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51.
Abstract:  Captive breeding is a commonly used strategy for species conservation. One risk of captive breeding is domestication selection—selection for traits that are advantageous in captivity but deleterious in the wild. Domestication selection is of particular concern for species that are bred in captivity for many generations and that have a high potential to interbreed with wild populations. Domestication is understood conceptually at a broad level, but relatively little is known about how natural selection differs empirically between wild and captive environments. We used genetic parentage analysis to measure natural selection on time of migration, weight, and morphology for a coho salmon ( Oncorhynchus kisutch ) population that was subdivided into captive and natural components. Our goal was to determine whether natural selection acting on the traits we measured differed significantly between the captive and natural environments. For males, larger individuals were favored in both the captive and natural environments in all years of the study, indicating that selection on these traits in captivity was similar to that in the wild. For females, selection on weight was significantly stronger in the natural environment than in the captive environment in 1 year and similar in the 2 environments in 2 other years. In both environments, there was evidence of selection for later time of return for both males and females. Selection on measured traits other than weight and run timing was relatively weak. Our results are a concrete example of how estimates of natural selection during captivity can be used to evaluate this common risk of captive breeding programs.  相似文献   
52.
This paper explores the positive aspects of collaboration in natural resources. Its purpose was to investigate participants' overall attitudes about keys to successful collaboration. The sample for the study consisted of 671 participants involved in 30 collaborative initiatives (CI) with the Forest Service. Using a mailed questionnaire, this study profiled the collaborative initiatives investigating purpose, problems addressed, groups involved, and years in existence. Respondents were queried on their overall perspectives on keys to successful collaboration. A total of more than 300 comments was collected from respondents and six categories emerged: development, information exchange, organizational support, personal communication, relationships/team building, and accomplishments. Continued research will need to explore the short- and long-term impacts of collaboration in natural resources.  相似文献   
53.
In a recent paper, it was suggested that one of the reasons behind the decline in public regard toward British Columbia's environmental movement was an increasingly negative portrayal of them by the print media. To investigate this suggestion, we undertook a content analysis of print media reporting of forestry and environmental activities in the province's most widely read newspaper, the Vancouver Sun, during 1993 and 1997. We hypothesized that if the print media did contribute to the decline in public regard toward the environmental movement, we would find increasingly negative coverage of the environmental movement over the periods studied. We also hypothesized that this would be accompanied by a decrease in the frequency of articles dealing with issues consistent with the agenda of the environmental movement. We were not able to provide support for our initial hypothesis, nor did we observe a decrease in coverage emphasizing the environmental issues. We did, however, observe an increase in coverage of articles emphasizing typically proindustry issues with many more articles written with a proforestry slant in 1997 than articles written in 1993. This suggests that there had been an agenda shift from environmentally oriented concerns in British Columbia to those associated with the forest industry. As an explanation for the agenda shift, we point to changes in the management and reporting philosophy at the Vancouver Sun, the emergence of an organized, proindustry counterframing strategy by the BC Forest Alliance, and the implementation of several government policies aimed at regulating the activities of the forest industry.  相似文献   
54.
Policy documents advocate that managers should keep their options open while planning to protect coastal ecosystems from climate‐change impacts. However, the actual costs and benefits of maintaining flexibility remain largely unexplored, and alternative approaches for decision making under uncertainty may lead to better joint outcomes for conservation and other societal goals. For example, keeping options open for coastal ecosystems incurs opportunity costs for developers. We devised a decision framework that integrates these costs and benefits with probabilistic forecasts for the extent of sea‐level rise to find a balance between coastal ecosystem protection and moderate coastal development. Here, we suggest that instead of keeping their options open managers should incorporate uncertain sea‐level rise predictions into a decision‐making framework that evaluates the benefits and costs of conservation and development. In our example, based on plausible scenarios for sea‐level rise and assuming a risk‐neutral decision maker, we found that substantial development could be accommodated with negligible loss of environmental assets. Characterization of the Pareto efficiency of conservation and development outcomes provides valuable insight into the intensity of trade‐offs between development and conservation. However, additional work is required to improve understanding of the consequences of alternative spatial plans and the value judgments and risk preferences of decision makers and stakeholders. Minimizando el Costo de Mantener Opciones Abiertas para la Conservación en un Clima Cambiante  相似文献   
55.
Anthropogenic climate change is a key threat to global biodiversity. To inform strategic actions aimed at conserving biodiversity as climate changes, conservation planners need early warning of the risks faced by different species. The IUCN Red List criteria for threatened species are widely acknowledged as useful risk assessment tools for informing conservation under constraints imposed by limited data. However, doubts have been expressed about the ability of the criteria to detect risks imposed by potentially slow‐acting threats such as climate change, particularly because criteria addressing rates of population decline are assessed over time scales as short as 10 years. We used spatially explicit stochastic population models and dynamic species distribution models projected to future climates to determine how long before extinction a species would become eligible for listing as threatened based on the IUCN Red List criteria. We focused on a short‐lived frog species (Assa darlingtoni) chosen specifically to represent potential weaknesses in the criteria to allow detailed consideration of the analytical issues and to develop an approach for wider application. The criteria were more sensitive to climate change than previously anticipated; lead times between initial listing in a threatened category and predicted extinction varied from 40 to 80 years, depending on data availability. We attributed this sensitivity primarily to the ensemble properties of the criteria that assess contrasting symptoms of extinction risk. Nevertheless, we recommend the robustness of the criteria warrants further investigation across species with contrasting life histories and patterns of decline. The adequacy of these lead times for early warning depends on practicalities of environmental policy and management, bureaucratic or political inertia, and the anticipated species response times to management actions. Detección del Riesgo de Extinción a partir del Cambio Climático por medio del Criterio de la Lista Roja de la UICNKeith et al.  相似文献   
56.
Despite decades of discussion and implementation, conservation monitoring remains a challenge. Many current solutions in the literature focus on improving the science or making more structured decisions. These insights are important but incomplete in accounting for the politics and economics of the conservation decisions informed by monitoring. Our novel depiction of the monitoring enterprise unifies insights from multiple disciplines (conservation, operations research, economics, and policy) and highlights many underappreciated factors that affect the expected benefits of monitoring. For example, there must be a strong link between the specific needs of decision makers and information gathering. Furthermore, the involvement of stakeholders other than scientists and research managers means that new information may not be interpreted and acted upon as expected. While answering calls for sharply delineated objectives will clearly add focus to monitoring efforts, for practical reasons, high‐level goals may purposefully be left vague, to facilitate other necessary steps in the policy process. We use the expanded depiction of the monitoring process to highlight problems of cooperation and conflict. We critique calls to invest in monitoring for the greater good by arguing that incentives are typically lacking. Although the benefits of learning accrued within a project (e.g., improving management) provide incentives for investing in some monitoring, it is unrealistic, in general, to expect managers to add potentially costly measures to generate shared benefits. In the traditional linear model of the role of science in policy decisions, monitoring reduces uncertainty and decision makers are rational, unbiased consumers of the science. However, conservation actions increasingly involve social conflict. Drawing insights from political science, we argue that in high‐conflict situations, it is necessary to address the conflict prior to monitoring. Las Inversiones y el Proceso de Políticas en el Monitoreo de la Conservación Sanchirico et al.  相似文献   
57.
Abstract:  Long-term research projects can provide important conservation benefits, not only through research specifically focused on conservation problems, but also from various incidental benefits, such as increased intensity of monitoring and building support for the protection of an area. At Gombe National Park, Tanzania, long-term research has provided at least four distinct benefits to wildlife conservation. (1) Jane Goodall's groundbreaking discoveries of chimpanzee (Pan troglodytes) tool use, hunting, and complex social relationships in what was then a game reserve drew attention to the area and created support for upgrading Gombe to national park status in 1968. (2) The highly publicized findings have earned Gombe and Tanzania the attention of a worldwide public that includes tourists and donors that provide financial support for Gombe, other parks in Tanzania, and chimpanzee conservation in general. (3) Crucial information on social structure and habitat use has been gathered that is essential for effective conservation of chimpanzees at Gombe and elsewhere. (4) A clear picture of Gombe's chimpanzee population over the past 40 years has been determined, and this has helped identify the greatest threats to the viability of this population, namely disease and habitat loss outside the park. These threats are severe and because of the small size of the population it is extremely vulnerable. Research at Gombe has led to the establishment of conservation education and development projects around Gombe, which are needed to build local support for the park and its chimpanzees, but saving these famous chimpanzees will take a larger integrated effort on the part of park managers, researchers, and the local community with financial help from international donors.  相似文献   
58.
59.
We evaluated the amounts and implications of changes in habitat connectivity on rural landscapes by modeling the colonization success and subsequent habitat colonization of a model edge organism within real landscapes. We first inventoried the changes in the fencerow and forest-edge network of two contiguous Ohio (U.S.A.) landscapes, an agriculturally dominated till plain and a more diverse and dynamic moraine landscape, from 1940 to 1988. On the moraine the number of fencerows changed little from 1940 to 1971. The number increased by 86 during 1971–1988 as marginal farms were subdivided. The total length of fencerows on the moraine increased 2.5-fold over 48 years. On the till plain the number and total length of fencerows remained relatively constant through the study period. The sum of fencerows and forest edges was used as a measure of total ecotonal edge. On the moraine total edge increased through the study period, whereas on the till plain it decreased. We selected two levels of landscape connectivity, low and high, to model animal habitat colonization success. As connectivity increased the earliest successful colonists preempted an increasingly large proportion of the total suitable habitat, and the probability of successful colonization by later-arriving individuals decreased. The changes in connectivity that resulted from changes in both the fencerow network and the proportion of forested land have resulted in contiguous landscapes that present very different colonization potentials to organisms with long-distance dispersal capability. Given the current uncertainty of the effects of corridors on species-preservation efforts, we suggest that further modeling of this type prior to field testing will add useful insights, especially if conducted using specific species and landscape types.  相似文献   
60.
6 tons C were released to the atmosphere during the period of time covered by our study, equal to approximately 34% of the 1975 vegetation C pool. The Chiapas highlands, while comprising just 0.3% of Mexico's surface area, contributed 3% of the net national C emissions.  相似文献   
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