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Energy production in the United States is in transition as the demand for clean and domestic power increases. Wind energy offers the benefit of reduced emissions, yet, like oil and natural gas, it also contributes to energy sprawl. We used a diverse set of indicators to quantify the ecological impacts of oil, natural gas, and wind energy development in Colorado and Wyoming. Aerial imagery was supplemented with empirical data to estimate habitat loss, fragmentation, potential for wildlife mortality, susceptibility to invasion, biomass carbon lost, and water resources. To quantify these impacts we digitized the land-use footprint within 375 plots, stratified by energy type. We quantified the change in impacts per unit area and per unit energy produced, compared wind energy to oil and gas, and compared landscapes with and without energy development. We found substantial differences in impacts between energy types for most indicators, although the magnitude and direction of the differences varied. Oil and gas generally resulted in greater impacts per unit area but fewer impacts per unit energy compared with wind. Biologically important and policy-relevant outcomes of this study include: 1) regardless of energy type, underlying land-use matters and development in already disturbed areas resulted in fewer total impacts; 2) the number and source of potential mortality varied between energy types, however, the lack of robust mortality data limits our ability to use this information to estimate and mitigate impacts; and 3) per unit energy produced, oil and gas extraction was less impactful on an annual basis but is likely to have a much larger cumulative footprint than wind energy over time. This rapid evaluation of landscape-scale energy development impacts could be replicated in other regions, and our specific findings can help meet the challenge of balancing land conservation with society's demand for energy.

Using a multidimensional large sieve inequality, we obtain a bound for the mean-square error in the Chebotarev theorem for division fields of elliptic curves that is as strong as what is implied by the Generalized Riemann Hypothesis. As an application we prove that, according to height, almost all elliptic curves are Serre curves, where a Serre curve is an elliptic curve whose torsion subgroup, roughly speaking, has as much Galois symmetry as possible.

Society’s growing demand for clean and abundant energy has repercussions for biodiversity and human well-being. Directives for renewable energy, energy security, and technological advancements such as horizontal drilling in conjunction with hydraulic fracturing have spurred a rapid increase in alternative and unconventional energy production over the last decade. Given the projected increases in oil, gas, and wind energy development, we synthesize and compare known impacts on wildlife mortality, habitat loss, fragmentation, noise and light pollution, invasive species, and changes in carbon stock and water resources. The literature on these impacts is unevenly distributed among energy types, geographic regions, and taxonomic groups. Therefore, we suggest priorities for research and practice, including using a landscape approach to predict and plan for the cumulative effects of development. Understanding the full consequences of energy production is necessary for meeting demand while also safeguarding the ecological systems on which we depend.

Methane emissions from small freshwater ecosystems represent one of the largest components of uncertainty in the global methane budget. While these systems are known to produce large amounts of methane relative to their size, quantifying the timing, magnitude, and spatial extent of their emissions remains challenging. We begin to address this challenge in seasonally inundated forested mineral soil wetlands by (1) measuring wetland methane fluxes and hydrologic regime across both inundated and non-inundated soils, (2) characterizing how wetland hydrologic regime impacts the spatial extent of methane emission source areas, and (3) modeling average daily wetland-scale flux rates using four different upscaling techniques. Our results show that inundation extent and duration, but not frequency or depth, were major drivers of wetland methane emissions. Moreover, we found that methane fluxes were best described by the direction of water level change (i.e. rising or falling), where emissions were generally higher when water levels were falling. Once soils were inundated, subsequent changes in water level did not explain observed variability of methane concentrations in standing water. Finally, our spatial modeling suggests that representing inundation and associated methane source areas is a critical step in estimating local to regional scale methane emissions. Intermittently inundated soils alternated between being sources and sinks of methane depending on water level, soil moisture, and the direction of water level change. These results demonstrate that quantifying the hydrologic regime of seasonally inundated forested freshwater wetlands enables a more accurate estimation of methane emissions.

Floodplain inundation poses both risks and benefits to society. In this study, we characterize floodplain inundation across the United States using 5800 stream gages. We find that between 4% and 12.6% of a river’s annual flow moves through its floodplains. Flood duration and magnitude is greater in large rivers, whereas the frequency of events is greater in small streams. However, the relative exchange of floodwater between the channel and floodplain is similar across small streams and large rivers, with the exception of the water-limited arid river basins. When summed up across the entire river network, 90% of that exchange occurs in small streams on an annual basis. Our detailed characterization of inundation hydrology provides a unique perspective that the regulatory, management, and research communities can use to help balance both the risks and benefits associated with flooding. The variations in overbank flow from rivers onto floodplains from regional to continental scales are understudied. Here, the authors investigate this variation as a function of hydroclimatic parameters and channel size in the conterminous U.S. and find that the timing of floodplain inundation is largely controlled by regional factors, while the frequency, duration and magnitude of these inundations vary consistently with channel size.

Non‐perennial streams, which lack year‐round flow, are widespread globally. Identifying the sources of water that sustain flow in non‐perennial streams is necessary to understand their potential impacts on downstream water resources, and guide water policy and management. Here, we used water isotopes (δ18O and δ2H) and two different modeling approaches to investigate the spatiotemporal dynamics of young water fractions (Fyw) in a non‐perennial stream network at Konza Prairie (KS, USA) during the 2021 summer dry‐down season, as well as over several years with varying hydrometeorological conditions. Using a Bayesian model, we found a substantial amount of young water (Fyw: 39.1–62.6%) sustained flows in the headwaters and at the catchment outlet during the 2021 water year, while 2015–2022 young water contributions estimated using sinusoidal models indicated smaller Fyw amounts (15.3% ± 5.7). Both modeling approaches indicate young water releases are highly sensitive to hydrological conditions, with stream water shifting to older sources as the network dries. The shift in water age suggests a shift away from rapid fracture flow toward slower matrix flow that creates a sustained but localized surface water presence during late summer and is reflected in the annual dynamics of water age at the catchment outlet. The substantial proportion of young water highlights the vulnerability of non‐perennial streams to short‐term hydroclimatic change, while the late summer shift to older water reveals a sensitivity to longer‐term changes in groundwater dynamics. Combined, this suggests that local changes may propagate through non‐perennial stream networks to influence downstream water availability and quality. Plain Language Summary Non‐perennial streams, which periodically dry, are common worldwide. Identifying the origin and age of water in non‐perennial streams will help guide water policy and management strategies. We used water isotopes (δ18O and δ2H), a common hydrologic tracer, to identify stream water sources and age during the 2021 summer dry‐down period of a non‐perennial watershed at the Konza Prairie (KS, USA) with two different statistical methods. We found that water sources and flow paths changed as the stream network dried. Approximately half of summer streamflow is young water, meaning it took less than 3 months to travel from precipitation to the stream. However, as the summer progressed, stream water shifted to older sources. We interpret this shift in the water age to indicate a shift in the source of water from rapid flow paths early in the summer to slower flow paths later in the summer, which sustain localized surface water during the driest parts of the year. Taken together, the substantial amount of young water highlights the vulnerability of non‐perennial streams to short‐term weather changes and longer‐term changes in groundwater dynamics that can alter the quantity and quality of water flowing through non‐perennial stream networks to ultimately influence downstream water availability and quality. Key Points Stream isotopic composition was progressively enriched in δ18O and δ2H as the stream network dried Stream isotopic enrichment is caused by evaporative effects and a decrease in surface water connectivity Most streamflow was young water (stored in the subsurface <3 months), with older and more variable water age as the stream network dried