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11.
Planning for the extraction of aggregates is typically dealt with at a case to case basis, without assessing environmental impacts strategically. In this study we assess the impact of sand mining in Poyang Lake, where dredging began in 2001 after sand mining in the Yangtze River had been banned. In April 2008 concern over the impact on the biodiversity led to a ban on sand mining in Poyang Lake until further plans could be developed. Planning will require consideration of both sand extraction in relation to available sediment resources and also environmental impacts within the context of future demand for sand in the lower Yangtze Valley. We used pairs of near-infrared (NIR) Aster satellite imagery to estimate the number of vessels leaving the lake. Based on this we calculated a rate of sand extraction of 236 million m3 year−1 in 2005–2006. This corresponds to 9% of the total Chinese demand for sand. It qualifies Poyang Lake as probably the largest sand mining operation in the world. It also indicates that sand extraction currently dominates the sediment balance of the lower Yangtze River. A positive relation between demand for sand and GDP, revealed by historic data from the USA, suggests that the current per capita demand for sand in China might increase in the near future from 2 to 4 m3 year−1. We review various environmental impacts and question whether it will be possible to preserve the rich biodiversity of the lake, while continuing at the same time satisfying the increasing Chinese demand for sand. Finally we review alternative options for sand mining, in order to relieve the pressure from the Poyang Lake ecosystem.  相似文献   
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The Noel Kempff Climate Action Project in Bolivia, nowin its third year, is breaking ground to establishcredible and verifiable methods to quantify greenhousegas (GHG) benefits of land-use change and forestry (LUCF)projects. Developed under the United Nations FrameworkConvention Climate Change (FCCC) Activities ImplementedJointly pilot phase, the project conserves naturalforests that would otherwise have been subjected tocontinued logging and future agricultural conversion.Carbon (C) monitoring began with a C inventory of theproject area in 1997. The total amount of C in theproject area was 118 Tg (Tg = 1012g) ± 4%(95% confidence interval). Periodic monitoring ofrelevant C pools (occurring in 1999 and every 5 yrthereafter) occurs over the 30-year life of theproject to establish the difference between thewith-project and projected without-project scenarios. Permanent sample plots were established both insidethe project area to monitor changes in C pools overtime and in a proxy logging concession near theproject area to determine changes in C pools inforests that have been impacted by logging. Ground-based monitoring is complemented by datacollection on forest industry trends and land-usechange patterns. Remote sensing was used to developa vegetation stratification map of the area, and workis ongoing to investigate the potential application ofdual-camera aerial videography to improve theefficiency of monitoring over time.  相似文献   
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Advances in acquiring and analyzing the spatial attributes of data have greatly enhanced the potential utility of wildlife disease surveillance data for addressing problems of ecological or economic importance. We present an approach for using wildlife disease surveillance data to identify areas for (or of) intervention, to spatially delineate paired treatment and control areas, and then to analyze these nonrandomly selected sites in a meta-analysis framework via before-after-control impact (BACI) estimates of effect size. We apply these methods to evaluate the effectiveness of attempts to reduce chronic wasting disease (CWD) prevalence through intensive localized culling of mule deer (Odocoileus hemionus) in north-central Colorado, USA. Areas where surveillance data revealed high prevalence or case clusters were targeted by state wildlife management agency personnel for focal scale (on average <17 km2) culling, primarily via agency sharpshooters. Each area of sustained culling that we could also identify as unique by cluster analysis was considered a potential treatment area. Treatment areas, along with spatially paired control areas that we constructed post hoc in a case-control design (collectively called "management evaluation sites"), were then delineated using home range estimators. Using meta-BACI analysis of CWD prevalence data for all management evaluation sites, the mean effect size (change of prevalence on treatment areas minus change in prevalence on their paired control areas) was 0.03 (SE = 0.03); mean effect size on treatment areas was not greater than on paired control areas. Excluding cull samples from prevalence estimates or allowing for an equal or greater two-year lag in system responses to management did not change this outcome. We concluded that management benefits were not evident, although whether this represented true ineffectiveness or was a result of lack of data or insufficient duration of treatment could not be discerned. Based on our observations, we offer recommendations for designing a management experiment with 80% power to detect a 0.10 drop in prevalence over a 6-12-year period.  相似文献   
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We reviewed recent work concerning the impact of geopolitics on wildlife conservation (and vice versa) and identified future priorities in conservation geopolitics research. Geopolitics is understood as both an analytical focus on geopolitical practices (especially concerning the behavior) of countries with respect to territory and national security and a set of theories developed to explain and predict those behaviors. We developed a typology of core geopolitical practices of relevance to conservation: territorial practices of colonization and the management of migrations and borders, and security practices relating to military, economic, and environmental security. We identified research that considers how these practices affect conservation situations and outcomes, noting the recent emergence of conceptual developments such as “environmental geopolitics” and “geopolitical ecology” that draw on multiple fields within the social sciences to theorize the links between geopolitics and environmental management. We defined a "geopolitical perspective" as a focus on geopolitical practices combined with an explicit engagement with geopolitical theory and identified conservation situations where this perspective could contribute to analytical clarity. We suggest the most pressing questions in conservation research to which the geopolitical perspective might contribute are how political and economic differences between countries affect biodiversity outcomes, how geopolitical practices to address those differences facilitate or frustrate conservation efforts, how national borders and human and wildlife movements can be better managed for the benefit of both, and how the most effective conservation strategies can be best selected to suit existing (and future) geopolitical realities.  相似文献   
16.
Ambio - The peregrine falcon (Falco peregrinus) and the gyrfalcon (Falco rusticolus) are top avian predators of Arctic ecosystems. Although existing monitoring efforts are well established for both...  相似文献   
17.
Conservation resources are limited, necessitating prioritization of species and locations for action. Most prioritization approaches are based solely on biologically relevant characteristics of taxa or areas and ignore geopolitical realities. Doing so risks a poor return on conservation investment due to nonbiological factors, such as economic or political instability. We considered felids, a taxon which attracts intense conservation attention, to demonstrate a new approach that incorporates both intrinsic species traits and geopolitical characteristics of countries. We developed conservation priority scores for wild felids based on their International Union for Conservation of Nature status, body mass, habitat, range within protected area, evolutionary distinctiveness, and conservation umbrella potential. We used published data on governance, economics and welfare, human population pressures, and conservation policy to assign conservation‐likelihood scores to 142 felid‐hosting countries. We identified 71 countries as high priorities (above median) for felid conservation. These countries collectively encompassed all 36 felid species and supported an average of 96% of each species’ range. Of these countries, 60.6% had below‐average conservation‐likelihood scores, which indicated these countries are relatively risky conservation investments. Governance was the most common factor limiting conservation likelihood. It was the major contributor to below‐median likelihood scores for 62.5% of the 32 felid species occurring in lower‐likelihood countries. Governance was followed by economics for which scores were below median for 25% of these species. An average of 58% of species’ ranges occurred in 43 higher‐priority lower‐likelihood countries. Human population pressure was second to governance as a limiting factor when accounting for percentage of species’ ranges in each country. As conservation likelihood decreases, it will be increasingly important to identify relevant geopolitical limitations and tailor conservation strategies accordingly. Our analysis provides an objective framework for biodiversity conservation action planning. Our results highlight not only which species most urgently require conservation action and which countries should be prioritized for such action, but also the diverse constraints which must be overcome to maximize long‐term success.  相似文献   
18.
The razorback sucker, Xyrauchen texanus , in the middle Green River (U.S.A.) has been described as a static population consisting of old individuals that will eventually disappear through attrition. Capture data between 1980 and 1992 indicated a constant length frequency despite a slow but positive growth rate of individual fish. Abundance and survival estimates indicated that the population of razorback sucker in the middle Green River is precariously low but dynamic. Although high variation existed among survival estimates, no significant decrease in the population between 1982 and 1992 could be detected. The low level of recruitment occurring in the razorback sucker population of the middle Green River was related to high-flow years, indicating that floodplain habitats may be necessary for survival of the species.  相似文献   
19.
We present three empirical methods for risk assessment in field studies of free-ranging vertebrates. First, we advocate statistical inference concerning population recruitment or mortality in response to ecological hazards. Second, if inferences about both recruitment and mortality are available, one can use a Leslie- Lefkovitch matrix to estimate the finite rate of population change () as a function of ecological hazards. Third, designed experiments can be conducted on samples of marked animals in natural environments to assess impacts and risks. These methods rely on either sophisticated capture-recapture or radio-tracking models, and on well-developed analysis theory. The use of uniquely marked animals is somewhat analogous to the use of tracers in other areas of risk assessment. We present examples of each approach and discuss some limitations.  相似文献   
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