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Roads are believed to be a major contributing factor to the ongoing spread of exotic plants. We examined the effect of road improvement and environmental variables on exotic and native plant diversity in roadside verges and adjacent semiarid grassland, shrubland, and woodland communities of southern Utah (U.S.A.). We measured the cover of exotic and native species in roadside verges and both the richness and cover of exotic and native species in adjacent interior communities (50 m beyond the edge of the road cut) along 42 roads stratified by level of road improvement ( paved, improved surface, graded, and four-wheeldrive track). In roadside verges along paved roads, the cover of Bromus tectorum was three times as...
Projecting the effects of climate change on plant distribution and abundance is critical for regional and landscape‐scale prioritization of natural resource management. For invasive plants in particular, projections of future invasion risk with climate change can inform early detection and rapid response (EDRR) efforts, listing status of species as noxious weeds, acquisition of land for conservation, and targets for ecological restoration. Although there have been significant recent advances made in the areas of 1) climate forecasting, 2) habitat niche modeling, 3) mechanistic modeling and 4) observational networks, these approaches must be integrated and inter‐compared for more robust management prioritization....
This document was created in order to detail installation instructions and use of the National Land Cover Dataset (NLCD) Mapping Tool designed, by MDA Federal, Inc., for the United States Geological Survey. All rights to this software are held by the USGS. The tools described in this document were developed for use within the ERDAS Imagine 8.7 software environment, and are for use with the Rulequest Research Cubist and See5/C5.0 software packages above version 1.12 of cubist, and above version 1.18 of see5. The software executables were compiled using the Imagine Toolkit 8.7 and Microsoft Visual C++ 6.0.
INDUCED SEISMICITY POTENTIAL AND ENERGY TECHNOLOGIES, credited to Hitzman, M, published in 2012. Published in The National Academy of Sciences http://www. nap. …, in 2012.
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: The National Academy of Sciences http://www. nap. …
Although tropical forests account for only a fraction of the planet's terrestrial surface, they exchange more carbon dioxide with the atmosphere than any other biome on Earth, and thus play a disproportionate role in the global climate. In the next 20 years, the tropics will experience unprecedented warming, yet there is exceedingly high uncertainty about their potential responses to this imminent climatic change. Here, we prioritize research approaches given both funding and logistical constraints in order to resolve major uncertainties about how tropical forests function and also to improve predictive capacity of earth system models. We investigate overall model uncertainty of tropical latitudes and explore the...
Categories: Publication;
Types: Citation
In this study, we analyzed the above-ground biomass data for 631 trees with a diameter ⩾10 cm from different biogeographical regions in Colombia. The aims of this research were (1) to evaluate the accuracy of the most commonly employed pantropical allometric models for the estimation of above-ground biomass of natural forests in different sites located along a complex environmental gradient, (2) to develop new models that enable more precise estimations of current carbon stores in the above-ground biomass of natural forest ecosystems in Colombia, and (3) to evaluate the effect on allometric models of forest type classifications as determinants of above-ground biomass variation. The Brown et al. (1989) model for...
Categories: Publication;
Types: Citation
Categories: Publication;
Types: Citation
Changes in the composition, structure, and functions of forest ecosystems typically occur over long periods of time. In the Pacific Northwest region of the United States, for example, it is not unusual for individual dominant trees to survive for 500 years or longer (Franklin and Dyrness, 1973; Waring and Franklin, 1979). Significant compositional and structural changes may continue to occur 750 years after a stand-initiating disturbance (Franklin and Spies, 1991). Documenting and understanding these changes requires a variety of approaches. At least five complementary approaches have been taken to increase, scientific understanding of these intrinsically slow changes: chronosequences (Pickett, 1989); palynology...
Categories: Publication;
Types: Citation
Grouping of citation references used by the Powell Center Working Group, titled: Characterizing a link in the terrestrial carbon cycle: a global overview of individual tree mass growth. These citation references were used to derive data for the dataset titled: Fitted parameters for the relationship between mass growth rate and the natural log of tree size (available at: https://www.sciencebase.gov/catalog/item/523ae759e4b08cabd166cbf7).
Dam removal is becoming an increasingly important component of river restoration, with > 1100 dams having been removed nationwide over the past three decades. Despite this recent progression of removals, the lack of pre- to post-removal monitoring and assessment limits our understanding of the magnitude, rate, and sequence of geomorphic and/or ecological recovery to dam removal. Taking advantage of the November 2012 removal of an old (~ 190 year-old) 6-m high, run-of-river industrial dam on Amethyst Brook (26 km 2) in central Massachusetts, we identify the immediate eco-geomorphic responses to removal. To capture the geomorphic responses to dam removal, we collected baseline data at multiple scales, both upstream...
Categories: Publication;
Types: Citation
The impacts of nitrogen (N) deposition on plant diversity loss have been well documented across N deposition gradients in Europe, but much less so in the U.S. Published N fertilizer studies suggest losses will occur in the US, but many of these were done at levels of N input that were higher than modeled and measured N deposition, and higher than presumed N critical loads. The recent availability of modeled N deposition across the U.S. (e.g. using CMAQ) has provided a high‐resolution tool to identify regions where steep N deposition gradients facilitate detection of ecological shifts. A number of plant diversity (richness plus abundance) data sets across the U.S. have explained diversity shifts based on anthropogenic...
Fluid injection induced seismicity has been reported since the 1960s. There are currently more than 150,000 injection wells associated with oil and gas production in 34 states in the conterminous US. Pore pressure disturbance caused by injection is generally considered the culprit for injection induced seismicity, but, not all injection causes seismicity. It is not well understood what mechanical and hydrologic conditions cause some sites to be more prone than others to seismicity. The objectives of this proposed research are to utilize existing data on fluid injection and seismicity to (1) identify spatial and temporal correlations between fluid injection and induced seismicity; (2) conduct a hydro-mechanical modeling...
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Energy and Minerals,
Natural Hazards,
Seismicity,
Summary Changes in tropical forest carbon sink strength during El Niño Southern Oscillation (ENSO) events can indicate future behavior under climate change. Previous studies revealed ˜6 Mg C ha-1 yr-1 lower net ecosystem production (NEP) during ENSO year 1998 compared with non-ENSO year 2000 in a Costa Rican tropical rainforest. We explored environmental drivers of this change and examined the contributions of ecosystem respiration (RE) and gross primary production (GPP) to this weakened carbon sink. For 1998-2000, we estimated RE using chamber-based respiration measurements, and we estimated GPP in two ways: using (1) the canopy process model MAESTRA, and (2) combined eddy covariance and chamber respiration data....
Categories: Publication;
Types: Citation
Managers make decisions regarding if and how to remove dams in spite of uncertainty surrounding physical and ecological responses, and stakeholders often raise concerns about certain negative effects, regardless of whether these concerns are warranted at a particular site. We used a dam-removal science database supplemented with other information sources to explore seven frequently raised concerns, herein Common Management Concerns (CMCs). We investigate the occurrence of these concerns and the contributing biophysical controls. The CMCs addressed are the following: degree and rate of reservoir sediment erosion, excessive channel incision upstream of reservoirs, downstream sediment aggradation, elevated downstream...
Categories: Publication;
Types: Citation
Increasing nitrogen concentrations in the world’s major rivers have led to over-fertilization of sensitive downstream waters. Flow through channel bed and bank sediments acts to remove riverine nitrogen through microbe-mediated denitrification reactions. However, little is understood about where in the channel network this biophysical process is most efficient, why certain channels are more effective nitrogen reactors, and how management practices can enhance the removal of nitrogen in regions where water circulates through sediment and mixes with groundwater-hyporheic zones. Here we present numerical simulations of hyporheic flow and denitrification throughout the Mississippi River network using a hydrogeomorphic...
Categories: Publication;
Types: Citation
Comprehensive, published, and publicly available data regarding the extent, location, and character of hydraulic fracturing in the United States are scarce. The objective of this data series is to publish data related to hydraulic fracturing in the public domain. The spreadsheets released with this data series contain derivative datasets aggregated temporally and spatially from the commercial and proprietary IHS database of U.S. oil and gas production and well data (IHS Energy, 2011). These datasets, served in 21 spreadsheets in Microsoft Excel (.xlsx) format, outline the geographical distributions of hydraulic fracturing treatments and associated wells (including well drill-hole directions) as well as water volumes,...
Categories: Publication;
Types: Citation
Unconventional oil and gas production provides a rapidly growing energy source; however, high-production states in the United States, such as Oklahoma, face sharply rising numbers of earthquakes. Subsurface pressure data required to unequivocally link earthquakes to injection are rarely accessible. Here we use seismicity and hydrogeological models to show that fluid migration from high-rate disposal wells in Oklahoma is potentially responsible for the largest swarm. Earthquake hypocenters occur within disposal formations and upper-basement, between 2-5 km depth. The modeled fluid pressure perturbation propagates throughout the same depth range and tracks earthquakes to distances of 35 km, with a triggering threshold...
Myriad field, laboratory, and modeling studies show that nutrient availability plays a fundamental role in regulating CO 2 exchange between the Earth's biosphere and atmosphere, and in determining how carbon pools and fluxes respond to climatic change. Accordingly, global models that incorporate coupled climate-carbon cycle feedbacks made a significant advance with the introduction of a prognostic nitrogen cycle. Here we propose that incorporating phosphorus cycling represents an important next step in coupled climate-carbon cycling model development, particularly for lowland tropical forests where phosphorus availability is often presumed to limit primary production. We highlight challenges to including phosphorus...
Categories: Publication;
Types: Citation
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