Integrated Ecosystem Assessments
by Phillip S. Levin, Michael J. Fogarty, and Gary C. Matlock
Background
The reports of the U.S. Oceans Commission, the Pew Oceans Commission, the Ocean Priorities Plan, and other nationwide reviews highlight the importance of incorporating ecosystem principles in ocean and coastal resource management. Specific to NOAA, a critical objective is to ìProtect, Restore, and Manage the use of Coastal, Ocean, and Great Lakes resources through an Ecosystem Approach to Management (EAM)î. An ecosystem approach to management is one that provides a comprehensive framework for marine, coastal, and Great Lakes resource decision making. In contrast to individual species or single issue management, EAM considers a wider range of ecological, environmental, and human factors bearing on diverse societal objectives regarding resource use and protection.
What is an ecosystem?
An ecosystem is defined by NOAA as:
"An ecosystem is a geographically specified system of organisms (including humans), the environment, and the processes that control its dynamics." NOAA further defines the environment as "The environment is the biological, chemical, physical, and social conditions that surround organisms. When appropriate, the term environment should be qualified as biological, chemical, and/or social."
What is an Integrated Ecosystem Assessment?
Integrated ecosystem assessments (IEAs) are a critical science–support element enabling an EAM strategy. An IEA is a formal synthesis and quantitative analysis of information on relevant natural and socio–economic factors in relation to specified ecosystem management goals. It involves and informs citizens, industry representatives, scientists, resource managers, and policy makers through formal processes to contribute to attaining the goals of EAM. In this white paper, we outline a stepwise approach that will guide the science of IEAs.
IEAs begin with an identification of critical management and policy questions to define the scope of information and analyses necessary to inform management. IEAs use quantitative analyses and ecosystem modeling to integrate a range of social, economic, and natural science data and information to assess the condition of the ecosystem relative to the identified scope. IEAs also identify potential management options, and these are evaluated against EAM goals. IEAs are peer–reviewed and communicated to stakeholders, resource managers and policy makers. IEAs differ from other assessments like Environmental Impact Statements in that they explicitly consider all components of the ecosystem and address the broad goals of EAM.
An IEA consists of the following components:
- Identification of key issues of concerns and stressors that management and policy should address;
- Assessment of status, indicators and trends of the ecosystem condition relative to established management targets or thresholds;
- Assessment of the environmental, social, and economic causes and consequences of these trends;
- Forecast of ecosystem condition under a range of policy and/or management actions;
- Periodically re–evaluate management effectiveness in the context of emerging ecosystem issues; and
- Identification of crucial knowledge and data gaps that will guide future research and data acquisition efforts.
Why IEAs?
A key goal of IEAs is to move towards clear, well–defined ecosystem objectives built upon a science strategy that fuses ecosystem components into a single, dynamic, fabric in which both human and natural factors are intertwined. Periodic assessment of biological, chemical, physical and socio–economic attributes of ecosystems allows for coordinated evaluations of national marine, coastal and Great Lakes ecosystems to promote their sustainability under a variety of human uses and environmental stresses. Moreover, IEAs involve and inform a wide variety of stakeholders and agencies that rely on science support. IEAs integrate knowledge and data collected by NOAA and other regional entities including other federal agencies, states, nongovernmental organizations, and academic institutions. IEAs also identify critical knowledge and data gaps, which, if filled, will reduce uncertainty and improve our ability to fully employ ecosystem approaches to management.
The importance of scale
IEAs must explicitly consider both spatial extent and the time domains over which ecosystem dynamics and management issues occur. Scales must be consistent with the ability to recognize and explain the most important drivers and threats to the ecosystem. Ecosystems typically do not have sharp boundaries; rather one ecosystem blends into another. As a consequence, ecosystem boundaries are human constructs, and a first step in any IEA endeavor must be to identify the spatial scale of the problem under consideration. The spatial scale of an IEA is a function of the ecology, geology, and oceanography of a region as well as the scale of management issues and governance structures. For example, while an IEA may focus on a small embayment, consideration of large–scale issues such as climatic variability as well as linkages to adjacent ecosystems is important. IEAs should address the linkage of terrestrial, coastal and oceanic environments as part of or affecting the ecosystem. Additionally, IEAs must be cognizant of appropriate temporal scales. In particular, IEAs require attention to the temporal baseline against which current status is compared. For example, different conclusions may be drawn when the comparing current ecosystem conditions to those of 25 years versus 75 years ago.
Applying the IEA Concept
An IEA uses approaches that determine the probability that ecological or socio–economic properties of systems will move beyond or return to within acceptable limits as defined by management objectives. An IEA must provide an efficient, transparent means of summarizing the status of ecosystem components, screening and prioritizing potential risks, and evaluating alternative management strategies against a backdrop of environmental (e.g., climatic, oceanographic, seasonal, real–time weather) variability. An IEA provides a means of evaluating tradeoffs in management strategies among potentially competing ecosystem use sectors.
A 5 step process for an Integrated Ecosystem Assessment
 Figure 1. A 5 step process for an Integrated Ecosystem Assessment. |
Step 1. A scoping process initiates the IEA. Scoping begins with a review of existing documents and information and concludes with stakeholder, resource manger, and policy maker involvement to identify the management objectives, articulate the ecosystem to be assessed, identify ecosystem attributes of concern, and identify stressors relevant to the ecosystem being examined. While general EAM goals may be broad, a key component of an IEA is to move from broad goals to specific ecosystem objectives that management and policy need to consider.
Step 2. Following the scoping process, researchers must develop and test indicators that reflect the ecosystem attributes and stressors specified in the scoping process. Specific indicators are dictated by the problem at hand and must be linked objectively to decision criteria. In some cases, this simply means following the abundance of a single species (for instance in the case of an endangered species) or suites of species (e.g., coral reefs, harmful algal blooms). In other instances, the indicator may be a proxy for an ecosystem attribute indicated in Step 1. For example, resiliency to perturbation might be an attribute and species diversity might be an indicator of resiliency. For many problems, suites of indicators that span a wide range of processes (with different associated rates), biological groups, and indicator types (e.g., "early warning," "integrated system state") will be necessary. Importantly, this step allows us to identify indicators that should be monitored even when current monitoring efforts are insufficient.
 Figure 2. A visualization of the risk status of theoretical indicators. Indicator A has low resiliency (ability to persist in the face of change) and high susceptibility to natural or human disturbance; thus, it has a high risk. C shows an indicator with low susceptibility and high resilience and thus has low risk. B, D, and E have different combinations of susceptibility and resilience yielding a moderate level of risk. |
Step 3. Once indicators are chosen, an analysis that evaluates the risk to the indicators posed by human activities and natural processes is performed. This analysis is hierarchical in approach and moves from a comprehensive, but qualitative analysis initially, through a more focused and semi–quantitative approach, and finally to a highly focused and fully quantitative approach. This step initially screens out many potential risks, so that more intensive and quantitative analyses are limited to a subset of ecosystem indicators and human or natural threats. The goal of these risk analyses is to fully explore the susceptibility of an indicator to natural or human threats as well as the ability of the indicator to return to its previous state after being perturbed. Another goal of these risk analyses is to explain whether, if the indicator has settled at a new value, the new value is due to natural variability in the system. A full discussion of ecological risk analysis as it pertains to marine ecosystems can be found in Hobday et al. (2006).
The likelihood of an ecosystem to change can be viewed as the relationship of the susceptibility of a particular indicator to impact versus the resiliency of the indicator (Figure 2). An indicator is likely to change when susceptibility to impact is high and resiliency is low, while an indicator is not likely to change when susceptibility to impact is low and resiliency is high. A full discussion of ecological risk analysis as it pertains to marine ecosystems can be found in Hobday et al. (2006). IEAs will also include a social and economic overlay to the ecological risk assessments to capture impacts to individuals and communities.
Step 4. Results from the risk analysis for each ecosystem indicator are then integrated in the assessment phase of the IEA. The assessment quantifies the status of the ecosystem relative to historical status and prescribed targets. Thus, the risk analysis rigorously quantifies the status of individual ecosystem indicators, while the full assessment considers the state of all indicators simultaneously.
 Figure 3. A schematic of the MSE. An ecosystem model is used to simulate the ecosystem. The ecosystem is then ìsampled,î an IEA is performed, and a management strategy is implemented. The cycle is then repeated, and ultimately the potential outcomes of a range of management strategies can be estimated. |
Step 5. The next phase of the IEA uses ecosystem modeling frameworks (e.g., the Atlantis ecosystem model, Brand et al. 2007) to evaluate the potential of different management strategies to influence the status of natural and human system indicators. To accomplish this, a formal Management Strategy Evaluation (MSE) is employed (Figure 3). In MSE, a simulation model is used to generate ‘true’ ecosystem dynamics. Data are sampled from the model to simulate research surveys, and then these data are passed to risk analysis and assessment models. These assessment models estimate the predicted status of individual indicators and the ecosystem as a whole. Based on this assessment of the simulated ecosystem, a management decision is simulated. Human response to this simulated decision is modeled, and potentially influences the simulated ecosystem state. By repeating this cycle, we can simulate the full management cycle. This allows us to test the utility of modifying indicators and threshold levels, assessments, monitoring plans, management strategies, or decision rules. Management Strategy Evaluation in the context of an IEA can thus serve as a filter to identify which policies and methods meet stated management objectives (e.g. Butterworth and Punt 1999).
IEA Products
IEAs are peer–reviewed and communicated to stakeholders, resource managers and policy makers. IEAs may be communicated in the form of a static Management Strategy Evaluation (MSE) framework. In MSE document, but may also be web–based dynamic documents that are updated as new data become available. The frequency with which IEAs should be revised and updated cannot not be fully prescribed. As new information arises or management changes occur, risks can be reevaluated, and documented as before. IEA products may also serve as a tool to educate a variety of stakeholders.
