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21.
It is a common experience that public administrations tend to shy away from the explicit acknowledgment of quantitative risk levels. Faced with extreme concentrations of population and of industrial activities, including LPG and liquid chlorine storage, within a very small land area, Hong Kong has faced up to the issue of major man-made hazards by “thinking the unthinkable” and adopting explicit risk guidelines. This article describes how these guidelines were developed and the arguments that led to their adoption. It is emphasized that the risk guidelines are not rigid standards but simply a method of focusing decision making and ensuring that any decision to contravene the guidelines is taken at an appropriately senior level in the administration. The way in which the guidelines have been incorporated intimately into the planning and decision-making process is described and details are given on how this has led to the implementation of a variety of measures that have greatly reduced both societal and individual risk from certain types of chemical storage and chemical processing installations in Hong Kong. The opinions in this paper represent the views of the authors and not necessarily those of the Hong Kong Government.  相似文献   
22.
Discard reduction is a component of the statutory requirements of the Sustainable Fisheries Act. One species of concern is scup, Stenotomus chrysops, discarded in the Loligo pealei fishery. Initially, regulations were imposed restricting the fishery in time and space to avoid areas and times associated with high scup discarding. Modified gear was required in 2003 on any boat fishing in areas otherwise closed to the fishery to reduce scup discarding. The purpose of this study was to evaluate the success of the 2003 net regulations and the potential influence of time-area closures (GRAs) in achieving a reduction in scup discarding. The regulations are based on three expectations. (1) Reduction in discarding in the Loligo squid fishery will materially reduce total scup discarding. (2) Exclusion of Loligo squid fishing vessels from the GRAs will result in these vessels fishing in areas that inherently produce fewer scup discards without equivalently increasing discarding in other sensitive species. (3) The use of a square-mesh large-mesh section in the extension will reduce scup discarding to the extent that otherwise would be achieved if the boats fished outside the GRAs without the economic cost imposed by redeploying the fleet. Analysis of the NMFS-NEFSC observer database offers no support for the belief that Expectation 1 has been met. Squid catches were too low to sustain a directed fishery in the northern GRA during this study. Thus, had this area been open, limited scup discarding would have occurred. In this study, squid catches averaged 1025 kg tow(-1) in the southern GRA. Thus, had the GRA been open, Loligo fishing would have taken place. Yet, in the 34 tows taken by two vessels, not a single scup was caught. Redeployment of the fleet clearly increased scup discarding in 2003. Thus, Expectation 2 was not met. Field tests demonstrated that the implemented net modification can produce reduced catches of mostly smaller-sized finfish without impairing squid catch, but the data also indicate that this result may not be routinely achieved. Thus, Expectation 3 was not completely met. Implementation of the 2003 net regulation was likely premature, in that the specification was not adequate to guarantee the desired results. The history of the scup discarding issue in the Loligo squid fishery demonstrates that discard reduction cannot be accomplished without adequate prior evaluation of the sources of discards, without the requisite and concomitant experimental evaluation of the results of regulatory reform, and without adequate commercial-scale testing of prospective reforms prior to implementation.  相似文献   
23.
Resource managers require objective methodologies to optimize decisions related to forest road deactivation and other aspects of road management, especially in steep terrain, where road-related slope failures inflict extensive environmental damage. Decision analysis represents a systematic framework that clearly identifies real options and critical decision points. This framework links current decisions with expected future outcomes and provides advantages such as a common currency to systematically explore the liability consequences of limited budget expenditures to road deactivation and other road-related activities. Furthermore, the decision framework prevents the analysis from becoming hopelessly entangled by the vast number of possibilities generated by the alternative occurrences, magnitudes, and consequences of landslide/debris flow events and provides the information required for the first step of an adaptive management process. Here, a structured analysis of potential environmental risks for a road deactivation project in coastal British Columbia, Canada is presented. The application of decision analysis generates a ranking of the expected benefits of proposed deactivation activities on various road sections. The ranking distinguishes between road sections that offer high expected benefit from those that offer moderate to low expected benefit. Seventeen of 171, 100–m road segments accounted for 18% of the cumulative cost and 98% of the cumulative expected net benefits from road deactivation. Furthermore, the cost of deactivating a section of road is related to the expected benefit from such deactivation, thus providing the basis for more effective resource allocation and budgeting decisions.  相似文献   
24.
Little is known about the occurrence and distribution of the herbicide diuron [3-(3,4-dichlorophenyl)-1,1-dimethyl urea] in soil, ground water, and surface water in areas affected by grass-seed production. A field study was designed to investigate the occurrence and distribution of diuron and its transformation products at a poorly drained field site located along an intermittent tributary of Lake Creek in the southern Willamette Valley of Oregon. The experimental sites consisted of a field under commercial grass seed production with a cultivated riparian zone and a second site that was part of the same grass seed field but with a noncultivated riparian zone. Diuron and its transformation product DCPMU [3-(3,4-dichlorophenyl)-1-methylurea] were the only significant residues detected in this study. Concentrations of diuron in surface water declined from a maximum of 28 microg/L immediately following application to low levels that persisted as long as flow was present. Diuron and DCPMU concentrations in shallow ground water (15-36 cm below ground surface) were highest (2-13 microg/L) in the zone immediately adjacent (0.5 m) to Lake Creek and indicated the influence of stream water on shallow ground water near the stream. Diuron and DCPMU detected in soil prior to the second season's application indicated the persistence of diuron and DCPMU from the previous year's application. Surface runoff during the rainy season removes only a very small percentage (<1%) of the applied herbicide. In addition, no evidence was obtained for the downward transport of diuron or its transformation products to deep ground water.  相似文献   
25.
26.
Ten ways remote sensing can contribute to conservation   总被引:1,自引:0,他引:1       下载免费PDF全文
In an effort to increase conservation effectiveness through the use of Earth observation technologies, a group of remote sensing scientists affiliated with government and academic institutions and conservation organizations identified 10 questions in conservation for which the potential to be answered would be greatly increased by use of remotely sensed data and analyses of those data. Our goals were to increase conservation practitioners’ use of remote sensing to support their work, increase collaboration between the conservation science and remote sensing communities, identify and develop new and innovative uses of remote sensing for advancing conservation science, provide guidance to space agencies on how future satellite missions can support conservation science, and generate support from the public and private sector in the use of remote sensing data to address the 10 conservation questions. We identified a broad initial list of questions on the basis of an email chain‐referral survey. We then used a workshop‐based iterative and collaborative approach to whittle the list down to these final questions (which represent 10 major themes in conservation): How can global Earth observation data be used to model species distributions and abundances? How can remote sensing improve the understanding of animal movements? How can remotely sensed ecosystem variables be used to understand, monitor, and predict ecosystem response and resilience to multiple stressors? How can remote sensing be used to monitor the effects of climate on ecosystems? How can near real‐time ecosystem monitoring catalyze threat reduction, governance and regulation compliance, and resource management decisions? How can remote sensing inform configuration of protected area networks at spatial extents relevant to populations of target species and ecosystem services? How can remote sensing‐derived products be used to value and monitor changes in ecosystem services? How can remote sensing be used to monitor and evaluate the effectiveness of conservation efforts? How does the expansion and intensification of agriculture and aquaculture alter ecosystems and the services they provide? How can remote sensing be used to determine the degree to which ecosystems are being disturbed or degraded and the effects of these changes on species and ecosystem functions?  相似文献   
27.
Advocates of community-based approaches to environmental management argue that by respecting local circumstances, skills, and concerns we may improve the prospects of achieving environmental sustainability; yet, within nation states such as Canada, environmental conditions, management and enforcement costs and capabilities, and power differentials within and among civic and public sectors may result in a highly differentiated capacity for environmental management across different localities and regions. This article draws on insights of political ecology to 1) create a conceptual framework that identifies key elements shaping regional environmental management regimes and to 2) undertake a comparative analysis to assess how elements interact to generate uneven management outcomes. I compare experiences of two Canadian biosphere reserves designated in 2000: Clayoquot Sound, BC; and Redberry Lake, SK. Analysis reveals that differences in governance and institutional capacities in the biosphere reserves are key to explaining uneven local outcomes. Where the public and civic sectors are strong, a robust and publicly vetted form of management will emerge. Where these sectors are weak and land is held as private property, environmental nongovernmental organizations can set the type and level of management, to the exclusion of effective civic and state involvement. This result may improve environmental sustainability but hinder social sustainability of a management regime and raises questions about the efficacy of community-based management.  相似文献   
28.
This study examined the toxicity of two pesticides (carbaryl and diquat dibromide) and one polycyclic aromatic hydrocarbon (fluoranthene), both singly and in mixture, to grass shrimp larvae (Palaemonetes pugio). These three chemicals are all present in coastal environments and can easily enter estuarine ecosystems. Fluoranthene was the most toxic chemical with a 96-h LC50 value of 32.45 μ g/L, followed by carbaryl (43.02 μ g/L) and diquat dibromide (1624 μ g/L). In the chemical mixture tests, the binary carbaryl/diquat dibromide mixture and the ternary carbaryl/diquat dibromide/fluoranthene mixture had additive results.  相似文献   
29.
Implementing the UNCCD: Participatory challenges   总被引:1,自引:0,他引:1  
The United Nations Convention to Combat Desertification (UNCCD) emphasizes the need for public participation in land degradation assessment and rehabilitation. While participatory approaches are supported by a growing body of research and practice, meaningfully involving the people affected by land degradation is far from straightforward. This paper investigates the challenge of using the UNCCD as a guide to influence community participation in policy‐making and practice at national and local levels by analyzing experiences from three southern African countries. We show that the UNCCD represents a useful normative framework for addressing degradation problems, but that the participatory ethos is difficult to enact at the national level. Whilst there is increasing evidence that combining local and scientific knowledge using participatory mechanisms can deliver the benefits that the Convention strives to achieve, communication between researchers and practitioners, and those involved in implementing the UNCCD at the national level needs to be strengthened. Broad lessons and best practices in incorporating participatory practices into policy development are elucidated. Our case studies show that a range of mixed‐method, interdisciplinary approaches can enable policy‐makers and practitioners to meaningfully engage those who are affected by land degradation in its definition, assessment and rehabilitation.  相似文献   
30.
The southern pine bark beetle guild (SPBG) is arguably the most destructive group of forest insects in the southeastern USA. This guild contains five species of bark beetles (Coleoptera: Curculionidae: Scolytinae): Dendroctonus frontalis, Dendroctonus terebrans, Ips avulsus, Ips calligraphus, and Ips grandicollis. A diverse community of illicit receivers is attracted to pheromones emitted by the SPBG, including the woodborers Monochamus carolinensis and Monochamus titillator (Coleoptera: Cerambycidae). These woodborers have been traditionally classified as resource competitors; however, laboratory assays suggest that larval M. carolinensis may be facultative intraguild predators of SPBG larvae. This study used polymerase chain reaction (PCR)-based molecular gut content analyses to characterize subcortical interactions between M. titillator and members of the SPBG. The half-lives of SPBG DNA were estimated in the laboratory prior to examining these interactions in the field. A total of 271 field-collected M. titillator larvae were analyzed and 26 (9.6?%) tested positive for DNA of members of the SPBG. Of these larvae, 25 (96.2?%) tested positive for I. grandicollis and one (3.8?%) for I. calligraphus. Failure to detect D. terebrans and D. frontalis was likely due to their absence in the field. I. avulsus was present, but primers developed using adult tissues failed to amplify larval tissue. Results from this study support the hypothesis that larval Monochamus spp. are facultative intraguild predators of bark beetle larvae. Additionally, this study demonstrates the capabilities of PCR in elucidating the interactions of cryptic forest insects and provides a tool to better understand mechanisms driving southern pine beetle guild population fluctuations.  相似文献   
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