Western United States Research Articles

Western US intraplate deformation controlled by the complex lithospheric structure

The western United States is one of Earth’s most tectonically active regions, characterized by extensive crustal deformation through intraplate earthquakes and geodetic motion. Such intracontinental deformation is usually ascribed to plate boundary forces, lithospheric body forces, and/or viscous drag from mantle flow. However, their relative importance in driving crustal deformation remains controversial due to inconsistent assumptions on crustal and mantle structures in prior estimations. Here, we utilize a fully dynamic three-dimensional modeling framework with data assimilation to simultaneously compute lithospheric and convective mantle dynamics within the western United States. This approach allows for quantitative estimations of crustal deformation while accounting for the realistic three-dimensional lithospheric structure. Our results show the critical role of the complex lithospheric structure in governing intraplate deformation. Particularly, the interaction between the asthenospheric flow and lithospheric thickness step along the eastern boundary of the Basin and Range represents a key driving mechanism for localized crustal deformation and seismicity.

Feeling a little uneasy: A comparative discourse analysis of White and BIPOC college students’ reflective writing about systemic racism

AbstractThis critical discourse analysis compares the ways in which White and BIPOC college students discuss their experiences of an educational intervention meant to promote better understanding of systemic racism. We analyzed reflective writing produced by 11 White psychology students from a private liberal arts college in the eastern United States and 17 BIPOC students from a Human Services program at a public university in the western United States. White students engaged in whiteness discourse that distanced themselves from the realities of systemic racism and/or relieved the cognitive dissonance associated with the self‐ and group‐image threat related to learning about systemic racism. In so doing, they unwittingly upheld white supremacy. BIPOC students, in contrast, engaged an antiracist discourse that employed critiques of the social systems that produce systemic racism and destabilized dominant colorblind narratives, often by drawing on lived experience. From the Critical Race Theory perspective that the centrality of lived experience is a legitimate lens through which to analyze racial subordination, we discuss the importance of attending to the action orientation and constructed nature of discourse in antiracist education.

Lay of the (wet)land: manager practices and challenges in wetland revegetation

Despite providing essential ecosystem services, wetlands are one of the most threatened ecosystems worldwide. Revegetation of wetlands is a critical aspect of restoring ecosystem services, yet little is known about common practices, the challenges managers face, or what resources they require to improve revegetation outcomes. We assessed current revegetation practices, obstacles, and potential solutions by surveying wetland managers in the Intermountain West of the United States, a vast, ecologically diverse region containing hundreds of millions of hectares of public lands. Survey results indicate that managers revegetate wetlands for erosion control, invasion resistance, enhanced wildlife habitat, and improved water quality despite small budgets and limited personnel. Drought, invasive species, and the timing and availability of water are the biggest ecological challenges that managers face and point to the need to prioritize wetland revegetation research to improve revegetation practices in a changing climate with dwindling water resources. Additionally, access to genetically‐ and species‐diverse native plant materials is a concern for many managers. To address these challenges, managers need additional financial and human resources, accessible information relating to revegetation methods, and greater collaboration with research institutions and native plant vendors. Our findings underscore the need for funding entities to prioritize money for wetland revegetation efforts, a natural resource management area that has been neglected relative to many other ecosystems. The results of this study provide insight into challenges and potential solutions for wetland revegetation in regions of the world, such as the western United States, where increasing water scarcity threatens wetlands and their restoration.

Divergent biophysical responses of western United States forests to wildfire driven by eco-climatic gradients

Abstract. Understanding vegetation recovery after fire is critical for predicting vegetation-mediated ecological dynamics in future climates. However, information characterizing vegetation recovery patterns after fire and their determinants over large geographical extents is limited. This study uses Moderate Resolution Imaging Spectroradiometer (MODIS) leaf area index (LAI) and albedo to characterize patterns of post-fire biophysical dynamics across the western United States (US) and further examines the influence of topo-climatic variables on the recovery of LAI and albedo at two different time horizons, 10 and 20 years post-fire, using a random forest model. Recovery patterns were derived for all wildfires that occurred between 1986 and 2017 across seven forest types and 21 level III ecoregions of the western US. We found differences in the characteristic trajectories of post-fire vegetation recovery across forest types and eco-climatic settings. In some forest types, LAI had recovered to only 60 %–70 % of the pre-fire levels by 25 years after the fire, while it recovered to 120 %–150 % of the pre-fire levels in other forest types, with higher absolute post-fire changes observed in forest types and ecoregions that had a higher initial pre-fire LAI. Our random forest results showed very little influence of fire severity on the recovery of both summer LAI and albedo at both post-fire time horizons. Post-fire vegetation recovery was most strongly controlled by elevation, with faster rates of recovery at lower elevations. Similarly, annual precipitation and average summer temperature had significant impacts on the post-fire recovery of vegetation. Full recovery was seldom observed when annual precipitation was less than 500 mm and average summer temperature was above the optimal range, i.e., 15–20 °C. Climate influences, particularly annual precipitation, were a major driver of post-fire summer albedo change through its impact on ecological succession. This study provides quantitative measures of primary controls that could be used to improve the modeling of ecosystem dynamics post-fire.

Understanding the Cascade: Removing GCM Biases Improves Dynamically Downscaled Climate Projections

AbstractPolarization surrounding bias correction (BC) in creating climate projections arises from its lack of physicality. Here, we perform and analyze 18 dynamical downscaling simulations (with and without BC) to better understand the physical impacts of BC, applied before downscaling, on regional climate output across the western United States. Without BC, downscaled precipitation is systematically and unrealistically wet biased compared to a hierarchy of observationally based datasets over the 1980–2014 period due to cascading mean‐state Global Climate Model (GCM) biases: (a) overly strong lower‐tropospheric lapse rates (5 K/km), (b) overly cold (2 K) tropospheric temperatures, and (c) anomalous mid‐tropospheric cyclonic vorticity advection. With BC, downscaled precipitation (snow) biases are virtually eliminated (halved). Identified GCM biases are common to the broader Coupled Model Intercomparison Project ensemble. Physical effects of BC on the quality of the regionalized projections, pending an evaluation of BC's distortion of the downscaled climate response, may motivate its broader application by dynamical downscalers.

Hibernacula of bats in Mexico, the southernmost records of hibernation in North America.

Although Mexico holds the southernmost hibernating bats in North America, information on winter behavior and hibernacula microclimate use of temperate Mexican bats is limited. We studied hibernating bats at high altitudes (>1,000 m a.s.l.) in northern and central Mexico during 5 consecutive winters. Our aims were to document and describe the hibernacula, winter behavior (such as abundance and roost pattern), and microclimates (estimated as adjacent substrate temperature) of cave-hibernating bats in Mexico. We found 78 hibernacula and 6,089 torpid bats of 10 vespertilionid species, increasing by over 50% the number of cave-hibernating bat species and quadrupling the number of hibernacula for Mexico. Hibernacula were at altitudes between 1,049 and 3,633 m a.s.l., located in 3 mountain ranges, mainly in oak and conifer forests. Myotis velifer was the most common species, followed by Corynorhinus townsendii and C. mexicanus. We recorded the adjacent substrate temperatures from 9 species totaling 1,106 torpid bats and found differences in microclimate use among the 3 most common species. In general, abundance of torpid bats in our region of study was similar to those in the western United States, with aggregations of tens to a few hundred individuals per cave, and was lower than in the eastern United States where a cave may hold thousands of individuals. Knowledge of bat hibernation is crucial for developing conservation and management strategies on current conditions while accommodating environmental changes and other threats such as emerging diseases.

Downed wood removal effects on survival and site fidelity of woodrats in a California oak woodland

AbstractOwing to the increasing intensity and frequency of wildfires in the western United States, the removal of woody debris (downed dead wood and snags) from fire‐prone landscapes is being evaluated for wildfire mitigation. Consequently, the study of the ecological value of coarse woody debris to sustain dependent species has become of foremost importance. From 2004–2009, we used a before‐after control‐impact (BACI) study design to assess the effects of downed wood removal on a population of big‐eared woodrats (Neotoma macrotis) in an oak woodland (Quercus spp.) in coastal‐central California, USA. Using Pollock's robust design mark‐recapture analyses (with 12 primary capture occasions represented by trapping each spring and fall, and secondary occasions composed of 3 trap nights), we estimated survival and emigration rates. Further, applying mixed‐effects models, we evaluated the effects of 7 habitat attributes on woodrat abundance and reproduction. Following the experimental removal of downed wood from the 11 randomly selected treatment plots, woodrat survival was higher (P = 0.013), and emigration was lower (P = 0.007) among 11 control plots on which downed wood was retained. Woodrat abundance within plots was best predicted by stem density, demonstrating positive demographic associations with habitat complexity. Plot‐level reproductive success (i.e., the presence of juveniles within a plot during spring) was more likely with increasing snag density. These findings indicate that snags and downed dead wood are key components of high‐quality habitat for big‐eared woodrats. Management of woody debris to mitigate wildfire risk should consider the ecological value of this habitat attribute for big‐eared woodrats and other dependent species.

The Spartan mother in America: 1865–1900

ABSTRACT This essay shows how newspapers in the postbellum United States invoked the memory of the ancient Spartan woman to express visions of women's place in the emergent American republic that deviated from the Victorian ideal. Journalists and social commentators from the Western, Southern, and Northern United States found in the fit, patriotic, and stoic demeanor of Spartan women, a model for the politically active and publicly involved the “new woman” that they increasingly desired. While primarily targeting middle-class white women, these newspapers and commentators hinted that one could venerate these qualities in females of other classes and social groups.

Surprising discovery of Sedecula pulvinata in Central Europe – is it really a species endemic to the western USA?

Surprising discovery of <i>Sedecula pulvinata</i> in Central Europe – is it really a species endemic to the western USA?

Prototyping structured decision making for water resource management in the San Francisco Bay-Delta

A structured decision making (SDM) approach can help evaluate tradeoffs between conservation and human-benefit objectives by fostering communication and knowledge transfer among stakeholders, decision makers, and the public. However, the process is iterative and completing the full process may take years. It can be difficult to initiate an SDM effort when problems seem insurmountable. Occasionally, SDM may not even be the best or correct approach for addressing the conservation problem at hand. We describe the implementation of an SDM process to help inform difficult decisions related to competing objectives. We convened a diverse stakeholder group from the largest estuary in the western United States; the San Francisco Bay and Sacramento-San Joaquin Delta (Bay-Delta). The stakeholder group consisted of representatives from local, state, and federal agencies, non-profit organizations, and recreational fishers. The stakeholder group agreed on a problem statement and identified four priority objectives related to Chinook salmon, delta smelt, water availability and reliability, and agricultural water use. Furthermore, they proposed 14 candidate management actions to achieve their objectives. The group then used existing quantitative models and data to evaluate trade-offs in proposed management actions to identify areas of agreement of proposed candidate actions. The clear communication of the problem statement and objectives among the stakeholder group, along with evaluation of tradeoffs and uncertainty via decision-support models suggest that a full SDM approach may work in the Bay-Delta. We further communicate lessons learned during our implementation of SDM to help guide future SDM efforts in the region and elsewhere.

Development of CRISPR/Cas9-Based Mouse Models for X-linked Alport Syndrome

Intro: Alport Syndrome (AS) is a rare hereditary disorder characterized by progressive renal impairment and sensorineural hearing loss, resulting from mutations in the genes that encode COL4 synthesis. X-linked Alport Syndrome (XLAS) is the most common form of AS, comprising an estimated 80% of all human AS cases (the others being various forms of autosomal recessive or autosomal dominant AS), and is caused by various mutations on the COL4A5 gene. However, to date, there are no animal models of XLAS. Methods: To facilitate comprehensive preclinical investigations and therapeutic developments, we established two novel mouse models of XLAS using CRISPR/Cas9 technology. Leveraging the robust C57Bl/6J mouse strain, we precisely introduced the L1655R and C1570S mutations, which represent the predominant human variants of XLAS observed in the Western United States. Discussion: Our innovative mouse models not only serve as invaluable tools for elucidating the underlying mechanisms of XLAS pathogenesis but also provide a platform for evaluating the effcacy of potential therapeutic interventions. The establishment of these faithful genetic replicas of human XLAS marks a significant advancement in the field, offering unprecedented opportunities for in-depth mechanistic studies and the development of targeted therapeutic strategies for this debilitating renal and auditory disorder. This research is supported by the National Institutes of Health under Ruth L. Kirschstein National Research Service Award 5T32DK091317 from the National Institute of Diabetes and Digestive and Kidney Diseases and the National Kidney Foundation of Utah and Idaho. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Functional reorganization of North American wintering avifauna.

Wintering birds serve as vital climate sentinels, yet they are often overlooked in studies of avian diversity change. Here, we provide a continental-scale characterization of change in multifaceted wintering avifauna and examine the effects of climate change on these dynamics. We reveal a strong functional reorganization of wintering bird communities marked by a north-south gradient in functional diversity change, along with a superimposed mild east-west gradient in trait composition change. Assemblages in the northern United States saw contractions of the functional space and increases in functional evenness and originality, while the southern United States saw smaller contractions of the functional space and stasis in evenness and originality. Shifts in functional diversity were underlined by significant reshuffling in trait composition, particularly pronounced in the western and northern United States. Finally, we find strong contributions of climate change to this functional reorganization, underscoring the importance of wintering birds in tracking climate change impacts on biodiversity.

Apparent absence of Trypanosoma cruzi in Mexican free-tailed bats (Tadarida brasiliensis) from Texas, USA

The Mexican free-tailed bat (Tadarida brasiliensis) is one of the most abundant mammals in North America. Mexican free-tailed bats have a wide geographic range stretching from northern South America to the western United States. Bats are theorized to be the original hosts for Trypanosoma cruzi —the causative agent of Chagas disease— and can serve as a source of infection to triatomine insect vectors that feed upon them. Chagas disease is a neglected tropical disease across the Americas where triatomines are present, including the southern United States, where Texas reports this highest number of locally-acquired human cases. To learn more about the role of bats in the ecology of Chagas disease in Texas, we surveyed a colony of Mexican free-tailed bats from Brazos County, Texas, for T. cruzi using carcasses salvaged after an extreme weather event. A total of 283 Mexican free-tailed bats collected in February 2021 were dissected and DNA from the hearts and kidneys was used for T. cruzi detection via qPCR. None of the bat hearts or kidneys tested positive for T. cruzi; this sample size affords 95% confidence that the true prevalence of T. cruzi in this population does not exceed 1%. Future sampling of multiple bat species as well as migrant and resident colonies of Mexican free-tailed bats across different times of the year over a broader geographic range would be useful in learning more about the role of bats in the ecology of Chagas disease in Texas.

Lethal combination for seedlings: extreme heat drives mortality of drought-exposed high-elevation pine seedlings.

Hotter drought- and biotically-driven tree mortality are expected to increase with climate change in much of the western United States, and species persistence will depend upon ongoing establishment under novel conditions or migration to track ecological niche requirements. High-elevation tree species may be particularly vulnerable to increasing water stress as snowpack declines, increasing the potential for adult mortality and simultaneous regeneration failures. Seedling survival will be determined by ecophysiological limitations in response to changing water availability and temperature. We exposed seedlings from populations of Pinus longaeva, Pinus flexilis, and Pinus albicaulis to severe drought and concurrent temperature stress in common gardens testing timing of drought onset under two different temperature regimes. We monitored seedling functional traits, physiological function, and survival. The combined stressors of water limitation and extreme heat led to conservative water use strategies and declines in physiological function, with these joint stressors ultimately exceeding species' tolerances and leading to complete episodic mortality across all species. Growing conditions were the primary determinant of seedling trait expression, with seedlings exhibiting more drought-resistant traits such as lower specific leaf area in the hottest, driest treatment conditions. Water stress-induced stomatal closure was also widely apparent. Under adequate soil moisture, seedlings endured prolonged exposure to high air and surface temperatures, suggesting broad margins for survival. The critical interaction between soil moisture and temperature suggests that rising temperatures will exacerbate growing season moisture stress. Our results highlight the importance of local conditions over population- and species-level influences in shaping strategies for stress tolerance and resistance to desiccation at this early life stage. By quantifying some of the physiological consequences of drought and heat that lead to seedling mortality, we can better understand the future effects of global change on the composition and distribution of high-elevation conifer forests.

Climate Change in the West

This piece documents climate change by exploring the historic development, present beauty, and threatened future of the Western United States through landscape photography. The website links to by photography, exploration, and personal research with climactic and spatial modeling techniques to visualize the impact of cliamte change on the uniquely vulnerable communities, cultures, and landscapes of the Western United States. See the full website: https://storymaps.com/stories/674559d093ad4c938f0861a55ec9dc52

California’s 2023 snow deluge: Contextualizing an extreme snow year against future climate change

The increasing prevalence of low snow conditions in a warming climate has attracted substantial attention in recent years, but a focus exclusively on low snow leaves high snow years relatively underexplored. However, these large snow years are hydrologically and economically important in regions where snow is critical for water resources. Here, we introduce the term "snow deluge" and use anomalously high snowpack in California's Sierra Nevada during the 2023 water year as a case study. Snow monitoring sites across the state had a median 41 y return interval for April 1 snow water equivalent (SWE). Similarly, a process-based snow model showed a 54 y return interval for statewide April 1 SWE (90% CI: 38 to 109 y). While snow droughts can result from either warm or dry conditions, snow deluges require both cool and wet conditions. Relative to the last century, cool-season temperature and precipitation during California's 2023 snow deluge were both moderately anomalous, while temperature was highly anomalous relative to recent climatology. Downscaled climate models in the Shared Socioeconomic Pathway-370 scenario indicate that California snow deluges-which we define as the 20 y April 1 SWE event-are projected to decline with climate change (58% decline by late century), although less so than median snow years (73% decline by late century). This pattern occurs across the western United States. Changes to snow deluge, and discrepancies between snow deluge and median snow year changes, could impact water resources and ecosystems. Understanding these changes is therefore critical to appropriate climate adaptation.

Using Financial Contracts to Facilitate Informal Leases Within a Western United States Water Market Based on Prior Appropriation

AbstractThe ability to reallocate water to higher‐value uses during drought is an increasingly important “soft‐path” tool for managing water resources in an uncertain future. In most of the Western United States, state‐level water market institutions that enable reallocation also impose substantial transaction costs on market participants related to regulatory approval and litigation. These transaction costs can be prohibitive for many participants in terms of both costs and lengthy approval periods, limiting transfers and reducing allocation efficiency, particularly during drought crises periods. This manuscript describes a mechanism to reduce transaction costs by adapting an existing form of informal leases to facilitate quicker and less expensive transfers among market participants. Instead of navigating the formal approval process to lease a water right, informal leases are financial contracts for conservation that enable more junior holders of existing rights to divert water during drought, thereby allowing the formal transfer approval process to be bypassed. The informal leasing approach is tested in the Upper Colorado River Basin, where drought and institutional barriers to transfers lead to frequent shortages for urban rights holders along Colorado's Front Range. Informal leases are facilitated via option contracts that include adaptive triggers and that define volumes of additional, compensatory, releases designed to mitigate impacts to instream flows and third parties. Results suggest that more rapid reallocation of water via informal leases could have resulted in up to $222 million in additional benefits for urban rights holders during the historical period 1950–2013.

A Longitudinal Analysis of Mortality Related to Chronic Viral Hepatitis and Hepatocellular Carcinoma in the United States.

(1) Background: Hepatocellular carcinoma (HCC) contributes to the significant burden of cancer mortality in the United States (US). Despite highly efficacious antivirals, chronic viral hepatitis (CVH) remains an important cause of HCC. With advancements in therapeutic modalities, along with the aging of the population, we aimed to assess the contribution of CVH in HCC-related mortality in the US between 1999-2020. (2) Methods: We queried all deaths related to CVH and HCC in the multiple-causes-of-death files from the CDC Wide-ranging Online Data for Epidemiologic Research (WONDER) database between 1999-2020. Using the direct method of standardization, we adjusted all mortality information for age and compared the age-adjusted mortality rates (AAMRs) across demographic populations and by percentile rankings of social vulnerability. Temporal shifts in mortality were quantified using log-linear regression models. (3) Results: A total of 35,030 deaths were identified between 1999-2020. The overall crude mortality increased from 0.27 in 1999 to 8.32 in 2016, followed by a slight reduction to 7.04 in 2020. The cumulative AAMR during the study period was 4.43 (95% CI, 4.39-4.48). Males (AAMR 7.70) had higher mortality rates compared to females (AAMR 1.44). Mortality was higher among Hispanic populations (AAMR 6.72) compared to non-Hispanic populations (AAMR 4.18). Higher mortality was observed in US counties categorized as the most socially vulnerable (AAMR 5.20) compared to counties that are the least socially vulnerable (AAMR 2.53), with social vulnerability accounting for 2.67 excess deaths per 1,000,000 person-years. (4) Conclusions: Our epidemiological analysis revealed an overall increase in CVH-related HCC mortality between 1999-2008, followed by a stagnation period until 2020. CVH-related HCC mortality disproportionately affected males, Hispanic populations, and Black/African American populations, Western US regions, and socially vulnerable counties. These insights can help aid in the development of strategies to target vulnerable patients, focus on preventive efforts, and allocate resources to decrease HCC-related mortality.

Evidence of increasing wildfire damage with decreasing property price in Southern California fires.

Across the Western United States, human development into the wildland urban interface (WUI) is contributing to increasing wildfire damage. Given that natural disasters often cause greater harm within socio-economically vulnerable groups, research is needed to explore the potential for disproportionate impacts associated with wildfire. Using Zillow Transaction and Assessment Database (ZTRAX), hereafter "Zillow", real estate data, we explored whether lower-priced structures were more likely to be damaged during the most destructive, recent wildfires in Southern California. Within fire perimeters occurring from 2000-2019, we matched property price data to burned and unburned structures. To be included in the final dataset, fire perimeters had to surround at least 25 burned and 25 unburned structures and have been sold at most seven years before the fire; five fires fit these criteria. We found evidence to support our hypothesis that lower-priced properties were more likely to be damaged, however, the likelihood of damage and the influence of property value significantly varied across individual fire perimeters. When considering fires individually, properties within two 2003 fires-the Cedar and Grand Prix-Old Fires-had statistically significantly decreasing burn damage with increasing property value. Occurring in 2007 and later, the other three fires (Witch-Poomacha, Thomas, and Woolsey) showed no significant relationship between price and damage. Consistent with other studies, topographic position, slope, elevation, and vegetation were also significantly associated with the likelihood of a structure being damaged during the wildfire. Driving time to the nearest fire station and previously identified fire hazard were also significant. Our results suggest that further studies on the extent and reason for disproportionate impacts of wildfire are needed. In the meantime, decision makers should consider allocating wildfire risk mitigation resources-such as fire-fighting and wildfire structural preparedness resources-to more socioeconomically vulnerable neighborhoods.

Spiritual Support Staff Influence Stress Among Hospital-Based Health Care Personnel: A Cross-Sectional Study.

Stress negatively affects well-being, relating to poor physical, emotional, and occupational outcomes for health care personnel. Health care professionals faced extreme stressors in the context of the COVID-19 pandemic, making occupational stress relief a top priority for hospital administrators. Many health systems employ specially trained spiritual support staff as one strategy to alleviate work-related stressors. It is unclear whether health care personnels' perceptions of the availability of spiritual care staff influence self-reported stress. The purpose of this study was to explore relationships between perceived stress and perceptions of availability of spiritual support among acute care health care personnel. This study analyzed cross-sectional, survey-based data collected between February and April 2022 from 1352 interdisciplinary health care staff working in a large, nonprofit Catholic health system in the Western United States. Bivariate tests and multivariate linear regression models were conducted to test for factors influencing perceived stress. Results support that high stress was prevalent in the sample. Perceived availability of spiritual support staff in the hospital and seeking coworker and professional support for work-related stress all independently influence stress in this population when controlling for confounders. Stress of health care personnel may be influenced by the perceived availability of specially trained spiritual support staff. Hospital administrators should advocate for spiritual support staff availability in all health care settings as one strategy to mitigate occupational stress that health care professionals may experience through providing high-stakes patient care. Further research is warranted to uncover targeted spirituality-related strategies to reduce stress and preserve well-being of health care personnel.