planning and response to disaster events.

Modelling an unconventional closed-loop deep borehole heat exchanger (DBHE): sensitivity analysis on the Newberry volcanic setting

Alternative (unconventional) deep geothermal designs are needed to provide a secure and efficient geothermal energy supply. An in-depth sensitivity analysis was investigated considering a deep borehole closed-loop heat exchanger (DBHE) to overcome the current limitations of deep EGS. A T2Well/EOS1 model previously calibrated on an experimental DBHE in Hawaii was adapted to the current NWG 55-29 well at the Newberry volcano site in Central Oregon. A sensitivity analysis was carried out, including parameters such as the working fluid mass flow rate, the casing and cement thermal properties, and the wellbore radii dimensions. The results conclude the highest energy flow rate to be 1.5 MW, after an annulus radii increase and an imposed mass flow rate of 5 kg/s. At 3 kg/s, the DBHE yielded an energy flow rate a factor of 3.5 lower than the NWG 55-29 conventional design. Despite this loss, the sensitivity analysis allows an assessment of the key thermodynamics within the wellbore and provides a valuable insight into how heat is lost/gained throughout the system. This analysis was performed under the assumption of subcritical conditions, and could aid the development of unconventional designs within future EGS work like the Newberry Deep Drilling Project (NDDP). Requirements for further software development are briefly discussed, which would facilitate the modelling of unconventional geothermal wells in supercritical systems to support EGS projects that could extend to deeper depths.

The relationship between hydroregime and coho salmon (Oncorhynchus kisutch) redd construction in the Smith River, Oregon

Abstract Adult salmonid migration to natal habitats and spawning are affected both by physiological factors and environmental conditions. While research has focused on physiological thresholds that influence the initiation of migration, few studies have investigated the relationship between both hydrological and thermal conditions and salmon spawning throughout the course of the reproductive period. We examined whether Oregon coastal coho salmon (Oncorhynchus kisutch) returning to three tributaries of the Smith River watershed (in the central Oregon Coast Range) responded to the stream hydroregime throughout their spawning period. Generalised linear mixed models were constructed to evaluate relationships between various stream discharge metrics, water temperature and redd count data collected between 2010 and 2016. Across the three sub‐basins we analysed, discharge and temperature metrics were important in explaining redd construction timing. However, the same parameters were not consistently important for every sub‐basin. Water temperature was important in explaining redd construction in the largest sub‐basin, North Sister Creek, and discharge metrics were consistently important in Beaver Creek, the smallest sub‐basin. At the sub‐basin scale, peak redd construction by coho salmon starts after increase in discharge (25th percentile) occurs but before the highest discharge events take place. However, synchrony among sub‐basins was evident in delayed redd construction during 2013 when the autumn rains were delayed. Understanding relationships between the timing of redd construction and characteristics of the hydrological regime are critical to analysis of potential future climate impacts on all life stages of Oregon Coastal coho salmon.

High-Resolution Stable Isotope Paleotopography of the John Day Region, Oregon, United States

The John Day region of central Oregon, United States contains ∼50 million years of near-continuous, fossiliferous sedimentation, representing one of the world’s richest archives of Cenozoic terrestrial ecosystems and climate. Stable isotope proxy data from this region are commonly used to infer the elevation history of the Cascades, which intercept westerly moisture in transit to the John Day region. However, the Blue Mountains, which accreted in the Mesozoic, create a region of local high topography that can confound signals of Cascades uplift. John Day deposits, including the John Day Formation, are divided into an eastern facies located within the Blue Mountains and a western facies in the adjacent plains. As a result, the Blue Mountains may have supported gradients in climate and ecology between the eastern and western facies, and constraining these gradients is necessary for reconstructing past topography and ecosystem change. In order to define the Cenozoic extent and magnitude of Blue Mountains topography we use oxygen isotopes in authigenic clay minerals to construct a spatially resolved map of local elevation. We find that the oxygen isotope composition of clay minerals within the Blue Mountains is ∼3‰ lower than in the adjacent high plains, and this offset is mostly constant throughout our record (spanning ∼50 – 5 Ma). We attribute this offset to Blue Mountains topography, either directly from upslope rainout or indirectly through the effect of elevation on local variations in precipitation seasonality. Our results highlight the importance of local topographic features in regional paleotopography reconstructions and provide important biogeographical context for the rich paleo-floral and -faunal records preserved in John Day sediments.

Tephrochronology of North America's most recent arc-sourced ignimbrite flare-up: The Deschutes Formation of the Central Oregon Cascades

The dangerous juxtaposition of human populations and active volcanic arcs worldwide makes elucidating the history of explosive eruptions of these arcs a crucial endeavor. The well-preserved Deschutes Formation, which forms part of the Deschutes Basin of central Oregon, USA, contains a distal record of a period of unusually frequent explosive eruptions between 5.45 and 6.25 Ma, which is atypical of the Cascades arc as a whole. However, no previous study has established the chronology, frequency, or total volume of all of the ignimbrites and tephra-fall units exposed within the Formation in order to compare to baseline activity of the arc. We use multivariate statistics on major and trace element compositions of pumice glass to correlate pyroclastic units across the Deschutes Basin, and combine these with recently published 40Ar/39Ar dates to establish, for the first time, a detailed and comprehensive tephrochronology of the Deschutes Formation. Our results suggest that at least 78 statistically distinct explosive eruptions occurred between 6.25 and 5.45 Ma. Eruption frequency is not constant throughout the 800 kyr of pyroclastic volcanism; a maximum rate of 1.7 to 3.0 explosive eruptions per 10 kyr occurred between 5.76 and 5.68 Ma and decreased for 340 kyr prior to graben formation. We estimate that the volume for 51 ignimbrite eruptions is 290 to 565 km3 (170 to 280 km3 DRE), assuming an equal westward flow component and a fall:flow ratio of 0.5:1 to 1.9:1. Using a single isopach method, we also estimate that a minimum volume of 110 km3 (45 km3 DRE) was deposited as 27 pumice-fall units which have no correlated ignimbrites. Thus, we estimate that a cumulative pyroclastic volume of 400 to 675 km3 (210 to 330 km3 DRE) was erupted in the central Oregon Cascades during this time. The volumetric rate (2.7 to 4.1 km3/10 kyr, DRE) and average frequency of ignimbrite eruptions (1.0 to 1.5 eruptions/ 10kyr) are more than a factor of ten greater than the Quaternary Cascades arc. Thus, the Deschutes Formation records North America's most recent arc-sourced ignimbrite flare-up. Although smaller in volume than most well-recognized flare-up events, this represents an important category of flare-ups that may be more common in arcs than previously recognized. We hypothesize that a heightened flux of basalt, possibly induced by slab-rollback, was focused beneath the arc and into the shallow crust by minor amounts of crustal extension. This extension allowed for the high flux of basalt to be stored at shallow levels beneath a new arc locus within fertile crust, resulting in an unusually silicic and explosive period of Cascade arc history.

Evaluating Coexistence of Fish Species with Coastal Cutthroat Trout in Low Order Streams of Western Oregon and Washington, USA

When multiple species of fish coexist there are a host of potential ways through which they may interact, yet there is often a strong focus on studies of single species without considering these interactions. For example, many studies of forestry–stream interactions in the Pacific Northwest have focused solely on the most prevalent species: Coastal cutthroat trout. To examine the potential for interactions of other fishes with coastal cutthroat trout, we conducted an analysis of 281 sites in low order streams located on Washington’s Olympic Peninsula and along the central Oregon coast. Coastal cutthroat trout and juvenile coho salmon were the most commonly found salmonid species within these streams and exhibited positive associations with each other for both presence and density. Steelhead were negatively associated with the presence of coastal cutthroat trout as well as with coho salmon and sculpins (Cottidae). Coastal cutthroat trout most frequently shared streams with juvenile coho salmon. For densities of these co-occurring species, associations between these two species were relatively weak compared to the strong influences of physical stream conditions (size and gradient), suggesting that physical conditions may have more of an influence on density than species interactions. Collectively, our analysis, along with a review of findings from prior field and laboratory studies, suggests that the net effect of interactions between coastal cutthroat trout and coho salmon do not appear to inhibit their presence or densities in small streams along the Pacific Northwest.

Stable isotope analysis suggests that tetrodotoxin-resistant Common Gartersnakes (Thamnophis sirtalis) rarely feed on newts in the wild

Toxin-resistant predators may suffer costs from eating chemically defended prey and do not feed exclusively on toxic prey. Common Gartersnakes (Thamnophis sirtalis (Linnaeus, 1758)) have been considered the drivers of an evolutionary arms race with highly toxic newts (genus Taricha Gray, 1850), which they consume with few or no deleterious effects. However, how frequently newts are consumed in nature is less clear. To address this question, we investigated the diets of Th. sirtalis at a site in central Oregon where snakes have high levels of resistance and newts have high levels of tetrodotoxin in the skin. Because snake diets are difficult to quantify using traditional means, we used stable isotopes to estimate the proportion of Th. sirtalis diets made up of newts. Our estimate for the proportion of Th. sirtalis diet made up of Rough-skinned Newts (Taricha granulosa (Skilton, 1849)) at this site is 3.2%. Mole Salamanders (genus Ambystoma Tschudi, 1838) were predicted to be the most important prey, followed by slugs, chorus frogs, and mice, with a very minor role for earthworms. Our results demonstrate that even though Th. sirtalis are physiologically capable of consuming toxic prey, they do not often do so. Generalist predators can be exposed to very strong selection from, and exert reciprocal selection on even rarely eaten, chemically defended prey.

Surrender: The Call of the American West by Joanna Pocock

Reviewed by: Surrender: The Call of the American West by Joanna Pocock O. Alan Weltzien, emeritus Joanna Pocock, Surrender: The Call of the American West. Toronto: House of Anansi Press, 2019. 373 pp. Paper, $22.95 CAN; e-book, $18.95 CAN. Londoner Joanna Pocock’s journalistic memoir joins an increasingly rich genre of trans-Atlantic interpretations of whatever the American West is becoming in the early twenty-first century. Pocock announces straightaway, “The mid-life crisis package I was handed came in a box marked with one simple word: Montana” (2). Pocock, her husband Jason, and young daughter Eve quit the city and spent two years (2014–16) residing in Missoula. She confesses to nomadism though she’s called London home for a quarter century, and during this period (as well as at least one subsequent trip), she ranges into central Oregon and Washington backcountry, following a series of “rewilders.” Her love and longing for Big Sky Country feels as palpable as her growing disillusionment with London. Pocock’s voice joins an old international chorus, entranced by the monumentality of western [End Page 91] American landscapes: “The vastness, the inscrutability of so much space, performs an act of initiation. It does things to you that cannot be undone” (364). Hers is a Missoula-centric version of Montana, and her version of the American West tracks both familiar and obscure topics. She and her family witness wolves in Yellowstone’s Lamar Valley, and she spends time with the Buffalo Field Campaign (and “Buffalo Bridge Collective”) outside Gardner, Montana. The annual bison culling and annual conflict between the stockgrower-led state forces and the federal agencies is old news. She reviews the Tintina Corporation’s proposed copper mine (the “Black Butte Project”) near Montana’s beloved Smith River as well as restoration efforts by Trout Unlimited upstream and downstream from Missoula. Oddly, Pocock doesn’t cover the removal of the Milltown Union Dam (2008) and subsequent Clark Fork River restoration projects. Farther afield, she glances at North Dakota’s Standing Rock protests (342–26) and the notorious Rajneesh community near Antelope, Oregon, in the early 1980s (309–11). Pocock unduly focuses upon certain fringe groups who might be lumped under the umbrella notion of survivalists. But most of her survivalists are not white supremacist groups whose loud online noise masks their tiny numbers: the sort of fringes tracked by organizations such as the Montana Human Rights Network. The 3 Percenters, or “Threepers,” fall under this category, and her closing scene of the Boundary County (Idaho) Fair highlights the booths of the NRA, tragically mainstream, as well as the “Oath Keepers” (359–62). It’s no surprise that Pocock surveys the annual Rainbow Gathering. She’s much more intrigued by a few rewilders who have adopted, in sundry ways, a hunter-gatherer ethos and not only live off the grid but forage for their “Paleo diet.” She profiles, for example, Peter Michael Brown, part of “Rewild Portland,” who leads a basket weaving workshop, and spends much more time with Finisia Medrano, a sixty-one-year-old rewilder who, over years and decades, lives “on the hoop.” It’s hard to see Medrano, a caustic, transgendered stoner specializing in digging biscuit root and planting seeds of edible wild plants, as the positive role model she becomes for Pocock. Despite Pocock’s admiring reference to [End Page 92] John Lanchester’s article about hunter gatherers (The New Yorker, 18 Sept. 2017), Medrano and her ilk lack the personal appeal let alone the audience Euell Gibbons commanded two generations ago. Lanchester’s claim— “‘It turns out that hunting and gathering is a good way to live. . . . The lives of most of our progenitors were better than we think’”— seems dubious at best. Pocock overstates the case when she claims, “So many of these fringe outliers are now having their cries taken up by academics and writers.” Here’s the issue, as she concedes: “We can’t all live as hunter-gatherers” (295). No kidding. Nor would most folks willingly adopt the tribal style “fringe outliers” and “hunter-gatherers” depend upon. That said, there is much to admire about widely disseminated knowledge of edible plants— what...

Geographic variability in lingcod Ophiodon elongatus life history and demography along the US West Coast: oceanographic drivers and management implications

Understanding the environmental and anthropogenic drivers of spatial patterns in life history variation for exploited fish populations is important when making management decisions and designating stock boundaries. These considerations are especially germane for stocks that are overfished or recently rebuilt, such as lingcodOphiodon elongatus, a commercially and recreationally valuable species of groundfish along the West Coast of North America. Between 2015 and 2017, we collected 2189 lingcod from 24 port locations, spanning 28° of latitude from southeast Alaska (60°N) to southern California (32°N), to investigate latitudinal patterns in size- and age-structure, growth, timing of maturity, condition, and mortality, as well as to identify biologically relevant population breakpoints along the coast. We found strong latitudinal patterns in these life history and demographic traits consistent with Bergmann’s rule: lingcod from colder, northern waters were larger-at-age, lived longer, matured at larger sizes, and had lower natural mortality rates than lingcod from warmer, southern waters. Female lingcod were larger-at-age, lived longer, and matured at larger sizes compared to males within each examined region. In addition, we found evidence for strong associations between lingcod life history traits and the oceanographic variables of sea surface temperature and chlorophylla. Cluster analysis using life history traits indicated that central Oregon is a biologically relevant breakpoint for lingcod along the US West Coast. This breakpoint based on life history traits, in conjunction with a recently identified population genetic breakpoint between central and northern California, highlights the need for future lingcod stock assessments to consider multiple sources of information to best inform management of this trans-boundary stock.

CT-scans of capsules from the Clarno Formation (Oregon, USA) reveal an extinct Eocene theaceous taxon

The economically important but relatively small family Theaceae can be traced back to the Late Cretaceous and is found today in the Western Hemisphere and Asia. Theaceous fruits are generally loculicidal capsules and have been found as fossils throughout the Northern Hemisphere. Using reflected light and μCT-scanning, we recognize Anubiscarpon andersonae MA Smith et Manchester gen. et sp. nov. from the middle Eocene Clarno Formation of north central Oregon, based on five-valved, loculicidal capsules with a central columella, persistent perianth and pedicel, preserved as impressions in lacustrine shale. Its most distinctive feature is its apically clefted valves which are not seen in any other species of the family. Anubiscarpon augments our understanding of former morphological diversity in the Theaceae

Petrogenesis of Pleistocene Basalts from the Western Snake River Plain, Idaho

Abstract We present new geochemical, Sr, Nd, and Pb isotope, and 40Ar/39Ar data from Pleistocene basalts of the Western Snake River Plain (WSRP), Idaho, USA to explore their petrogenesis and to investigate the nature of the lithosphere at the western boundary of the North American craton. The basalts are divided into three groups based on their geochemical and isotopic characteristics. Prior to ∼1 Ma, volcanoes in the WSRP erupted iron-rich tholeiites (FeB1), but subsequent volcanism was dominated by concurrent eruptions of mildly alkaline, alumina-rich lavas (AlB) and iron-rich tholeiites (FeB2) with isotopic signatures similar to the AlB lavas. New 40Ar/39Ar dates of AlB and FeB2 basalts range from 0·920 ± 0·049 to 0·287 ± 0·014 Ma. MELTS models of FeB1 differentiation trends indicate that the range of compositions in this suite can be produced by 10–15 % crystallization of olivine and plagioclase at low pressure using the least evolved FeB1 composition as a parental magma; isotopic ratios can be produced via combined assimilation of a Miocene rhyolite and fractional crystallization. Additional modeling suggests that parental magmas at AlB centers were produced by 3–12 % equilibrium melting of a garnet–spinel-enriched mantle source, slightly different from that proposed for the youngest mildly alkaline lavas of the eastern and central Snake River Plain. Our new geochemical, isotopic, and geochronological data for the FeB2 basalts suggests that they are related to AlB-type magmas via a combination of fractional crystallization and assimilation of evolved mafic crust. MELTS models suggest that crystallization of an AlB parental melt at a depth of 6–8 km (2·5 kbar) could produce residual liquids having many of the major oxide characteristics of FeB2 ferrobasalts. Sr–Nd–Pb isotopic signatures of these three suites indicate a dominant contribution from an enriched plume source. FeB1 lavas are probably products of mixing between melts of an enriched plume mantle source (represented by Imnaha and Steens Basalts of the Columbia River Basalt Group) and isotopically heterogeneous sub-continental lithospheric mantle (SCLM) that has been isolated from the convecting mantle since the Archean. Isotopic ratios of FeB2 and AlB lavas capture mixing between enriched plume mantle and a more isotopically homogeneous ancient SCLM domain characteristic of the eastern and central Snake River Plain, with a coupled decrease in lithospheric contribution and degree of partial melting through time to the present. Mixtures of enriched asthenospheric reservoirs with lithospheric mantle have been proposed for neighboring volcanic fields to the east along the strike of the Yellowstone–SRP hotspot track, and to the west owing to differences in the mantle underlying the boundary of the North American craton and accreted terranes. Our petrogenetic model for the Pleistocene WSRP basalts suggests that there is also a lateral, across-strike gradient in the geometry and interaction of enriched plume mantle and ancient lithosphere. We reiterate suggestions that the WSRP is a lithosphere-scale conduit connecting initial plume-head impingement in east–central Oregon with the subsequent Yellowstone–SRP hotspot plume-tail track.

Minimal stratigraphic evidence for coseismic coastal subsidence during 2000 yr of megathrust earthquakes at the central Cascadia subduction zone

AbstractLithology and microfossil biostratigraphy beneath the marshes of a central Oregon estuary limit geophysical models of Cascadia megathrust rupture during successive earthquakes by ruling out >0.5 m of coseismic coastal subsidence for the past 2000 yr. Although the stratigraphy in cores and outcrops includes as many as 12 peat-mud contacts, like those commonly inferred to record subsidence during megathrust earthquakes, mapping, qualitative diatom analysis, foraminiferal transfer function analysis, and 14C dating of the contacts failed to confirm that any contacts formed through subsidence during great earthquakes. Based on the youngest peat-mud contact’s distinctness, >400 m distribution, ∼0.6 m depth, and overlying probable tsunami deposit, we attribute it to the great 1700 CE Cascadia earthquake and(or) its accompanying tsunami. Minimal changes in diatom assemblages from below the contact to above its probable tsunami deposit suggest that the lower of several foraminiferal transfer function reconstructions of coseismic subsidence across the contact (0.1–0.5 m) is most accurate. The more limited stratigraphic extent and minimal changes in lithology, foraminifera, and(or) diatom assemblages across the other 11 peat-mud contacts are insufficient to distinguish them from contacts formed through small, gradual, or localized changes in tide levels during river floods, storm surges, and gradual sea-level rise. Although no data preclude any contacts from being synchronous with a megathrust earthquake, the evidence is equally consistent with all contacts recording relative sea-level changes below the ∼0.5 m detection threshold for distinguishing coseismic from nonseismic changes.

Oregon Spotted Frog (Rana pretiosa) Migration from an Aquatic Overwintering Site: Timing, Duration, and Potential Environmental Cues

Relatively few North American anurans overwinter in water and information is sparse on their movement from overwintering habitat to breeding sites. Oregon spotted frogs (Rana pretiosa) breed explosively in early spring and often overwinter submerged at sites that are distanced from breeding habitats. In montane parts of their range, wintering and breeding habitats can remain frozen for months. We investigated timing, duration, and potential cues for R. pretiosa migrations from a wintering lake near the Cascade Mountains in central Oregon, U.S.A. First and median migrant males moved slightly earlier than females. Onset of migration was as early as February 12 (males) and as late as April 4 (females) in years of mild and extended winters, respectively. Frogs were active at water temperatures below those associated with early breeding activities in one lowland R. pretiosa population. Higher proportions of frogs migrated before ice-out in years of prolonged winter conditions. Migrations were temporally compressed in years of later movement. This migration ‘rush’, along with the ability to move at cold temperatures and to vary timing of migrations likely helps montane R. pretiosa deal with colder and more variable spring conditions than lowland populations.