Formulating an ecosystem approach to environmental protection

The U.S. Environmental Protection Agency (EPA) has embraced a new strategy of environmental protection that is place-driven rather than program-driven. This new approach focuses on the protection of entire ecosystems. To develop an effective strategy of ecosystem protection, however, EPA will need to: (1) determine how to define and delineate ecosystems and (2) categorize threats to individual ecosystems and priority rank ecosystems at risk. Current definitions of ecosystem in use at EPA are inadequate for meaningful use in a management or regulatory context. A landscape-based definition that describes an ecosystem as a volumetric unit delineated by climatic and landscape features is suggested. Following this definition, ecosystems are organized hierarchically, from megaecosystems, which exist on a continental scale (e.g., Great Lakes), to small local ecosystems.Threats to ecosystems can generally be categorized as: (1) ecosystem degradation (occurs mainly through pollution) (2) ecosystem alteration (physical changes such as water diversion), and (3) ecosystem removal (e.g., conversion of wetlands or forest to urban or agricultural lands). Level of threat (i.e., how imminent), and distance from desired future condition are also important in evaluating threats to ecosystems. Category of threat, level of threat, and distance from desired future condition can be combined into a three-dimensional ranking system for ecosystems at risk. The purpose of the proposed ranking system is to suggest a preliminary framework for agencies such as EPA to prioritize responses to ecosystems at risk.     

Disturbance regimes,resilience, and recovery of animal communities and habitats in lotic ecosystems

Disturbance regime is a critical organizing feature of stream communities and ecosystems. The position of a given reach in the river basin and the sediment type within that reach are two key determinants of the frequency and intensity of flow-induced disturbances. We distinguish between predictable and unpredictable events and suggest that predictable discharge events are not disturbances. We relate the dynamics of recovery from disturbance (i.e., resilience) to disturbance regime (i.e., the disturbance history of the site). The most frequently and predictably disturbed sites can be expected to demonstrate the highest resilience. Spatial scale is an important dimension of community structure, dynamics, and recovery from disturbance. We compare the effects on small patches (⩽1 m²) to the effects of large reaches at the river basin level. At small scales, sediment movements and scour are major factors affecting the distribution of populations of aquatic insects or algae. At larger scales, we must deal with channel formation, bank erosion, and interactions with the riparian zone that will affect all taxa and processes. Our understanding of stream ecosystem recovery rests on our grasp of the historical, spatial, and temporal background of contemporary disturbance events.     

Ecosystem health: I. Measuring ecosystem health

Ecosystem analysis has been advanced by an improved understanding of how ecosystems are structured and how they function. Ecology has advanced from an emphasis on natural history to consideration of energetics, the relationships and connections between species, hierarchies, and systems theory. Still, we consider ecosystems as entities with a distinctive character and individual characteristics. Ecosystem maintenance and preservation form the objective of impact analysis, hazard evaluation, and other management or regulation activities. In this article we explore an approach to ecosystem analysis which identifies and quantifies factors which define the condition or state of an ecosystem in terms of health criteria. We relate ecosystem health to human/nonhuman animal health and explore the difficulties of defining ecosystem health and suggest criteria which provide a functional definition of state and condition. We suggest that, as has been found in human/nonhuman animal health studies, disease states can be recognized before disease is of clinical magnitude. Example disease states for ecosystems are functionally defined and discussed, together with test systems for their early detection.This article is contribution VI in D.J. Schaeffer's Environmental Audit series.     

Disturbance and recovery of large floodplain rivers

Disturbance in a river-floodplain system is defined as an unpredictable event that disrupts structure or function at the ecosystem, community, or population level. Disturbance can result in species replacements or losses, or shifts of ecosystems from one persistent condition to another. A disturbance can be a discrete event or a graded change in a controlling factor that eventually exceeds a critical threshold. The annual flood is the major driving variable that facilitates lateral exchanges of nutrients, organic matter, and organisms. The annual flood is not normally considered a disturbance unless its timing or magnitude is “atypical.” The record flood of 1973 had little effect on the biota at a long-term study site on the Mississippi River, but the absence of a flood during the 1976–1977 Midwestern drought caused short- and long-term changes. Body burdens of contaminants increased temporarily in key species, because of increased concentration resulting from reduced dilution. Reduced runoff and sediment input improved light penetration and increased the depth at which aquatic macrophytes could grow. Developing plant beds exerted a high degree of biotic control and were able to persist, despite the resumption of normal floods and turbidity in subsequent years. In contrast to the discrete event that disturbed the Mississippi River, a major confluent, the Illinois River, has been degraded by a gradual increase in sediment input and sediment resuspension. From 1958 to 1961 formerly productive backwaters and lakes along a 320-km reach of the Illinois River changed from clear, vegetated areas to turbid, barren basins. The change to a system largely controlled by abiotic factors was rapid and the degraded condition persists. Traditional approaches to experimental design are poorly suited for detecting control mechanisms and for determining the critical thresholds in large river-floodplains. Large river-floodplain systems cannot be manipulated or sampled as easily as small streams, and greater use should be made of man-made or natural disturbances and environmental restoration as opportunistic experiments to measure thresholds and monitor the recovery process. Coauthors are listed in alphabetical order.     

Ecosystem approaches to environmental quality assessment

Environmental quality assessment has to focus more on the quality of whole ecosystems, instead of focusing on the direct effects of a specific stressor, because of a more integrated environmetal policy approach. Yet, how can the ecosystem quality be measured? Partly this is a normative question, a question of what is considered good and bad. At the same time, it is a scientific question, dealing with the problem of low the state of a system as complex as an ecosystem could be measured. Measuring all abiotic and biotic components, not to mention their many relationships, is not feasible. In this article we review several approaches dealing with this scientific question. Three approaches are distinguished; they differ in type of variable set and ecosystem model used. As a result of this, the information about the state of the ecosystem differs: ultimate breadth, comprising information about the whole ecosystem, is at the expense of detail, while ultimate detail is at the expense of breadth. We discuss whether the resultant quality assessments differ in character and are therefore suitable to answer different policy questions.     

Indicators for sustainable energy development in Mexico

This article presents a summary of a study on the application to the Mexican energy sector of a core set of indicators for sustainable energy development (ISED), developed by the International Atomic Energy Agency (IAEA). The study focused on the elaboration of socio‐economic and environmental indicators related to energy production and use, and was aimed at assessing Mexico's existing energy policies and identifying strategies and possible policies that could bring about improvements in major priority areas: energy intensity, atmospheric emissions, energy import dependency and use of renewables. While positive trends have been observed in relation to energy intensity and atmospheric emissions, Mexico is becoming more dependent on imports of gasoline, natural gas and other high‐value secondary energy sources, while exporting significant amounts of primary fuels, such as crude oil. Also, no significant increase has been observed in the use of renewable sources of energy. Social, economic and environmental policies need to be formulated for the energy sector and related investments (public and private) reinforced so that all economic sectors have access to energy from cleaner and more diverse sources.     

Defining Acceptable Levels for Ecological Indicators: An Approach for Considering Social Values

Ecological indicators can facilitate an adaptive management approach, but only if acceptable levels for those indicators have been defined so that the data collected can be interpreted. Because acceptable levels are an expression of the desired state of the ecosystem, the process of establishing acceptable levels should incorporate not just ecological understanding but also societal values. The goal of this research was to explore an approach for defining acceptable levels of ecological indicators that explicitly considers social perspectives and values. We used a set of eight indicators that were related to issues of concern in the Lake Champlain Basin. Our approach was based on normative theory. Using a stakeholder survey, we measured respondent normative evaluations of varying levels of our indicators. Aggregated social norm curves were used to determine the level at which indicator values shifted from acceptable to unacceptable conditions. For seven of the eight indicators, clear preferences were interpretable from these norm curves. For example, closures of public beaches because of bacterial contamination and days of intense algae bloom went from acceptable to unacceptable at 7–10 days in a summer season. Survey respondents also indicated that the number of fish caught from Lake Champlain that could be safely consumed each month was unacceptably low and the number of streams draining into the lake that were impaired by storm water was unacceptably high. If indicators that translate ecological conditions into social consequences are carefully selected, we believe the normative approach has considerable merit for defining acceptable levels of valued ecological system components.     

Stress and recovery assessment during simulated microgravity: Effects of exercise during a long-term head-down tilt bed rest in women

The aim of this study was to determine the effects of a 60-day head-down tilt long-term bed rest (HDT) on stress and recovery in sixteen healthy female volunteers. Participants were randomly assigned to either an exercise group (Exe) that followed a training program combining resistive and aerobic exercises, or to a no-exercise control group (Ctl). Psychological states were assessed using the Rest-Q, a validated questionnaire based on stress–recovery responses. A longitudinal analysis revealed significant changes in the general and specific-stress scales for all participants throughout the experiment with a critical stage from supine to standing posture leading to a significant decrease in physical recovery. During HDT, Exe reported higher scores on stress subscales, as well as lower recovery scores compared to the Ctl. During the post-HDT ambulatory recovery period, the exercisers still reported higher scores than the non-exercisers on the Lack of energy stress-related scale, along with lower scores in general well-being and personal accomplishment. The present findings show that simulated weightlessness such as HDT may induce psychological stress and lead to subsequent alterations in perceived recovery. Exercise did not reduce HDT impaired effects on stress and recovery states. Several suggestions, including psychological preparation, are proposed to support the beneficial effects of exercise on psychological factors.     

Input- and output-oriented approaches to implementing ecosystem management

Input- and output-oriented approaches to landscape management have distinct roles for resource protection, environmental restoration, and sustainable land management. Implementing recent proposals for ecosystem management in the western United States involves a synthesis of input and output management. Within the broader context of ecosystem management, input management focuses on tailoring land use to the landscape, whereas output management employs assessments of resource condition to trigger modified management activity once resources are degraded to specified threshold conditions. Current approaches to landscape-scale management, however, tend to rely primarily on output-oriented strategies that are most effective for monitoring environmental conditions. Current uses of input management focus on environmental impact assessments, which generally are site- or project-specific analyses. The compeexity and dynamic nature of ecosystems, and the range of scales over which ecological processes operate, imply that development and incorporation of input-oriented approaches into landscape-scale management is necessary to implement ecosystem management as a strategy for sustainable land use.     

A Vegetation-Based Method for Ecological Diagnosis of Riverine Wetlands

/ The management of riverine wetlands, recognized as a major component of biodiversity in fluvial hydrosystems, is problematic. Preservation or restoration of such ecosystems requires a method to assess the major ecological processes operating in the wetlands, the sustainability of the aquatic stage, and the restoration potential of each riverine wetland. We propose a method of diagnosis based on aquatic macrophytes and helophytes. Plant communities are used because they are easy to survey and provide information about (1) the origin of a water supply (i.e., groundwater, seepage, or surface river water) and its nutrient content, (2) effects of flood disturbances, and (3) terrestrialization processes. The novelty of the method is that, in contrast to available typologies, it is based on the interference of gradients resulting from several processes, which makes it possible to predict wetland sustainability and restoration potential. These predictions result from knowledge of the processes involved in terrestrialization, i.e., the influence of flood disturbances, occurrence of groundwater supplies, trophic degree, and water permanency of the habitat during a yearly cycle. The method is demonstrated on five different river systems.     

Theory of the physical environment: An introduction

This paper suggests a way of classifying human physical environment according to its location and function. Environmental science is viewed as a branch of ecology, and the concept of the complex ecosystem is introduced. By using differential equations, the author draws attention to four factors that must be considered when evaluating the effect of any environmental agent on a human subject: the agent's extensive quality of rate of flow, its intensive quality of concentration or intensity, duration of the subject's exposure, and the uniformity of agent's stress in space and time. The environmental agents, individually or in jointly acting groups, produce environmental stress, which acts on the subject to produce strain and its contingent symptoms. The microclimate in this setting can be classified according to the type of stress involved. The human physical environment may be evaluated in three ways: objectively, subjectively, and from the standpoint of regulations or standards. The benefit or advantage of using this equation in evaluating or measuring the human physical environment is discussed.     

土地利用总体规划的环境影响评价指标体系研究

科学合理的土地利用总体规划环境影响评价指标体系既可提高规划的科学性,又可为新一轮规划的修编提供科学依据。运用系统分析法、归纳演绎法、专家咨询法等方法研究建立土地利用总体规划的环境影响评价指标体系,初步将其构建为目标层、准则层和指标层3个层次,包括社会指标、环境指标及资源指标。     

Biodiversity and industry ecosystem management

The term biodiversity describes the array of interacting, genetically distinct populations and species in a region, the communities they comprise, and the variety of ecosystems of which they are functioning parts. Ecosystem health, a closely related concept, is described in terms of a process identifying biological indicators, end points, and values. The decline of populations or species, an accelerating trend worldwide, can lead to simplification of ecosystem processes, thus threatening the stability and sustainability of ecosystem services directly relevant to human welfare in the chain of economic and ecological relationships. The challenge of addressing issues of such enormous scope and complexity has highlighted the limitations of ecology-as-science. Additionally, biosphere-scale conflicts seem to lie beyond the scope of conventional economics, leading to differences of opinion about the commodity value of biodiversity and of the services that intact ecosystems provide. In the face of these uncertainties, many scientists and economists have adopted principles that clearly assign burdens of proof to those who would promote the loss of biodiversity and that also establish near-trump (preeminent) status for ecological integrity. Electric utility facilities and operations impact biodiversity whenever construction, operation, or maintenance of generation, delivery, and support facilities alters landscapes and habitats and thereby impacts species. Although industry is accustomed to dealing with broad environmental concerns (such as global warming or acid rain), the biodiversity issue invokes hemisphere-wide, regional, local, and site-specific concerns all at the same time. Industry can proactively address these issues of scope and scale in two main ways: first, by aligning strategically with the broad research agenda put forth by informed scientists and institutions; and second, by supporting focused management processes whose results will contribute incrementally to the broader agenda of rebuilding or maintaining biodiversity.     

Animals as indicators of ecosystem responses to air emissions

With existing and proposed air-quality regulations, ecological disasters resulting from air emissions such as those observed at Copperhill, Tennessee, and Sudbury, Ontario, are unlikely. Current air-quality standards, however, may not protect ecosystems from subacute and chronic exposure to air emissions. The encouragement of the use of coal for energy production and the development of the fossil-fuel industries, including oil shales, tar sands, and coal liquification, point to an increase and spread of fossil-fuel emissions and the potential to influence a number of natural ecosystems. This paper reviews the reported responses of ecosystems to air-borne pollutants and discusses the use of animals as indicators of ecosystem responses to these pollutants. Animal species and populations can act as important indicators of biotic and abiotic responses of aquatic and terrestrial ecosystems. These responses can indicate long-term trends in ecosystem health and productivity, chemical cycling, genetics, and regulation. For short-term trends, fish and wildlife also serve as monitors of changes in community structure, signaling food-web contamination, as well as providing a measure of ecosystem vitality. Information is presented to show not only the importance of animals as indicators of ecosystem responses to air-quality degradation, but also their value as air-pollution indices, that is, as air-quality-related values (AQRV), required in current air-pollution regulation.     

Adaptive management for sound ecosystem management

Sound ecosystem management meshes socioeconomic attitudes and values with sustainable natural resource practices. Adaptive management is a model for guiding natural resource managers in this process. Ecosystems and the societies that use them are continually evolving. Therefore, managers must be flexible and adaptable in the face of uncertainty and lack of knowledge. To couple good science to management, it is important to develop goals, models, and hypotheses that allow us to systematically learn as we manage. Goals and models guide the development and implementation of management practices. The need to evaluate models and test hypotheses mandates monitoring, which feeds into a continuous cycle of goal and model reformulation. This paper reviews the process of adaptive management and describes how it is being applied to oak/pine savanna restoration at Necedah National Wildlife Refuge as an illustration. Our aim is to help managers design their own adaptive management models for successful ecosystem management.     

Operational Indicators for Measuring Agricultural Sustainability in Developing Countries

This paper reviews relevant literature on the sustainability indicators theoretically proposed and practically applied by scholars over the past 15 years. Although progress is being made in the development and critical analysis of sustainability indicators, in many cases existing or proposed indicators are not the most sensitive or useful measures in developing countries. Indicator selection needs to meet the following criteria: relative availability of data representing the indicators, sensitivity to stresses on the system, existence of threshold values and guidelines, predictivity, integratability and known response to disturbances, anthropogenic stresses, and changes over time. Based on these criteria, this paper proposes a set of operational indicators for measuring agricultural sustainability in developing countries. These indicators include ecological indicators involving amounts of fertilizers and pesticides used, irrigation water used, soil nutrient content, depth to the groundwater table, water use efficiency, quality of groundwater for irrigation, and nitrate content of both groundwater and crops. Economic indicators include crop productivity, net farm income, benefit–cost ratio of production, and per capita food grain production. Social indicators encompass food self-sufficiency, equality in food and income distribution among farmers, access to resources and support services, and farmers knowledge and awareness of resource conservation. This article suggests that the selection of indicators representing each aspect of sustainability should be prioritized according to spatial and temporal characteristics under consideration.     

A model of multi-purpose ecosystem management for degraded Mediterranean uplands

In order to reconcile the need for conserving and improving neglected Mediterranean upland ecosystems with socio-economic advancement, new concepts of integrated landscape management are required. For this purpose a mode of a closely interwoven network of multiple land-use patterns is suggested, based on vegetation management and manipulation of the soil-plant-animal complex and on multi-purpose environmental landscaping and afforestation. The latter is essential for revegetation of denuded slopes and for fire protection and buffer zones, and is aimed at the creation of semi-natural, multi-layered forests, parks and woodlands. From these, highest overall multiple use benefits can be expected for environmental and watershed protection, resistance to fire hazard, biotic diversity and wildlife, recreation amenity., and plant and animal production.For optimization and dynamic land-use planning such relative values of multiple use benefits should be expressed in quantitative data and applied in dynamic planning of multiple use strategies, which could be tested first in combined research and demonstration schemes.     

耕地质量指标体系的构建

根据土地质量的概念及其影响因素，构建了耕地质量指标体系。认为耕地质量的影响因素包括自然、社会和经济因素，而PSR（压力——状态——响应）框架则是构建耕地质量指标体系的最佳思路。在此基础上提出具体评价指标，其中生态功能指标体系包括土壤质量、气候质量、生物多样性质量和景观生态质量，生产功能指标体系（即耕地生产力）则通过耕地生产潜力、耕地基础地力和耕地现实生产力进行评价。     

资源节约型社会评价指标体系的构建

建设资源节约型社会是当前中国极为迫切的任务。在分析资源节约型社会内涵基础上，根据整体性原则、针对性原则、应用性原则、可操作性原则和动态性原则，从经济节约指数、社会节约指数、科技支持指数和环境支持指数4个准则层面给出29个具体指标，基本涵盖了节约型社会的各个方面；最后从推进循环经济的发展、增强节约意识推进节约社会的发展、加快科技进步促进科技成果转化和改善、提高环境支持水平等方面，对提升资源节约型社会节约水平提出了建议。