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51.
David M Lodge Susan Williams Hugh J MacIsaac Keith R Hayes Brian Leung Sarah Reichard Richard N Mack Peter B Moyle Maggie Smith David A Andow James T Carlton Anthony McMichael 《Ecological applications》2006,16(6):2035-2054
The Ecological Society of America has evaluated current U.S. national policies and practices on biological invasions in light of current scientific knowledge. Invasions by harmful nonnative species are increasing in number and area affected; the damages to ecosystems, economic activity, and human welfare are accumulating. Without improved strategies based on recent scientific advances and increased investments to counter invasions, harm from invasive species is likely to accelerate. Federal leadership, with the cooperation of state and local governments, is required to increase the effectiveness of prevention of invasions, detect and respond quickly to new potentially harmful invasions, control and slow the spread of existing invasions, and provide a national center to ensure that these efforts are coordinated and cost effective. Specifically, the Ecological Society of America recommends that the federal government take the following six actions: (1) Use new information and practices to better manage commercial and other pathways to reduce the transport and release of potentially harmful species; (2) Adopt more quantitative procedures for risk analysis and apply them to every species proposed for importation into the country; (3) Use new cost-effective diagnostic technologies to increase active surveillance and sharing of information about invasive species so that responses to new invasions can be more rapid and effective; (4) Create new legal authority and provide emergency funding to support rapid responses to emerging invasions; (5) Provide funding and incentives for cost-effective programs to slow the spread of existing invasive species in order to protect still uninvaded ecosystems, social and industrial infrastructure, and human welfare; and (6) Establish a National Center for Invasive Species Management (under the existing National Invasive Species Council) to coordinate and lead improvements in federal, state, and international policies on invasive species. Recent scientific and technical advances provide a sound basis for more cost-effective national responses to invasive species. Greater investments in improved technology and management practices would be more than repaid by reduced damages from current and future invasive species. The Ecological Society of America is committed to assist all levels of government and provide scientific advice to improve all aspects of invasive-species management. 相似文献
52.
S.H. Cadle R.L. Williams 《Journal of the Air & Waste Management Association (1995)》2013,63(5):502-507
This paper is directed to air pollution scientists interested in special mobile emission sources. The purpose was to determine the contribution which automobile tires make to air pollution. The gaseous hydrocarbon and sulfur compounds emitted in laboratory tests were identified. Although these hydrocarbons can participate in smog reactions, their mass emission rate is less than 0.1 % of the current exhaust hydrocarbon emission rate. Hydrocarbons from tires are not measurable near a freeway. The particulate emitted from tires ranges in size from 0.01 μm to more than 30 μm, with the larger particles dominating the total mass. Measurements along a California freeway showed that most of the tire debris had settled within 5 m of the pavement edge. Airborne rubber concentrations were less than 0.5 μg/m3, or less than 5% of the total tire wear. These field measurements confirm the indoor emission pattern and verify that tire wear products are not a significant air pollution problem. 相似文献
53.
Howard Moore Kathryn R. Williams 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1043-1045
The techniques of Principal Component Analysis (PCA) and subsequent regression analysis were used in an attempt to describe local and upwind chemical and physical factors which affect the variability of SO4 –2 concentrations observed in a rural area of the northeastern U.S. The data used in the analyses included upwind and local O3 concentrations, temperature, relative humidity and other climatological information, SO2, and meteorological information associated with backward trajectories. The investigation identified five principal components, three major (eigenvalues >1) and two minor (eigenvalues < one), which accounted for 52% (r = 0.72) of the variability in the SO4 –2 regression model. These components can be described as representing local and upwind photochemistry, droplet growth, SO2 emissions, and air mass characteristics. The study also indicated that in future studies it will be necessary to a priori select air pollution and meteorological variables for measurement to potentially increase the sensitivity of this type of receptor model. 相似文献
54.
55.
Sather ME Slonecker ET Mathew J Daughtrey H Williams DD 《Environmental monitoring and assessment》2007,124(1-3):211-221
Nitrogen Dioxide (NO2) is a common urban air pollutant that results from the combustion of fossil fuels. It causes serious human health effects,
is a precursor to the formation of ground level ozone, another serious air pollutant, and is one of the six criteria air pollutants
established by the United States (U.S.) Clean Air Act (CAA). Ogawa Passive Sampling Devices (PSDs) for NO2 were collocated and operated at six NO2 Federal Reference Method (FRM) monitor locations in the El Paso, Texas area for the 2004 calendar year. Passive samples were
taken at 2-week, 3-week, and 4-week intervals and compared against the continuously operating FRM monitors. Results showed
that the collective NO2 annual arithmetic mean for all passive monitors was identical to the NO2 mean for all FRM monitors. Of the individual locations, three passive annual NO2 means were identical to their corresponding FRM means, and three passive annual NO2 means differed from their corresponding FRM means by only one part per billion (ppb). Linear correlation analysis between
all readings of the individual NO2 PSDs and FRM values showed an average absolute difference of 1.2 ppb with an r
2 of 0.95. Paired comparison between high and low concentration annual NO2 sites, seasonal considerations, and interlab quality control comparisons all showed excellent results. The ease of deployment,
reliability, and the cost-savings that can be realized with NO2 PSDs could make them an attractive alternative to FRM monitors for screening purposes, and even possibly an equivalent method
for annual NO2 monitoring. More tests of the Ogawa NO2 PSD are recommended for different ecosystem and climate regimes. 相似文献
56.
Wendy A. Williams Mark E. Jensen J. Chris Winne Roland L. Redmond 《Environmental monitoring and assessment》2000,64(1):105-114
Accurate delineation and characterization of valley-bottom settings is crucial to the assessment of the biological and geomorphological components of riverine systems; yet, to date, most valley-bottom mapping endeavors have been done manually. To improve this situation, we developed automated techniques in a Geographic Information System (GIS) for delineating and characterizing valley-bottom settings in river basins ranging in size from approximately 1,000–10,000 km2. All procedures were developed with ARC/INFO GIS software and fully automated in Arc Macro Language (AML). The GRID module is required for valley-bottom delineation and slope calculations; whereas characterization (i.e., measuring the width of the valley-bottom zone) requires Coordinate Geometry (COGO) in the ARCEDIT module. The process requires three inputs: a polygon coverage of the analysis area; an arc coverage of its hydrography, and a grid representing its digital elevation. The AML is designed to operate within a wide range of computer memory/disk space options, and it allows users to customize several procedures to match the scale and complexity of a given analysis area with available computer hardware. 相似文献
57.
A.J. Wheeler I. Williams R.A. Beaumont R.S. Hamilton 《Environmental monitoring and assessment》2000,65(1-2):69-77
The personal exposure of children aged 9 – 11 years to particulate matter (PM10 and PM2.5) was carried out between January and September 1997 in the London Borough of Barnet. Personal sampling along with home, garden and classroom microenvironmental monitoring was completed for all ten children. Each child was monitored for five days during winter, spring and summer. All children completed daily time activity diaries to provide information on any potential activities that could influence their exposure to particulate matter. Each evening a household activity questionnaire was also completed by the parents. Personal Environmental Monitors were used to sample personal exposure to PM10 and PM2.5. Harvard Impactors were used for the microenvironmental sampling of both size fractions. The children's mean personal exposure concentrations for PM10 during winter, spring and summer were 72, 54 and 35 µg/m3 respectively and for PM2.5 22, 17 and 18 µg/m3 respectively. In order to determine the potential sources of particulate matter, analysis of the Teflon filters has been undertaken. The physical characteristics of the particles have been identified using Scanning Electron Microscopy. The relationships between personal exposure concentrations and the different microenvironments will be discussed. 相似文献
58.
Williams BK 《Journal of environmental management》2011,92(5):1371-1378
Adaptive management is a framework for resource conservation that promotes iterative learning-based decision making. Yet there remains considerable confusion about what adaptive management entails, and how to actually make resource decisions adaptively. A key but somewhat ambiguous distinction in adaptive management is between active and passive forms of adaptive decision making. The objective of this paper is to illustrate some approaches to active and passive adaptive management with a simple example involving the drawdown of water impoundments on a wildlife refuge. The approaches are illustrated for the drawdown example, and contrasted in terms of objectives, costs, and potential learning rates. Some key challenges to the actual practice of AM are discussed, and tradeoffs between implementation costs and long-term benefits are highlighted. 相似文献
59.
Adaptive management of natural resources--framework and issues 总被引:4,自引:0,他引:4
Williams BK 《Journal of environmental management》2011,92(5):1346-1353
Adaptive management, an approach for simultaneously managing and learning about natural resources, has been around for several decades. Interest in adaptive decision making has grown steadily over that time, and by now many in natural resources conservation claim that adaptive management is the approach they use in meeting their resource management responsibilities. Yet there remains considerable ambiguity about what adaptive management actually is, and how it is to be implemented by practitioners. The objective of this paper is to present a framework and conditions for adaptive decision making, and discuss some important challenges in its application. Adaptive management is described as a two-phase process of deliberative and iterative phases, which are implemented sequentially over the timeframe of an application. Key elements, processes, and issues in adaptive decision making are highlighted in terms of this framework. Special emphasis is given to the question of geographic scale, the difficulties presented by non-stationarity, and organizational challenges in implementing adaptive management. 相似文献
60.
Steven J Phillips Paul Williams Guy Midgley Aaron Archer 《Ecological applications》2008,18(5):1200-1211
We introduce a new way of measuring and optimizing connectivity in conservation landscapes through time, accounting for both the biological needs of multiple species and the social and financial constraint of minimizing land area requiring additional protection. Our method is based on the concept of network flow; we demonstrate its use by optimizing protected areas in the Western Cape of South Africa to facilitate autogenic species shifts in geographic range under climate change for a family of endemic plants, the Cape Proteaceae. In 2005, P. Williams and colleagues introduced a novel framework for this protected area design task. To ensure population viability, they assumed each species should have a range size of at least 100 km2 of predicted suitable conditions contained in protected areas at all times between 2000 and 2050. The goal was to design multiple dispersal corridors for each species, connecting suitable conditions between time periods, subject to each species' limited dispersal ability, and minimizing the total area requiring additional protection. We show that both minimum range size and limited dispersal abilities can be naturally modeled using the concept of network flow. This allows us to apply well-established tools from operations research and computer science for solving network flow problems. Using the same data and this novel modeling approach, we reduce the area requiring additional protection by a third compared to previous methods, from 4593 km2 to 3062 km , while still achieving the same conservation planning goals. We prove that this is the best solution mathematically possible: the given planning goals cannot be achieved with a smaller area, given our modeling assumptions and data. Our method allows for flexibility and refinement of the underlying climate-change, species-habitat-suitability, and dispersal models. In particular, we propose an alternate formalization of a minimum range size moving through time and use network flow to achieve the revised goals, again with the smallest possible newly protected area (2850 km2). We show how to relate total dispersal distance to probability of successful dispersal, and compute a trade-off curve between this quantity and the total amount of extra land that must be protected. 相似文献