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1.
Preservation of extraordinary natural resources, protection of water quality, and restoration of impaired waters require a strategy to identify and protect least-disturbed streams and rivers. We applied two objective, quantitative methods to determine stream ecological integrity of headwater reaches of 10 Ozark rivers, 5 with Wild and Scenic River federal protective status. Thirty-four variables representing macroinvertebrate and fish assemblage characteristics, in-stream habitat, riparian vegetation, water quality, and watershed attributes were quantified for each river and analyzed using two multivariate approaches. The first approach, cluster and discriminant analyses, identified two groups of river with only one variable (% forested watershed) reliably distinguishing groups. Our second approach employed ordinal scaling to compare variables for each river to conceptually ideal conditions that were developed as a composite of optimal attributes among the 10 rivers. The composite distance of each river from ideal was then calculated using a unidimensional ranking technique. Two rivers without Wild and Scenic River designation ranked highest relative to ideal (highest ecological integrity), and two others, also without designation, ranked most distant from ideal (lowest ecological integrity). Fish density, number of intolerant fish species, and invertebrate density were influential biotic variables for scaling. Contributing physical variables included riparian forest cover, water nitrate concentration, water turbidity, percentage of forested watershed, percentage of private land ownership, and road density. These methods provide a framework for refinement and application in other regions to facilitate the process of establishing least-disturbed reference conditions and identifying rivers for protection and restoration.  相似文献   

2.
River restoration is becoming a priority in many countries because of increasing the awareness of environmental degradation. In Europe, the EU Water Framework Directive (WFD) has significantly reinforced river restoration, encouraging the improvement of ecological status for water bodies. To fulfill the WFD requirements, the Spanish Ministry of the Environment developed in 2006 a National Strategy for River Restoration whose design and implementation are described in this paper. At the same time many restoration projects have been conducted, and sixty of them have been evaluated in terms of stated objectives and pressures and implemented restoration measures. Riparian vegetation enhancement, weir removal and fish passes were the most frequently implemented restoration measures, although the greatest pressures came from hydrologic alteration caused by flow regulation for irrigation purposes. Water deficits in quantity and quality associated with uncontrolled water demands seriously affect Mediterranean rivers and represent the main constraint to achieving good ecological status of Spanish rivers, most of them intensively regulated. Proper environmental allocation of in-stream flows would need deep restrictions in agricultural water use which seem to be of very difficult social acceptance. This situation highlights the need to integrate land-use and rural development policies with water resources and river management, and identifies additional difficulties in achieving the WFD objectives and good ecological status of rivers in Mediterranean countries.  相似文献   

3.
ABSTRACT: Ecologically effective ecosystem management will require the development of a robust logic, rationale, and framework for addressing the inherent limitations of scientific understanding. It must incorporate a strategy for avoiding irreversible or large-scale environmental mistakes that arise from social and political forces that tend to promote fragmented, uncritical, short-sighted, inflexible, and overly optimistic assessments of resource status, management capabilities, and the consequences of decisions and policies. Aquatic resources are vulnerable to the effects of human activities catchment-wide, and many of the landscape changes humans routinely induce cause irreversible damage (e.g., some species introductions, extinctions of ecotypes and species) or give rise to cumulative, long-term, large-scale biological and cultural consequences (e.g., accelerated erosion and sedimentation, deforestation, toxic contamination of sediments). In aquatic ecosystems, biotic impoverishment and environmental disruption caused by past management and natural events profoundly constrain the ability of future management to maintain biodiversity and restore historical ecosystem functions and values. To provide for rational, adaptive progress in ecosystem management and to reduce the risk of irreversible and unanticipated consequences, managers and scientists must identify catchments and aquatic networks where ecological integrity has been least damaged by prior management, and jointly develop means to ensure their protection as reservoirs of natural biodiversity, keystones for regional restoration, management models, monitoring benchmarks, and resources for ecological research.  相似文献   

4.
Studies have shown that ecological restoration projects are more likely to gain public support if they simultaneously increase important human services that natural resources provide to people. River restoration projects have the potential to influence many of the societal functions (e.g., flood control, water quality) that rivers provide, yet most projects fail to consider this in a comprehensive manner. Most river restoration projects also fail to take into account opportunities for revitalization of large-scale river processes, focusing instead on opportunities presented at individual parcels. In an effort to avoid these pitfalls while planning restoration of the Sacramento River, we conducted a set of coordinated studies to evaluate societal impacts of alternative restoration actions over a large geographic area. Our studies were designed to identify restoration actions that offer benefits to both society and the ecosystem and to meet the information needs of agency planning teams focusing on the area. We worked with local partners and public stakeholders to design and implement studies that assessed the effects of alternative restoration actions on flooding and erosion patterns, socioeconomics, cultural resources, and public access and recreation. We found that by explicitly and scientifically melding societal and ecosystem perspectives, it was possible to identify restoration actions that simultaneously improve both ecosystem health and the services (e.g., flood protection and recreation) that the Sacramento River and its floodplain provide to people. Further, we found that by directly engaging with local stakeholders to formulate, implement, and interpret the studies, we were able to develop a high level of trust that ultimately translated into widespread support for the project.  相似文献   

5.
我国新时期生态保护修复总体战略与重大任务   总被引:2,自引:2,他引:0  
生态保护修复是美丽中国建设的重大任务,是加快推进生态文明建设的优先行动,是推动生态产品价值实现的重要基础。近年来,我国生态保护修复取得显著进展,但生态系统本底脆弱、保护修复基础薄弱、管理机制不协调等问题依然突出。在大力推进生态文明建设的新的历史时期,面对百年未有之大变局,我国生态保护修复工作所面临的形势更加严峻,与实现国家生态治理体系和治理能力现代化的要求依然存在较大差距,尚难以满足人民日益增长的优质生态产品需要。本文在总结近年来我国生态保护修复主要进展基础上,分析了未来一段时期生态保护修复面临的问题与挑战,提出新时期生态保护修复应以习近平生态文明思想为统领,以提升生态系统服务功能、协同改善生态环境质量、维护国家生态安全为核心,探索构建生态保护修复与污染防治统筹推进机制,强化监管制度设计、示范样板引领、体制机制创新,加快实现山水林田湖草整体保护、系统修复、综合治理,筑牢美丽中国生态根基。  相似文献   

6.
In order for habitat restoration in regulated rivers to be effective at large scales, broadly applicable frameworks are needed that provide measurable objectives and contexts for management. The Ecological Limits of Hydrologic Alteration (ELOHA) framework was created as a template to assess hydrologic alterations, develop relationships between altered streamflow and ecology, and establish environmental flow standards. We tested the utility of ELOHA in informing flow restoration applications for fish and riparian communities in regulated rivers in the Upper Tennessee River Basin (UTRB). We followed the steps of ELOHA to generate univariate relationships between altered flows and ecology within the UTRB. By comparison, we constructed multivariate models to determine improvements in predictive capacity with the addition of non-flow variables. We then determined whether those relationships could predict fish and riparian responses to flow restoration in the Cheoah River, a regulated system within the UTRB. Although ELOHA provided a robust template to construct hydrologic information and predict hydrology for ungaged locations, our results do not suggest that univariate relationships between flow and ecology (step 4, ELOHA process) can produce results sufficient to guide flow restoration in regulated rivers. After constructing multivariate models, we successfully developed predictive relationships between flow alterations and fish/riparian responses. In accordance with model predictions, riparian encroachment displayed consistent decreases with increases in flow magnitude in the Cheoah River; however, fish richness did not increase as predicted 4 years after restoration. Our results suggest that altered temperature and substrate and the current disturbance regime may have reduced opportunities for fish species colonization. Our case study highlights the need for interdisciplinary science in defining environmental flows for regulated rivers and the need for adaptive management approaches once flows are restored.  相似文献   

7.
Space and Time Scales in Human-Landscape Systems   总被引:2,自引:0,他引:2  
Exploring spatial and temporal scales provides a way to understand human alteration of landscape processes and human responses to these processes. We address three topics relevant to human-landscape systems: (1) scales of human impacts on geomorphic processes, (2) spatial and temporal scales in river restoration, and (3) time scales of natural disasters and behavioral and institutional responses. Studies showing dramatic recent change in sediment yields from uplands to the ocean via rivers illustrate the increasingly vast spatial extent and quick rate of human landscape change in the last two millennia, but especially in the second half of the twentieth century. Recent river restoration efforts are typically small in spatial and temporal scale compared to the historical human changes to ecosystem processes, but the cumulative effectiveness of multiple small restoration projects in achieving large ecosystem goals has yet to be demonstrated. The mismatch between infrequent natural disasters and individual risk perception, media coverage, and institutional response to natural disasters results in un-preparedness and unsustainable land use and building practices.  相似文献   

8.
9.
Ecological regions are areas of similar climate, landform, soil, potential natural vegetation, hydrology, or other ecologically relevant variables. The makeup of aquatic biological assemblages (e.g., fish, macroinvertebrates, algae, riparian birds, etc.) varies dramatically over the landscape, as do the environmental stresses that affect the condition of those assemblages. Ecoregions delineate areas where similar assemblages are likely to occur and, therefore, where similar expectations can be established. For this reason, ecological regions have proven to be an important tool for use in the process of ecological assessment. This article describes four examples of the use of ecological regions in important aspects of environmental monitoring and assessment: (1) design of monitoring networks; (2) estimating expected conditions (criteria development); (3) reporting of results; (4) setting priorities for future monitoring and restoration. By delineating geographic areas with similar characteristics, ecological regions provide a framework for developing relevant indicators, setting expectations through the use of regional reference sites, establishing ecoregion-specific criteria and/or standards, presenting results, focusing models based on relationships between landscape and surface water metrics, and setting regional priorities for management and restoration. The Environmental Protection Agency and many state environmental departments currently use ecoregions to aid the development of environmental criteria, to illustrate current environmental condition, and to guide efforts to maintain and restore physical, chemical and biological integrity in lakes, streams, and rivers.  相似文献   

10.
从湿地现状、服务功能和外环境影响3方面构建了城镇区域内湿地生态健康评价指标体系,采用层次分析法(AHP)和模糊综合评价法,对广汉鸭子河湿地这一城镇区域内河滩型湿地生态系统健康状况进行评价。结果表明,在广汉市城市化进程中,该湿地的生态系统受到了一定程度的影响,就总体而言,湿地生态系统结构完整,基本功能依然具备,但栖息地功能有一定的退化,在整体上属于亚健康状态。根据评价结果及退化成因分析,提出了相应的恢复措施,对广汉市城市化进程中鸭子河湿地的保护提供了重要的决策依据,对同类型的湿地保护具有指导意义和借鉴价值。  相似文献   

11.
Planners are being called on to prioritize marine shorelines for conservation status and restoration action. This study documents an approach to determining the management strategy most likely to succeed based on current conditions at local and landscape scales. The conceptual framework based in restoration ecology pairs appropriate restoration strategies with sites based on the likelihood of producing long-term resilience given the condition of ecosystem structures and processes at three scales: the shorezone unit (site), the drift cell reach (nearshore marine landscape), and the watershed (terrestrial landscape). The analysis is structured by a conceptual ecosystem model that identifies anthropogenic impacts on targeted ecosystem functions. A scoring system, weighted by geomorphic class, is applied to available spatial data for indicators of stress and function using geographic information systems. This planning tool augments other approaches to prioritizing restoration, including historical conditions and change analysis and ecosystem valuation.  相似文献   

12.
ABSTRACT: Most of the application of the organophosphate insecticide diazinon in the San Joaquin River Basin occurs in winter to control wood-boring insects in dormant almond orchards. A federalstate collaborative study found that diazinon accounted for most of the observed toxicity of San Joaquin River water in February 1993. Previous studies focused mainly on west-side inputs to the San Joaquin River. In this 1994 study, the three major east-side tributaries to the San Joaquin River - the Merced, Tuolumne, and Stanislaus rivers - and a downstream site on the San Joaquin River were sampled throughout the hydrographs of a late January and an early February storm. In both storms, the Tuolumne River had the highest concentrations of diazinon and transported the largest load of the three tributaries. The Stanislaus River was a small source in both storms. On the basis of previous storm sampling and estimated travel times, ephemeral west-side creeks probably were the main diazinon source early in the storms, whereas the Tuolumne and Merced rivers and east-side drainages directly to the San Joaquin River were the main sources later. Although 74 percent of diazinon transport in the San Joaquin River during 1991–1993 occurred in January and February, transport during each of the two 1994 storms was only 0.05 percent of the amount applied during preceding dry periods. Nevertheless, some of the diazinon concentrations in the San Joaquin River during the January storm exceeded 0.35 μ/L, a concentration shown to be acutely toxic to water fleas. On the basis of this study and previous studies, diazinon concentrations and streamflow are highly variable during January and February storms, and frequent sampling is required to evaluate transport in the San Joaquin River Basin.  相似文献   

13.
Ecosystems, though impacted by global environmental change, can also contribute to the adaptation and mitigation of such large scale changes. Therefore, sustainable ecosystem management is crucial in reaching a sustainable future for the biosphere. Based on the published literature and publicly accessible data, this paper discussed the status and trends of forest, grassland, and wetland ecosystems in China that play important roles in the ecological integrity and human welfare of the nation. Ecological degradation has been observed in these ecosystems at various levels and geographic locations. Biophysical (e.g., climate change) and socioeconomic factors (e.g., intensive human use) are the main reasons for ecosystem degradation with the latter factors serving as the dominant driving forces. The three broad categories of ecosystems in China have partially recovered from degradation thanks to large scale ecological restoration projects implemented in the last few decades. China, as the largest and most populated developing nation, still faces huge challenges regarding ecosystem management in a changing and globalizing world. To further improve ecosystem management in China, four recommendations were proposed, including: (1) advance ecosystem management towards an application-oriented, multidisciplinary science; (2) establish a well-functioning national ecological monitoring and data sharing mechanism; (3) develop impact and effectiveness assessment approaches for policies, plans, and ecological restoration projects; and (4) promote legal and institutional innovations to balance the intrinsic needs of ecological and socioeconomic systems. Any change in China’s ecosystem management approach towards a more sustainable one will benefit the whole world. Therefore, international collaborations on ecological and environmental issues need to be expanded.  相似文献   

14.
A fuzzy adaptive management framework is proposed for evaluating the vulnerability of an ecosystem to losing ecological integrity as a result of climate change in an historical period (ex post evaluation) and selecting the best compensatory management action for reducing potential adverse impacts of future climate change on ecological integrity in a future period (ex ante evaluation). The ex post evaluation uses fuzzy logic to test hypotheses about the extent of past ecosystem vulnerability to losing ecological integrity and the ex ante evaluation uses the fuzzy minimax regret criterion to determine the best compensatory management action for alleviating potential adverse impacts of climate change on ecosystem vulnerability to losing ecological integrity in a future period. The framework accounts for uncertainty regarding: (1) the relationship between ecosystem vulnerability to losing ecological integrity and ecosystem resilience; (2) the relationship between ecosystem resilience and the extent to which observed indicators of ecological integrity depart from their thresholds; (3) the extent of future climate change; and (4) the potential impacts of future climate change on ecological integrity and ecosystem resilience. The adaptive management element of the framework involves using the ex post and ex ante evaluations iteratively in consecutive time segments of the future time period to determine if and when it is beneficial to adjust compensatory management actions to climate change. A constructed example is used to demonstrate the framework.  相似文献   

15.
Connectivity is a fundamental but highly dynamic property of watersheds. Variability in the types and degrees of aquatic ecosystem connectivity presents challenges for researchers and managers seeking to accurately quantify its effects on critical hydrologic, biogeochemical, and biological processes. However, protecting natural gradients of connectivity is key to protecting the range of ecosystem services that aquatic ecosystems provide. In this featured collection, we review the available evidence on connections and functions by which streams and wetlands affect the integrity of downstream waters such as large rivers, lakes, reservoirs, and estuaries. The reviews in this collection focus on the types of waters whose protections under the U.S. Clean Water Act have been called into question by U.S. Supreme Court cases. We synthesize 40+ years of research on longitudinal, lateral, and vertical fluxes of energy, material, and biota between aquatic ecosystems included within the Act's frame of reference. Many questions about the roles of streams and wetlands in sustaining downstream water integrity can be answered from currently available literature, and emerging research is rapidly closing data gaps with exciting new insights into aquatic connectivity and function at local, watershed, and regional scales. Synthesis of foundational and emerging research is needed to support science‐based efforts to provide safe, reliable sources of fresh water for present and future generations.  相似文献   

16.
浊漳河山西省潞城市境内干流段及南源段河道生态环境目前最突出的问题在于水质恶化、水量减少以及生物多样性衰退。本文从水质、水量、生物状况三个要素出发,通过建立浊漳河潞城市境内河段的水生态健康评价体系,对浊漳南源及干流段进行了生态健康诊断。结果显示,浊漳干流段生态健康总指数36.74,呈生态病态状;南源段生态健康总指数60.03,呈基本健康状态。据此,浊漳河潞城境内段目前的核心问题是生态恢复问题,应当针对其存在的问题选择适当的生态修复模式,采取相应的生态环境管理方法,把生态系统的恢复和重建作为其流域治理的最终目标。  相似文献   

17.
绿色矿山建设是矿业领域践行"绿水青山就是金山银山"的重要体现。本文从矿山生态修复的内涵到外延,从问题识别到任务措施,从单一治理修复目标到生态系统功能修复目标,从矿山生态修复系统到与经济社会发展系统相结合等多个方面,系统地梳理矿山生态修复的解决路径,围绕矿业绿色发展提出一系列建议。  相似文献   

18.
Between 1850 and 1970, rivers throughout Sweden were channelized to facilitate timber floating. Floatway structures were installed to streamline banks and disconnect flow to secondary channels, resulting in simplified channel morphologies and more homogenous flow regimes. In recent years, local authorities have begun to restore channelized rivers. In this study, we examined the effects of restoration on riparian plant communities at previously disconnected secondary channels of the Pite River. We detected no increase in riparian diversity at restored sites relative to unrestored (i.e., disconnected) sites, but we did observe significant differences in species composition of both vascular plant and bryophyte communities. Disconnected sites featured greater zonation, with mesic-hydric floodplain species represented in plots closest to the stream and mesic-xeric upland species represented in plots farthest from the stream. In contrast, restored sites were most strongly represented by upland species at all distances relative to the stream. These patterns likely result from the increased water levels in reconnected channels where, prior to restoration, upland plants had expanded toward the stream. Nonetheless, the restored fluvial regime has not brought about the development of characteristic flood-adapted plant communities, probably due to the short time interval (ca. 5 years) since restoration. Previous studies have demonstrated relatively quick responses to similar restoration in single-channel tributaries, but secondary channels may respond differently due to the more buffered hydrologic regimes typically seen in anabranching systems. These findings illustrate how restoration outcomes can vary according to hydrologic, climatic and ecological factors, reinforcing the need for site-specific restoration strategies.  相似文献   

19.
Riverine wetlands, which provide numerous valuable functions, are disappearing in floodplains of a channelized European river. A restoration project has been proposed by scientists to restore a former braided channel of the Rhône River by the removal of fine organic sediments in order to enhance groundwater supply. A precise and intensive prerestoration monitoring program during one year (including comparison with a reference channel) has taken into account several variables and ecological performance indicators measured at various spatial and temporal scales. Three restoration techniques were then suggested, taking into account two characteristics of ecosystem functions for increasing restoration success and self-sustainability: (1) the riparian forest as well as the shores must be preserved or disturbed as little as possible; and (2) the upstream alluvial plug must be preserved to prevent direct supply of nutrientrich water from the Rhône River. Among the three restoration options proposed, it was not possible to carry out the less ecologically disturbing one as it was considered too expensive, time consuming, and difficult to realize. A precise and intensive postrestoration monitoring program, conducted over two years, demonstrated restoration success but also unpredicted problems, such as a locally thick layer of fine organic sediment. As long as a self-sustainable state is not achieved, this monitoring should be continued. Afterwards, a less precise and less intensive long-term monitoring should enable the detection of future events that may influence ecosystem changes.  相似文献   

20.
Retrospective ecological risk assessment, restoration, natural resource damage assessment (NRDA) and managing ecosystems all require having a baseline. This policy and practice paper explores the factors that influence baseline selection, and it is suggested that ecological resources would best be served by: (1) integrating NRDA considerations into both future land-use planning and remediation/restoration; (2) selecting a baseline for NRDA that approximates the land-use conditions at the time of occupation (or a preferred ecosystem); and (3) integrating both the positive and negative aspects of industrial occupation into restoration decisions, baseline selection and NRDA. Under the Comprehensive Environmental Response and Compensation and Liability Act (CERCLA), natural resource damages are assessed for injuries incurred since 1980 due to releases, but the release itself may have occurred before 1980. The paper uses the Department of Energy as a case study to examine NRDA and the management of ecosystems. Releases occurred at many DOE sites from the 1950s to the 1980s during nuclear bomb production. It is suggested that the DOE has been responsible not only for injuries to natural resources that occurred as a result of releases, but for significant ecosystem recovery since DOE occupation, because some lands were previously farmed or industrialized. Natural resource injuries due to releases occurred simultaneously with ecosystem recovery that resulted from DOE occupation. While the 1980 date is codified in CERCLA law as the time after which damages can be assessed, baseline can be defined as the conditions the natural resources would have been in today, but for the release of the hazardous substance. It is also suggested that NRDA considerations should be incorporated into the remediation and restoration process at DOE sites, thereby negating the need for formal NRDA following restoration, and reducing the final NRDA costs.  相似文献   

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