112 research outputs found

    Experimental chronic noise is related to elevated fecal corticosteroid metabolites in lekking male greater Sage-Grouse (Centrocercus urophasianus).

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    There is increasing evidence that individuals in many species avoid areas exposed to chronic anthropogenic noise, but the impact of noise on those who remain in these habitats is unclear. One potential impact is chronic physiological stress, which can affect disease resistance, survival and reproductive success. Previous studies have found evidence of elevated stress-related hormones (glucocorticoids) in wildlife exposed to human activities, but the impacts of noise alone are difficult to separate from confounding factors. Here we used an experimental playback study to isolate the impacts of noise from industrial activity (natural gas drilling and road noise) on glucocorticoid levels in greater sage-grouse (Centrocercus urophasianus), a species of conservation concern. We non-invasively measured immunoreactive corticosterone metabolites from fecal samples (FCMs) of males on both noise-treated and control leks (display grounds) in two breeding seasons. We found strong support for an impact of noise playback on stress levels, with 16.7% higher mean FCM levels in samples from noise leks compared with samples from paired control leks. Taken together with results from a previous study finding declines in male lek attendance in response to noise playbacks, these results suggest that chronic noise pollution can cause greater sage-grouse to avoid otherwise suitable habitat, and can cause elevated stress levels in the birds who remain in noisy areas

    Effects of Experimentally Elevated Traffic Noise on Nestling White-Crowned Sparrow Stress Physiology, Immune Function and Life History

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    Roads have been associated with behavioral and physiological changes in wildlife. In birds, roads decrease reproductive success and biodiversity and increase physiological stress. Although the consequences of roads on individuals and communities have been well described, the mechanisms through which roads affect birds remain largely unexplored. Here, we examine one mechanism through which roads could affect birds: traffic noise. We exposed nestling mountain white-crowned sparrows (Zonotrichia leucophrys oriantha) to experimentally elevated traffic noise for 5 days during the nestling period. Following exposure to traffic noise we measured nestling stress physiology, immune function, body size, condition and survival. Based on prior studies, we expected the traffic noise treatment to result in elevated stress hormones (glucocorticoids), and declines in immune function, body size, condition and survival. Surprisingly, nestlings exposed to traffic noise had lower glucocorticoid levels and improved condition relative to control nests. These results indicate that traffic noise does affect physiology and development in white-crowned sparrows, but not at all as predicted. Therefore, when evaluating the mechanisms through which roads affect avian populations, other factors (e.g. edge effects, pollution and mechanical vibration) may be more important than traffic noise in explaining elevated nestling stress responses in this species

    Recommended management strategies to limit anthropogenic noise impacts on greater sage-grouse in Wyoming

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    Recent research has demonstrated that noise from natural gas development negatively impacts sage-grouse (Centrocercus urophasianus) abundance, stress levels, and behaviors. Other types of anthropogenic noise sources are similar to gas-development noise and, thus, the response by sage-grouse is likely to be similar. The results of research suggest that effective management of the natural soundscape is critical to the conservation and protection of sage-grouse. The goals of this review are to discuss current approaches in the management of new and existing noise sources in Wyoming and recommend research priorities for establishing effective noise management strategies. We make 4 interim recommendations: (1) that noise-management objectives should be set relative to typical ambient noise levels in sage-grouse habitat before development; the best currently available measuremenet of residual noise levels levels (L90) in undisturbed areas suggest an ambient level of 16 to 20 dBA; (2) that an increase in median noise levels (L50) of 10 dBA above ambient be allowed; (3) that management strategies be expanded to protect the soundscape in areas critical for mating, foraging, nesting, and brood-rearing activities of sage-grouse, rather than protecting the lek area alone; and (4) management strategies be focused on the siting of roads or limiting of traffic volumes during crucial times of the day (0600 to 0900 hours) and season (i.e., breeding season), rather than setting targets for vehicle noise exposure. Roads should be sited or traffic should be seasonally limited within 1.3 to 1.7 km from the edge of critical areas for nesting, foraging and breeding. We emphasize that protections based on these interim recommendations may need to be revised upon completion of ongoing and future research

    What are Employers Looking for in New Veterinary Graduates? A Content Analysis of UK Veterinary Job Advertisements

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    As veterinary educators, we have a responsibility to ensure that our graduates are prepared for working life. Veterinary practices, like any other businesses, rely on good employees, and the implications of a poor match between newly employed veterinarian and employing practice could be extremely costly in terms of personal well-being and enjoyment of work as well as the time, financial, and goodwill costs of high staff turnover for the practice. Contemporary veterinary curricula encompass a range of teaching to complement the clinical content; including communication, teamwork, problem solving, and business skills, to support good practice and increase the employability of new graduates. Previous studies have examined the qualities required of early career veterinarians as viewed by educators, recent graduates, pet owners, and practitioners; however, nobody has previously constructed a picture of the employment market for new veterinary graduates by exploring the nature of its recruitment advertising. Three months of UK veterinary job advertisements were examined. Content analysis yielded 10 distinct characteristics desired by employers of early career veterinarians. The most common by far was “enthusiasm,” followed by an interest in a particular area of practice, being an “all-rounder” (i.e., having a broad range of skills), demonstrating good communication skills, teamwork, client care, and independence, as well as being caring, ambitious, and having high clinical standards. While several of these qualities are expected and are specifically taught in veterinary school, the dominance of “enthusiasm” as a specifically desired trait raises interesting questions about the characteristics of veterinary students who we are supporting, encouraging, or maybe even suppressing, during veterinary training

    Acoustic risk balancing by marine mammals : anthropogenic noise can influence the foraging decisions by seals

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    Funding: Natural Environment Research Council (Grant Number(s): NE/J004251/1, NE/R015007/1)1. Avoidance of anthropogenic sounds has been measured in many species. The results, which are typically based on observations in limited exposure contexts, are frequently used to inform policy and the regulation of industrial activities. However, the occurrence and magnitude of avoidance may be a consequence of complex risk-balancing decisions made by animals. The importance of the factors in decision-making, such as perceived risks associated with the sounds or prey quantity and quality during sound exposure, is unknown. 2. Here we address this knowledge gap by measuring the relative influence of perceived –risk of a sound (silence, pile driving, and a tidal turbine) and prey patch quality on decision-making and foraging success in grey seals Halichoerus grypus. 3. Seals were given access to two underwater ‘prey patches’ in an experimental pool where fish were delivered at controlled rates to simulate a low-density (LD) and a high-density (HD) prey patch. Acoustic playbacks were made using an underwater speaker above one of the prey patches (randomised during the study), and three decision and foraging metrics (foraging duration, foraging effort allocation between the prey patches, and foraging success) were measured. 4. Foraging success was highest during silent controls and was similar regardless of speaker location (LD/HD). Under the tidal turbine and pile-driving treatments, foraging success was similar to the controls when the speaker was located at the HD prey patch but was significantly reduced (~16%–28% lower) when the speaker was located at the LD prey patch. Foraging decisions by the seals were consistent with a risk/profit balancing approach. Avoidance rates depend on the quality of the prey patch as well as the perceived risk. 5. Policy implications. The results suggest that foraging context is important when interpreting avoidance behaviour and should be considered when predicting the effects of anthropogenic activities. For example, sound exposure in different prey patch qualities may result in markedly different avoidance behaviour, potentially leading to contrasting predictions of impact in Environmental Assessments. We recommend future studies explicitly consider foraging context, and other contextual factors such as behavioural state (e.g. foraging or travelling) and habitat quality.Publisher PDFPeer reviewe

    Nanomaterials in the Environment: Behavior, Fate, Bioavailability, and Effects-An Updated Review.

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    This review covers developments in studies of nanomaterials (NMs) in the environment, since the much-cited review of Klaine et al. (2008). It discusses novel insights on fate and behavior, metrology, transformations, bioavailability, toxicity mechanisms and environmental impacts, with a focus on terrestrial and aquatic systems. Overall the findings were that: i) despite the substantial developments, there remain critical gaps, in large part due to the lack of analytical, modelling and field capabilities and in part due to the breadth and complexity of the area; ii) a key knowledge gap is the lack of data on environmental concentrations and dosimetry generally; iii) there is substantial evidence that there are nano-specific effects (different from both ions and larger particles) in the environment in terms of fate, bioavailability and toxicity, but this is not consistent for all NMs, species and all relevant processes; iv) a paradigm is emerging that NMs are less toxic than equivalent dissolved materials but more toxic than the corresponding bulk materials; v) translation of incompletely understood science into regulation and policy continues to be challenging. There is a developing consensus that NMs may pose a relatively low environmental risk, however, with the uncertainty and lack of data in many areas, definitive conclusions cannot be drawn. In addition, this emerging consensus will likely change rapidly with qualitative changes in the technology and increased future discharges. This article is protected by copyright. All rights reserved

    Synthesis and Electrochemical Characterization of Layered Oxides for Aqueous Energy Storage

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    Energy storage devices are quickly becoming a major requirement for human society, especially with the advancement of renewable energy and the rise of electric cars. However, current energy storage technologies can be dangerous, environmentally unfriendly, and expensive. Li-ion batteries, the most common rechargeable energy storage devices used commercially, utilize flammable electrolytes and in some cases toxic electrode materials. In order to overcome these drawbacks, new rechargeable energy storage devices are being investigated. One such technology that can address many of these issues is an aqueous-based energy storage device. These energy storage systems use water as the electrolyte solvent rather than expensive, environmentally hazardous, and flammable organic compounds. Aqueous energy storage devices tend to exhibit pseudocapacitance, and because of this, are often called "pseudocapacitors." Pseudocapacitance is a form of energy storage behavior that may exhibit both surface or near-surface reactions as well as some form of intercalation mechanism. Unlike typical battery intercalation reactions, pseudocapacitive storage is not limited by the diffusion of intercalating species. The focus of this thesis research is on the effect of structure and composition of layered transition metal oxide electrodes on their intercalation-based pseudocapacitive properties in aqueous systems Chemically preintercalated vanadium oxide (δ-MxV2O5, M = Li, Na, K, Mg, and Ca), which has been previously studied in non-aqueous Li-, Na-, and K-ion batteries, was investigated for its aqueous pseudocapacitive capabilities. First, the effect of post synthesis treatments on the initial capacitance and capacitance retention of δ-NaxV2O5 samples was investigated in order to identify the treatment combination leading to the highest performance. It was found that δ-NaxV2O5 samples that were aged and hydrothermally treated demonstrated the highest initial capacitance values of 230 F/g while samples that were aged and vacuum annealed exhibited the best capacitance retentions (68% after 50 cycles). The aged and hydrothermally treated and the aged and annealed post-synthesis treatment combinations were used on all five preintercalated δ-MxV2O5, materials (M = Li, Na, K, Mg, and Ca) and the effect of preintercalated ion on pseudocapacitive performance was studied. For all five phases, and a pH study was conducted to investigate the relationship between electrolyte pH and vanadium oxide stability in aqueous electrolyte. It was found that by lowering the pH from 6.67 to 2.35, an increase in capacitance retention of up to 35% and an increase in initial capacitance of 39 F/g could be achieved. The best initial capacity of 214 F/g observed was for aged and annealed δ-CaxV2O5 at a pH of 2.35. The highest capacity retention observed was 96.1 % for aged and hydrothermally treated of δ-LixV2O5 ¬at a pH of 2.35. The second part of this master's research was focused on the adaptation of the chemical preintercalation method developed in the Materials Science and Engineering group at Drexel for the fabrication of new layered transition metal oxides beyond vanadium oxide. For the first time, a novel family of layered tungsten oxides (MxWO3·nH2O, M= Na, K, Mg, and Ca) was synthesized. Na0.2WO3·0.8H2O phase demonstrated an initial capacitance of 60 F/g in an aqueous-based 1M H2SO4 electrolyte. Also, a pressure induced color change phenomenon was observed.M.S., Materials Science and Engineering -- Drexel University, 201

    The effects of anthropogenic noise on Greater Sage-Grouse ( Centrocercus urophasianus) lek attendance, communication, and behavior

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    Noise associated with human activity is widespread and expanding rapidly in terrestrial environments, but there is still much to learn about its effects on animals. To determine the effect of introduced noise on lek attendance and strutting behavior, I played back recorded continuous and intermittent anthropogenic sounds associated with natural gas drilling and roads at leks of Greater Sage-Grouse (Centrocercus urophasianus). For 3 breeding seasons, I monitored sage-grouse abundance at leks with and without noise. Peak male attendance (i.e., abundance) at leks experimentally treated with noise from natural gas drilling and roads decreased 29% and 73% respectively relative to paired controls. Decreases in abundance at leks treated with noise occurred in the first year of the study and were sustained throughout the experiment. There was limited evidence for an effect of noise playback on peak female attendance during the experiment or on male attendance the year after the experiment ended. These results suggest that sage-grouse avoid leks with anthropogenic noise and that intermittent noise has a greater effect on attendance than continuous noise. To quantify the potential for noise from natural gas infrastructure to mask sage-grouse vocalizations over both long and short distances, I analyzed both the individual notes of mating vocalizations produced by male sage-grouse and recordings of such noise. Noise produced by natural gas infrastructure is predicted to mask sage-grouse vocalizations substantially, reducing the active space of detection and discrimination of all vocalization components, particularly impacting notes that are low frequency and low amplitude. Such masking could increase the difficulty of mate assessment for lekking sage-grouse. Significant impacts to sage-grouse populations have been measured at noise levels that predict little to no masking. I investigated whether male sage-grouse adjust the repetition and timing of their strut displays in response to playback of noise associated with natural gas development. I compared the signaling behavior of male sage-grouse on leks with long-term drilling and road noise playback to that of males on similar leks with no noise playback. Males exposed to long-term drilling noise playback strutted at higher rates and in longer bouts than males on control leks, while males on road noise leks strutted at lower rates and in shorter bouts than males on control leks; these differences were only observed during close courtship, when strut rate is most important in influencing female mate choice. I did a short-term playback of intermittent traffic noise and compared the strut timing of individuals during noisy and quiet periods. Males performed fewer struts overall during noisy periods, but male strutting behavior was related to female proximity. Males that were not closely approached by females strutted less during noisy periods than quiet periods and males that engaged in close courtship with females strutted at similar rates during noisy and quiet periods, even when females were far away. Introduced noise associated with natural gas development causes large declines in sage-grouse lek attendance and is likely to cause substantial masking of sage-grouse vocalizations. However, masking is not likely to be the only mechanism of noise impact on this species. Sage-grouse may at least partially reduce masking impacts through behavioral plasticity, adjusting the timing of their signals in a manner that may reduce the impacts of masking on communication
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