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PubMed | University of Wisconsin - Madison, Northern Research Station, University of Colorado at Boulder, Western Ecological Research Center and 10 more.
Type: Journal Article | Journal: Proceedings of the National Academy of Sciences of the United States of America | Year: 2016

Atmospheric nitrogen (N) deposition has been shown to decrease plant species richness along regional deposition gradients in Europe and in experimental manipulations. However, the general response of species richness to N deposition across different vegetation types, soil conditions, and climates remains largely unknown even though responses may be contingent on these environmental factors. We assessed the effect of N deposition on herbaceous richness for 15,136 forest, woodland, shrubland, and grassland sites across the continental United States, to address how edaphic and climatic conditions altered vulnerability to this stressor. In our dataset, with N deposition ranging from 1 to 19 kg Nha(-1)y(-1), we found a unimodal relationship; richness increased at low deposition levels and decreased above 8.7 and 13.4 kg Nha(-1)y(-1) in open and closed-canopy vegetation, respectively. N deposition exceeded critical loads for loss of plant species richness in 24% of 15,136 sites examined nationwide. There were negative relationships between species richness and N deposition in 36% of 44 community gradients. Vulnerability to N deposition was consistently higher in more acidic soils whereas the moderating roles of temperature and precipitation varied across scales. We demonstrate here that negative relationships between N deposition and species richness are common, albeit not universal, and that fine-scale processes can moderate vegetation responses to N deposition. Our results highlight the importance of contingent factors when estimating ecosystem vulnerability to N deposition and suggest that N deposition is affecting species richness in forested and nonforested systems across much of the continental United States.

PubMed | Pacific Southwest Research Station, Bat Conservation International Austin, Wildlife Veterinary Consulting Fort Collins and Fort Collins Science Center
Type: Journal Article | Journal: Ecology and evolution | Year: 2015

Determining the detailed movements of individual animals often requires them to carry tracking devices, but tracking broad-scale movement of small bats (<30g) has been limited by transmitter technology and long-term attachment methods. This limitation inhibits our understanding of bat dispersal and migration, particularly in the context of emerging conservation issues such as fatalities at wind turbines and diseases. We tested a novel method of attaching lightweight global positioning system (GPS) tags and geolocating data loggers to small bats. We used monofilament, synthetic, absorbable sutures to secure GPS tags and data loggers to the skin of anesthetized big brown bats (Eptesicus fuscus) in Colorado and hoary bats (Lasiurus cinereus) in California. GPS tags and data loggers were sutured to 17 bats in this study. Three tagged bats were recaptured 7months after initial deployment, with tags still attached; none of these bats showed ill effects from the tag. No severe injuries were apparent upon recapture of 6 additional bats that carried tags up to 26days after attachment; however, one of the bats exhibited skin chafing. Use of absorbable sutures to affix small tracking devices seems to be a safe, effective method for studying movements of bats over multiple months, although additional testing is warranted. This new attachment method has the potential to quickly advance our understanding of small bats, particularly as more sophisticated miniature tracking devices (e.g., satellite tags) become available.

News Article | October 28, 2015

FILE- In this Aug. 6, 2009, file photo, bats take flight outside the Old Tunnel Wildlife Management Area near Fredericksburg, Texas. Researchers with the North American Bat Monitoring Program are conducting pilot acoustic surveys to detect the high-pitched frequencies emitted by the flying mammals to capture bugs in flight and navigate in the dark. (AP Photo/Harry Cabluck, File) More BOISE, Idaho (AP) — An effort spanning 31 states and 10 Canadian provinces has been working to better understand the ecological role that bats play, and the threats they face from climate change, habitat loss and wind energy development. The North American Bat Monitoring Program involves acoustic surveys to detect the high-pitched frequencies emitted by the flying mammals as they capture bugs and navigate in the dark. "It's long overdue," said Patty Stevens, the U.S. Geological Survey's branch chief for Trust Species and Habitats at the Fort Collins Science Center in Colorado where the program's data will be stored and made available. "It's going to provide a lot of information to natural resource managers." Researchers say the monitoring program has been spurred by a disease called white-nose syndrome that has killed millions of bats and is spreading. North America has some 150 species of bats, 47 of them in the United States. Some migrate more than 500 miles, and others hibernate in caves or abandoned mines. Less than a handful of bat species are well understood. "Most of our bats are very small, they fly at night, and they're very difficult to study," said Susan Loeb, a research ecologist with the U.S. Forest Service based in Clemson, South Carolina. "In the last 10, 20 years, we're getting better and better technology that allows us to learn about bats." For example, she said, acoustic monitoring of bats at one time involved carrying equipment on a vehicle. Now, she said, a device can be hooked up to an iPhone. Scientists are also trying to perfect software that can identify the species of bat making the sound. Loeb is the lead author of the U.S. Department of Agriculture's Plan for the North American Bat Monitoring Program that sets out the initial strategy. The plan relies heavily on acoustic monitoring that includes both mobile monitoring sites and stationary sites, with the number of sites varying by state as the program gets going. Idaho got off to a tough start this year after giant wildfires hindered efforts at about 10 sites, Loeb said. Researchers are using other methods as well, including counting hibernating bats in winter, and in summer doing maternity colony counts. In five years, Loeb said, researchers should have enough information to spot trends. "We know that many bat populations are declining, but we don't know the magnitude of that decline," she said. Information like that is important because bats are thought to be a key component in forest health, she said, due to their diet of insects. Not much information exists on bat insect consumption, but scientists estimate the Brazilian free-tailed bat colonies in Texas that often number more than a million individuals can consume more than 8 tons of insects in a night. Most North American bats eat insects, but there are some nectar-feeding bats that help pollinate plants. The iconic saguaro cactus in Arizona, for example, is pollinated by the lesser long-nosed bat and the Mexican long-tongued bat. A more recent threat to bats, scientists say, are wind farms, where an estimated 200,000 to 800,000 bats die annually in collisions with spinning blades. "We still don't know why bats are getting killed by these turbines," said Loeb. "Why can't they detect them? Are they attracted? And how do we deter them?" Scientists are trying to figure that out, and Loeb said clues might ultimately be found in the bat monitoring program. Meanwhile, scientists are also working to raise awareness of bats, coordinating much of those efforts leading up to Halloween with National Bat Week. Loeb herself is spending part of the week at a meeting of The North American Society for Bat Research. "Using Halloween as a means to engage people that bats aren't bad maybe one way to do it," Loeb said. "The public perception of bats is changing as people learn how important they are and how fascinating they are."

News Article | February 1, 2016

White-nose syndrome is a fungal disease of hibernating bats that has caused dramatic bat population declines in North America since 2007 – yet certain bats survive infection. The collaborative research was centered at Colorado State University as part of the postdoctoral fellowship of David Hayman, now at New Zealand's Massey University. While at CSU, Hayman was mentored by Colleen Webb, professor of biology in the College of Natural Sciences, as well as by Paul Cryan, a research biologist at the USGS Fort Collins Science Center, and Juliet Pulliam of the University of Florida. The researchers used a mathematical model integrating the effects of bat body size and metabolism with growth of the fungus across a range of winter temperature and humidity conditions. They then showed why some bats survive infection while others do not. The model found larger bats that hibernate in cold and dry sites might be the most likely to survive infection by the fungus. This finding fits with previous studies, which found high humidity and temperature in hibernation sites to be associated with bat death. The researchers also mapped their model results across North America and Europe to show differences in species mortality at continental scales – with European species surviving and North American species faring much worse. Hayman, now an infectious disease specialist and senior lecturer at Massey University's Institute of Veterinary, Animal and Biomedical Sciences, said this may have to do with behavioral adaptations as well as environmental factors. "Our study shows how interactions between fungal growth and the needs of hibernating bats can cause death during winter in warmer and more humid caves and mines," he said. "We speculate that the North American species of bats most affected by white-nose syndrome are confined to using wet hibernation sites where the fungus can thrive on their bodies. European bats may have also adapted physical and behavioral traits to survive hibernation in the presence of the fungus." CSU's Webb says the findings are of interest because bats play important ecological roles in most of our planet's ecosystems. "Because bats serve as the main predators of night-flying insects, such as moths and beetles, insect-eating bats are estimated to save farmers billions of dollars each year by providing natural pest suppression," Webb said. "The economic and ecological effects of bat populations declining in the wake of white-nose syndrome remain unknown." The practical implications of this research could include predicting species and populations most likely to decline due to white-nose syndrome, finding places where bats might survive the disease, and prioritizing protection of sites with the right conditions for survival. Co-author Cryan says "keeping a close eye on the survivors and the places they hang out may be our best chance of finding a good way to help." Hayman completed the work as part of a David H. Smith Conservation Research Fellowship. Disease ecology is a major area of focus for Webb's lab. She takes a modeling approach to understanding how highly virulent diseases, particularly zoonotic diseases that can affect humans, persist in wildlife reservoirs. "White nose syndrome is impacting only the bats, but we have done a lot of work with bat diseases that also affect humans," Webb said. "Bats have been hypothesized to be "special" hosts, in that they seem to host more highly dangerous, emerging diseases, such as SARS and Ebola." More information: D. T. S. Hayman et al. Environment, host, and fungal traits predict continental-scale white-nose syndrome in bats, Science Advances (2016). DOI: 10.1126/sciadv.1500831

Keith Barker F.,University of Minnesota | Oyler-Mccance S.,Fort Collins Science Center | Tomback D.F.,University of Colorado at Denver
Mitochondrial DNA | Year: 2015

Next generation sequencing methods allow rapid, economical accumulation of data that have many applications, even at relatively low levels of genome coverage. However, the utility of shotgun sequencing data sets for specific goals may vary depending on the biological nature of the samples sequenced. We show that the ability to assemble mitogenomes from three avian samples of two different tissue types varies widely. In particular, data with coverage typical of microsatellite development efforts (∼1×) from DNA extracted from avian blood failed to cover even 50% of the mitogenome, relative to at least 500-fold coverage from muscle-derived data. Researchers should consider possible applications of their data and select the tissue source for their work accordingly. Practitioners analyzing low-coverage shotgun sequencing data (including for microsatellite locus development) should consider the potential benefits of mitogenome assembly, including internal barcode verification of species identity, mitochondrial primer development, and phylogenetics. © 2013 Informa UK Ltd. All rights reserved: reproduction in whole or part not permitted.

Perry L.G.,Colorado State University | Perry L.G.,Fort Collins Science Center | Blumenthal D.M.,U.S. Department of Agriculture | Monaco T.A.,U.S. Department of Agriculture | And 2 more authors.
Oecologia | Year: 2010

Increased soil N availability may often facilitate plant invasions. Therefore, lowering N availability might reduce these invasions and favor desired species. Here, we review the potential efficacy of several commonly proposed management approaches for lowering N availability to control invasion, including soil C addition, burning, grazing, topsoil removal, and biomass removal, as well as a less frequently proposed management approach for lowering N availability, establishment of plant species adapted to low N availability. We conclude that many of these approaches may be promising for lowering N availability by stimulating N immobilization, even though most are generally ineffective for removing N from ecosystems (excepting topsoil removal). C addition and topsoil removal are the most reliable approaches for lowering N availability, and often favor desired species over invasive species, but are too expensive or destructive, respectively, for most management applications. Less intensive approaches, such as establishing low-N plant species, burning, grazing and biomass removal, are less expensive than C addition and may lower N availability if they favor plant species that are adapted to low N availability, produce high C:N tissue, and thus stimulate N immobilization. Regardless of the method used, lowering N availability sufficiently to reduce invasion will be difficult, particularly in sites with high atmospheric N deposition or agricultural runoff. Therefore, where feasible, the disturbances that result in high N availability should be limited in order to reduce invasions by nitrophilic weeds. © Springer-Verlag 2010.

Heath J.,Colorado State University | Baron J.S.,Colorado State University | Baron J.S.,Fort Collins Science Center
Aquatic Geochemistry | Year: 2014

Watershed mass-balance methods are valuable tools for demonstrating impacts to water quality from atmospheric deposition and chemical weathering. Owen Bricker, a pioneer of the mass-balance method, began applying mass-balance modeling to small watersheds in the late 1960s and dedicated his career to expanding the literature and knowledge of complex watershed processes. We evaluated long-term trends in surface-water chemistry in the Loch Vale watershed, a 660-ha. alpine/subalpine catchment located in Rocky Mountain National Park, CO, USA. Many changes in surface-water chemistry correlated with multiple drivers, including summer or monthly temperature, snow water equivalent, and the runoff-to-precipitation ratio. Atmospheric deposition was not a significant causal agent for surface-water chemistry trends. We observed statistically significant increases in both concentrations and fluxes of weathering products including cations, SiO2, SO4 2-, and ANC, and in inorganic N, with inorganic N being primarily of atmospheric origin. These changes are evident in the individual months June, July, and August, and also in the combined June, July, and August summer season. Increasingly warm summer temperatures are melting what was once permanent ice and this may release elements entrained in the ice, stimulate chemical weathering with enhanced moisture availability, and stimulate microbial nitrification. Weathering rates may also be enhanced by sustained water availability in high snowpack years. Rapid change in the flux of weathering products and inorganic N is the direct and indirect result of a changing climate from warming temperatures and thawing cryosphere. © 2013 The Author(s).

News Article | November 7, 2016

It’s no secret that wind power has experienced a boom in recent years, as demand for renewable energy sources grows. But while the technology is adept at helping curb greenhouse-gas emissions, the thousands of new turbines popping up around the globe do have some drawbacks. Wind farms have a long-documented history of killing hundreds of thousands of birds and bats each year. As it turns out, the bat toll may be higher than previously estimated. In a study published Monday, researchers in the United Kingdom found that environmental impact assessments — the main tool used to predict the ecological effects of a new energy development — commonly failed to predict the number of bats that would have fatal collisions with wind turbines’ spinning blades. Even in the few cases where researchers said early assessments accurately predicted the danger to bats, efforts to mitigate those risks often did not succeed. “The findings highlight the difficulty of establishing with certainty the effect of major developments before they occur,” co-author Fiona Mathews said in announcing the results, which were published in the journal Cell Press. [The nation’s first offshore wind farm is ready to go, despite critics’ blowback] Mathews, a mammalian biologist at the University of Exeter, and several colleagues surveyed 46 wind farms across the U.K. over the course of a month to estimate bat fatalities, relying heavily on search dogs to locate fallen bats. They then compared their findings from each site to the environmental assessments they were able to access. In most cases, the pre-construction assessments had not accurately predicted the risk of bat fatalities. And even where companies had put in place mitigation measures to try to steer bats clear of the turbines, the researchers found that bats were still killed. The reasons aren’t entirely clear. The researchers say it is uncertain whether the acoustic surveys widely used to estimate bat activity are not precise enough or whether bats’ “highly variable” activity means they change their patterns too often to predict with accuracy. “Bat activity recording during pre-construction surveys may not accurately reflect activity post-construction,” the authors write. “This may be due to bats changing their behavior at turbines, as bats may be attracted to wind farm sites for a variety of reasons, including the emission of ultrasound from turbines and increased prey availability.” [The surprising way that birds and wind turbines can coexist] In an in-depth article on the problem this year, Scientific American detailed how the wind industry had put in place voluntary guidelines to halt turbines at low wind speeds when bats are most active. Conservationists praised the move, even as some scientists said more needed to be done. Paul Cryan, a bat biologist with the U.S. Geological Survey, told the magazine he worries about the ongoing impact of turbines on bat populations, which are an essential link in certain ecosystems. “Bats are long-lived and very slow reproducers,” he said. “Their populations rely on very high adult survival rates. That means their populations recover from big losses very slowly.” USGS scientists at the Fort Collins Science Center in Colorado have built a research program aimed at investigating the causes and repercussions of bat fatalities at wind farms, with the goal of minimizing deaths over time even as wind energy proliferates. “We need to remember,” Mathews said, “that bats have been around for at least 30 million years and during that time have been able to fly happily without the risk of colliding with a spinning object.” Wind turbines are already huge, but they’re about to get way, way bigger Why companies like Google and Walmart are buying so much wind power

Dharmarajan G.,Purdue University | Dharmarajan G.,Indian Institute of Science | Beasley J.C.,Purdue University | Beasley J.C.,Savannah River Ecology Laboratory | And 4 more authors.
Animal Conservation | Year: 2014

Kin structure, the spatial aggregation of related individuals, impacts many processes important to conservation (e.g. inbreeding), and patterns of kin structure could be impacted by human-mediated habitat fragmentation and loss. While kin structure is expected to increase with habitat fragmentation (reduced connectivity), the effects of habitat loss (reduced resource availability) remain unclear. Disentangling the effects of habitat fragmentation and loss is challenging because they usually are spatially correlated, and because most species are negatively affected by both processes. Raccoons Procyon lotor is a model species to test how habitat loss affects kin structure because, although relatively unaffected by habitat fragmentation (because of high dispersal ability), they are negatively affected by habitat loss (forest-related resources being important for female reproductive success). To elucidate the causes and consequences of kin structure in raccoons, we utilized genetic and demographic data collected from 998 individuals trapped from 27 spatially distinct habitat patches (local populations) situated in an agricultural ecosystem. Our results highlight an important, but often ignored fact: structural connectivity does not necessarily predict functional dispersal patterns in natural populations. Thus, in raccoons, local populations with low kin structure were associated with high landscape disturbance (i.e. high levels of habitat loss and low connectivity), and were characterized by demographic instability (i.e. high immigration, emigration and/or mortality). Alternatively, local populations exhibiting high kin structure were associated with low landscape disturbance and high demographic stability (i.e. high natality and philopatry). We propose that such increased philopatry in resource-rich patches could lead to a functional isolation ('isolation by resource') exacerbating the negative effects of landscape modification because of isolation by distance and/or resistance, especially in species with low dispersal capability. Our results also indicate that high levels of genetic diversity may be associated with low (rather than high) patch quality because populations in such patches could be composed predominantly of (unrelated) immigrants. © 2013 The Zoological Society of London.

Allen K.E.,University of Georgia | Moore R.,University of Georgia | Moore R.,Fort Collins Science Center
Ecosystem Services | Year: 2016

There has been much discussion across the ecosystem services literature as to the role of economic valuation in identifying ecosystem service values and shaping policy. This article demonstrates a non-typical use of a nonmarket valuation technique known as the stated choice experiment (CE) for understanding a range of public preferences for stream-related ecosystem services in Macon County, NC. The experiment was carried out as part of the National Science Foundation funded Coweeta Long Term Ecological Research initiative, and it reflects an interdisciplinary attempt to produce knowledge regarding ecosystem service values that is of relevance to policy makers. The CE uses a split-sample design to test for the impact of mechanism of program implementation on respondent preferences and demonstrate a range of public willingness to pay (WTP) for stream health improvements. Responses are analyzed with a latent class logit and the results show that altering the mechanism of program implementation changes the latent class composition. Results also demonstrate consistent preferences for certain attributes of stream health, but WTP for ecosystem service provisioning varies widely with proposed program implementation. The use of the CE in this research demonstrates the flexibility of the tool for combining with interdisciplinary knowledge, as well as the usefulness of information provided by nonmarket valuation techniques for informing policy design. © 2016 Published by Elsevier B.V.

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