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151.
Northeast British Columbia (BC), Canada, is the site of a fast-growing shale gas industry that is a cornerstone of the current provincial government's economic policy. In this paper, we explore the perspectives of local First Nations (members of Treaty 8) regarding governance of this industry, focusing in particular on the experiences of the Fort Nelson First Nation (FNFN). Based on findings from 15 in-depth interviews with staff from four Treaty 8 First Nations, the Treaty 8 Tribal Association, oil and gas companies, and the Government of BC, we argue that current governance processes fail to adequately protect the environment and treaty rights. We also explore the diverse tactics that the FNFN is using to gain influence over shale gas development within its territories as the Nation seeks to achieve “balanced development” that protects the local ecology and treaty rights while maximising local economic benefits. Through an array of tactics and collaboration with diverse actors, the FNFN has been partially successful in challenging industry's social license to operate and has brought the provincial government back to the table to negotiate new decision-making arrangements on a “government to government” basis. Still, the regulation and management of a fast-paced global industry are a vast burden for a small community to bear. The FNFN's work has also shown the need for further research on how local efforts for equitable and environmentally sustainable approaches to shale gas regulation can be scaled up, institutionalised, and used to create political opportunities in other contexts.  相似文献   
152.
Abstract: The objective of this study was to use applied and naturally occurring geochemical tracers to study the hydrology of clay settling areas (CSAs) and the hydrological connectivity between CSAs and surrounding hydrological landscapes. The study site is located on the Fort Meade Mine in Polk County, Florida. The CSA has a well‐developed, subangular‐blocky, clay‐rich surface layer with abundant desiccation cracks and other macropores, and a massive, clay‐rich sublayer that is saturated below ~1.0‐2.5 m. A bromide tracer was applied to study hydrological processes in the upper part of the CSA. Bromide infiltrated rapidly and perched on a massive, clay‐rich sublayer. Bromide concentrations decreased in the upper part of the profile without being transported vertically down through the lower part of the profile suggesting that bromide was lost to lateral rather than to vertical transport. Infiltration and lateral flow were rapid suggesting that preferential flow through desiccation cracks and other macropores likely dominates flow in the upper part of the CSA. Naturally occurring solute and stable isotope tracers were used to study the hydrological connectivity between the CSA and the surrounding hydrological landscape. Three‐end mass‐balance mixing model results indicate that shallow and/or deep CSA water can be found in all downgradient waters and must be as much as ~50% of some downgradient waters. Discharge from the CSA to the surrounding surface water‐bodies and surficial aquifer occurs laterally through the berms and/or vertically through the massive, clay‐rich sublayer. However, the precise flow paths from the CSA to the surrounding hydrological landscape are unclear and the fluxes remain unquantified, so the precise effects of CSAs on the hydrology of the surrounding hydrological landscape also remain unquantified.  相似文献   
153.
Pyrethroid insecticides are hydrophobic compounds that partition to streambed sediments and have been shown to cause toxicity to non-target organisms; their occurrence is well documented in parts of California, but there have been limited studies in other urban and agricultural areas across the United States. To broaden geographic understanding of pyrethroid distributions, bed sediment samples were collected and analyzed from 36 streams in 25 states, with about 2/3 of the sites in urban areas and 1/3 in agricultural areas. At least one pyrethroid (of the 14 included in the analysis) was detected in 78% of samples. Seven pyrethroids were detected in one or more samples. Bifenthrin was the most frequently detected (58% of samples), followed by permethrin (31%), resmethrin (17%), and cyfluthrin (14%). The other three detected pyrethroids (cyhalothrin, cypermethrin and delta/tralomethrin) were found in two or fewer of the samples. Concentrations ranged from 0.3 to 180 ng g(-1) dry weight. The number of pyrethroids detected were higher in the urban samples than in the agricultural samples, but the highest concentrations of individual pyrethroids were split between urban and agricultural sites. The pyrethroids detected in the agricultural areas generally followed use patterns. Predicted toxicity was greater for urban areas and attributed to bifenthrin, cyfluthrin and cypermethrin, while in agricultural areas the toxicity was mainly attributed to bifenthrin.  相似文献   
154.
We examined the effects of nectar availability and competition on foraging preferences and revisit intervals of traplining female purple-throated caribs hummingbirds (Eulampis jugularis) to Heliconia patches shared by two individuals or visited solely by one individual. Birds at both shared and solitary patches preferred multiflowered to single-flowered inflorescences, but the magnitude of this preference depended on food availability and competition. During a year of low flower availability, females visited multiflowered inflorescences more frequently than single-flowered inflorescences only when nectar availability was experimentally enhanced; similarly, females at shared patches exhibited a significant preference for multiflowered inflorescences only after experimental increases in nectar availability. Experimental manipulations of nectar availability also had different effects on revisit intervals of birds at shared vs solitary patches. Birds at shared patches responded to patch-wide increases in nectar rewards by increasing the duration of their visit intervals, whereas birds at solitary patches did not. In contrast, birds at solitary patches responded to abrupt losses of nectar at flowers (simulating competition) by decreasing the duration of their visit intervals, whereas a bird at a shared patch did not alter its return interval. The contrasting results between shared vs solitary patches suggest that future studies of traplining behavior should incorporate levels of competition into their design.  相似文献   
155.
We developed and tested patch occupancy models for an endemic understory bird with limited dispersal ability, the Chucao Tapaculo (Scelorchilus rubecula), in two South American temperate rain forest landscapes that differed in levels and duration of forest loss. We assessed cover changes since 1961 in each landscape and surveyed patches for Chucao Tapaculo occupancy. We then developed incidence-based predictive models independently for each landscape and tested each model reciprocally in the alternative study area. We thereby assessed the domain of model applicability and identified those predictor variables with general effects and those that varied between the two landscapes. The two models were consistent regarding variable selection, and predictive accuracy of each model was high in the landscape where training data were collected. However, the models differed substantially in the magnitudes of effects related to patch size, with larger unoccupied patches observed in the landscape with the more advanced stage of fragmentation. Due to this discrepancy, each model performed poorly when applied to the alternative landscape, potentially reflecting the contrasting stages of habitat loss. Although it was impossible to dissociate effects of level and duration of forest loss, we viewed the landscapes as representing two extremes along a continuum of fragmentation, providing insights into potential trajectories for portions of the biome where deforestation is occurring. Further, our data suggest that static equilibrium models developed from distribution patterns in recently fragmented landscapes may overestimate persistence when used as a forecasting tool, or when extrapolated to alternative landscapes where fragmentation is more advanced. Thus, we suggest that landscapes used as standards for model building should be selected with caution. We recommend that distribution patterns be obtained from landscapes where fragmentation is advanced, preferably with histories of fragmentation long enough that time-delayed extinctions already would have occurred.  相似文献   
156.
Background Monitoring biological responses that are mediated via the aryl-hydrocarbon receptor (AhR) in animals exposed to environmental contaminants can indicate both the presence to chemicals that act through this biochemical pathway and whether these chemicals are bioavailable. Objectives The use of an ex-situ method that incorporated biological responsiveness monitoring in mice for determining the presence of ‘biologically active’ hydrocarbons in contaminated soils was investigated. Methods The use of C57BL/6 as a test organism was validated by determining hepatic and immune responsiveness to two polyaromatic hydrocarbons (PAHs): 3,4 benz[a]pyrene (B[a]P) and 1,2 benz (a)anthracene (BA) administered via intraperitoneal (i.p.) injection. The responsiveness of mice exposed to soils spiked with hydrocarbons or ex situ exposures to soil removed from two contaminated sites was also investigated. Results and Discussion Mice that were exposed to B[a]P via i.p. injections showed a 14-fold increase in liver microsomal ethoxyresorufin O-deethylase (EROD) activity compared to the control group. In contrast EROD activity following BA exposure at the same level was not significantly enhanced. Mouse immune response was significantly inhibited in a dose-dependent manner by i.p. injections of B[a]P. No significant inhibition occurred with the same doses of BA. Following i.p. exposure, the retention of B[a]P in mouse carcasses was greater than BA. Mice exposed to clean soils spiked with environmentally relevant concentrations of B[a]P and BA failed to show any significantly different hepatic or immune responses. Carcass residue data indicated a limited uptake of PAH from the soil. In contrast, EROD activity in mice exposed (ex situ) to hydrocarbon-contaminated soils removed from a fuel-loading depot and decommissioned gas works was significantly enhanced (4- and 2-fold respectively). However, this increase in EROD activity did not appear to correlate with either soil or carcass PAH concentrations. Conclusions and Outlook These results support the assumption that B[a]P has a higher affinity for the aryl hydrocarbon receptor (AhR) compared to BA. Soil parameters such as organic carbon content, structure and particle size distribution can modulate the bioavailability of contaminants to biological receptors. These factors are implicated in the lack of responsiveness demonstrated in the spiked soil experiments. However the responsiveness of EROD activity in mice exposed (ex situ) to soil contaminated with complex mixtures of hydrocarbon compounds confirms the potential usefulness of this model to determine the presence of ‘biologically active’ compounds in aged soils removed from contaminated sites.  相似文献   
157.
Marine ecosystems worldwide are threatened by aquatic pollution; however, there is a paucity in data from the Caribbean region. As such, five heavy metals (arsenic, cadmium, copper, zinc, mercury) were measured in tissues of the scleractinian corals Porites furcata and Agaricia tenuifolia and in adjacent sediments in the Bocas del Toro Archipelago, Panama. Samples were collected from five reef sites along a gradient of distance from an international shipping port and were analysed using inductively coupled plasma optical emission spectrometry and atomic absorption spectrophotometry for mercury. Copper and zinc were the most abundant metals and ranged from 11 to 63 mg kg?1 and from 31 to 185 mg kg?1 in coral tissues, respectively. The highest concentration of each metal was measured in P. furcata tissues, with copper and mercury concentrations significantly higher in P. furcata than in A. tenuifolia at every site. These results suggest that P. furcata has a higher affinity for metal accumulation and storage than A. tenuifolia. With the exception of cadmium, metal concentrations in coral tissues were generally elevated at coral reefs in closer proximity to the port; however, this pattern was not observed in sediments. Hard coral cover was lowest at reefs in closest proximity to the port, suggesting that metal pollution from port-related activities is influencing hard coral abundance at nearby coral reefs.  相似文献   
158.
Scientists increasingly rely on protected areas to assist in biodiversity conservation, yet the efficacy of these areas is rarely systematically assessed, often because of underfunding. Still, adaptive management strategies to maximize conservation success often rely on understanding the temporal and spatial dynamism of populations therein. Examination of environmental DNA (eDNA) is a time and cost‐effective way to monitor species’ distribution, and quantitative polymerase chain reaction (qPCR) provides information on organismal abundance. To date, however, such techniques remain underused for population assessments in protected areas. We determined eDNA concentration of the critically endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) to describe its occurrence, range, and use of the Tian e‐Zhou National Nature Reserve in Hubei, China, across seasons and hydrological depths. Despite the observation that total eDNA concentrations were highest in surface waters in summer, finless porpoise eDNA concentrations were significantly higher in deeper waters than in surface waters in summer. During the breeding season (spring), eDNA signals were site specific and restricted to the core area of the reserve. However, postbreeding eDNA concentrations were widespread across the reserve, encompassing sites previously thought to be unfrequented by the species. Our results suggest spatiotemporal idiosyncrasies in site, depth, and seasonal use of the reserve and a propensity for postbreeding population dispersal. With eDNA and qPCR we were able to assess an entire population's use of a protected area. Illuminating nuances in habitat use via eDNA could be valuable to set pragmatic conservation goals for this, and other, species.  相似文献   
159.
Bumblebee colonies experience daily and seasonal fluctuations in ambient temperature, but proper brood development requires a stable nest temperature. This study examined how adaptive colony responses to changing ambient temperature are achieved through the in-nest workers’ behavioral plasticity. We studied three Bombus huntii colonies in the laboratory. In the first experiment, we manipulated ambient temperature and recorded brood cell incubation and wing fanning by individually marked, known-age bees. The colonies maintained their nests closer to appropriate brood development temperatures (28 to 32°C) when exposed to a range of ambient temperatures from 10.3 to 38.6°C. Incubation activity was greater in cooler treatment conditions, whereas in the highest temperature treatment, some bees fanned and others moved off the brood. As the ambient temperature dropped, workers increased the duration of their incubating bouts, but, except at the highest temperature, the number of workers that incubated did not differ significantly among treatments. A subset of the bees incubated significantly more than their nest mates, some of which never incubated. Worker body size, but not age, was a good predictor of incubation rates, and smaller bees incubated at higher rates. In the second experiment, we removed the most actively incubating workers. Immediately after removals, the total colony incubation effort was lower than pre-removal levels, but incubation effort rebounded toward pre-removal levels after 24 h. The increased thermoregulatory demand after removals was met primarily by bees increasing their rates of incubation rather than by bees switching from a different task to incubation. We conclude that some B. huntii workers specialize on nest thermoregulation, and that changes in work rates are more important than task switching in meeting thermal challenges.  相似文献   
160.
Reintroductions are important components of conservation and recovery programs for rare plant species, but their long-term success rates are poorly understood. Previous reviews of plant reintroductions focused on short-term (e.g., ≤3 years) survival and flowering of founder individuals rather than on benchmarks of intergenerational persistence, such as seedling recruitment. However, short-term metrics may obscure outcomes because the unique demographic properties of reintroductions, including small size and unstable stage structure, could create lags in population growth. We used time-to-event analysis on a database of unusually well-monitored and long-term (4–28 years) reintroductions of 27 rare plant species to test whether life-history traits and population characteristics of reintroductions create time-lagged responses in seedling recruitment (i.e., recruitment time lags [RTLs]), an important benchmark of success and indicator of persistence in reintroduced populations. Recruitment time lags were highly variable among reintroductions, ranging from <1 to 17 years after installation. Recruitment patterns matched predictions from life-history theory with short-lived species (fast species) exhibiting consistently shorter and less variable RTLs than long-lived species (slow species). Long RTLs occurred in long-lived herbs, especially in grasslands, whereas short RTLs occurred in short-lived subtropical woody plants and annual herbs. Across plant life histories, as reproductive adult abundance increased, RTLs decreased. Highly variable RTLs were observed in species with multiple reintroduction events, suggesting local processes are just as important as life-history strategy in determining reintroduction outcomes. Time lags in restoration outcomes highlight the need to scale success benchmarks in reintroduction monitoring programs with plant life-history strategies and the unique demographic properties of restored populations. Drawing conclusions on the long-term success of plant reintroduction programs is premature given that demographic processes in species with slow life-histories take decades to unfold.  相似文献   
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