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Abstract Bacterial contamination of surface water is a public health concern. To quantify the efflux ofEscherichia coliinto ephemeral and intermittent streams and assess its numbers in relation to secondary body contact standards, we monitored runoff and measuredE. colinumbers from 10 experimental watersheds that differed in vegetation cover and cattle access in north‐central Oklahoma.Escherichia colinumbers were not significantly different among the watersheds, with one exception; the grazed prairie watershed (GP1) had greater numbers compared to one ungrazed prairie watershed (UP2). MedianE. colinumbers in runoff from ungrazed watersheds ranged from 260 to 1482 MPN/100 mL in comparison with grazed watersheds that ranged from 320 to 8878 MPN/100 mL. In the GP1 watershed, higher cattle stocking rates during pre‐ and post‐calving (February–May) resulted in significantly greater bacterial numbers and event loading compared to periods with lower stocking rates. The lack of significance among watersheds is likely due to the grazed sites being rotationally (and lightly) grazed, data variability, and wildlife contributions. To address wildlife sources, we used camera trap data to assess the usage in the watersheds; however, the average number of animals in a 24‐h period did not correlate with observed medianE. colinumbers. Because of its impacts onE. colinumbers in water, grazing management (stocking rate, rotation, and timing) should be considered for improving water quality in streams and reservoirs. 

Abstract Recent advancements in network science showed that the topological credentials of the elements (i.e., links) in a network carry important implications. Likewise, roadway segments (i.e., links) in a road network should be assessed based on their network position along with traffic conditions at a given geographic scale. The goal of this study is to present a framework that can identify and select critical links in a road network based on their topological importance such as centrality, and the effects of systematic interventions conducted on such links in improving overall system performance (vehicle delay, travel time) to provide an adequate level of service (LOS). A real-world road network (Boise downtown) is investigated by applying lane interventions on roadways experiencing high congestion. Microscopic traffic simulation and analyses are conducted to estimate the traffic flow parameters hence the performance of the road segments. The findings of this study show that interventions applied to critical and congested road segments improve the serviceability from LOS F to LOS E as well as from LOS D to LOS C. Besides, reduced travel time and vehicular delay (after applying intervention on critical components) are also observed for high demand OD pairs of the road network. As such the proposed framework has the potential to incorporate the topological credentials with traffic flow parameters and improve the performance of the road network. This systematic approach will help traffic managers and practitioners to develop strategies that enhance road network performance. 

Abstract Research has demonstrated that members of the public recognize anomalous weather patterns, and that subjective perceptions of the weather are related to beliefs about the occurrence of climate change. Yet despite two decades of scholarship and dozens of studies, inconsistent and insufficient data have made it difficult to credibly identify the causal impact of objective experiences on perceptions, and the impact of perceptions on beliefs regarding climate change occurrence. Here, we overcome these limitations by collecting and analyzing data from a 5-y panel survey of 2,500 individuals in Oklahoma, a US state that is highly divided on questions about climate change. Our findings indicate that the relationship between local weather anomalies and climate change beliefs is heavily dependent on baseline beliefs about whether climate change was occurring. For people who did not believe in climate change in the initial survey in our series, perceptions of anomalously hot and dry seasons shifted their beliefs towards the occurrence of anthropogenic climate change, whereas their perceptions of anomalously cool and wet seasons shifted their beliefs away from anthropogenic climate change. This relationship was not present among people who believed that climate change was occurring at the beginning of the study; their perceptions of seasonal temperature and precipitation anomalies had no effect on their beliefs about climate change. These patterns have substantial implications for the evolution of public beliefs about climate change. 

Abstract The February 2021 cold air outbreak (CAO) was a high‐impact event in the South‐Central Plains of the United States. This study examines important precursors to the event that likely impacted its predictability in subseasonal forecasts. We use reanalysis to show that the CAO was facilitated by two distinct wave breaks—an East Siberian Sea anticyclonic wave break and a Labrador Sea cyclonic wave break. We also use European Center for Medium‐Range Weather Forecasts and National Center for Environmental Prediction subseasonal‐to‐seasonal models to investigate the impact of the wave breaks on the forecast skill of the event at a ∼2–3 weeks lead time. Ensemble members successfully simulating these features produce more negative temperature anomalies across the Great Plains, corresponding to better positioning of anomalous ridging. These results demonstrate that successfully simulating persistent anticyclones can improve central US extreme cold forecasts at long leads. 

Abstract Plants affect associated biotic and abiotic edaphic factors, with reciprocal feedbacks from soil characteristics affecting plants. These two‐way interactions between plants and soils are collectively known as plant–soil feedbacks (PSFs). The role of phylogenetic relatedness and evolutionary histories have recently emerged as a potential driver of PSFs, although the strength and direction of feedbacks among sympatric congeners are not well‐understood. We examined plant–soil feedback responses ofAsclepias syriaca, a common clonal milkweed species, with several sympatric congeners across a gradient of increasing phylogenetic distances (A. tuberosa,A. viridis,A. sullivantii, andA. verticillata, respectively). Plant–soil feedbacks were measured through productivity and colonization by arbuscular mycorrhizal (AM) fungi.Asclepias syriacaproduced less biomass in soils conditioned by the most phylogenetically distant species (A. verticillata), relative to conspecific‐conditioned soils. Similarly, arbuscular mycorrhizal (AM) fungal colonization ofA. syriacaroots was reduced when grown in soils conditioned byA. verticillata, compared with colonization in plants grown in soil conditioned by any of the other threeAsclepiasspecies, indicating mycorrhizal associations are a potential mechanism of observed positive PSFs. This display of differences between the most phylogenetically distant, but not close or intermediate, paring(s) suggests a potential phylogenetic threshold, although other exogenous factors cannot be ruled out. Overall, these results highlight the potential role of phylogenetic distance in influencing positive PSFs through mutualists. The role of phylogenetic relatedness and evolutionary histories have recently emerged as a potential driver of plant–soil feedbacks (PSFs), although the strength and direction of feedbacks among sympatric congeners are not well‐understood. Congeneric, sympatric milkweeds typically generated positive PSFs in terms of productivity and AM fungal colonization, suggesting the low likelihood of coexistence among tested pairs, with a strength of feedback increasing as the phylogenetic distance increases. 

Abstract Wintertime cold air outbreaks (CAOs) in the Great Plains of the United States have significant socioeconomic, environmental, and infrastructural impacts; the events of December 1983 and February 2021 are key examples of this. Previous studies have investigated CAOs in other parts of North America, particularly the eastern United States, but the development of CAOs in the Great Plains and their potential subseasonal-to-seasonal (S2S) predictability have yet to be assessed. This study first identifies 37 large-scale CAOs in the Great Plains between 1950 and 2021, before examining their characteristics, evolution, and driving mechanisms. These events occur under two dominant weather regimes at event onset: one set associated with anomalous ridging over Alaska and the other set associated with anomalous pan-Arctic ridging. Alaskan ridge CAOs evolve quickly (i.e., on synoptic time scales) and involve stratospheric wave reflection. Conversely, Arctic high CAOs are preceded by weak stratospheric polar vortex conditions several weeks prior to the event. Both categories of CAOs feature anomalous upward wave activity flux from Siberia, with downward wave activity flux over Canada seen only in the Alaskan ridge CAOs. The rapid development of the Alaskan ridge CAOs, also linked with a North Pacific wave train and anomalous wave activity flux from the central Pacific, suggests that these events could be forced by tropical modes of variability. These findings present evidence that different forcing mechanisms, with contrasting time scales, may produce distinct sources of predictability for these CAOs on the S2S time scale. 

Societal Impact Statement Agriculture touches all aspects of society and global environmental health. Dwindling phosphorous reserves are a looming crisis for civilization, and soil erosion typically far outpaces pedogenesis. Improving plant–mycorrhizal symbioses can enhance sustainable agriculture because mycorrhizas typically improve host‐plant nutrition and stabilize soils. Selective breeding of plants that gain greater benefits from mycorrhizas can provide considerable economic and environmental benefits. Our assessments demonstrate switchgrass genetic improvement increased or maintained production of two populations, and low‐input breeding increased mycorrhizal responsiveness, compared to parent lines. Selecting for increased mycorrhizal reliance may be an effective strategy for more sustainable and economical agricultural production. SummaryPlant–mycorrhizal interactions are not typically assessed in crop breeding programs. Our experiment addresses this by determining host‐plant outcomes of newly developed synthetic (agronomic) populations compared with parent lines, following low‐input selective breeding. Assessing the potential of low‐input breeding to enhance crop mycorrhizal benefits is a critical step toward more sustainable agricultural production.We compared four synthetic populations ofPanicum virgatum, from a low‐input biofuel breeding program at Oklahoma State University, to corresponding parent lines. Plants were grown in a greenhouse in native prairie soils that were either steam‐pasteurized (nonmycorrhizal) or non‐steamed (mycorrhizal).We assessed shoot and root biomass, shoot P concentration and P content, mycorrhizal growth response (MGR), and mycorrhizal phosphorous response (MPR). Importantly, we provide novel evidence that low‐input selective breeding increased mycorrhizal reliance of switchgrass synthetics compared to parent lines, with implications for global agricultural systems.There are substantial opportunities for plant traits associated with increased MGR and MPR to be transferred to a wide array of crops. Our findings indicate low‐input selective breeding can improve MGR and MPR. We propose these traits serve as a useful proxy for host‐plant mycorrhizal reliance, facilitating successful hologenome breeding to reduce fertilizer requirements. 

Abstract The plant microbiome is critical to plant health and is degraded with anthropogenic disturbance. However, the value of re‐establishing the native microbiome is rarely considered in ecological restoration. Arbuscular mycorrhizal (AM) fungi are particularly important microbiome components, as they associate with most plants, and later successional grassland plants are strongly responsive to native AM fungi.With five separate sites across the United States, we inoculated mid‐ and late successional plant seedlings with one of three types of native microbiome amendments: (a) whole rhizosphere soil collected from local old‐growth, undisturbed grassland communities in Illinois, Kansas or Oklahoma, (b) laboratory cultured AM fungi from these same old‐growth grassland sites or (c) no microbiome amendment. We also seeded each restoration with a diverse native seed mixture. Plant establishment and growth was followed for three growing seasons.The reintroduction of soil microbiome from native ecosystems improved restoration establishment.Including only native arbuscular mycorrhizal fungal communities produced similar improvements in plant establishment as what was found with whole soil microbiome amendment. These findings were robust across plant functional groups.Inoculated plants (amended with either AM fungi or whole soil) also grew more leaves and were generally taller during the three growing seasons.Synthesis and applications. Our research shows that mycorrhizal fungi can accelerate plant succession and that the reintroduction of both whole soil and laboratory cultivated native mycorrhizal fungi can be used as tools to improve native plant restoration following anthropogenic disturbance. 

Abstract The southern Great Plains of the USA has great potential to produce biofuel feedstock while minimizing the dual stresses of woody plant encroachment and climate change. Switchgrass (Panicum virgatum) cultivation, woody biomass captured during removal of the encroaching eastern redcedar (Juniperus virginiana) to restore grasslands and thinning of the native oak forest can provide an integrated source of feedstock and improve ecosystem services. In north‐central Oklahoma, we quantified productivity and ecosystem water use of switchgrass stands and degraded ecosystems encroached by eastern redcedar and compared these to native oak forest and tallgrass prairie ecosystems. We measured aboveground net primary productivity (ANPP) using allometric equations (trees) and clip plots (herbaceous), and evapotranspiration (ET) using a water balance approach from gauged watersheds, and calculated water use efficiency (WUE = ANPP/ET) from 2016 to 2019. Among vegetation cover types, ANPP averaged 5.1, 5.4, 6.0, and 7.8 Mg ha⁻¹ year⁻¹for the prairie, oak, eastern redcedar, and switchgrass watersheds and was significantly greater for switchgrass in 2018 and 2019 (2 and 3 years post establishment) when it reached 8.6 Mg ha⁻¹ year⁻¹. Averaged across 2017–2019, ET was significantly greater in the forested watersheds than the grassland watersheds (1022 mm year⁻¹for eastern redcedar, 1025 mm year⁻¹for oak, 874 mm year⁻¹for prairie, and 828 mm year⁻¹for switchgrass). The mean WUE was significantly greater (9.47 kg ha⁻¹ mm⁻¹) for switchgrass than for the prairie, eastern redcedar, and oak cover types (6.03, 6.02, and 5.31 kg ha⁻¹ mm⁻¹). Switchgrass offered benefits of greater ANPP, less ET, and greater WUE. Our findings indicate that an integrated biofuel feedstock system that includes converting eastern redcedar encroached areas to switchgrass and thinning the oak forest can increase productivity, increase runoff to streams, and improve ecosystem services. 

Abstract Considering the temporal responses of carbon isotope discrimination (Δ13C) to local water availability in the spatial analysis of Δ13C is essential for evaluating the contribution of environmental and genetic facets of plant Δ13C. Using tree-ring Δ13C from years with contrasting water availability at 76 locations across the natural range of loblolly pine, we decomposed site-level Δ13C signals to maximum Δ13C in well-watered conditions (Δ13Cmax) and isotopic drought sensitivity (m) as a change in Δ13C per unit change of Palmer’s Drought Severity Index (PDSI). Site water status, especially the tree lifetime average PDSI, was the primary factor affecting Δ13Cmax. The strong spatial correlation exhibited by m was related to both genetic and environmental factors. The long-term average water availability during the period relevant to trees as indicated by lifetime average PDSI correlated with Δ13Cmax, suggesting acclimation in tree gas-exchange traits, independent of incident water availability. The positive correlation between lifetime average PDSI and m indicated that loblolly pines were more sensitive to drought at mesic than xeric sites. The m was found to relate to a plant’s stomatal control and may be employed as a genetic indicator of efficient water use strategies. Partitioning Δ13C to Δ13Cmax and m provided a new angle for understanding sources of variation in plant Δ13C, with several fundamental and applied implications.