Bayesian predictive inference for the proportion of eroded land in a small area in Iowa

There is an increasing interest in the quality of soil, especially for small geographical areas. We present a method to estimate the percent of the area in a county or hydrological basin that is eroded. There are sample data (for several counties in eastern Iowa) from the National Resources Inventory and population data on land use, land capability class, rainfall and slope length and steepness. Using the Gibbs sampler we perform Bayesian predictive inference to obtain estimates for the non-sampled units. These estimates, together with the sample data, provide an estimate of the proportion of the total area that is eroded. We assess the quality of fit of our model using two cross-validation exercises and graphical methods.     

Statistical hypothesis testing formulations for U.S. environmental regulatory standards for ozone

Environmental regulatory standards are intended to protect human health and environmental welfare. Current standards are based on scientific and policy considerations but appear to lack rigorous statistical foundations and may have unintended regulatory consequences. We examine current and proposed U.S. environmental regulatory standards for ozone from the standpoint of their formulation and performance within a statistical hypothesis testing framework. We illustrate that the standards can be regarded as representing constraints on a percentile of the ozone distribution, where the percentile involved depends on the defined length of ozone season and the constraint is stricter in regions with greater variability. A hypothesis testing framework allows consideration of error rates (probability of false declaration of violation and compliance) and we show that the existing statistics on which the standards are based can be improved upon in terms of bias and variance. Our analyses also raise issues relating to network design and the possibilities of defining a regionally based standard that acknowledges and accounts for spatial and temporal variability in the ozone distribution.     

Statistical evaluation of the attainment of interim cleanup standards at hazardous waste sites

Cleanup standards at hazardous waste sites include (i) numeric standards (often risk-based), (ii) background standards in which the remediated site is compared with data from a supposedly clean region, and (iii) interim standards in which the remediated site is compared with preremediation data from the same site. The latter are especially appropriate for verifying progress when an innovative, but unproven, technology is used for remediation. Standards of type (i) require one-sample statistical tests, while those of type (ii) and type (iii) call for two-sample tests. This paper considers two-sample tests with an emphasis upon the type (iii) scenario. Both parametric (likelihood ratio) and nonparametric (linear rank) protocols are examined. The methods are illustrated with preremediation data from a site on the National Priorities List. The results indicate that nonparametric procedures can be quite competitive (in terms of power) with distributional modelling provided a near optimal rank test is selected. Suggestions are given for identifying such rank tests. The results also confirm the importance of sound baseline sampling; no amount of post-remediation sampling can overcome baseline deficiencies.This paper has been prepared with partial support from the United States Environmental Protection Agency under a Cooperative Agreement Number CR-815273. The contents have not been subject to Agency review and therefore do not necessarily reflect the views or policies of the Agency and no official endorsement should be inferred.     

大气环境影响评价中理解和执行国家标准的几个问题

就大气环境影响评价中理解和执行ＧＢ／Ｔ１３２０１－９１、ＧＢ３０９５－８２的几个问题提出了看法和建议。     

论灾害防治指导思想的转变

在与灾害进行斗争的长期过程中，人类逐步形成了关于灾害防治的指导思想，其中既有正确的、科学的成分．也有错误的、不合理的成分。本文依据灾害本身的性质与规律，从灾害与自然生态──社会经济系统的相互关系原理出发，分析并重新认识当代社会人类进行灾害防治工作的指导思想．以图确立正确的灾害防治指导思想．为减灾防灾工作顺利而有效的展开奠定基础。     

Cross-boundary issues for national parks: What works “on the ground”

In recent years, cross-boundary management has become an essential part of park management. In this article we compare the perspectives of managers of several US national parks to the advice on this issue presented in the published literature. Data were obtained from interviews of the superintendents, assistant superintendents and resources managers of five major western national parks and from a survey of participants in a NPS workshop attended by park superintendents, scientists, and resource managers; law enforcement personnel; and interpreters. Three themes related to boundary management were consistently stressed by park managers: (10 a lack of sufficient funds and personnel within the parks; (2) the need for reliable information on both political and natural processes; and, (3) the importance of personal interactions between park staff and individuals from the surrounding area. Basic data collection, the documentation of trends, cooperative groups and personal contacts, educational programs, and land acquisition were the most useful strategies. A lack of funds and information, ineffective communication, enforcement problems, and a lack of motivation for parties to reach a negotiated agreement were the most serious obstacles. A wide range of valuable institutional knowledge concerning boundary management exists within the National Park Service; however, there appears to be a gap between published strategies and the approaches that work “on the ground”.     

MANAGEMENT AND ANALYSIS OF WATER-USE DATA USING A GEOGRAPHIC INFORMATION SYSTEM1

ASSTRACT: As part of its mission, the U.S. Geological Survey conducts water-resources research. Site-specific and aggregate water-use data are used in the Survey's National Water-Use Information Program and in various hydrologic investigations. Both types of activities have specific requirements in terms of water-use data access, analysis, and display. In Kansas, the Survey obtains water-use information from several sources. Trpically, this information is in a format that is not readily usable by the Survey. Geographic information system (GIS) technology is being used to restructure the available water-use data into a format that allows users to readily access and summarize site-specific water-use data by source (i.e., surface or ground water), type of use, and user-defined area.     

A case study of resources management planning with multiple objectives and projects

Each National Park Service unit in the United States produces a resources management plan (RMP) every four years or less. The plans commit budgets and personnel to specific projects for four years, but they are prepared with little quantitative and analytical rigor and without formal decision-making tools. We have previously described a multiple objective planning process for inventory and monitoring programs (Schmoldt and others 1994). To test the applicability of that process for the more general needs of resources management planning, we conducted an exercise on the Olympic National Park (NP) in Washington State, USA. Eight projects were selected as typical of those considered in RMPs and five members of the Olympic NP staff used the analytic hierarchy process (AHP) to prioritize the eight projects with respect to their implicit management objectives. By altering management priorities for the park, three scenarios were generated. All three contained some similarities in rankings for the eight projects, as well as some differences. Mathematical allocations of money and people differed among these scenarios and differed substantially from what the actual 1990 Olympic NP RMP contains. Combining subjective priority measures with budget dollars and personnel time into an objective function creates a subjective economic metric for comparing different RMP’s. By applying this planning procedure, actual expenditures of budget and personnel in Olympic NP can agree more closely with the staff’s management objectives for the park.     

Adapting regional eutrophication targets for surface waters—influence of the EU Water Framework Directive, national policy and climate change

Large amounts of waterborne nutrients are major problems for society since they can cause harmful algal blooms in surface water bodies. Consequently, there are a variety of national and international guidelines, e.g. Swedish National Environmental Quality Objectives and the EU Water Framework Directive, which include targets to be achieved within a certain time frame. This paper uses the example of a large Swedish lake to show that national and international targets must be adapted to the local situations. Despite decreasing nutrient concentrations, cyanobacterial blooms in the lake have increased over recent years. We found that these blooms coincide with depleted nitrate–nitrogen concentrations and increased water temperatures. We propose a simple model with water temperature, nitrate–nitrogen and total phosphorus concentrations as input variables as a basis for formulation of regional eutrophication targets. Political decisions should be preceded by open discussion between policymakers and scientists to differentiate between real knowledge, assumptions or feelings. For optimal results, recommendations for reducing nutrient load should consider all sources, including urban stormwater and wastewater from rural houses, and should be founded on a balanced reduction in emissions of algae-available nutrients. In addition, climate change calls for more effective environmental policy to protect surface water resources.     

Simulation modeling to understand how selective foraging by beaver can drive the structure and function of a willow community

Beaver–willow (Castor-Salix) communities are a unique and vital component of healthy wetlands throughout the Holarctic region. Beaver selectively forage willow to provide fresh food, stored winter food, and construction material. The effects of this complex foraging behavior on the structure and function of willow communities is poorly understood. Simulation modeling may help ecologists understand these complex interactions. In this study, a modified version of the SAVANNA ecosystem model was developed to better understand how beaver foraging affects the structure and function of a willow community in a simulated riparian ecosystem in Rocky Mountain National Park, Colorado (RMNP). The model represents willow in terms of plant and stem dynamics and beaver foraging in terms of the quantity and quality of stems cut to meet the energetic and life history requirements of beaver. Given a site where all stems were equally available, the model suggested a simulated beaver family of 2 adults, 2 yearlings, and 2 kits required a minimum of 4 ha of willow (containing about10 stems m⁻²) to persist in a steady-state condition. Beaver created a willow community where the annual net primary productivity (ANPP) was 2 times higher and plant architecture was more diverse than the willow community without beaver. Beaver foraging created a plant architecture dominated by medium size willow plants, which likely explains how beaver can increase ANPP. Long-term simulations suggested that woody biomass stabilized at similar values even though availability differed greatly at initial condition. Simulations also suggested that willow ANPP increased across a range of beaver densities until beaver became food limited. Thus, selective foraging by beaver increased productivity, decreased biomass, and increased structural heterogeneity in a simulated willow community.