Valued Ecosystem Components Research Articles

A Conceptual Model of Natural and Anthropogenic Drivers and Their Influence on the Prince William Sound, Alaska, Ecosystem

Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems.

Derivation of a GIS-based watershed-scale conceptual model for the St. Jones River Delaware from habitat-scale conceptual models

Conceptual modeling is a useful tool for identifying pathways between drivers, stressors, Valued Ecosystem Components (VECs), and services that are central to understanding how an ecosystem operates. The St. Jones River watershed, DE is a complex ecosystem, and because management decisions must include ecological, social, political, and economic considerations, a conceptual model is a good tool for accommodating the full range of inputs. In 2002, a Four-Component, Level 1 conceptual model was formed for the key habitats of the St. Jones River watershed, but since the habitat level of resolution is too fine for some important watershed-scale issues we developed a functional watershed-scale model using the existing narrowed habitat-scale models. The narrowed habitat-scale conceptual models and associated matrices developed by Reiter et al. (2006) were combined with data from the 2002 land use/land cover (LULC) GIS-based maps of Kent County in Delaware to assemble a diagrammatic and numerical watershed-scale conceptual model incorporating the calculated weight of each habitat within the watershed. The numerical component of the assembled watershed model was subsequently subjected to the same Monte Carlo narrowing methodology used for the habitat versions to refine the diagrammatic component of the watershed-scale model. The narrowed numerical representation of the model was used to generate forecasts for changes in the parameters “Agriculture” and “Forest”, showing that land use changes in these habitats propagated through the results of the model by the weighting factor. Also, the narrowed watershed-scale conceptual model identified some key parameters upon which to focus research attention and management decisions at the watershed scale. The forecast and simulation results seemed to indicate that the watershed-scale conceptual model does lead to different conclusions than the habitat-scale conceptual models for some issues at the larger watershed scale.

Stress tolerance of a subtropical Crassostrea virginica population to the combined effects of temperature and salinity

The combination of salinity and temperature has synergistic effects on virtually all aspects of the biology of estuarine organisms. Of interest were site-specific characteristics in the response of the eastern oyster, Crassostrea virginica, from the St. Lucie River Estuary to the interactive effects of temperature and salinity. This estuary, one of the largest on the central east coast of Florida, is strongly influenced by anthropogenic modifications due to management needs to control the patterns of freshwater flow in the St. Lucie River watershed. Crassostrea virginica is designated a valued ecosystem component for monitoring the health of this estuary. Our approach used a multidimensional response surface design to study the effects of temperature and salinity on sublethal measures of oyster performance: (1) body condition index as an overall indicator of bioenergetic status and (2) the RNA/DNA ratio as a biochemical indicator of cellular stress. The results showed that there was a greater ability to withstand extreme salinity conditions at lower temperatures. However, there were no site-specific attributes that differentiated the response of the St. Lucie Estuary population from populations along the distribution range. Condition index was a less variable response than the RNA/DNA ratio, and the final models for mean condition index and the RNA/DNA ratios explained 77.3 and 35.8% of the respective variances.

An interdisciplinary conceptual metamodel for the St. Jones River Watershed, Delaware: development, results, and implications.

An integrated, interdisciplinary conceptual model was developed for the St. Jones River watershed, Delaware for use as a management and research tool. The model utilized the two-component approach of the Environmental Cooperative Science Center methodology (drivers∆stressors, stressors∆valued ecosystem components), and expanded upon it to include a third (valued ecosystem components∆services) and fourth (services∆drivers) component. The four-component models provide an expanded capability to link human activities not only to ecological impacts but to potential social and economic impacts, including feedbacks upon the initiating drivers. The St. Jones model suggests that climate, development, and agriculture are likely to be the most important drivers, that aquatic habitats are likely to be of particular concern, and that feedbacks are particularly likely to impact development, land use regulation, and habitat mitigation/restoration.

Ecological significance of residual exposures and effects from theExxon Valdezoil spill

AbstractAn ecological significance framework is used to assess the ecological condition of Prince William Sound (PWS), Alaska, USA, in order to address the current management question: 17 y following theExxon Valdezoil spill (EVOS), are there any remaining and continuing ecologically significant exposures or effects on the PWS ecosystem caused by EVOS? We examined the extensive scientific literature funded by the Exxon Valdez Trustees or by ExxonMobil to assess exposures and effects from EVOS. Criteria to assess ecological significance include whether a change in a valued ecosystem component (VEC) is sufficient to affect the structure, function, and/or health of the system and whether such a change exceeds natural variability. The EVOS occurred on 24 March 1989, releasing over 250,000 barrels of crude oil into PWS. Because PWS is highly dynamic, the residual oil was largely eliminated in the first few years, and now only widely dispersed, highly weathered, or isolated small pockets of residual contamination remain. Many other sources of polycyclic aromatic hydrocarbons (PAHs) exist in PWS from past or present human activities or natural oil seeps. Multiple‐lines‐of‐evidence analyses indicate that residual PAHs from EVOS no longer represent an ecologically significant exposure risk to PWS. To assess the ecological significance of any residual effects from EVOS, we examined the literature on more than 20 VECs, including primary producers, filter feeders, fish and bird primary consumers, fish and bird top predators, a bird scavenger, mammalian primary consumers and top predators, biotic communities, ecosystem‐level properties of trophodynamics and biogeochemical processes, and landscape‐level properties of habitat mosaic and wilderness quality. None of these has any ecologically significant effects that are detectable at present, with the exception of 1 pod of orcas and possibly 1 subpopulation of sea otters; however, in both those cases, PWS‐wide populations appear to have fully recovered. Many other stressors continue to affect PWS adversely, including climate and oceanographic variability, increased tourism and shipping, invasive species, the 1964 earthquake, and overexploitation of marine resources, with associated cascading effects on populations of PWS fish and predators. We conclude that the PWS ecosystem has now effectively recovered from EVOS.

Ecological Significance of Residual Exposures and Effects from the Exxon Valdez Oil Spill

An ecological significance framework is used to assess the ecological condition of Prince William Sound (PWS), Alaska, USA, in order to address the current management question: 17 y following the Exxon Valdez oil spill (EVOS), are there any remaining and continuing ecologically significant exposures or effects on the PWS ecosystem caused by EVOS? We examined the extensive scientific literature funded by the Exxon Valdez Trustees or by ExxonMobil to assess exposures and effects from EVOS. Criteria to assess ecological significance include whether a change in a valued ecosystem component (VEC) is sufficient to affect the structure, function, and/or health of the system and whether such a change exceeds natural variability. The EVOS occurred on 24 March 1989, releasing over 250,000 barrels of crude oil into PWS. Because PWS is highly dynamic, the residual oil was largely eliminated in the first few years, and now only widely dispersed, highly weathered, or isolated small pockets of residual contamination remain. Many other sources of polycyclic aromatic hydrocarbons (PAHs) exist in PWS from past or present human activities or natural oil seeps. Multiple-lines-of-evidence analyses indicate that residual PAHs from EVOS no longer represent an ecologically significant exposure risk to PWS. To assess the ecological significance of any residual effects from EVOS, we examined the literature on more than 20 VECs, including primary producers, filter feeders, fish and bird primary consumers, fish and bird top predators, a bird scavenger, mammalian primary consumers and top predators, biotic communities, ecosystem-level properties of trophodynamics and biogeochemical processes, and landscape-level properties of habitat mosaic and wilderness quality. None of these has any ecologically significant effects that are detectable at present, with the exception of 1 pod of orcas and possibly 1 subpopulation of sea otters; however, in both those cases, PWS-wide populations appear to have fully recovered. Many other stressors continue to affect PWS adversely, including climate and oceanographic variability, increased tourism and shipping, invasive species, the 1964 earthquake, and overexploitation of marine resources, with associated cascading effects on populations of PWS fish and predators. We conclude that the PWS ecosystem has now effectively recovered from EVOS.

The Impotence of Cumulative Effects Assessment in Canada: Ailments and Ideas for Redeployment

Cumulative effects assessment (CEA) in Canada is in dire straits. Despite a huge amount of talk and a flurry of developmental activity associated with CEA concepts, it has not lived up to its glowing promise of helping to achieve sustainability of diverse valued ecosystem components. This article aims to articulate that failure, to examine it in terms of six major problems with CEA, and to propose solutions. The six problem areas include (1) application of CEA in project-level environmental impact assessments (EIAs), (2) an EIA focus on project approval instead of environmental sustainability, (3) a general lack of understanding of ecologic impact thresholds, (4) separation of cumulative effects from project-specific impacts, (5) weak interpretations of cumulative effects by practitioners and analysts, and (6) inappropriate handling of potential future developments. We advocate improvements not only within the purview of project-specific EIAs, but also mainly in the domain of region-scale CEAs and regional environmental effects frameworks (or perhaps land use planning). Only then will the CEA begin to approach the promise of securing sustainability of valued ecosystem components.

Improving the TMDL Process Using Watershed Risk Assessment Principles

Ecological risk assessment (ERA) evaluates potential causal relationships between multiple sources and stressors and impacts on valued ecosystem components. ERAs applied at the watershed scale have many similarities to the place-based analyses that are undertaken to develop Total Maximum Daily Loads (TMDLs), in which linkages are established between stressors, sources, and water quality standards, including support of designated uses. TMDLs focus on achieving water quality standards associated with attainment of designated uses. In attempting to attain the water quality standard, many TMDLs focus on the stressor of concern rather than the ecological endpoint or indicators of the designated use that the standard is meant to protect. A watershed ecological risk assessment (WERA), at least in theory, examines effects of most likely stressors, as well as their probable sources in the watershed, to prioritize management options that will most likely result in meeting environmental goals or uses. Useful WERA principles that can be applied to TMDL development include: development and use of comprehensive conceptual models in the Problem Identification step of TMDLs; use of a transparent process for selecting Numeric Targets for TMDLs based on assessment endpoints derived from the management goal or designated use under consideration; analysis of co-occurring stressors likely to cause beneficial use impairment based on the conceptual model; use of explicit uncertainty analyses in the Linkage Analysis step of TMDL development; and frequent stakeholder interactions throughout the process. WERA principles are currently most applicable to those TMDLs in which there is no numeric standard and, therefore, indicators and targets need to be developed, such as many nutrient or sediment TMDLs. WERA methods can also be useful in determining TMDL targets in situations where simply targeting the water quality standard may re-attain the numeric criterion but not the broader designated use. Better incorporation of problem formulation principles from WERA into the TMDL development process would be helpful in improving the scientific rigor of TMDLs.

Cumulative environmental impacts and integrated coastal management: the case of Xiamen, China

This paper examines the assessment of cumulative environmental impacts and the implementation of integrated coastal management within the harbour of Xiamen, China, an urban region in which the coastal zone is under increasing pressure as a result of very rapid economic growth. The first stage of analysis incorporates components of a cumulative effects assessment, including (a) identification of sources of environmental impacts, notably industrial expansion, port development, shipping, waste disposal, aquaculture and coastal construction, (b) selection of a set of valued ecosystem components, focusing on circulation and siltation, water quality, sediment, the benthic community, and mangrove forests, and (c) use of a set of key indicators to examine cumulative impacts arising from the aggregate of human activities. In the second stage of analysis, the paper describes and assesses the development of an institutional framework for integrated coastal management in Xiamen, one that combines policy and planning (including legislative and enforcement mechanisms) with scientific and monitoring mechanisms (including an innovative ‘marine functional zoning’ system). The paper concludes that the integrated coastal management framework in Xiamen has met all relevant requirements for ‘integration’ as laid out in the literature, and has explicitly incorporated consideration of cumulative impacts within its management and monitoring processes.

Cumulative environmental impacts and integrated coastal management: the case of Xiamen, China

This paper examines the assessment of cumulative environmental impacts and the implementation of integrated coastal management within the harbour of Xiamen, China, an urban region in which the coastal zone is under increasing pressure as a result of very rapid economic growth. The first stage of analysis incorporates components of a cumulative effects assessment, including (a) identification of sources of environmental impacts, notably industrial expansion, port development, shipping, waste disposal, aquaculture and coastal construction, (b) selection of a set of valued ecosystem components, focusing on circulation and siltation, water quality, sediment, the benthic community, and mangrove forests, and (c) use of a set of key indicators to examine cumulative impacts arising from the aggregate of human activities. In the second stage of analysis, the paper describes and assesses the development of an institutional framework for integrated coastal management in Xiamen, one that combines policy and planning (including legislative and enforcement mechanisms) with scientific and monitoring mechanisms (including an innovative ‘marine functional zoning’ system). The paper concludes that the integrated coastal management framework in Xiamen has met all relevant requirements for ‘integration’ as laid out in the literature, and has explicitly incorporated consideration of cumulative impacts within its management and monitoring processes.

Achieving an Industry Standard in the Assessment of Environmental Risk: Oil Spill Risk Management and the Mira Method

ABSTRACT A quantitative approach to assess environmental risks from offshore petroleum activities is developed in this paper. Taking into account both reservoir- and project-specific data, different kinds of oil spill scenarios are analyzed. Oil characteristics and weathering properties are incorporated in a standardized geographical information system (GIS)-based oil spill modeling system, simulating oil trajectories based on wind and current data. Mapping of environmental resources is combined with a sensitivity evaluation and protection value classification. Nationally accepted criteria in Norway for identification of valued ecosystem components (VECs) are adopted to select a limited number of high priority risk indicators. Oil spill statistics are combined with occurrences of VEC resources on a seasonal basis. Oil pollution effect and damage keys have been established based on past oil spill incidents and scientific documentation. Impact assessments are based on available specific resource data and provide results related to the recovery potential of each resource component included. The recovery time is adopted as a general stand-alone parameter that allows classification of severity and ecological significance of acute oil pollution incidents. Quantitative risk results are used to describe and rank environmental risks issued from different sources and scenarios, covering different seasons and activity plans. The ranking also is used to identify high priority resources and geographic areas for contingency actions. The variability in presence and vulnerability of natural resources gives the operator the possibility of adjusting activity plans according to the time-window providing the lowest environmental risk. Contingency plans can be designed for and focused on periods or geographic areas with increased risk. The results are further used in combination with oil spill statistics to determine specific requirements for oil spill contingency systems. Requirements for key factors—such as response time, equipment, functional capability, and efficiency with respect to weather, oil type, and oil quantity—also are established. The overall efficiency of contingency systems is assessed and the risk reanalyzed to identify the potential for risk reduction. Further developments are proposed advising that risk reduction should be considered in combination with costs involved in investments, maintenance and exercises, as well as real combat action costs and compensation costs. Cost-benefit could then be assessed for different contingency arrangements, providing a basis for selection of optimal solutions for contingency systems according to the ALARP principle—“as low as reasonably practicable”—where costs of countermeasures are weighted against potential risk reduction.

An environmental radionuclide baseline study near three Canadian naval ports.

This paper summarizes an environmental radionuclide baseline study undertaken for the Department of National Defence in Canada. The purpose of the project was to establish levels of radionuclides present in the environment around areas where nuclear propelled vessels may be berthed. Specifically, this report describes environmental baselines near Halifax (Nova Scotia), Esquimalt (British Columbia), and Nanoose Bay (British Columbia). Valued ecosystem component samples were taken from dairy farms, beef producers, market gardens, vegetables, tree fruits and berries within the study areas, as well as marine bivalves (mussels and clams), salmon, seaweed, and food from native fisheries. Numerous naturally occurring isotopes were detected and quantified. The only non-naturally occurring isotope positively identified was in the form of trace quantities of 131I, measured in the Halifax study zone (attributed to local hospital cancer therapy). 137Cs is the only other anthropogenic radionuclide detected. Its origin may be the combination of fallout from the Chernobyl accident and fallout from atmospheric nuclear weapon tests. The results indicate that nuclear-powered vessels have not resulted in activity levels that would contribute a significant radiation exposure to the public, the biota, and the environment within the three study zones.

The Distribution, Population Status and Ecology of Marine Birds Selected as Valued Ecosystem Components in the Northern Sea Route Area

The Distribution, Population Status and Ecology of Marine Birds Selected as Valued Ecosystem Components in the Northern Sea Route Area

Cumulative effects assessment: learning from Canadian case studies

Cumulative effects assessment (CEA) for environmental impact assessments are required by some Canadian and American legislation. However, there is confusion concerning exactly what CEA involves. This clarifies the requirements of CEA and illustrates its use in a number of case studies. Practitioners must: identify valued ecosystem components (VECs) affected by the proposed project; determine what other past, present and future human activities have affected or will affect these VECs; predict the impacts on the VECs of the combined activities; and suggest how to manage these cumulative effects.

APPLICATION OF ECOLOGICAL RISK ASSESSMENT PRINCIPLES TO NATURAL RESOURCES DAMAGE ASSESSMENT

ABSTRACT Ecological risk assessment principles are basic to the assessment of environmental injury during the Natural Resources Damage Assessment (NRDA) process; however, what is sought is quantified injury, rather than quantified risk, to valued ecosystem components. These principles were used to develop an NRDA program for studies of injury to herring and pink salmon populations in Prince William Sound (PWS), Alaska, following the Exxon Valdez oil spill. Overall, exposures and subsequent effects of the spill on herring and salmon were minimal and post-spill harvests of the year's classes that were at greatest risk of spill injury were at or near record levels.

An approach to integrate impact scoping with environmental impact assessment

Impact scoping is the process of identifying important issues of a proposal and focusing the environmental impact assessment (EIA) on the high-priority issues. Although impact scoping in one form or another has been inherent to EIA for some time, documentation of its development and discussion of refinements to impact scoping processes have not been forthcoming. This article traces the development of impact scoping through time and highlights the need for such processes in EIA. A focused environmental assessment (FEA) approach to impact scoping that is suitable for implementation in an EIA is presented here and advantages of its use are delineated. FEA is a three-staged process that encourages impact scoping through progressive steps including impact identification, assessment and management planning. FEA combines a suite of EIA methods including: issues matrices, impact hypotheses, valued ecosystem components, and stakeholder participation sessions to effectively integrate impact scoping with EIA.

Improving Aquatic Environmental Impact Assessment in Canada – A Northern Case Study

Abstract This paper presents and applies a conceptual framework which addresses the causal relationships linking contaminant doses with responses in aquatic environments. The paper is focused on metal contaminants and reviews a northern case study in which the framework was applied. The approach emphasizes the environmental factors regulating the potential effects of contaminants and stresses the importance of understanding the physical environmental processes in monitoring design and the selection of linkages between the contaminant dose and the valued ecosystem components.