Predicting the effects of ionising radiation on ecosystems by a generic model based on the Lotka–Volterra equations

The present work describes a model for predicting the population dynamics of the main components (resources and consumers) of terrestrial ecosystems exposed to ionising radiation. The ecosystem is modelled by the Lotka–Volterra equations with consumer competition. Linear dose–response relationships without threshold are assumed to relate the values of the model parameters to the dose rates. The model accounts for the migration of consumers from areas characterised by different levels of radionuclide contamination. The criteria to select the model parameter values are motivated by accounting for the results of the empirical studies of past decades. Examples of predictions for long-term chronic exposure are reported and discussed.     

Environmental Impact Evaluation Model for Industrial Processes

This paper proposes a model to evaluate the environmental impact of manufacturing processes. This model uses the potency factor approach to classify environmental impacts into five ecological health impact groups and uses their toxicological, cancer, and physical effects as the bases to rate the seven groups of human health impacts. The environmental impacts in each impact group are reported, and their hazard scores on ecological and human health are determined. The model also generates a single score for the overall environmental impacts of a process. This single score system helps to identify, among all the viable processes, which is the most environmentally friendly process. This model can serve as a tool to highlight the potential environmental hazards of process operations and to provide information about environmental performance for decision making. The model has been developed into a computer software program, Environmental Impact Evaluation System, and is demonstrated by using the processes employed for the manufacture of paper bags.     

Modeling Long-Term Risk to Environmental and Human Systems at the Hanford Nuclear Reservation: Scope and Findings from the Initial Model

The Groundwater Protection Project at the US Department of Energy Hanford Site in Washington State is currently developing the means to assess the cumulative impact to human and ecological health and the regional economy and cultures from radioactive and chemical waste that will remain at the Hanford Site after the site closes. This integrated system is known as the System Assessment Capability (SAC). The SAC Risk/Impact Module discussed in the article uses media- and time-specific concentrations of contaminants estimated by the transport models of the integrated system to project potential impacts on the ecology of the Columbia River corridor, the health of persons who might live in or use the corridor or the upland Hanford environment, the local economy, and cultural resources. Preliminary Monte Carlo realizations from the SAC modeling system demonstrate the feasibility of large-scale uncertainty analysis of the complex relationships in the environmental transport of contaminants on the one hand and ecological, human, cultural, and economic risk on the other. Initial impact results show very small long-term risks for the 10 radionuclides and chemicals evaluated. The analysis also helps determine science priorities to reduce uncertainty and suggests what actions matter to reduce risks.     

Modeling wilderness campsites: Factors that influence amount of impact

A standard campsite model is proposed and then manipulated to examine the influence of individual variables on amount of vegetation loss. Amount of impact is influenced by amount of use, vegetation fragility, vegetation density, and the degree to which activities are concentrated spatially on the site. Degree of concentration also influences the importance of the other explanatory variables. Amount of use and vegetation fragility are equally important determinants of impact and are most influential where activity concentration is low. The curvilinear relationship between amount of use and amount of impact can be explained by the tendency for activities to become increasingly concentrated as amount of use increases. This relationship should not vary with regional or environmental characteristics except where these influence degree of activity concentration.     

Ecological land classification: A survey approach

A landscape approach to ecological land mapping, as illustrated in this article, proceeds by pattern recognition based on ecological theory. The unit areas delineated are hypotheses that arise from a knowledge of what is ecologically important in the land. Units formed by the mapper are likely to be inefficient or irrelevant for ecological purposes unless he possesses a sound rationale as to the interactions and controlling influences of the structural components of ecosystems. Here is the central problem with what have been called objective multivariate approaches to mapping based on grid units and the sometimes arbitrary attributes thereof; they tend to conceal the importance of ecological theory and the necessity for theory-based supervision of pattern recognition. Multivariate techniques are best used iteratively to verify and refine map units initially recognized and delineated by theoretical considerations. These ideas are illustrated by an example of a reconnaissance survey in the Northwest Territories of Canada.     

由长江洪水引发的思考

1998年长江特大洪水给我国人民和国家财产造成巨大损失。本文通过分析长江洪水的原因,提出生态保护对策。     

武陵山区猕猴桃产业化发展探讨

武陵山区猕猴桃生产已显现出产业化发展的前景,但仍然存在基地规模发展、龙头企业品牌创立和市场开拓、科研单位研究开发的协调联动问题,解决的途径在于协调公司、基地农户、科研单位诸方面的利益.     

生态城市的数学模型建立

本文首先论述了生态城市的概念和内涵；其次对于目前的生态城市的系统模型和指标体系进行了综述；然后建构了新的生态城市数学模型，重点讨论了建构该模型的理论基础及其指标体系的相关运算；最后指出该生态系统数学模型的理论和实践意义并对今后相关研究进行展望。     

四川盆地农牧区生态失调的综合整治初探

四川盆地农林牧区是处于我省腹心地带，人口稠密，经济发展较快。本文针对该区出现的自然灾害现状，提出该区发展方向，和具体措施，供有关部门领导参考。     

The reversible process concept applied to the environmental management of large river systems

The wetland ecosystems occurring within alluvial floodplains change rapidly. Within the ecological successions, the life span of pioneer and transient stages may be measured in several years or decades depending on the respective influences of allogenic (water dynamics, erosion, and deposition) and autogenic developmental processes (population dynamics, eutrophication, and terrestrialization). This article emphasizes the mechanisms that are responsible for the ecosystem changes and their importance to environmental management. Two case studies exemplify reversible and irreversible successional processes in reference to different spatial and temporal scales. On the scale of the former channels, the standing-water ecosystems with low homeostasis may recover their previous status after human action on the allogenic processes. On the scale of a whole reach of the floodplain, erosion and deposition appear as reversible processes that regenerate the ecological successions. The concepts of stability and reversibility are discussed in relation to different spatiotemporal referential frameworks and different levels of integration. The reversible process concept is also considered with reference to the energy inputs into the involved subsystems. To estimate the probability of ecosystem regeneration or the cost of restoration, a concept of degrees of reversibility is proposed.