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761.
Ecological Benefits of the Conservation Reserve Program   总被引:8,自引:0,他引:8  
The Conservation Reserve Program was initiated in 1985 to reduce soil loss on highly erodible agricultural land. This stated objective of the program has been quite successful. However, there are other unintentional yet significant ecological benefits to the program that merit evaluation. These benefits include the reversal of landscape fragmentation, maintenance of regional biodiversity, creation of wildlife habitat, and favorable changes in regional carbon flux. These and other benefits should be used by policy makers and federal officials to maintain the program even after enrollment expectations have been achieved.  相似文献   
762.
763.
The controversy surrounding planning approval for certain developments associated with a proposal to generate electricity from gas produced at a large coke works is examined. Although the case begins as another conflict in the ‘planning versus pollution control jurisdiction’ tradition, these concerns are eventually superseded by the wider implications for planning of a residents group's attempt to advance its campaign against this long‐standing ‘bad neighbour’ by citing the principle of the ‘direct effect’ of a European Community directive on industrial air pollution.  相似文献   
764.
Investment in increased capacity of the major metal producers is examined in the light of changing metal prices and the business cycle. Historically, as metal prices rise, the producers have invested in new mine capacity. This process results in increased production which often comes on stream just as the business cycle is beginning to wane. During the present business cycle the investment pattern of the major mining companies appears to have broken with this historical pattern in that investment strategies are less directed toward increasing capacity.  相似文献   
765.
Summary The ideal dominance distribution model predicts that competition between individuals of a species for territories will result in socially dominant individuals acquiring territories in higher quality habitat than their subordinates. Although the dispersion and relative reproductive success of male red-winged blackbirds (Agelaius phoeniceus) across habitats in eastern Ontario appears to conform to the ideal dominance distribution model, data from a study of three captive groups comprised of males from both high (marsh) and low (upland field) quality habitats failed to support the prediction that males from marsh habitat are dominant to those from upland habitat. Contrary to the prediction males from uplands were generally dominant to males from marshes. We found a significant positive correlation between dominance and both increased epaulet size and increased body size. Controlling for these positive effects, upland males remained generally dominant to marsh males. Measurements of independent samples of males from both habitats indicated that the overall distribution of males does not conform to ideal dominance. We suggest that the strong between-year territory fidelity shown by male red-winged blackbirds and chance events when they initially acquire territories may contribute to this lack of conformity.  相似文献   
766.
In the Imperial County, California, earthquake of 15th October 1979, the Imperial County Services Building was seriously damaged — and has subsequently been demolished. At the time of the earthquake there were approximately 123 occupants in the six-storey reinforced concrete building which housed a number of county service departments. This paper investigates occupant behavior in a building subjected to an earthquake, and describes, in detail, what people do during and immediately subsequent to the shock.  相似文献   
767.
This paper illustrates a landscape ecology approach for land trusts undertaking conservation at the watershed scale. A conservation plan was created for the Grand Traverse Regional Land Conservancy (GTRLC) in the headwaters of Michigan's Manistee River Watershed (USA). Eight conservation drivers were devised to identify Conservation Focus Areas (CFAs) of highest ecological importance. The CFAs were ranked based on ecological importance, feasibility of protection and size. Parcels were ranked, totalling nearly 5000 ha, within the three highest-ranking CFAs in one key county. This approach is useful to land trusts trying to operationalize three distinct goals in conservation planning: to find areas of high ecological importance, to promote the landscape's spatial integrity and to delineate threats to ecological systems and processes.  相似文献   
768.
This paper explores the influence and use of agrarian thought on collective understandings of food practices as sources of ethical and communal value in urban contexts. A primary proponent of agrarian thought that this paper engages is Paul Thompson and his exceptional book, The Agrarian Vision. Thompson aims to use agrarian ideals of agriculture and communal life to rethink current issues of sustainability and environmental ethics. However, Thompson perceives the current cultural mood as hostile to agrarian virtue. There are two related claims of this paper. The first argues that contrary to Thompson’s perception of hostility, agrarian thought is popularly and commercially mobilized among urban populations. To establish this claim I extend Charles Taylor’s notion of a social imaginary and suggest that urban agriculture can be theorized as an agrarian imaginary. Entwined with the first claim is the second, that proponents selectively use agrarian history to overemphasis a narrative of virtue while ignoring or marginalizing historical practices of agrarian violence, exclusion and dispossession. I do not discount or deny the significance of agrarian virtue. By situating agrarian thought within a clearer virtue ethics framework and acknowledging potential manifestation of agrarian vice, I suggest that the idea of agrarian virtue is strengthened.  相似文献   
769.
The Clinch River, in eastern United States, supports a diverse freshwater fauna including endangered mussels. Although mussel populations are stable in the Clinch's northeastern Tennessee segment, long‐term declines have been documented upstream in Virginia. We analyzed water and sediment quality data collected by government agencies from the 1960s through 2013 in an effort to inform current management. The river was divided into sections considering data availability and major tributaries. We tested for spatial differences among river sections and for temporal trends, and compared measured values to potentially protective levels if available. Ammonia concentrations approaching and exceeding protective levels were recorded, most often during the 1970s and 1980s in upstream sections. Sediment metals occurred at levels potentially causing biological effects, mainly during the 1980s and 1990s. In the 2000s, water‐column metals have been well below protective levels for general aquatic life. Dissolved solids (DS) increased in most river sections over the study period but mussel‐specific protective levels are not known. Analysis of water pH, total N, and total P did not generate conservation concern. Enhanced monitoring for sediment metals, water‐column metals, and ionic composition of DS; closer alignment of agency water monitoring practices in the two states; and research to determine biological effects of DS at current and anticipated levels can aid future conservation management.  相似文献   
770.
Sustainability appraisals produce evidence for how well water governance regimes operate and where problems exist. This evidence is particularly relevant for regions that face water scarcity and conflicts. In this study, we present a criteria-based and participatory sustainability appraisal of water governance in a region with such characteristics—the dry tropics of NW Costa Rica. Data collection included 47 interviews and three stakeholder workshops. The appraisal was conducted through a collaborative and iterative process between researchers and stakeholders. Out of the 25 sustainability criteria used, seven posed a significant challenge for the governance regime. We found challenges faced by the governance regime primarily clustered around and were re-enforced by failing coordination related to the use, management, and protection of groundwater resources; and inadequate leadership to identify collective goals and to constructively deliberate alternative ways of governing water with diverse groups. The appraisal yielded some positive impact in the study area, yet we found its application provided only limited strategic information to support broader problem-solving efforts. Insights from this study suggest key starting points for sustainable water governance in the Central American dry tropics, including investing in increasingly influential collective organizations that are already active in water governance; and leveraging policy windows that can be used to build confidence and disperse more governing authority to regional and local governing actors that are in-tune with the challenges faced in the dry tropics. We conclude the article with reflections on how to produce research results that are actionable for sustainable water governance.  相似文献   
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