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Probabilities of coastal extreme water levels (EWLs) are increasing as sea levels rise. Using a time‐dependent statistical model on tide gauge data along U.S. and Pacific Basin coastlines, we show that EWL probability distributions also shift on an annual basis from climate forcing and long‐period tidal cycles. In some regions, combined variability (>15 cm) can be as large or larger than the amount of sea level rise (SLR) experienced over the past 30 years and projected over the next 30 years. Considering SLR and variability by 2050 at a location like La Jolla, California suggests a moderate‐level (damaging) flood today with a 50‐year return level (2% annual chance) would occur about 3–4 times a year during an El Nino nearing the peak of the nodal tide cycle. If interannual variability is overlooked, SLR related impacts could be more severe than anticipated based solely upon decadal‐scale projections. Plain Language Summary: Coastal communities are flooding more often due to sea level rise (SLR), but some years are worse than others. We use a statistical model to show how the probabilities of coastal high waters, often referred to as extreme water levels—a combination of above average tides and storm surge—have shifted higher or lower every year with SLR and from changes in the tides and climatic (persistent weather and ocean) patterns. There are many U.S. and Pacific coastal regions where year‐to‐year variability is 15 cm or more, which is as large as the last 30 years of SLR and this pattern is projected to continue over the next 30 years. Considering additional SLR over the next 30 years could help compensate for year‐to‐year variability. Key Points: Probability distributions of coastal extreme water levels shift higher and lower with tide cycles, climatic patterns and sea level rise (SLR)Annual shifts of >15 cm from variability along Pacific coasts exceed SLR over the last 30 years and projected over the next 30 yearsAnnual‐scale variability envelopes are envisioned to assist in decadal‐scale SLR and flood frequency assessments [ABSTRACT FROM AUTHOR]

Studies of community assembly typically focus on the effects of abiotic environmental filters and stabilizing competition on functional trait dispersion within single trophic levels. Predation is a well‐known driver of community diversity and composition, yet the role of functionally diverse predator communities in filtering prey community traits has received less attention. We examined functionally diverse communities of predators (fishes) and prey (epifaunal crustaceans) in eelgrass (Zostera marina) beds in two northern California estuaries to evaluate the filtering effects of predator traits on community assembly and how filters acting on predators influence their ability to mediate prey community assembly. Fish traits related to bottom orientation were correlated with more clustered epifauna communities, and epifauna were generally overdispersed while fishes were clustered, suggesting prey may be pushed to disparate areas of trait space to avoid capture by benthic sit‐and‐wait predators. We also found correlations between the trait dispersions of predator and prey communities that strengthened after accounting for the effects of habitat filters on predator dispersion, suggesting that habitat filtering effects on predator species pools may hinder their ability to affect prey community assembly. Our results present compelling observational evidence that specific predator traits have measurable impacts on the community assembly of prey, inviting experimental tests of predator trait means on community assembly and explicit comparisons of how the relative effects of habitat filters and intraguild competition on predators impact their ability to affect prey community assembly. Integrating our understanding of traits at multiple trophic levels can help us better predict the impacts of community composition on food web dynamics as regional species pools shift with climate change and anthropogenic introductions. [ABSTRACT FROM AUTHOR]

Spatial and temporal patterns of water supply and consumptive water use were analyzed from 475 Detailed Analysis Units by County (DAUCOs) spatial units across California during 2002 through 2016 to evaluate spatial and temporal variability and how it might associate with precipitation variability and other factors. Many, but not all, DAUCOs have relatively low total water supply variability compared to that of state-wide precipitation. Such low variability, in DAUCOs having sufficient diversity of water supply sources, is the result of switching between sources as needed to maintain a reliable total water supply. We used multiple approaches to explore these variations which involved four categories of water supply (local, groundwater, imported, and other) and two categories of water use (agricultural and urban). First, a cluster analysis of the volumetric water balance data identified a small set of clusters having similar magnitudes and proportions of water supply sources and water use—some of them composed of only a few DAUCOs but accounting for a disproportionate amount of the state’s water use. Second, a principal components analysis identified leading modes of anomalous water supply and water use among the 475 DAUCOs, capturing most of the time variation during 2002 to 2016. The most prominent mode exhibits a multi-year trend, most strongly involving increasing groundwater supply and agricultural water use, and decreasing urban water use and imported water supply. Over the study period, trends in both supply and use were pronounced, but differed considerably across California DAUCOs. One predominant subset of DAUCOs grew their agricultural water use with increased groundwater supply; in contrast to a widespread group of DAUCOs which reduced their urban water use. An important result for planners is our finding that variation in precipitation—itself important—is amplified by the human response to water supply availability and regulatory policy. [ABSTRACT FROM AUTHOR]

Alleviating disadvantage in low-income environments predicts higher cognitive abilities during early childhood. It is less established whether family income continues to predict cognitive growth in later childhood or whether there may even be bidirectional dynamics. Notably, living in poverty may moderate income-cognition dynamics. In this study, we investigated longitudinal dynamics over 7 waves of data collection from 1,168 children between the ages of 4.6 and 12 years, 226 (19%) of whom lived in poverty in at least 1 wave, as part of the NICHD Study of Early Child Care and Youth Development. Two sets of dual change-score models evaluated, first, whether a score predicted change from that wave to the next and, second, whether change from 1 wave to the next predicted the following score. As previous comparisons have documented, poor children had substantially lower average starting points and cognitive growth slopes through later childhood. The first set of models showed that income scores did not predict cognitive change. In reverse, child cognitive scores positively predicted income change. We speculated that parents may reduce their work investment, thus reducing income gains, when their children fall behind. Second, income changes continued to positively predict higher cognitive scores at the following wave for poor children only, which suggests that income gains and losses continue to be a leading indicator in time of poor children's cognitive performance in later childhood. This study underlined the need to look at changes in income, allow for poverty moderation, and explore bidirectional income--cognition dynamics in middle childhood.

Fire suppression and past selective logging of large trees have fundamentally changed frequent-fire-adapted forests in California. The culmination of these changes produced forests that are vulnerable to catastrophic change by wildfire, drought, and bark beetles, with climate change exacerbating this vulnerability. Management options available to address this problem include mechanical treatments (Mech), prescribed fire (Fire), or combinations of these treatments (Mech + Fire). We quantify changes in forest structure and composition, fuel accumulation, modeled fire behavior, intertree competition, and economics from a 20-year forest restoration study in the northern Sierra Nevada. All three active treatments (Fire, Mech, Mech + Fire) produced forest conditions that were much more resistant to wildfire than the untreated control. The treatments that included prescribed fire (Fire, Mech + Fire) produced the lowest surface and duff fuel loads and the lowest modeled wildfire hazards. Mech produced low fire hazards beginning 7 years after the initial treatment and Mech + Fire had lower tree growth than controls. The only treatment that produced intertree competition somewhat similar to historical California mixed-conifer forests was Mech + Fire, indicating that stands under this treatment would likely be more resilient to enhanced forest stressors. While Fire reduced modeled wildfire hazard and reintroduced a fundamental ecosystem process, it was done at a net cost to the landowner. Using Mech that included mastication and restoration thinning resulted in positive revenues and was also relatively strong as an investment in reducing modeled wildfire hazard. The Mech + Fire treatment represents a compromise between the desire to sustain financial feasibility and the desire to reintroduce fire. One key component to long-term forest conservation will be continued treatments to maintain or improve the conditions from forest restoration. Many Indigenous people speak of "active stewardship" as one of the key principles in land management and this aligns well with the need for increased restoration in western US forests. If we do not use the knowledge from 20+ years of forest research and the much longer tradition of Indigenous cultural practices and knowledge, frequent-fire forests will continue to be degraded and lost. [ABSTRACT FROM AUTHOR]

Predator populations are imperiled globally, due in part to changing habitat and trophic interactions. Theoretical and laboratory studies suggest that heterogeneous landscapes containing prey refuges acting as source habitats can benefit both predator and prey populations, although the importance of heterogeneity in natural systems is uncertain. Here, we tested the hypothesis that landscape heterogeneity mediates predator–prey interactions between the California spotted owl (Strix occidentalis occidentalis)—a mature forest species—and one of its principal prey, the dusky‐footed woodrat (Neotoma fuscipes)—a younger forest species—to the benefit of both. We did so by combining estimates of woodrat density and survival from live trapping and very high frequency tracking with direct observations of prey deliveries to dependent young by owls in both heterogeneous and homogeneous home ranges. Woodrat abundance was ~2.5 times higher in owl home ranges (14.12 km2) featuring greater heterogeneity in vegetation types (1805.0 ± 50.2 SE) compared to those dominated by mature forest (727.3 ± 51.9 SE), in large part because of high densities in young forests appearing to act as sources promoting woodrat densities in nearby mature forests. Woodrat mortality rates were low across vegetation types and did not differ between heterogeneous and homogeneous home ranges, yet all observed predation by owls occurred within mature forests, suggesting young forests may act as woodrat refuges. Owls exhibited a type 1 functional response, consuming ~2.5 times more woodrats in heterogeneous (31.1/month ± 5.2 SE) versus homogeneous (12.7/month ± 3.7 SE) home ranges. While consumption of smaller‐bodied alternative prey partially compensated for lower woodrat consumption in homogeneous home ranges, owls nevertheless consumed 30% more biomass in heterogeneous home ranges—approximately equivalent to the energetic needs of producing one additional offspring. Thus, a mosaic of vegetation types including young forest patches increased woodrat abundance and availability that, in turn, provided energetic and potentially reproductive benefits to mature forest‐associated spotted owls. More broadly, our findings provide strong empirical evidence that heterogeneous landscapes containing prey refuges can benefit both predator and prey populations. As anthropogenic activities continue to homogenize landscapes globally, promoting heterogeneous systems with prey refuges may benefit imperiled predators. [ABSTRACT FROM AUTHOR]

In response to the wildfire crisis across the American West, governments are increasing investments in forest health. Guidelines for these investments often include environmental justice (EJ) provisions. However, current processes for addressing EJ aren't consistently meeting the needs of communities in forested areas. We analyze one source of wildfire mitigation funds in California, Forest Health Grants, to assess its adherence to distributive, procedural, and Indigenous aspects of EJ. We find that this program is not necessarily serving "disadvantaged" communities according to the State's definition. We argue that current metrics for identifying "disadvantaged" communities don't fully capture rural complexity, including the praxis of procedural and Indigenous EJ, respectively. We propose a rubric to evaluate projects along socioecological criteria and address EJ holistically via partnership building, long-term commitment to place, local capacity building, and mobilization of Traditional Ecological Knowledge. This rubric may also benefit other funding processes across California and other states. [ABSTRACT FROM AUTHOR]

A successful digital conversion for classrooms, districts, and states is not determined by the technology, but by how technology enables teaching and learning. The purpose of our multisite case study was to document digital instructional strategies teachers use to enhance and transform student learning, and align that use with learning research. We conducted focus groups and interviews, and observed classrooms in seven exemplary schools across the United States. We surveyed teachers' familiarity, use, and comfort with technology as well. We document six common strategies used across the seven sites and identify five roles that technology plays in enhancing teaching and learning, and discuss how these strategies benefit teachers and learners.

The sudden leaks from the Nord Stream gas pipelines, which began in September 2022, released a substantial amount of methane (CH4) into the atmosphere. From the IASI instrument onboard EUMETSAT's MetOp-B, we document the first satellite-based retrievals of column-average CH4 (XCH4) that clearly show the large CH4 plume emitted from the pipelines. The data displays elevations greater than 200 parts per billion (ppb, ~11 %) above observed background values (1882 ± 21 ppb). Based on the IASI data, together with an integrated mass enhancement technique and formal model-based inversions applied for the first time to thermal infrared satellite methane plume data, we quantify the total mass of CH4 emitted to the atmosphere during the first two days of the leaks to be 215–390 Gg CH4. Substantial temporal heterogeneity is displayed in our model-derived flux rate, with three distinct peaks in emission rate over the first two days. Our range overlaps with other previous estimates, which were 75–230 Gg CH4 and were mostly based on inversions that assimilated in situ observations from nearby tower sites. However, our derived values are generally larger than those previous results, with the differences likely due to the fact that our results are the first to use satellite-based observations of XCH4 from the days following the leaks. We incorporate multiple satellite overpasses that monitored the CH4 plume as it was transported across Scandinavia and the North Sea up to the evening of the 28th September 2022. We produced model simulations of the atmospheric transport of the plume using the Eulerian atmospheric transport model, TOMCAT, which show good representation of the plume location in the days following the leaks. The simulated CH4 mixing ratios at three of the four nearby in situ measurement sites are larger than the observed in situ values by up to hundreds of ppb, which highlights the challenges inherent in representing short-term plume movement over a specific location using a model such as TOMCAT with a relatively coarse Eulerian grid. Our results confirm the leak of the Nord Stream pipes to clearly be the largest individual fossil fuel-related leak of CH4 on record, greatly surpassing the previous largest leak (95 Gg CH4) at the Aliso Canyon gas facility in California in 2015–16. [ABSTRACT FROM AUTHOR]

Context: The concept of landscape heterogeneity is central to species conservation; yet understanding the processes by which heterogeneity affects species can be challenging in practice. Complex and sometimes difficult-to-measure responses of species may reflect the outcome of life-history trade-offs shaped by different landscape properties. Objectives: We tested the hypothesis that a mosaic of forest stand types affected hunting and breeding success for California spotted owls (Strix occidentailis occidentalis). Methods: We integrated high-temporal-resolution GPS tags, video monitoring of nest sites, long-term assessments of reproductive status, and high-resolution remotely sensed vegetation data in a mixed-ownership landscape in the Sierra Nevada, California to test our hypothesis. Results: Spotted owls made shorter nocturnal movements in homogenous territories with large areas of medium-aged forest apparently because this forest type allowed direct movement paths to foraging sites. However, spotted owls delivered prey at a higher rate to nest sites when they had more forest edge in their territory, which presumably provided greater access to large-bodied woodrat (Neotoma spp.) prey. Further, spotted owl reproductive output was relatively high in heterogenous territories containing a mix of mature and open forest. Conclusions: The benefits heterogenous forests provide to hunting success appeared to outweigh costs associated with additional commuting distance to foraging sites and provided potential fitness benefits to spotted owls. We suggest that the effects of landscape heterogeneity can vary not only among, but also within, species and can reflect the outcome of trade-offs among different life history activities. Understanding the effects of landscape properties on biological communities will benefit from additional empirical and mechanistic studies of individual species. [ABSTRACT FROM AUTHOR]

A vast literature documents a host of advantages conferred upon middle class European American children whose parents employ an authoritative style of parenting, including enhanced academic achievement and positive behavioral outcomes. The literature is much less clear about the relationship between parental authority style and child outcomes in other cultural contexts. In this study, we examined the relations among authoritative, authoritarian, and permissive parenting styles and practices and several academic and behavioral outcomes among fifth grade Latino/a students. We found significant positive relations between parental authoritativeness and grades, academic engagement, social competence, self-regulation, and perspective-taking as well as negative relations between authoritativeness and aggression. We found no relations between authoritarian or permissive parenting styles and child outcomes. We consider these findings in light of what other researchers have posited about collectivist parenting styles and practices.

Copyright of Fire Ecology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Vocal territory defense can vary within a species due to many factors such as sex and breeding status, influencing territory size and thus population density across a landscape. Therefore, understanding what influences variation in territorial vocalizations can help to illuminate trade‐offs between territoriality and other life history demands, which benefits our general understanding of animal ecology as well as helps to inform emerging passive acoustic monitoring approaches. Here, we investigated how sex and breeding status affected territoriality and vocal behavior in the California spotted owl Strix occidentalis occidentalis in the Sierra Nevada, California, USA, using high‐resolution acoustic/GPS tags. We discovered that territorial vocal behavior was related to breeding status and to a lesser extent sex. Breeding owls with fledged young had a less diverse vocal repertoire, produced fewer and quieter territorial calls, and typically called only when close to their nest. Males were also more likely to engage in territorial calling than females. Breeding spotted owls also maintained significantly smaller territories – but utilized larger home ranges – than non‐breeding individuals. Our results suggest that breeding spotted owls may reduce their investment in territorial behaviors to mitigate the demands and risks associated with rearing young. Further, our results have important implications for the passive acoustic monitoring of spotted owls and, more broadly, highlight the utility of using multiple call types to detect species of interest. [ABSTRACT FROM AUTHOR]

One objective of eco‐evolutionary dynamics is to understand how the interplay between ecology and evolution on contemporary timescales contributes to the maintenance of biodiversity. Disturbance is an ecological process that can alter species diversity through both ecological and evolutionary effects on colonization and extinction dynamics. While analogous mechanisms likely operate among genotypes within a population, empirical evidence demonstrating the relationship between disturbance and genotypic diversity remains limited. We experimentally tested how disturbance altered the colonization (gain) and extinction (loss) of genets within a population of the marine angiosperm Zostera marina (eelgrass). In a 2‐year field experiment conducted in northern California, we mimicked grazing disturbance by migratory geese by clipping leaves at varying frequencies during the winter months. Surprisingly, we found the greatest rates of new colonization in the absence of disturbance and that clipping had negligible effects on extinction. We hypothesize that genet extinction was not driven by selective mortality from clipping or from any stochastic loss resulting from the reduced shoot densities in clipped plots. We also hypothesize that increased flowering effort and facilitation within and among clones drove the increased colonization of new genets in the undisturbed treatment. This balance between colonization and extinction resulted in a negative relationship between clipping frequency and net changes in genotypic richness. We interpret our results in light of prior work showing that genotypic diversity increased resistance to grazing disturbance. We suggest that both directions of a feedback between disturbance and diversity occur in this system with consequences for the maintenance of eelgrass genotypic diversity. [ABSTRACT FROM AUTHOR]

Invasive species are a primary threat to biodiversity and are challenging to manage once populations become established in previously unoccupied areas. But removing them is further complicated when invasions occur in continental, mixed‐ownership systems. We demonstrate a rare conservation success: the regional‐scale removal of an invasive predator – the barred owl (Strix varia) – to benefit the spotted owl (Strix occidentalis) in California. Barred owl site occupancy declined sixfold, from 0.19 to 0.03, following 1 year of removals, and site extinction (0.92) far exceeded colonization (0.02). Spotted owls recolonized 56% of formerly occupied territories within 1 year, contrasting starkly with removals conducted after barred owls achieved high densities in the Pacific Northwest. Our study therefore averted the otherwise likely extirpation of California spotted owls (Strix occidentalis occidentalis) by barred owl competition. Collectively, leveraging technological advances in population monitoring, early intervention, targeting defensible biogeographic areas, and fostering public–private partnerships will reduce invasive species‐driven extinction of native fauna in continental systems. [ABSTRACT FROM AUTHOR]

Climate change and fire suppression have altered disturbance regimes in forest ecosystems globally. In the seasonally dry forests of western North America, large‐scale restoration may reduce severe fire and increase forest resilience but also eliminate existing habitat for sensitive wildlife species. We modeled bioregional‐scale effects of forest restoration on future severe fire activity and occupancy dynamics of an old‐forest species declining in abundance, the spotted owl (Strix occidentalis), in the Sierra Nevada mountains of California. Our findings suggest restoring historical forest structure may mitigate severe fire activity as the climate warms, particularly when restoration occurs in owl habitat. On average, benefits provided by restoration to owls (reduced severe fire) were found to exceed potential costs (direct habitat alteration) by mid‐century. However, the magnitude and direction of restoration trade‐offs varied spatially, which informs restoration planning. When large, old trees are maintained, forest restoration can provide co‐benefits to old‐forest species and forest ecosystem resilience under climate change. [ABSTRACT FROM AUTHOR]

For millennia, forest ecosystems in California have been shaped by fire from both natural processes and Indigenous land management, but the notion of climatic variation as a primary controller of the pre-colonial landscape remains pervasive. Understanding the relative influence of climate and Indigenous burning on the fire regime is key because contemporary forest policy and management are informed by historical baselines. This need is particularly acute in California, where 20th-century fire suppression, coupled with a warming climate, has caused forest densification and increasingly large wildfires that threaten forest ecosystem integrity and management of the forests as part of climate mitigation efforts. We examine climatic versus anthropogenic influence on forest conditions over 3 millennia in the western Klamath Mountains—the ancestral territories of the Karuk and Yurok Tribes—by combining paleoenvironmental data with Western and Indigenous knowledge. A fire regime consisting of tribal burning practices and lightning were associated with long-term stability of forest biomass. Before EuroAmerican colonization, the long-term median forest biomass was between 104 and 128 Mg/ha, compared to values over 250 Mg/ha today. Indigenous depopulation after AD 1800, coupled with 20th-century fire suppression, likely allowed biomass to increase, culminating in the current landscape: a closed Douglas fir–dominant forest unlike any seen in the preceding 3,000 y. These findings are consistent with precontact forest conditions being influenced by Indigenous land management and suggest large-scale interventions could be needed to return to historic forest biomass levels. [ABSTRACT FROM AUTHOR]

Enhanced immune functioning in response to biodiversity may explain potential health benefits from exposure to green space. Using unique data on urban forest biodiversity at the zip code level for California measured from 2014 to 2019 we test whether greater diversity of street trees is associated with reduced death from cardiovascular disease. We find that urban forests with greater biodiversity measured via the Shannon Index at the genus level are associated with a lower mortality rate for heart disease and stroke. Our estimates imply that increasing the Shannon Index by one standard deviation (0.64) is associated with a decrease in the mortality rate of 21.4 per 100,000 individuals for heart disease or 13% and 7.7 per 100,000 individuals for stroke or 16%. Our estimates remain robust across several sensitivity checks. A policy simulation for tree planting in Los Angeles based on our estimates suggests that if these relationships were causal, investment in planting for a more biodiverse set of street trees would be a cost-effective way to reduce mortality related to cardiovascular disease in urban areas. [ABSTRACT FROM AUTHOR]

• Comparative analysis of environmental federalism approaches to EIA policy. • Detailed legislative and regulatory evolution in all four case studies. • Lessons learned and policy reforms for EIA in Brazil, Paraná, US, and California. The literature on environmental impact assessments (EIA) tends to focus on national case studies, while neglecting subnational EIA systems. Federalist countries represent 40 % of the world's population and by their design link national and subnational governments in institutional arrangements that delineate or share power across administrative and sectorial areas. Therefore, the study of institutional arrangements' influence on the conduct of environmental policy such as EIA is important in evaluating its effectiveness. This research aims to contribute to this area by examining the national and subnational EIA systems in two federalist countries, Paraná, Brazil and California, United States (US). This involved a literature review of the scientific and grey literature as well as legislation and regulations of each case study. This analysis was organized along operational, legislative, administrative, and procedural characteristics building upon existing methods from the EIA literature. The results show each federal country presents different approaches to EIA policy. Brazil represents a more centralized top-down approach based on a licensing system, which offers broader coverage of projects and in theory more standardized implementation. In the case of Paraná, there has been a recent shift towards decentralizing the EIA process for smaller projects to municipalities, although there remain institutional and technical challenges. The US EIA system covers only public projects and therefore is considerably limited in its coverage. California presents the most institutionally and technically competent EIA system of those compared in this study. However, it still suffers from problems of inconsistent implementation and litigation abuse. All case studies are facing increasing political pressures to streamline their processes, often with the proposal of arbitrary timelines. [ABSTRACT FROM AUTHOR]

Mountain ecosystems contain strong elevational gradients in climate and vegetation that shape species distributions and the structure of animal communities. Nevertheless, studies of habitat selection for individual species rarely account for such gradients that often result in species being managed uniformly across their range, which may not improve conservation as intended. Therefore, we characterized variation in nocturnal habitat selection by 18 GPS‐tagged California spotted owls (Strix occidentalis occidentalis) along a 1400‐m elevational gradient in the Sierra Nevada, California. We characterized three‐dimensional forest structure with light detection and ranging data that we used in mixed‐effects resource‐ and step‐selection analyses of owl habitat selection. At lower elevations, owls selected stands with shorter trees, sites closer to hard edges between tall forests and open areas, sites with less diversity in forest seral types and sites with more ridge and southwest aspects. In contrast, owls at higher elevations selected the opposite. Within public forests that had taller trees and within their home range core (45% kernel density estimate of GPS points) areas, owls selected forests with less and more canopy cover at low and high elevations, respectively. Outside of their core areas, owls selected areas with fewer and more tall trees at low and high elevations, respectively. These findings may be explained by elevational gradients in prey distribution and variation in owl diet because owls consume more woodrats (Neotoma spp; earlier seral species) at lower elevations and more flying squirrels (Glaucomys sabrinus; older forest species) at higher elevations. Thus, at low elevations and in areas unlikely to support nesting, spotted owls could benefit from management that promotes woodrat habitat by encouraging oak regeneration and creating small brushy openings within forests with shorter (younger) trees. Conversely, at higher elevations, (1) enhancing flying squirrel habitat by promoting large trees and denser canopy on mesic sites and (2) managing for greater cover type diversity on southwest‐facing slopes and ridgetops is more likely to improve foraging habitat quality for spotted owls. The patterns of owl selection over elevational gradients has not been explicitly considered in most habitat management plans but clearly would improve management throughout mountain ecosystems. [ABSTRACT FROM AUTHOR]

Quantitative reconstructions of vegetation abundance from sediment-derived pollen systems provide unique insights into past ecological conditions. Recently, the use of pollen accumulation rates (PAR, grains cm−2 year−1) has shown promise as a bioproxy for plant abundance. However, successfully reconstructing region-specific vegetation dynamics using PAR requires that accurate assessments of pollen deposition processes be quantitatively linked to spatially-explicit measures of plant abundance. Our study addressed these methodological challenges. Modern PAR and vegetation data were obtained from seven lakes in the western Klamath Mountains, California. To determine how to best calibrate our PAR-biomass model, we first calculated the spatial area of vegetation where vegetation composition and patterning is recorded by changes in the pollen signal using two metrics. These metrics were an assemblage-level relevant source area of pollen (aRSAP) derived from extended R-value analysis (sensu Sugita, 1993) and a taxon-specific relevant source area of pollen (tRSAP) derived from PAR regression (sensu Jackson, 1990). To the best of our knowledge, aRSAP and tRSAP have not been directly compared. We found that the tRSAP estimated a smaller area for some taxa (e.g. a circular area with a 225 m radius for Pinus) than the aRSAP (a circular area with a 625 m radius). We fit linear models to relate PAR values from modern lake sediments with empirical, distance-weighted estimates of aboveground live biomass (AGLdw) for both the aRSAP and tRSAP distances. In both cases, we found that the PARs of major tree taxa – Pseudotsuga, Pinus, Notholithocarpus, and TCT (Taxodiaceae, Cupressaceae, and Taxaceae families) – were statistically significant and reasonably precise estimators of contemporary AGLdw. However, predictions weighted by the distance defined by aRSAP tended to be more precise. The relative root-mean squared error for the aRSAP biomass estimates was 9% compared to 12% for tRSAP. Our results demonstrate that calibrated PAR-biomass relationships provide a robust method to infer changes in past plant biomass. [ABSTRACT FROM AUTHOR]

Copyright of Conservation Biology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The mixed-conifer forests in California's Sierra Nevada include species from several genera (Pinus , Abies , Pseudotsuga , Calocedrus and Sequoiadendron). These forests have complex disturbance regimes dominated by low to moderate severity fire that often resulted in patchy spatial patterns and multiaged stands. Leaf area index (LAI) describes the total leaf surface area per unit area in a forest community and is related to wood and biomass production and ecosystem values such as water usage, water yields and carbon sequestration. LAI can also serve as a representation of growing space occupancy and the basis for stocking control, including in multiaged stands. Nine study sites were sampled with 22–37 0.05 ha plots per study site to estimate LAI and other metrics. LAI was highest in study sites with greater proportions of shade tolerant Abies and Calocedrus species and on higher productivity sites. Recent drought-related mortality has reduced stocking and LAI. The combination of fire suppression and timber harvest over the past century has resulted in stands with higher densities, and greater proportions of shade tolerant species. Managing these structures to restore their presettlement character will involve reducing overall stocking, increasing proportions of intolerant species and increasing fine-scale heterogeneity. LAI allocation—allocating leaf area to age classes, species or canopy strata—can be used to design new structures that resemble presettlement structures and are resilient to disturbances. [ABSTRACT FROM AUTHOR]

Historical baselines of forest conditions provide reference states to assess how forests have changed through time. In California, the Public Land Survey System (PLSS) provides tree inventory data between 1872 and 1884 at 93.2‐km2 (36 mi2) resolution. Although these data provide a spatially extensive record of settlement‐era forest conditions, reconstructions using PLSS data have been limited and controversial in western landscapes. Recent improvements in the application of plotless density estimators (PDE) have made reconstructions more accurate and robust. The purpose of this study was to use PDE to reconstruct the settlement‐era forest conditions in Six Rivers National Forest—a floristically diverse temperate forest in the Klamath Mountains of northwestern California—to quantify differences with modern conditions. Records of fires and harvests were used in conjunction with the PLSS data to understand the influence of forest management during the previous century. The contemporary forest in Six Rivers contains three times more trees than in the settlement era with a comparable increase in tree basal area. Forest composition during the settlement era was predominantly Douglas‐fir (34.4%), pine (24.2%), and oak (21.9%) by basal area. Contemporary forests support more Douglas‐fir (45.2%) and a similar amount of pine (26.1%), while oaks have decreased by more than half (9.3%). These increases in tree abundance occurred despite extensive, mid‐century timber harvesting in Six Rivers. Although large fires have burned in Six Rivers between 2000 and 2019, far fewer fires occurred during the twentieth century. Our results suggest that effective fire suppression contributed to the densification of the contemporary forests in Six Rivers. [ABSTRACT FROM AUTHOR]

Background: Falls and hip fractures among older people are associated with high morbidity and mortality. Hyponatraemia may be a risk for falls/hip fractures, but the effect of hyponatraemia duration is not well understood. Aims: To evaluate individuals with periods of sub‐acute and chronic hyponatraemia on subsequent risk for serious falls and/or hip fractures. Methods: Retrospective cohort study in the period 1 January 1998 to 14 June 2016 within an integrated health system of individuals aged ≥55 years with ≥2 outpatient serum sodium measurements. Hyponatraemia was defined as sodium <135 mEq/L with sub‐acute (<30 days) and chronic (≥30 days) analysed as a time‐dependent exposure. Multivariable Cox proportional‐hazards modelling was used to estimate hazard ratios (HR) for serious falls/hip fractures based on sodium category. Results: Among 1 062 647 individuals totalling 9 762 305 sodium measurements, 96 096 serious falls/hip fracture events occurred. Incidence (per‐1000‐person‐years) of serious falls/hip fractures were 11.5, 27.9 and 19.8 for normonatraemia, sub‐acute and chronic hyponatraemia. Any hyponatraemia duration compared to normonatraemia had a serious falls/hip fractures HR (95%CI) of 1.18 (1.15, 1.22), with sub‐acute and chronic hyponatraemia having HR of 1.38 (1.33, 1.42) and 0.91 (0.87, 0.95), respectively. Examined separately, the serious falls HR was 1.37 (1.32, 1.42) and 0.92 (0.88, 0.96) in sub‐acute and chronic hyponatraemia, respectively. Hip fracture HR were 1.52 (1.42, 1.62) and 1.00 (0.92, 1.08) for sub‐acute and chronic hyponatraemia, respectively, compared to normonatraemia. Conclusions: Our findings suggest that early/sub‐acute hyponatraemia appears more vulnerable and associated with serious falls/hip fractures. Whether hyponatraemia is a marker of frailty or a modifiable risk factor for falls remains to be determined. [ABSTRACT FROM AUTHOR]

Many former military training sites contain unexploded ordnance (UXO) and require environmental remediation. For the first phase of UXO remediation, locations of geomagnetic anomalies are recorded over a subregion of the study area to infer the spatial intensity of anomalies and identify high concentration areas. The data resulting from this sampling process contain locations of anomalies across narrow regions that are surveyed; however, the surveyed regions only constitute a small proportion of the entire study area. Existing methods for analysis require selecting a window size to transform the partially surveyed point pattern to a point-referenced dataset. To model the partially surveyed point pattern and infer intensity of anomalies at unsurveyed regions, we propose a Bayesian spatial Poisson process model with a Dirichlet process mixture as the inhomogeneous intensity function. A data augmentation step is used to impute anomalies in unsurveyed locations and reconstruct clusters of anomalies that span surveyed and unsurveyed regions. To verify that data augmentation reconstructs the underlying structure of the data, we demonstrate fitting the model to simulated data, using both the full study area and two different sampled subregions. Finally, we fit the model to data collected at the Victorville Precision Bombing range in southern California to estimate the intensity surface in anomalies per acre. Supplementary materials accompanying this paper appear online. [ABSTRACT FROM AUTHOR]

Regional tree die-off events generate large quantities of standing dead wood, raising concern over catastrophic wildfire and other hazards. Governmental responses to tree die-off have often focused on incentivizing biomass energy production that utilizes standing dead trees removed for safety concerns. However, the full distribution of potential woody bioenergy feedstock after tree die-off has not been evaluated due to the complexities of surveying and precisely measuring large forested areas. In this paper, we present a novel method for estimating standing dead biomass at a fine spatial resolution that combines aerial survey data with forest structure maps. Using this method, we quantify biomass generated by the unprecedented tree die-off that occurred in California following a 4-year drought and widespread pest outbreaks. The results are used to estimate feasibly recoverable feedstock for energy production. We find that approximately 95.1 million bone-dry tons (BDT) of dead biomass resulted from 2012–2017 mortality, with a lower bound of 26.2 million BDT. In other words, of the aboveground live tree biomass in 2012, ~1.3–4.8% died by 2017. Of the standing dead biomass, 29% meets minimum constraints for potential cost-effective bioenergy feedstock. This proportion drops to as low as 15% in the most affected areas due to terrain slope, wilderness status, and other factors, highlighting the need to complement disposal via biomass energy with other strategies to mitigate the risks of the tree mortality crisis, which is likely to only become more severe over time due to climate change. [ABSTRACT FROM AUTHOR]

• Forests impacted by drought-induced die-back in California contain >150 Mg ha−1 of snag biomass. • From 2017 to 2021, fine woody debris increased >145 %; litter and duff fuel loads increased >55 %. • The rates of snag fall were 20–40% slower (i.e., longer snag persistence) than previously reported. • Snag fall is expected to contribute from 49.4 Mg ha−1 to 136.1 Mg ha−1 of surface fuels by 2040. Forest die-backs linked to extreme droughts are expected to increase as the climate dries and warms. An example is the 2012–2016 hotter drought in California that induced widespread tree mortality in the Sierra Nevada, California. The sudden increase in snags (i.e., standing dead trees) raised immediate concerns about their impact on wildfire hazard and longer-term questions about their effect on ecosystem structure and function. We quantified the likely progression of snag fall and fuel succession following the recent extensive mortality event in the southern Sierra Nevada mixed conifer forest. Our results used data from a long-term demography study to project trends in surface fuel loads at three study sites in Yosemite, Sequoia and Kings Canyon national parks. In the short term (2017–2021), fine woody debris and litter + duff significantly increased across all three sites (>145 % and >55 %, respectively); coarse woody debris increased significantly at one site (48.6 %); and total fuel loads increased significantly at two of the three sites (38 % and 69 %). Snag longevity increased with size, with the relationship varying by species. Yellow pine was a notable outlier: size played a small role in influencing its fall rates. Overall, species-specific snag fall rates in the southern Sierra Nevada were 20 % to 40 % slower than previously reported. By 2040, projected median cumulative inputs of biomass from future snag fall range from 49.4 Mg ha−1 to 136.1 Mg ha-1across our three sites, which exceeds the amounts currently present (47.17–89.97 Mg ha−1) and is well above estimates of historical coarse woody debris amounts in the Sierra Nevada (17.7 Mg ha -1). These results provide a robust empirical basis to refine the snag fall algorithm in vegetation simulation models. Options to manage the impact of extreme number of snags and their large surface combustible biomass include salvage operations and prescribed burning, with both methods having operational, financial, and legal limitations that need to be considered. [ABSTRACT FROM AUTHOR]

Highlights • We proposed a new LiDAR-based profile area change (PAC) method for fire severity assessment. • PAC metrics are highly correlated to field measured changes in basal area and leaf area index. • PAC metrics outperformed traditional LiDAR-based canopy cover and tree height change metrics, and Landsat-derived RdNBR. • PAC metrics can be applied at multiple scales from individual trees to plot-level fire assessments. Abstract This study proposes a new method (profile area change, PAC) to quantify fire-induced forest structural changes at the individual tree and clump of trees scales using pre- and post-fire LiDAR data. The PAC measures the difference in profile area summarized from pre- and post-fire LiDAR points. We applied the PAC method to assess the effects of the 2013 American Fire in the Sierra Nevada, California, USA. Our LiDAR PAC metrics were compared to changes in commonly used LiDAR-derived canopy cover and tree height metrics at tree level, and to Landsat-8 imagery-derived relative differenced normalized burn ratio (RdNBR) at the 30m pixel level. A quantitative validation using field measured changes in basal area and leaf area index (LAI) confirmed that correlations between PAC metrics and field measurements (R2 ≥ 0.67) were significantly higher than those from canopy cover or tree height metrics (R2 ≤ 0.43), and much stronger than that from RdNBR (R2 ≤ 0.26). The PAC metrics can also be used to infer the extent of tree canopy disturbance caused by fire, based on whether the majority of biomass loss occurred above or below the tree crown base height. Mapping of canopy disturbance indicated that over half (57.0%) of the American Fire region had tree canopy loss from fire, 22.5% of trees had sub-canopy loss, while the remaining area had no detectable tree canopy change. Overall, the LiDAR PAC metric, as a simple and integrated method, demonstrated promising potential in characterizing fine-grained changes in forest structure. The method can be beneficial for forest managers in evaluating fire-induced environmental and economic losses, and provide useful information for forest restoration design. [ABSTRACT FROM AUTHOR]

Highlights • We studied California spotted owl demography in mixed-ownership landscapes. • Forest conditions and topography better-explained variation in data than ownership. • Occupancy and reproduction were higher in study areas with more private lands. • Differences between study areas due to elevation and young forest with hardwoods. • Including private lands in conservation research provides valuable insights. Abstract Biodiversity conservation in mixed-ownership landscapes often depends on contributions from privately-owned lands, where natural resource development can alter and produce novel habitat conditions for species of conservation concern. A lack of research on private lands stemming from access issues and concerns over regulatory outcomes, however, often limits evaluation of the impact of land management. The California spotted owl (Strix occidentalis occidentalis), for example, often occurs in mixed-ownership landscapes but research on this species has occurred primarily on public lands. Therefore, we conducted the first large-scale private-public cooperative and comparative analyses of California spotted owls inhabiting mixed-ownership landscapes in the Sierra Nevada, California, USA. We surveyed 151 spotted owl sites from 2013 to 2017 within two study systems: one comprised primarily of public lands (national forests) where the owl population has declined over the last ∼20 years and a set of study areas comprised mostly of private lands on which relatively high estimates of site occupancy were recently reported. Multistate occupancy modeling indicated that the probability of occupancy and successful reproduction by owls depended on site status in the previous year, with both probabilities highest at sites where owls successfully reproduced in the previous year, intermediate at occupied sites where owls had not successfully reproduced, and lowest at previously unoccupied sites. Site occupancy probability was higher at low-elevation sites and lower at sites that contained more open area and younger forest. Successful reproduction by owls was also more likely at low-elevation sites and at sites with more north-facing slope and younger forest with high basal area of hardwoods. Study areas with more private lands tended to occur at lower elevations and have greater amounts of younger forest with high basal area of hardwoods, which may have contributed to higher occupancy and reproductive probabilities than the study area with more public land. Thus, differences in occupancy and reproductive probabilities between study areas appeared to be the result of differences in topographic and vegetation conditions that likely promote populations of key spotted owl prey species. Our results suggest that private lands in mixed-ownership landscapes may contribute to spotted owl conservation by conferring different benefits to owls than public lands and, more broadly, highlight the importance of including private lands in conservation research and planning. [ABSTRACT FROM AUTHOR]

The article evaluates the U.S. immigration history musuem the New Americans Museum in San Diego, California.

• The 2012–2016 California drought caused massive tree mortality throughout Sierra Nevada forests. • Ground (duff) and surface fuels were measured across a large plot network. • Heavy duff and surface fuel loads were common (138.2 ± 21.7 Mg ha−1, Mean ± 95 % CI). • Overstory metrics were weakly correlated with duff and surface fuel loads. • Higher fuel loads tended to occur in plots with no record of disturbance. The 2012–2016 hotter drought in the Sierra Nevada, California, USA led to the mortality of millions of trees. This disruption to the disturbance regime is an example of how climate extremes can exacerbate current and future wildfire risks. In this study, we used data from an extensive network of forest plots across 13 different sites in the Sierra Nevada to characterize ground (i.e., duff) and surface fuels and their potential drivers shortly after the drought (2016–2018), but before snag (standing dead tree) fall associated with this massive tree mortality event occurred. Overall, we found high biomass of fuels for most sites (138.2 ± 21.7 Mg ha−1, Mean ± 95 % CI), especially in areas lacking recent fire or active management, with values up to five times higher than estimates for pre-settlement conditions for mixed-conifer forests in the region. Four major groups of forest overstory structure were identified with some distinct fuel characteristics. These ranged from a cluster of ponderosa pine (Pinus ponderosa Douglas ex Lawson)-dominated plots with the highest density of snags, lowest live tree basal area, and lowest total ground and surface fuel biomass (mean = 90.1 Mg ha−1) to a group of giant sequoia (Sequoiadendron giganteum (Lindl.) J. Buchholz)-dominated plots with the highest live tree basal area and highest total fuel biomass (mean = 547.6 Mg ha−1). Although we found relatively weak relationships between forest characteristics and fuel loads, their inclusion in a model selection framework that also considered biophysical variables and disturbance history explained>80 % of the observed variation in litter + fine woody debris loads. The baseline fuel conditions described here will not only inform the management of drought-impacted forests in the Sierra Nevada, but also help identify key drivers of fuel succession in a changing environment. [ABSTRACT FROM AUTHOR]

In April-August 2018, samples of galled roots with rhizosphere soil were collected from almond orchards in Atwater, Merced County and Bakersfield, Kern County, California. Almond trees ( Prunus dulcis) grafted on 'Hansen 536' and 'Brights Hybrid®5' (peach-almond hybrid) rootstocks showed strong symptoms of growth decline. Extracted root-knot nematodes were identified by both morphological and molecular methods as M. floridensis. Meloidogyne floridensis was initially found in Florida, USA, and has not been reported from any other states and countries. This is a first report of M. floridensis in California and outside of Florida. [ABSTRACT FROM AUTHOR]

California spotted owls (CSOs) (Strix occidentalis occidentalis) have received significant conservation attention beginning with the U.S. Forest Service interim management guidelines in 1992. The most commonly reported forest habitat feature for successful nesting habitat of CSO is canopy cover > 70%. Loss and degradation of Sierra Nevada CSO habitat, however, has been a growing concern, initially from commercial tree harvesting and, more recently, from wildfire. This study examined trends in wildfire impacts on potential nesting habitat of the CSO and discusses different management approaches that might lead to the conservation of CSO in fire-dependent forests. A total of 85,046 ha of CSO potential nesting habitat was burned by fire that resulted in ≥ 50% tree basal area (BA) mortality, reducing canopy cover on average to < 25%, during 2000-2014; this included 2.7%, 12.3%, and 7.6% of dense red fir (Abies magnifica), eastside pine, and westside forests, respectively. Based on regression predictions, within the next 75 yr, the cumulative amount of nesting habitat burned at ≥ 50% tree basal area mortality will exceed the total existing habitat. Four management strategies are discussed that could enhance the conservation of the CSO: (1) increased fire suppression, (2) strategically reducing fire hazards using mechanical treatments and/or prescribed fire, (3) increasing the amount of managed wildfire in CSO habitat, and (4) developing a landscape strategy that uses historical forest structure information to identify areas where high-canopy cover forests are more sustainable. Our estimates of how moderate-and high-severity fire may affect forests into the future poise a substantial threat to CSO persistence. More comprehensive forest restoration activities may be needed in CSO habitat to avoid significant losses of older forests. [ABSTRACT FROM AUTHOR]

BACKGROUND: Substance exposure is thought to contribute to reports of suspected maltreatment made to child protective services (CPS) at or shortly after birth. There are limited data, however, on whether clinicians are more likely to report black and Hispanic substance-exposed infants compared with white infants. METHODS: We examined racial differences in diagnosed substance exposure and subsequent maltreatment reports by using linked birth, hospital discharge, and CPS records. Diagnostic codes were used to document substance exposure; CPS records provided information on maltreatment reports. Prevalence of infant exposure was calculated by race or ethnicity, substance type, and sociodemographic covariates. We estimated racial differences in maltreatment reporting among substance-exposed infants using multivariable models. RESULTS: In a 2006 population-based California birth cohort of 474 071 black, Hispanic, and white infants, substance exposure diagnoses were identified for 1.6% of infants (n = 7428). Exposure varied significantly across racial groups (P < .001), with the highest prevalence observed among black infants (4.1%) and the lowest among Hispanic infants (1.0%). Among white and Hispanic infants, the most frequently observed substances were amphetamine and cannabis; for black infants, cannabis was the most common, followed by cocaine. After adjusting for sociodemographic and pregnancy factors, we found that substance-exposed black and Hispanic infants were reported at significantly lower or statistically comparable rates to substance-exposed white infants. CONCLUSIONS: Although we were unable to address potential racial and ethnic disparities in screening for substances at birth, we found no evidence that racial disparities in infant CPS reports arise from variable responses to prenatal substance exposure. [ABSTRACT FROM AUTHOR]

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Dead wood plays important structural and biogeochemical roles in forest ecosystem processes. Some aspects of woody debris dynamics have been carefully studied, but the decay patterns and carbon density of standing dead (SD) trees are only weakly characterized. Climbing forest mortality rates are also driving increases in the creation and abundance of SD trees. All forms of forest carbon accounting, from stand-level biomass calculations to dynamic earth systems models, are improved by a better understanding of SD tree physical and chemical traits. Using dimensional analysis, we described the patterns of density, carbon concentration, and net carbon density in decaying SD trees of six California mixed conifer species. As decay class advanced, trees showed a progressively lower density and a small increase in carbon concentration. Net carbon density of the most decayed SD trees was only 60% that of live trees. The key characteristics of SD trees that determine these patterns are species, surface to volume ratio, and relative position within the tree. The decay of SD trees and how deadwood biomass is estimated in large scale inventories also have repercussions in greenhouse gas accounting. When the measured changes in carbon density are applied to SD carbon stock estimates for California mixed conifer forests, the decay-adjusted estimates are 3.66–3.74 Tg (18%) lower than estimates that do not incorporate change due to decay. [ABSTRACT FROM AUTHOR]