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101.
The drainage of abandoned mines leads to several ecological problems, particularly the acidification of surface freshwater systems and heavy metal contamination. In order to study the possibility of using the behavioural early warning responses of Portuguese indigenous benthic invertebrates to detect an acute short-term pulse of Acid Mine Drainage (AMD), experiments with the Multispecies Freshwater Biomonitor MFB™ were performed and locomotion and ventilation were measured as endpoints. AMD was collected from the “São Domingos” mine (Southeast Portugal) and the following species were selected: Echinogammarus meridionalis (Pinkster, 1973), Hydropsyche pellucidula (Curtis, 1834) and Choroterpes picteti (Eaton, 1870). For simulating the pulsed exposure, AMD was added to river water where invertebrates were collected and pH was lowered until reaching 3.5. The effects of H+ and heavy metals were discriminated using HCl positive controls. In addition to behaviour, mortality was registered. E. meridionalis was the most sensitive species in terms of mortality and behavioural endpoints, followed by C. picteti and H. pellucidula. E. meridionalis early warning responses consisted of increased locomotion with subsequent increase in ventilation, whereas for C. picteti only an increase in locomotion was observed. H. pellucidula showed no early warning responses. This work demonstrates the suitableness of using benthic invertebrates' behavioural early warning responses for detecting spikes of pollutants like AMD.  相似文献   
102.
With record-breaking tourist visits in Kenya in 2005–2006, communities near the country’s renowned protected areas must undertake or revisit planning efforts to conserve and enhance the region’s natural, social, and economic resources. This article examines the differences between two stakeholder groups in the Samburu region of central Kenya: (1) protected area leadership and staff; and (2) members of the communities adjacent to the protected areas. Based on the results and analysis of 30 in-depth interviews, the authors identify differences between protected area staff and their community members regarding perceptions about communication between the two groups, and the economic benefits of tourism. The different stakeholders agreed, however, about challenges related to equitable distribution of tourism-based employment and revenue. The results indicate a need to reach consensus about what constitutes sufficient communication between national reserves and their community, and to what extent tourism-related revenue and employment should be distributed within the region. A discussion of the potential role of indicators and standards to make such decisions is presented.  相似文献   
103.
Tetrachloroethene (PCE)‐ and trichloroethene (TCE)‐impacted sites pose significant challenges even when site characterization activities indicate that biodegradation has occurred naturally. Although site‐specific, regulatory, and economic factors play roles in the remedy‐selection process, the application of molecular biological tools to the bioremediation field has streamlined the assessment of remedial alternatives and allowed for detailed evaluation of the chosen remedial technology. The case study described here was performed at a PCE‐impacted site at which reductive dechlorination of PCE and TCE had led to accumulation of cis‐dichlorethene (cis‐DCE) with concentrations ranging from approximately 10 to 100 mg/L. Bio‐Trap® samplers and quantitative polymerase chain reaction (qPCR) enumeration of Dehalococcoides spp. were used to evaluate three remedial options: monitored natural attenuation, biostimulation with HRC®, and biostimulation with HRC‐S®. Dehalococcoides populations in HRC‐S‐amended Bio‐Traps deployed in impacted wells were on the order of 103 to 104 cells/bead but were below detection limits in most unamended and HRC‐amended Bio‐Traps. Thus the in situ Bio‐Trap study identified biostimulation with HRC‐S as the recommended approach, which was further evaluated with a pilot study. After the pilot HRC‐S injection, Dehalococcoides populations increased to 106 to 107 cells/bead, and concentrations of cis‐DCE and vinyl chloride decreased with concurrent ethene production. Based on these results, a full‐scale HRC‐S injection was designed and implemented at the site. As with the pilot study, full‐scale HRC‐S injection promoted growth of Dehalococcoides spp. and stimulated reductive dechlorination of the daughter products cis‐DCE and vinyl chloride. © 2008 Wiley Periodicals, Inc.  相似文献   
104.
In modern aquaculture, animal-production technology is used to increase aquatic food sources. Such controlled rearing of seafood can, in principle, shift the pressure off wild stocks and aquatic ecosystems by reducing fishing activities, which may advance marine conservation goals. We examined resource displacement—the reduced consumption of a resource due to its replacement with a more environmentally benign substitute—in fisheries. We employed panel regression techniques in an analysis of time-series data from 1970 through 2014 to assess the extent to which aquaculture production displaced fisheries captures for all nations for which data were available. We estimated 9 models to assess whether aquaculture production suppresses captures once other factors related to demand have been controlled for. Only 1 model predicted significant suppression of fisheries captures associated with aquaculture systems within nations over time. These results suggest that global aquaculture production does not substantially displace fisheries capture; instead, aquaculture production largely supplements fisheries capture.  相似文献   
105.
Current conservation templates prioritize biogeographic regions with high intensity ecosystem values, such as exceptional species richness or threat. Intensity-based targets are an important consideration in global efforts, but they do not capture all available opportunities to conserve ecosystem values, including those that accrue in low intensity over large areas. We assess six globally-significant ecosystem values—intact wilderness, freshwater availability, productive marine environments, breeding habitat for migratory wildlife, soil carbon storage, and latitudinal potential for range shift in the face of climate change—to highlight opportunities for high-impact broadly-distributed contributions to global conservation. Nations can serve as a cohesive block of policy that can profoundly influence conservation outcomes. Contributions to global ecosystem values that exceed what is predicted by a nation's area alone, can give rise to countries with the capacity to act as ‘conservation superpowers’, such as Canada and Russia. For these conservation superpowers, a relatively small number of national policies can have environmental repercussions for the rest of the world.  相似文献   
106.
Although deforestation and forest degradation have long been considered the most significant threats to tropical biodiversity, across Southeast Asia (Northeast India, Indochina, Sundaland, Philippines) substantial areas of natural habitat have few wild animals (>1 kg), bar a few hunting‐tolerant species. To document hunting impacts on vertebrate populations regionally, we conducted an extensive literature review, including papers in local journals and reports of governmental and nongovernmental agencies. Evidence from multiple sites indicated animal populations declined precipitously across the region since approximately 1980, and many species are now extirpated from substantial portions of their former ranges. Hunting is by far the greatest immediate threat to the survival of most of the region's endangered vertebrates. Causes of recent overhunting include improved access to forests and markets, improved hunting technology, and escalating demand for wild meat, wildlife‐derived medicinal products, and wild animals as pets. Although hunters often take common species, such as pigs or rats, for their own consumption, they take rarer species opportunistically and sell surplus meat and commercially valuable products. There is also widespread targeted hunting of high‐value species. Consequently, as currently practiced, hunting cannot be considered sustainable anywhere in the region, and in most places enforcement of protected‐area and protected‐species legislation is weak. The international community's focus on cross‐border trade fails to address overexploitation of wildlife because hunting and the sale of wild meat is largely a local issue and most of the harvest is consumed in villages, rural towns, and nearby cities. In addition to improved enforcement, efforts to engage hunters and manage wildlife populations through sustainable hunting practices are urgently needed. Unless there is a step change in efforts to reduce wildlife exploitation to sustainable levels, the region will likely lose most of its iconic species, and many others besides, within the next few years.  相似文献   
107.
For more than half a century, ecologists and historians have been integrating the contemporary study of ecosystems with data gathered from historical sources to evaluate change over broad temporal and spatial scales. This approach is especially useful where ecosystems were altered before formal study as a result of natural resources management, land development, environmental pollution, and climate change. Yet, in many places, historical documents do not provide precise information, and pre-historical evidence is unavailable or has ambiguous interpretation. There are similar challenges in evaluating how the fire regime of chaparral in California has changed as a result of fire suppression management initiated at the beginning of the 20th century. Although the firestorm of October 2003 was the largest officially recorded in California (approximately 300,000 ha), historical accounts of pre-suppression wildfires have been cited as evidence that such a scale of burning was not unprecedented, suggesting the fire regime and patch mosaic in chaparral have not substantially changed. We find that the data do not support pre-suppression megafires, and that the impression of large historical wildfires is a result of imprecision and inaccuracy in the original reports, as well as a parlance that is beset with hyperbole. We underscore themes of importance for critically analyzing historical documents to evaluate ecological change. A putative 100 mile long by 10 mile wide (160 x 16 km) wildfire reported in 1889 was reconstructed to an area of chaparral approximately 40 times smaller by linking local accounts to property tax records, voter registration rolls, claimed insurance, and place names mapped with a geographical information system (GIS) which includes data from historical vegetation surveys. We also show that historical sources cited as evidence of other large chaparral wildfires are either demonstrably inaccurate or provide anecdotal information that is immaterial in the appraisal of pre-suppression fire size. Since historical evidence is inadequate for reconstructing a statistical distribution of pre-suppression fire sizes to compare with post-suppression data, other more propitious methods of evaluating change are discussed.  相似文献   
108.
Previous research has shown that burnout in staff members at psychiatric hospitals is significantly associated with state anxiety and collegial support. The directionality of these relationships may be inferred using a cross-lagged panel design. To do this, 35 staff members representing various clinical disciplines completed measures of burnout, support, and anxiety twice, eight months apart. Burnout comprised three factors: emotional exhaustion, depersonalization, and personal accomplishment. Findings from one cross-lagged panel suggested that emotional exhaustion causes state anxiety. The second panel showed that lack of collegial support caused depersonalization. Understanding causes and effects of burnout for inpatient psychiatric staff may lead to training and resource development that will improve the quality of their work environment.  相似文献   
109.
ABSTRACT: Recent stream survey data (1989–1993) from 31 stream segments of 21 streams within the upper South Umpqua Watershed Oregon were compared to 1937 stream survey data collected from these same stream segments. Current low-flow wetted stream widths of 22 of the 31 surveyed stream segments were significantly different than in 1937; 19 stream segments were significantly wider while the remaining three stream segments were significantly narrower. In only 1 of 8 tributaries to the South Umpqua River which had headwaters within land designated wilderness area did low-flow stream channel width increase since 1937. Conversely, 13 of the 14 tributaries to the South Umpqua River which originated from lands designated as timber emphasis were significantly wider than in 1937. The observed change in stream width was linearly related to timber harvest (r2= 0.44), road density (r2= 0.45), and the amount of large organic debris remaining within the active stream channel (r2= 0.43). These findings suggest that timber harvest and road construction may have resulted in changes in channel characteristics. These channel changes may also be a factor in the observed decline of three of the four populations of anadromous salmonids within the basin.  相似文献   
110.
The synthetic growth-promoting hormones trenbolone and melengestrol acetate have been detected in the environment near beef cattle feedlots and are reportedly transported via wind-borne particulate matter. Therefore, movement of synthetic hormones from beef cattle feedlots to water bodies via particulate matter is possible. Our objective was to evaluate potential effects of 17α-trenbolone (17α-TB), melengestrol acetate (MGA), and combinations of both on growth, development, and survival of Xenopus laevis larvae. On post-hatch day 2 (stage 33/34), X. laevis larvae were exposed to three nominal concentrations of 17α-TB (10, 100, and 500 ng/L), MGA (1, 10, and 100 ng/L), a combination of both (1/10, 10/100, and 100/500 ng/L MGA/17α-TB), frog embryo teratogenesis assay-Xenopus medium, or a solvent control. Significant increases in all X. laevis growth metrics were observed among larvae in the 1 ng/L MGA?+?10 ng/L 17α-TB and 10 ng/L MGA?+?100 ng/L 17α-TB treatments. Stage of development was increased among larvae in the 1 ng/L MGA?+?10 ng/L 17α-TB treatment group and significantly decreased among those in the 500 ng/L 17α-TB treatment. Total body mass and snout–vent length of X. laevis larvae were significantly reduced in the 100 ng/L MGA and 100 ng/L MGA?+?500 ng/L 17α-TB treatment groups. Larvae exposed to 500 ng/L 17α-TB had decreased total body mass, snout–vent length, and total length. In general, growth measurements decreased with increasing concentration of MGA, 17α-TB, or a combination of both. Survival among all treatments was not significantly different from controls. Amphibians exposed to MGA and 17α-TB in the environment may experience alterations in growth and development.  相似文献   
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