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101.
Mediterranean temporary ponds (MTPs) comprise an endangered habitat with several endemic species that can be found in many countries, mainly in the Mediterranean region but are disappearing at a high rate. For designing optimal conservation and management strategies for the particular ecosystems, appropriate characterization and classification of these ponds is necessary based on the different type of habitats and on their varying environmental conditions. This paper presents the current ecological status and the threats of Mediterranean temporary ponds and summarizes some management and conservation issues based on the existing experience on a regional level. Emphasis is given in the Greek MTPs with respect to their characteristics and the pressures received mainly from human activities such as agriculture and water overexploitation. Restoration practices should be commenced immediately aiming at the reestablishment of the ponds' hydroperiod and water quality at the natural levels.  相似文献   
102.
In urban watersheds, stormwater inputs largely bypass the buffering capacity of riparian zones through direct inputs of drainage pipes and lowered groundwater tables. However, vegetation near the stream can still influence instream nutrient transformations via maintenance of streambank stability, input of woody debris, modulation of organic matter sources, and temperature regulation. Stream restoration seeks to mimic many of these functions by engineering channel complexity, grading stream banks to reconnect incised channels, and replanting lost riparian vegetation. The goal of this study was to quantify these effects by measuring nitrate and phosphate uptake in five restored streams in Charlotte and Raleigh, North Carolina, with a range of restoration ages. Using nutrient spiraling methods, uptake velocity of nitrate (0.02‐3.56 mm/min) and phosphate (0.14‐19.1 mm/min) was similar to other urban restored streams and higher than unimpacted forested streams with variability influenced by restoration age and geomorphology. Using a multiple linear regression approach, reach‐scale phosphate uptake was greater in newly restored sites, which was attributed to assimilation by algal biofilms, whereas nitrate uptake was highest in older sites potentially due to greater channel stability and establishment of microbial communities. The patterns we observed highlight the influence of riparian vegetation on energy inputs (e.g., heat, organic matter) and thereby on nutrient retention.  相似文献   
103.
One of the key determinants of success in biodiversity conservation is how well conservation planning decisions account for the social system in which actions are to be implemented. Understanding elements of how the social and ecological systems interact can help identify opportunities for implementation. Utilizing data from a large‐scale conservation initiative in southwestern of Australia, we explored how a social–ecological system framework can be applied to identify how social and ecological factors interact to influence the opportunities for conservation. Using data from semistructured interviews, an online survey, and publicly available data, we developed a conceptual model of the social–ecological system associated with the conservation of the Fitz‐Stirling region. We used this model to identify the relevant variables (remnants of vegetation, stakeholder presence, collaboration between stakeholders, and their scale of management) that affect the implementation of conservation actions in the region. We combined measures for these variables to ascertain how areas associated with different levels of ecological importance coincided with areas associated with different levels of stakeholder presence, stakeholder collaboration, and scales of management. We identified areas that could benefit from different implementation strategies, from those suitable for immediate conservation action to areas requiring implementation over the long term to increase on‐the‐ground capacity and identify mechanisms to incentivize implementation. The application of a social–ecological framework can help conservation planners and practitioners facilitate the integration of ecological and social data to inform the translation of priorities for action into implementation strategies that account for the complexities of conservation problems in a focused way.  相似文献   
104.
Soil microbes in temperate forest ecosystems are able to cycle several hundreds of kilograms of N per hectare per year and are therefore of paramount importance for N retention. Belowground C allocation by trees is an important driver of seasonal microbial dynamics and may thus directly affect N transformation processes over the course of the year. Our study aimed at unraveling plant controls on soil N cycling in a temperate beech forest at a high temporal resolution over a time period of two years, by investigating the effects of tree girdling on microbial N turnover. In both years of the experiment, we discovered (1) a summer N mineralization phase (between July and August) and (2) a winter N immobilization phase (November-February). The summer mineralization phase was characterized by a high N mineralization activity, low microbial N uptake, and a subsequent high N availability in the soil. During the autumn/winter N immobilization phase, gross N mineralization rates were low, and microbial N uptake exceeded microbial N mineralization, which led to high levels of N in the microbial biomass and low N availability in the soil. The observed immobilization phase during the winter may play a crucial role for ecosystem functioning, since it could protect dissolved N that is produced by autumn litter degradation from being lost from the ecosystem during the phase when plants are mostly inactive. The difference between microbial biomass N levels in winter and spring equals 38 kg N/ha and may thus account for almost one-third of the annual plant N demand. Tree girdling strongly affected annual N cycling: the winter N immobilization phase disappeared in girdled plots (microbial N uptake and microbial biomass N were significantly reduced, while the amount of available N in the soil solution was enhanced). This was correlated to a reduced fungal abundance in autumn in girdled plots. By releasing recently fixed photosynthates to the soil, plants may thus actively control the annual microbial N cycle. Tree belowground C allocation increases N accumulation in microorganisms during the winter which may ultimately feed back on plant N availability in the following growing season.  相似文献   
105.
Antarctic krill, Euphausia superba, hatched from eggs and maintained for four years, were sampled periodically for age-pigment analysis. Extractable pigments from the eye and eyestalk ganglia were quantified using fluorescence intensity and standardised against protein. Three peak fluorescence intensities were detected at wavelengths of excitation 280 nm, emission 625 nm (pigment 1); excitation 355 nm, emission 510 nm (pigment 2); and excitation 463 nm, emission 620 nm (pigment 3). There was a positive correlation between the quantity of pigments 1 and 3 and the age of Antarctic krill. A model was developed to predict age from pigment 3 and to compare it with other age proxies (carapace length and eyeball diameter). The quantity of pigment 3 was the best predictor of age. The pigment method can discriminate between similar sized krill aged 12 and 36 months. Age pigments provide an improved tool for age estimation in Antarctic krill, particularly if used in conjunction with other demographic information.  相似文献   
106.
This study is aimed at verifying the relevance of Ucides cordatus as a bioindicator of oil contamination and PAH bioavailability in mangrove sediments. For this, crabs and sediment cores were sampled from five mangroves, including an area suspected of contamination derived from an MF380 oil spillage, and analyzed for the 16 PAH in the USEPA priority list as well as for the five series of alkylated homologues. Concentrations in sediments varied from 35 microg kg-1 in the lower core layer of the control area to 33,000 microg kg-1 in the upper layer of the most contaminated area. Total PAH contents in crabs varied from 206 to 62,000 microg kg-1 and were closely correlated to that in sediments. In general, individual PAH profiles in both matrices were in good agreement. Phenanthrenes, however, were more predominant in crabs making up to 30-46% of the Total PAH. Accumulation factors found in the range of 0.7 to 35 were highly variable even after normalizing concentrations for organic carbon and lipid content. Survival in highly contaminated environment and reliable record of environmental contamination in the tissue provide evidence that U. cordatus is an excellent bioindicator for oil in mangroves.  相似文献   
107.
During the 1997–98 El Niño, Tumbes, Peru received 16 times the annual average rainfall. This study explores how Tumbes residents perceived the impact of the El Niño event on basic necessities, transport, health care, jobs and migration. Forty‐five individuals from five rural communities, some of which were isolated from the rest of Tumbes during the event, participated in five focus groups; six of these individuals constructed nutrition diaries. When asked about events in the past 20 years, participants identified the 1997–98 El Niño as a major negative event. The El Niño disaster situation induced a decrease in access to transport and health care and the rise in infectious diseases was swiftly contained. Residents needed more time to rebuild housing; recover agriculture, livestock and income stability; and return to eating sufficient animal protein. Although large‐scale assistance minimized effects of the disaster, residents needed more support. Residents' perspectives on their risk of flooding should be considered in generating effective assistance policies and programmes.  相似文献   
108.
A detailed cradle‐to‐grave life‐cycle assessment (LCA) of an in situ thermal treatment remedy for a chlorinated‐solvent‐contaminated site was performed using process LCA. The major materials and activities necessary to install, operate, monitor, and deconstruct the remedy were included in the analysis. The analysis was based on an actual site remedy design and implementation to determine the potential environmental impacts, pinpoint major contributors to impacts, and identify opportunities for improvements during future implementation. The Electro‐Thermal Dynamic Stripping Process (ET‐DSP?) in situ thermal technology coupled with a dual‐phase extraction and treatment system was evaluated for the remediation of 4,400 yd3 of tetrachloroethene‐ and trichloroethene‐impacted soil, groundwater, and bedrock. The analysis was based on an actual site with an estimated source mass of 2,200 lbs of chlorinated solvents. The remedy was separated into four stages: remedy installation, remedy operation, monitoring, and remedy deconstruction. Environmental impacts were assessed using Sima Pro software, the ecoinvent database, and the ReCiPe midpoint and endpoint methods. The operation stage of the remedy dominated the environmental impacts across all categories due to the large amount of electricity required by the thermal treatment technology. Alternate sources of electricity could significantly reduce the environmental impacts of the remedy across all impact categories. Other large impacts were observed in the installation stage resulting from the large amount of diesel fuel, steel, activated carbon, and asphalt materials required to implement the technology. These impacts suggest where opportunities for footprint reductions can be found through best management practices such as increased materials reuse, increased recycled‐content materials use, and clean fuels and emission control technologies. Smaller impacts were observed in the monitoring and deconstruction stages. Normalized results show the largest environmental burdens to fossil depletion, human toxicity, particulate matter formation, and climate‐change categories resulting from activities associated with mining of fossil fuels for use in electricity production. In situ thermal treatment can reliably remediate contaminated source areas with contaminants located in low‐permeability zones, providing complete destruction of contaminants in a short amount of time, quick return of the site to productive use, and minimized quantities of hazardous materials stored in landfills for future generations to remediate. However, this remediation strategy can also result in significant emissions over a short period of time. It is difficult to quantify the overall value of short‐term cleanups with intense treatment emissions against longer‐term cleanups with lower treatment emissions because of the environmental, social, and economic trade‐offs that need to be considered and understood. LCA is a robust, quantitative tool to help inform stakeholder discussions related to the remedy selection process, trade‐off considerations, and environmental footprint‐reduction opportunities, and to complement a broader toolbox for the evaluation of sustainable remediation strategies. © 2012 Wiley Periodicals, Inc.  相似文献   
109.
The loss and degradation of nature can lead to hopelessness and despair, which may undermine engagement in conservation actions. Emerging movements, such as that behind the organization Conservation Optimism, aim to avert potential despair of those involved in conservation. Some argue that fostering positive states, such as hope or optimism, can motivate engagement and action; however, others question whether fostering hope or optimism may inadvertently undermine perceived gravity of conservation challenges. We examined this issue by quantifying dispositional hope and optimism with a representative sample of Australians (n = 4285) and assessing their relationship with indicators of conservation engagement. We used the Great Barrier Reef (GBR) in Australia as a case study. We asked participants what they could do to help the GBR, then classified their responses into 2 outcome variables: identifying climate actions (i.e., actions that tackle the main threat to the reef) and identifying plastic actions (i.e., actions that are popular among community members). We also quantified likelihood of performing these actions and appraisals of both threats and actions. One dimension of hope, hope pathways (defined by Snyder's hope theory as knowing different ways to act), was associated with greater capacity to identify climate-related behaviors (odds ratio [OR] = 1.44) and plastic reduction behaviors (OR = 1.22) and greater likelihood of adopting climate-related actions (β = 0.20). Optimism was associated with recognition of plastic reduction behaviors only (OR = 1.22). Neither hope nor optimism undermined appraisal of conservation threats. The effects of optimism were mediated by reduced action futility, and effects of hope pathways were mediated by stronger perceptions of threats to the reef (threat appraisal) and confidence in performing useful actions (coping appraisal). Our findings suggest that dispositional hope can strengthen, rather than undermine, appraisal of conservation challenges and solutions and thereby increase conservation engagement.  相似文献   
110.
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