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Monitoring an ecosystem at risk: What is the degree of grassland fragmentation in the Canadian Prairies? 总被引:1,自引:0,他引:1
Increasing fragmentation of grassland habitats by human activities is a major threat to biodiversity and landscape quality. Monitoring their degree of fragmentation has been identified as an urgent need. This study quantifies for the first time the current degree of grassland fragmentation in the Canadian Prairies using four fragmentation geometries (FGs) of increasing specificity (i.e. more restrictive grassland classification) and five types of reporting units (7 ecoregions, 50 census divisions, 1,166 municipalities, 17 sub-basins, and 108 watersheds). We evaluated the suitability of 11 datasets based on 8 suitability criteria and applied the effective mesh size (m eff) method to quantify fragmentation. We recommend the combination of the Crop Inventory Mapping of the Prairies and the CanVec datasets as the most suitable for monitoring grassland fragmentation. The grassland area remaining amounts to 87,570.45 km2 in FG4 (strict grassland definition) and 183,242.042 km2 in FG1 (broad grassland definition), out of 461,503.97 km2 (entire Prairie Ecozone area). The very low values of m eff of 14.23 km2 in FG4 and 25.44 km2 in FG1 indicate an extremely high level of grassland fragmentation. The m eff method is supported in this study as highly suitable and recommended for long-term monitoring of grasslands in the Canadian Prairies; it can help set measurable targets and/or limits for regions to guide management efforts and as a tool for performance review of protection efforts, for increasing awareness, and for guiding efforts to minimize grassland fragmentation. This approach can also be applied in other parts of the world and to other ecosystems. 相似文献
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The US Environmental Protection Agency maintains networks of pollution monitors for two basic purposes: to check and enforce the attainment of national ambient air quality standards (NAAQS) and to provide useful data for studying pollution and its effects. These purposes imply conflicting criteria for the locations of a limited number of monitors. To check the attainment of standards, monitors are placed where pollution levels are highest. Monitors are not required where standards have always been met and there are no new pollution sources. To provide useful data for studying pollution and its effects, monitors would be placed to observe outcomes under a variety of pollution levels. This study asks the following questions. What factors affect when a monitor is retired from the network? What drives the decision to add a new site? What causes year-to-year changes in the number of monitors? We tackle these questions with a particular focus on the role of regulatory compliance and pollution levels in the context of monitors for tropospheric ozone (O3). Using a panel dataset of monitors in the contiguous US spanning the years 1993 to 2011, we find that the peak O3 readings in the prior period are significantly associated with the regulator’s decision of whether to add or to drop a monitor in the following period. While compliance with the NAAQS for O3 is not consistently associated with network composition, compliance with the PM2.5 NAAQS does appear to affect changes to the network. 相似文献
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Luciano Gomes Estela P. Troiani Jorge Nozaki 《Environmental monitoring and assessment》2011,173(1-4):489-498
The contribution of wastewater from a tannery industry to the pollution of a stream was investigated. The main parameters studied were biochemical oxygen demand, chemical oxygen demand, chromium, dissolved oxygen, fecal and total coliforms, nitrogen, oils and greases, pH, phosphorous, sulfides, suspended solids, turbidity, and volatile solids. Three sampling points were located: (1) at the discharge point of tannery wastewater, (2) 50 m upstream, and (3) 80 m downstream of discharge point. Also was investigated the pollution at the stream source. 相似文献
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Iosif Vorovencii 《Environmental monitoring and assessment》2017,189(10):524
The desertification risk affects around 40% of the agricultural land in various regions of Romania. The purpose of this study is to analyse the risk of desertification in the south-west of Romania in the period 1984–2011 using the change vector analysis (CVA) technique and Landsat thematic mapper (TM) satellite images. CVA was applied to combinations of normalised difference vegetation index (NDVI)-albedo, NDVI-bare soil index (BI) and tasselled cap greenness (TCG)-tasselled cap brightness (TCB). The combination NDVI-albedo proved to be the best in assessing the desertification risk, with an overall accuracy of 87.67%, identifying a desertification risk on 25.16% of the studied period. The classification of the maps was performed for the following classes: desertification risk, re-growing and persistence. Four degrees of desertification risk and re-growing were used: low, medium, high and extreme. Using the combination NDVI-albedo, 0.53% of the analysed surface was assessed as having an extreme degree of desertification risk, 3.93% a high degree, 8.72% a medium degree and 11.98% a low degree. The driving forces behind the risk of desertification are both anthropogenic and climatic causes. The anthropogenic causes include the destruction of the irrigation system, deforestation, the destruction of the forest shelterbelts, the fragmentation of agricultural land and its inefficient management. Climatic causes refer to increase of temperatures, frequent and prolonged droughts and decline of the amount of precipitation. 相似文献
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We model the climate change issue as a pollution control game with the purpose of comparing two possible departures from the business as usual (BAU) where countries noncooperatively choose their emission levels. In the first scenario, players have to agree on a global emission cap (GEC) that is enforced by a uniform taxation scheme. They still behave strategically when choosing emission levels but are now subject to the coupled constraint imposed by the cap. The second scenario consists of the implementation of an international cap and trade (ICT) system. In this case, players decide on their emission quotas, and emission trading is allowed. A three heterogenous player quadratic game serves as a basis for the analysis. When the cap is binding, among all the coupled constraints Nash equilibria, we select a particular normalized equilibrium by solving a variational inequality. Comparing the normalized equilibrium with the Nash equilibria of the BAU and the ICT, we first show that if the cap is appropriately chosen, then the GEC system improves all players’ payoffs, relative to the BAU. The GEC system may thus be unanimously approved whereas the ICT is not, because moving from the BAU to the ICT is costly for one player. Second, for some values of the cap, all players get a higher payoff under the GEC than under the ICT. Therefore, the GEC outperforms the ICT both in terms of feasibility and efficiency. 相似文献
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It is argued that standard environmental economic and 'ecological economics', have the same fundamentals of valuation in terms of money, based on a demand curve derived from utilitymaximization. But this approach leads to three different measuresof value. An invariant measure of value exists only if the consumer has 'homothetic preferences'. In order to obtain a numerical estimate of value, specific functional forms are necessary, but typically these estimates do not converge. This is due to the fact that the underlying economic model is not structurally stable.According to neoclassical economics, any environmental remediation can be justified only in terms of increases in consumer satisfaction, balancing marginal gains against marginal costs. It is not surprising that the optimal policy obtained fromthis approach suggests only small reductions in greenhouse gases.We show that a unidimensional metric of consumer's utility measured in dollar terms can only trivialize the problem of global climate change. 相似文献
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Recent years have witnessed an international increase of capital and human flows, this being accelerated by globalization. Several studies show that this phenomenon positively influences growth whilst being detrimental for the environment. This article aims to shed a light on the relationship between environment, growth and international capitalism and human flows. By making use of yearly data in a panel constructed around 36 OECD countries over the timespan 2000–2017, we run Pooled Ordinary Least Squares, Fixed Effects and Random Effects regressions with Driscoll-Kraay standard error correction, as well as the Generalized Method of Moments and the Dynamic Ordinary Least Squares, to obtain both short and long-run relationship. The main results provide evidence supporting the Environmental Kuznets Curve hypothesis in the short-run, while offering some variation in the long-run. The FDI bolster the economic growth by means of no green technologies. The international touristic demand just impacts on the growth, while the migration flows improve the environmental performance both in the short and long-run, implying that international human flows generate positive spill-over in terms of environmental behaviours and growth. 相似文献
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The Clean Development Mechanism (CDM) suggests that both developed and developing countries can take actions to mitigate global climate change. Carbon reduction and sustainable development are the goals of the CDM. However, the uneven distribution of the CDM projects in developing countries may jeopardize the fulfilment of these goals. This paper uses panel data from 107 host countries to explore the influencing factors of the CDM using a negative binomial regression. The club convergence model is used to divide the host countries into different sub-groups according to their numbers of operating CDM projects in a year. The results show that affluence, the sophisticated international trading experience, and the growing demands for energy of the host countries have a positive impact on the successful registrations of the CDM projects, while the cost of carbon emission abatement hinders the registration. But for countries with fewer CDM projects, the industrial level and national carbon emission have no significant impacts on the distribution of CDM projects. In the end, target policy implications were made based on the results. 相似文献
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Correcting the carbon cycle representation: How important is it for the economics of climate change?
F. Joos G. Müller-Fürstenberger G. Stephan 《Environmental Modeling and Assessment》1999,4(2-3):133-140
Economic analyses of the greenhouse effect are typically carried out within the framework of computable general equilibrium models which represent the climate system by simple two box proxies based upon the pioneering work of Nordhaus. Since errors in predicting the carbon budget can imply high costs, there is some need to include more sophisticated climate models into the economics of global climate change. This paper presents a non-linear pulse representation of the process-based and data-validated Bern carbon model. Compared to the Nordhaus approach this leads to different results with respect to optimal climate policy and atmospheric carbon dioxide concentration. In particular, our results suggest that economic studies which use a Nordhaus representation of the climate system are biased towards high carbon emission and low abatement levels. 相似文献
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Samuel Barsanelli Costa Roberto Wagner Louren?o 《Environmental monitoring and assessment》2011,172(1-4):329-337
Noise mapping has been used as an instrument for assessment of environmental noise, helping to support decision making on urban planning. In Brazil, urban noise is not yet recognized as a major environmental problem by the government. Besides, cities that have databases to drive acoustic simulations, making use of advanced noise mapping systems, are rare. This study sought an alternative method of noise mapping through the use of geoprocessing, which is feasible for the Brazilian reality and for other developing countries. The area chosen for the study was the central zone of the city of Sorocaba, located in São Paulo State, Brazil. The proposed method was effective in the spatial evaluation of equivalent sound pressure level. The results showed an urban area with high noise levels that exceed the legal standard, posing a threat to the welfare of the population. 相似文献
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In macroeconomic analyses usually a simple proportional trade-off between economic growth and environmental pressure is assumed, i.e. constant return to scale (CRS). In this study authors show how changing CRS assumption affects environmental policy effectiveness based on Polish example. The problem revealed in the conducted analysis is actual in many countries, where the local perspective may efface global threats. The empirical objective of this paper is to assess cost-effectiveness of environmental policies at the county level under various return to scale (RTS) scenarios. First, environmental pressure was measured in four dimensions: air, soil, water pollution and bio-uniformity; second, the double-bootstrapped truncated regression model under different RTS were estimated, verifying the cost-effectiveness of county and transnational policies. The results send a message that the adoption of CRS assumption recommended in a such case by literature and usually followed by local authorities may lead to misleading assessment of the eco-efficiency level. It was found that local policy loses its impact on the eco-efficiency under VRS and 40% of local authorities in Poland can no longer benefit from economies of scale. The article offers original methodology, first, for measuring eco-efficiency in macroeconomic approach, second, a frontier-based cost-effectiveness analysis (CEA), adopting the double-bootstrapped modelling procedure. 相似文献
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Angela M. Wallace Melanie V. Croft-White Jan Moryk 《Environmental monitoring and assessment》2013,185(9):7857-7875
Impacts of urbanization on aquatic ecosystems are intensifying as urban sprawl spreads across the global land base. The urban stream syndrome (USS) identifies “symptoms” associated with urban development including changes in biotic communities, hydrology, water chemistry, and channel morphology. Direct relationships between road density (as surrogate of urbanization) and indicators of the USS were identified for streams in the Toronto region. Significant negative relationships were revealed between road density and biological (fish and benthic macroinvertebrate) richness, diversity, and fish Index of Biotic Integrity scores. Significant positive relationships were found between road density and tolerant fish/benthic macroinvertbrates, benthos Family Biotic Index scores, mean summer stream temperature, stream flashiness, and several water quality variables. Analysis of biological data showed that only four fish species and a reduced number of benthic macroinvertebrate families remained at the most urbanized sites. Road density was found to be a major determinant in both the fish and benthic macroinvertebrate community structure. 相似文献