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This dataset is the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3800 observations representing 27 temperature manipulation studies, spanning nine biomes and nearly two decades of warming experiments. Data for this study were obtained from a combination of unpublished data and published literature values. We find that although warming increases soil respiration rates, there is limited evidence for a shifting respiration response with experimental warming. We also note a universal decline in the temperature sensitivity of respiration at soil temperatures >25°C. This dataset includes 3817 observations, from control (n=1812), first (i.e., lowest or sole) level...
Categories: Data,
Publication;
Types: Citation;
Tags: Boreal Forest,
Desert,
Ecology,
Meadow,
Northern Shrubland,
Summary 1. Metabolic scaling theory predicts that diameter growth rates of tree species are related to tree diameter by a universal scaling law. This model has been criticised because it ignores the influence of competition for resources such as light on the scaling of demographic rates with size. 2. We here test whether scaling exponents of abundant tropical tree species comply with the prediction of metabolic scaling theory and evaluate whether the scaling of growth with size depends on light availability. Light reaching each individual tree was estimated from yearly vertical censuses of canopy density, and a hierarchical Bayesian approach allowed quantifying confidence intervals for scaling exponents and accounting...
It is well know that every earthquake can spawn others (e.g., as aftershocks), and that such triggered events can be large and damaging, as recently demonstrated by L’Aquila, Italy and Christchurch, New Zealand earthquakes. In spite of being an explicit USGS strategic-action priority (http://pubs.usgs.gov/of/2012/1088; page 32), the USGS currently lacks an automated system with which to forecast such events and official protocols for disseminating the potential implications. This capability, known as Operational Earthquake Forecasting (OEF), could provide valuable situational awareness to emergency managers, the public, and other entities interested in preparing for potentially damaging earthquakes. With the various...
Categories: Data,
Project;
Tags: Active,
All Working Groups,
California,
Earthquakes,
Natural Hazards
There has been increasing attention placed on the need for water availability information at ungauged locations, particularly related to balancing human and ecological needs for water. Critical to assessing water availability is the necessity for daily streamflow time series; however, most of the rivers in the United States are ungauged. This proposal leverages over $1M currently allocated to the USGS National Water Census Program towards developing an integrated modeling approach to estimate daily streamflow at ungauged locations, with the ultimate goal of providing daily streamflow estimates at 160,000 ungauged catchments across the United States. By assembling a diverse and prolific group of international scientists,...
A nested sampling network on the Colorado (CR) and Missouri Rivers (MR) provided data to assess impacts of large-scale reservoir systems and climate on carbon export. The Load Estimator (LOADEST) model was used to estimate both dissolved inorganic and organic carbon (DIC and DOC) fluxes for a total of 22 sites along the main stems of the CR and MR. Both the upper CR and MR DIC and DOC fluxes increased longitudinally, but the lower CR fluxes decreased while the lower MRs continued to increase. We examined multiple factors through space and time that help explain these flux patterns. Seasonal variability in precipitation and temperature, along with site-level concentration versus discharge relationships proved to...
Migratory species support ecosystem process and function in multiple areas, establishing ecological linkages between their different habitats. As they travel, migratory species also provide ecosystem services to people in many different locations. Previous research suggests there may be spatial mismatches between locations where humans use services and the ecosystems that produce them. This occurs with migratory species, between the areas that most support the species' population viability - and hence their long-term ability to provide services - and the locations where species provide the most ecosystem services. This paper presents a conceptual framework for estimating how much a particular location supports the...
Advancing our mechanistic understanding of ecosystem responses to climate change is critical to improve ecological theories, develop predictive models to simulate ecosystem processes, and inform sound policies to manage ecosystems and human activities. Manipulation of temperature in the field, or the “ecosystem warming experiment,” has proved to be a powerful tool to understand ecosystem responses to changes in temperature. No comprehensive synthesis has been conducted since the last one more than 10 years ago. A new synthetic analysis is critically needed to advance our understanding of ecosystem responses to warming, to highlight experimental artifacts and appropriate interpretations, and to guide development...
Categories: Data,
Project;
Types: Downloadable,
GeoTIFF,
Map Service,
Raster;
Tags: Active,
All Working Groups,
Ecosystems,
Land Resources
Tropical forests contain > 50% of the world’s known species (Heywood 1995), 55% of global forest biomass (Pan et al. 2011), and exchange more carbon (C), water and energy with the atmosphere than any other ecosystem type (e.g., Saugier et al. 2001). Despite their importance, there is more uncertainty associated with predictions of how tropical forests will respond to warming than for any other biome (Randerson et al. 2009). This uncertainty is of global concern due to the large quantity of C cycled by these forests and the high potential for biodiversity loss. Given the importance of tropical forests, decision makers and land managers around the globe need increased predictive capacity regarding how tropical forests...
Categories: Data,
Project;
Types: Downloadable,
GeoTIFF,
Map Service,
Raster;
Tags: Active,
All Working Groups,
Climate,
Ecosystems,
Forests,
Special Issue Forward in Programmetric Engineering and Remote Sensing journal
Two recent earthquakes left their mark on Santiago de Chile and Tokyo, well beyond the rupture zones, raising questions about the future vulnerability of these and other cities that lie in seismically active regions. Though spared strong shaking, the megacities nevertheless lit up in small quakes, perhaps signaling an abrupt change in the condition for failure on the faults beneath the cities. To detect such changes in earthquake rate requires good seismic monitoring networks; to respond to such hazard increases with civic preparations requires good government.
Amphibian populations are declining globally at unprecedented rates but statistically rigorous identification of mechanisms is lacking. Identification of reasons underlying large-scale declines is imperative to plan and implement effective conservation efforts. Most research on amphibian population decline has focused on local populations and local factors. However, the ubiquity of declines across species and landscapes suggests that causal factors at a broader scale are also important. Elucidation of the mechanisms driving population change has lagged, mainly because data have been unavailable at continental scales. We propose to address this need by assembling data to answer questions about broad-scale drivers...
Categories: Data,
Project;
Types: Downloadable,
GeoTIFF,
Map Service,
Raster;
Tags: Active,
All Working Groups,
Amphibians,
Ecosystems,
Land Resources,
Abstract: In trying to mitigate natural hazards, society plays a high-stakes game against nature. Often nature surprises us when an earthquake, hurricane, or flood is bigger or has greater effects than expected from detailed natural hazard assessments. In other cases, nature outsmarts us, doing great damage despite expensive mitigation measures. These difficulties are illustrated by the March 2011 earthquake off Japan’s Tohoku coast. The earthquake was much larger than anticipated from hazard maps and generated a tsunami much larger than anticipated, which overtopped coastal defenses, causing more than 15,000 deaths and US$210 billion damage. Similar situations occur in predicting earthquake ground shaking (Stein...
Recruitment often varies substantially in fish populations, and residual variability may have serial autocorrelation due to environmental effects even after accounting for a stock-recruitment relationship. However, the likely magnitude of variability and autocorrelation in recruitment has yet to be formally estimated. We therefore developed a hierarchical model for recruitment variability and autocorrelation and applied it to data for 154 fish populations. Results were similar when using either the Ricker or Beverton-Holt stock-recruitment model, and showed that autocorrelated recruitment has a marginal standard deviation of 0.74 (SD = 0.35) and a mean autocorrelation of 0.43 (SD = 0.28) when predicting for an unobserved...
Abstract: "Alien grass invasions in arid and semi-arid ecosystems are resulting in grass-fire cycles and ecosystem-level transformations that severely diminish ecosystem services. Our capacity to address the rapid and complex changes occurring in these ecosystems can be enhanced by developing an understanding of the environmental factors and ecosystem attributes that determine resilience of native ecosystems to stress and disturbance, and resistance to invasion. Cold desert shrublands occur over strong environmental gradients and exhibit significant differences in resilience and resistance. They provide an excellent opportunity to increase our understanding of these concepts. Herein, we examine a series of linked...
Count data arise frequently in ecological analyses, but regularly violate the equi-dispersion constraint imposed by the most popular distribution for analyzing these data, the Poisson distribution. Several approaches for addressing overdispersion have been developed (e.g., negative-binomial distribution) but methods for including both underdispersion and overdispersion have been largely overlooked. We provide three specific examples drawn from life history theory, spatial ecology, and community ecology and illustrate the use of the Conway-Maxwell Poisson (CMP) distribution as compared to other common models for count data. We find that where equi-dispersion is violated, the CMP distribution performs significantly...
Headwater stream networks are considered heterogeneous riverscapes, but it is challenging to characterize spatial variability in demographic rates. We estimated site-scale (50 m) survival of adult (>age 1+) brook trout (Salvelinus fontinalis) within two intensively surveyed headwater stream networks by applying an open-population N-mixture approach to count data collected over two consecutive summers. The estimated annual apparent survival rate was 0.37 (95% CI: 0.28-0.46) in one network and 0.31 (95% CI: 0.15-0.45) in the other network. In both networks, trout survival was higher in stream sites characterized by more abundant pool habitats. Trout survival was negatively associated with mean depth in one network...
Approximately 44.1 million people (about 14 percent of the U.S. population) rely on domestic wells as their source of drinking water. Unlike community water systems, which are regulated by the Safe Drinking Water Act, there is no comprehensive national program for testing domestic well water to ensure that is it safe to drink. There are many activities, e.g., resource extraction, climate change-induced drought, and changes in land use patterns that could potentially affect the quality of the ground water source for domestic wells. The Health Studies Branch (HSB) of the National Center for Environmental Health, Centers for Disease Control and Prevention, created a Clean Water for Health Program to help address domestic...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Arsenic,
Conterminous United States,
Domestic wells,
Logistic models,
Water quality,
State-space estimation methods are increasingly used in ecology to estimate productivity and abundance of natural populations while accounting for variability in both population dynamics and measurement processes. However, functional forms for population dynamics and density dependence often will not match the true biological process, and this may degrade the performance of state-space methods. We therefore develop a Bayesian semi-parametric state-space model, which uses a Gaussian process (GP) to approximate the population growth function. This offers two benefits for population modeling. First, it allows data to update a specified 'prior' on the population growth function, while reverting to this prior when data...
Geographically Isolated Wetlands (GIWs) occur along gradients of hydrologic and ecological connectivity and isolation, even within wetland types (e.g., forested, emergent marshes) and functional classes (e.g., ephemeral systems, permanent systems, etc.). Within a given watershed, the relative positions of wetlands and open-waters along these gradients influence the type and magnitude of their chemical, physical, and biological effects on downgradient waters. In addition, the ways in which GIWs connect to the broader hydrological landscape, and the effects of such connectivity on downgradient waters, depends largely upon climate, geology, and relief, the heterogeneity of which expands with increasing scale. Developing...
Categories: Data,
Project;
Types: Downloadable,
GeoTIFF,
Map Service,
Raster;
Tags: Active,
All Working Groups,
Ecosystems,
Geographically isolated wetlands, depressional wetlands, perimeter,
Water,
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