The US National Ocean Policy calls for ecosystem-based management (EBM) of the ocean to help realize the vision advanced in the 2010 Executive Order on the Stewardship of the Ocean, Our Coasts, and the Great Lakes. However, no specific approach for incorporating EBM into planning was provided. We explore how a set of ecological principles and ecosystem vulnerability concepts can be integrated into emerging comprehensive assessment frameworks, including Australia's National Marine Bioregional Assessments, California's Marine Life Protection Act Initiative's regional profiles, Canada's Eastern Scotian Shelf Integrated Management Initiative, and the US National Oceanic and Atmospheric Administration's (NOAA) Integrated Ecosystem Assessment (IEA) program, to transition to ecosystem-based ocean planning. We examine NOAA's IEA framework to demonstrate how these concepts could be incorporated into existing frameworks. Although our discussion is focused on US ocean policy, comprehensive ecological assessments are applicable to a wide array of management strategies and planning processes.
The stated goal of most ocean and coastal management regimes is to promote the sustainable use and long-term health of the ocean. In spite of this goal, many resource management approaches, in practice, are narrowly constrained and tend to (a) depict humans as resource users who are independent of and external to ecosystems (Shackeroff et al. 2009); (b) manage each ocean use sector independently of other relevant sectors (Crowder et al. 2006); (c) optimize short-term resource allocations among users (Stanford and Poole 1996); and (d) depend on markets to value resources, such as fish or fossil fuels, causing resources with no generally acceptable quantifiable market value, such as biodiversity or storm protection, to become collateral damage in the pursuit of targeted resources (Nelson et al. 2009).
In response to these challenges, there have been increasing calls for ecosystem-based management (EBM) of ocean and coastal areas. EBM has been described as “an integrated approach to management that considers the entire ecosystem, including humans” (McLeod et al. 2005, p. 1), and it explicitly recognizes the connection between the provision of ecosystem services and human well-being (MA 2005). EBM provides an overarching vision to design, develop, and apply scientifically informed management practices. Importantly, it has enabled the development of place-based management approaches, such as marine spatial planning and the establishment of networked marine protected areas (MPAs; Douvere 2008, Halpern et al. 2010). Decisionmakers can move beyond single-sector management practices and promote the sustainable use and long-term health of the ocean by (a) incorporating lessons from the theory and practice of EBM; (b) understanding the range of impacts that human uses have on marine resources; and (c) using the best available science to define, assess, and monitor attributes of healthy, productive, and resilient ecosystems (McLeod and Leslie 2009). (We prefer to use the singular ocean because all ocean basins are connected.)
Moving toward ecosystem-based approaches requires comprehensive ecosystem assessments to characterize planning areas and inform plans that meet specified social and ecological goals. Ecosystem assessment has been defined as “a formal synthesis and quantitative analysis of information on relevant natural and socioecological factors, in relation to specified ecosystem management objectives” (Levin et al. 2009). Such assessments are recognized as a critical step in conservation-planning processes worldwide (Pressey and Bottrill 2009). In the US ocean policy arena, for example, the National Ocean Policy recommends the development of regional assessments that include descriptions of the existing biological, chemical, physical, and historical characteristics; identification of sensitive habitats and areas; identification of areas of human activities; analyses of ecosystem conditions; and assessments, forecasts, and modeling of cumulative impacts (IOPTF 2010).
Although directives such as the National Ocean Policy provide opportunities to conduct relevant ecosystem assessments, they often do not provide specific approaches for incorporating EMB into ocean and coastal planning or other management decisions. Consequently, practitioners may benefit from guidance on how to structure and focus their efforts. Needed guidance includes frameworks that direct the collection, synthesis, and analysis of necessary information, as well as ways in which assessments are likely to be used in the course of policymaking and management processes. We seek to fill this gap by evaluating existing ecosystem assessment frameworks and their application in real-world ocean planning initiatives. First, we provide an overview of four ecological attributes that focus attention on biophysical characteristics of the ecosystem (hereafter referred to as ecological principles; Foley et al. 2010). These ecological principles were identified in 2009 by a group of 20 experts in the fields of marine ecology and conservation biology who were asked to identify the fundamental attributes of ecosystems that should be considered in management and planning processes in order to maintain resilient ecosystems. We also briefly explore how these principles and the concept of ecosystem vulnerability can be woven explicitly into a comprehensive ecosystem assessment framework. Although we acknowledge the important role of social and economic information in EBM and ocean planning, we restrict our focus to biophysical principles in order to constrain our analysis. Second, we review the assessment methodologies used in regional ocean planning initiatives around the world and evaluate them on the basis of the types of information and analyses included. Although there are many more comprehensive frameworks that have been developed, we chose to focus on the four that have been used in actual planning and management contexts, that advance EBM, and that already incorporate at least one component of the ecological principles or ecosystem vulnerability. Third, we describe in more detail a particularly promising approach—the framework developed in the US National Oceanic and Atmospheric Administration's (NOAA) Integrated Ecosystem Assessment (IEA) program (we use the same abbreviation—IEA—for the documents created through this framework)—and discuss how the ecological principles can be woven into the existing IEA framework. Finally, we conclude by exploring some of the challenges associated with comprehensive assessments and highlight emerging tools that can be used to address some of these challenges associated with EBM in ocean planning and policy contexts. We use the US ocean policy to focus the application of our work, noting that our analysis and recommendations can be tailored to any transparent, participatory ecosystem-based planning process.
In addressing the role of comprehensive ecosystem assessments in planning, we focus here on a synthesis of two particularly promising frameworks—that of ecological principles and the IEA framework—rather than conducting a full review of ecological assessment practices. These two frameworks have gained traction for advancing EBM (Levin et al. 2009, Foley et al. 2010) and are being actively used in decisionmaking contexts (Erickson et al. 2012; www.pcouncil.org/resources/archives/briefing-books/november-2012-briefing-book/#ecosystemNov2012).
Guiding ecological principles for comprehensive ecosystem assessments
There are a number of approaches available to address the many challenges facing the world's ocean. The use of comprehensive ecosystem assessments in marine planning processes, for example, is one such strategy. Within this context, we limit our discussion to the biophysical components of the ecosystem, including four ecological principles and two components that affect the vulnerability of the system—cumulative impacts and climate change. Both the ecological principles and ecosystem vulnerability contain spatial and temporal components that are important to planning processes. In addition, they can be used to establish planning goals that guide management actions, including avoidance, mitigation, or adaptation measures.
Fundamental biophysical attributes of marine ecosystems.
Foley and colleagues (2010) presented four ecological principles for marine spatial planning that are based on fundamental biophysical attributes of healthy, functioning ecosystems. These biophysical attributes—native species diversity, habitat diversity and heterogeneity, populations of key species, and connectivity—were chosen by a group of experts to reflect components of the ecosystem that are most important for maintaining a relatively wide array of ecosystem goods and services. Maintaining and, where it is possible, restoring these attributes can help resource managers support productive, resilient ecosystems (Steneck et al. 2009) and make ecosystems less vulnerable to natural and anthropogenic impacts (Thrush et al. 2008).
These ecological principles can also help planners and managers distill the complexity of ecosystems into specific, measurable dimensions and structure important aspects of ocean planning processes, such as the development of management objectives, thresholds, monitoring programs, and adaptive management measures (Erickson et al. 2012). Spatial data that represent these principles and their underlying attributes, or at least reasonable proxies for them, are often available and can help identify where species and habitats are located, how they are connected, and their relative importance and sensitivity to human activities. When planning objectives are aligned with EBM principles, accounting and managing for these biophysical attributes can advance marine resource management beyond single-species or single-sector approaches. These fundamental biophysical attributes are consistent with the goals for regional spatial plans identified in the US National Ocean Policy (IOPTF 2010) and can be used as a foundation to describe existing biological, chemical, physical, and historical characteristics; identify sensitive habitats and areas; and analyze current ecosystem condition. Management decisions, however, are also best considered in the broader context of ecosystem vulnerability, which describes how human interactions influence particular biophysical attributes and, ultimately, the structure and functioning of marine ecosystems as a whole.
The vulnerability of a species or habitat to a stressor is determined by the intensity and frequency of an impact and the extent to which that impact compromises the ecosystem's ability to withstand or rebound from change. Habitats and species are often differentially affected by particular types of stressors because of their variety of morphologies, physiologies, and life histories. It is therefore important to understand the compatibility of different human activities with multiple habitat types and species. The vulnerability of a species or habitat can be assessed by evaluating the sensitivity of a resource to a stressor (using characteristics of the specific stressor, including the susceptibility of the species or habitat, frequency, spatial scale, and functional impact) with the likelihood that the stressor or disturbance will occur (Halpern et al. 2007, Samhouri and Levin 2012).
Vulnerability assessments can link biophysical attributes to one another and to human stressors that are currently or are expected to be present in an area. Understanding system vulnerability is essential for effective resource management, whether management is focused on single or multiple species. In the United States, the National Ocean Policy and its supporting documents make reference to the necessity of vulnerability assessments in the context of ecosystem resilience planning and management. They also identify the importance of cumulative impact analyses and climate change planning in evaluating environmental risks and resiliency, informing trade-off decisions, and setting priorities (IOPTF 2010). We explore these components of vulnerability in more detail below.
Habitats and species can be vulnerable to the accumulation of stressors in time and space. Therefore, ecosystem structure and functioning can be shaped by the cumulative impact level—the number and intensity of co-occurring activities. Cumulative impacts can accumulate in a linear or additive fashion (Kaplan et al. 2013), but they can also accumulate synergistically (with the total impact greater than the sum of its parts) or antagonistically (with the total impact less than the sum of its parts). Recent meta-analyses of stressor experiments in marine systems indicated that a majority of stressors interact in a nonadditive fashion—either antagonistically or synergistically (Crain et al. 2008, Darling and Côté 2008). More important, when more than two stressors were present in a system, the number of synergistic interactions doubled, and the cumulative impact was more negative than was predicted by single-stressor experiments (Crain et al. 2008).
Rising atmospheric carbon dioxide.
The fundamental attributes of ocean ecosystems are also highly vulnerable to the effects of rising atmospheric carbon dioxide, including sea-level rise, coastal inundation, sea surface temperature increases, and ocean acidification (Hauri et al. 2009). These changes are likely to alter the provision of ecosystem services on which humans rely (e.g., oxygen production, storm protection, food provisioning; Cooley et al. 2009). For instance, the observed effects under increasingly acidic ocean conditions to date include shifts in species abundance and distribution (Fabry et al. 2009), losses of habitats to erosion and inundation (Heberger et al. 2009), and food web–scale changes (Kaplan et al. 2010). The pervasive effects of increasing atmospheric carbon dioxide may further erode the resilience of ecological systems, making them more vulnerable to additional disturbance (Cooley et al. 2009). Assessments of the current and predicted impacts of climate change on the biophysical attributes of healthy ecosystems are important for determining how much additional stress ecological systems can withstand before undergoing significant undesirable changes.
Reviewing comprehensive ecosystem assessments in practice
In ecosystem-based planning processes, essential attributes of functioning ecosystems should be recognized and ecological interactions accounted for in a way that is understandable and useful to resource managers and users. For the United States in particular, achieving these goals means building on existing environmental statutes and assessment frameworks by establishing institutions and accounting methods to address the fundamental biophysical attributes of ecosystems and vulnerability. These frameworks allow managers and decisionmakers to gain a more thorough understanding of the effects that multiple human activities have on biophysical attributes and to highlight the benefits and drawbacks of reactive, single-sector management practices relative to more proactive, comprehensive approaches. We reviewed four existing comprehensive ecosystem assessments—conducted in various geographies around the world—to determine how these ideas have been incorporated. Because none of the assessments fully integrate all of the ecological principles and ecosystem vulnerabilities, we used the most developed and applied framework—that of NOAA's IEA program—to demonstrate how the full suite could be incorporated into an established assessment framework.
Australia's national marine bioregional assessments.
In 1998, Australia formally recognized the need for ecosystem-based planning and management of its waters (beyond the Great Barrier Reef; COA 1998). Since 2005, Australia has been conducting large-scale bioregional assessments with the ultimate goal of assessing its entire exclusive economic zone (EEZ; the region up to 200 nautical miles from its coast; COA 2006). Australia's bioregional assessments compile and synthesize biological, geological, and oceanographic data to identify the units and boundaries of ecological systems at a scale that is useful for regional planning and management. The regionalization framework parses the ocean ecosystem into two components—benthic and pelagic (Heap et al. 2005, Lyne et al. 2005). The benthic assessment is focused on physical and biological attributes, including bathymetry, sediment, and the diversity and distribution of demersal fish and sponges. Data are collected in 41 bioregions that have unique assemblages of species in areas with geomorphic features. The pelagic assessment describes the structure of the water column on the basis of physical attributes, such as temperature, salinity, and primary productivity. The data from the pelagic assessment describes 25 water masses in Australia's ocean, which are presumed to affect species distributions. The combined assessment, which covers 80% of Australia's EEZ, helps planners and managers (a) understand the complex relationships that exist among the biological, physical, chemical, and geological aspects of ecosystems and how they affect habitat and species distributions; (b) inform regional spatial planning efforts; and (c) focus on the objectives of protection, conservation, and sustainable use of Australia's national waters (Day et al. 2008).
Australia's bioregional assessment methodology encapsulates the four ecological principles by mapping the distribution of habitats and species of importance in each bioregion and focusing on biophysical indicators that contribute to ecosystem structure and functioning. The process of mapping pelagic and benthic species and habitats yields important benefits for decisionmakers by better informing management deliberations, especially when determining the compatibility of human activities with biophysical attributes of marine ecosystems and evaluating the trade-offs associated with their management decisions. Future work in which the links between the benthic and pelagic data are visualized will help assess ecosystem connectivity within Australia's EEZ and between the EEZ and international waters.
The California Marine Life Protection Act Initiative's regional profiles.
Comprehensive assessments were compiled to facilitate the implementation of California's Marine Life Protection Act (MLPA), which required the designation of a network of MPAs in the state's waters (up to 3 nautical miles from the coast; DFG 2008). For each of the four planning regions, program leaders produced in-depth regional profiles to identify the key ecological, socioeconomic, governance, and institutional features necessary to help stakeholders and decisionmakers understand the region (e.g., see the North Coast Regional Profile, available at www.dfg.ca.gov/marine/mpa/ncprofile.asp). These regional profiles increased in scope and depth through the 7-year open-coast planning process.
Each profile described the ecological setting of the region by mapping the distribution of habitat features and species of importance. For the fourth planning region, the North Coast, the analysis included 11 habitat types, ranging from intertidal and estuarine habitats to submarine canyons and oceanographic habitats. Specific species were included in the analysis on the basis of their importance to commercial and recreational fisheries or their special legal status (e.g., threatened, endangered). Spatial distributions were characterized for species, including invertebrates, sea birds, and marine mammals. Points of connection between the land and sea were also examined to determine, for example, how MPAs could be affected by watershed runoff and human activities, such as coastal recreation. The regional profiles also included social and economic components, such as population distribution, Native American resource interactions, commercial and recreational uses, management jurisdiction, and existing management areas.
The regional profiles capture all four ecological principles, with a strong focus on mapping habitat locations. Multiple researchers and contractors undertook an extensive bathymetry and habitat mapping effort to map the full extent of California's state waters to help inform MPA placement. The second focal point of the regional profiles was to identify pathways of ecosystem connectivity, which was an important component of meeting the mandate to create a network of connected MPAs rather than a series of individual reserves along the coast. To help facilitate meeting this mandate, the science advisory team developed MPA size and spacing guidelines based on oceanographic features and the dispersal distance of regionally important species (Carr et al. 2010). These general guidelines helped guide stakeholders in MPA network proposal development and allowed planners, stakeholders, and decisionmakers alike to transparently evaluate whether proposed MPAs met the network criteria.
The regional profiles provided a solid framework for structuring the initial assessment of ecological communities and directly informed the MPA proposals, plan review by the science advisory team, and plan acceptance by the Fish and Game Commission. The profiles ensured that the same information was available to all parties involved in the process and that decisions were made on the basis of the best available science.
Canada's Eastern Scotian Shelf Integrated Management Plan.
Fisheries and Oceans Canada (DFO) developed an ecosystem assessment framework for its Integrated Fisheries Management Plan process for Canadian waters (DFO 2007). The framework addresses the need to synthesize biological data on the scale of ecosystems rather than single species and to understand the relationships between biophysical and human components of marine ecosystems. The framework comprises eight priority areas: (1) setting clear objectives, (2) developing ecological indicators, (3) developing risk-based frameworks, (4) generating integrated information, (5) identifying habitats of special importance, (6) considering impacts on biodiversity, (7) understanding pathways of change, and (8) understanding climate variability.
The assessment (DFO 2005) for the Eastern Scotian Shelf Integrated Management (ESSIM) area, one of Canada's first ocean planning regions, identifies additional core ecological, social, and economic objectives, including the preservation of ecosystem structure, ecosystem functioning, and habitat and the maintenance of human use of marine resources. Additional ecosystem elements of concern were identified by the Maritimes Region ESSIM Science Working Group to be consistent with national objectives while covering the following elements of the ecosystem: community-related objectives (e.g., benthic communities), species-related objectives (e.g., commercially harvested species), cross-cutting objectives (e.g., invasive species), productivity-related objectives (e.g., phytoplankton), and habitat-related objectives (e.g., rare habitats). In addition, the ESSIM Science Working Group distinguished between objectives that could be subject to management decisions and objectives that involve monitoring ecosystem components that affect the ecosystem but are not managed (DFO 2005).
For each of the ESSIM plan's (DFO 2005) objectives, outcome and management performance indicators were selected to enable evaluations of both individual management actions and overall success in plan implementation. Decision rules were created to address potential conflicts among multiple objectives, which allow decisionmakers to carefully weigh the trade-offs between increased human pressure and ecosystem condition in order to meet human-use objectives and limits on human use to achieve ecosystem objectives (see box 1).
Trade-offs are a part of nearly all resource planning and management decisions. Decisionmakers make trade-offs among ecological, economic, and social goals and objectives throughout the decisionmaking process but rarely assess those trade-offs in an explicit and transparent manner. Comprehensive ecosystem assessment frameworks and analytical tools can help determine when trade-offs may be necessary and identify methods for assessing them. When an ecosystem assessment is being conducted as part of a larger planning process, there are many stages during the process at which trade-offs may be made. First, trade-offs may be necessary in order to complete a planning process within a specified time frame. For example, short planning periods may limit the amount of data that could be collected and may, therefore, result in incomplete information being used in the decisionmaking process. However, extending the time frame of planning to allow for the inclusion of additional data may significantly increase the cost of the process. Second, trade-offs are often associated with the attainment of different management goals. For example, two goals of a planning process might include the maintenance of the structure and functioning of ocean and coastal ecosystems for future generations and support for healthy coastal communities and economies. These goals are not mutually exclusive in the abstract sense, but they may be seen to conflict when the political context and time frames are taken into account. Trade-offs may also exist among objectives that serve a single goal. For example, a healthy coastal economy may include a portfolio of fishery, energy, and recreational uses. However, the expansion of wave-energy facilities and fishing grounds may be incompatible uses within a particular ocean area; therefore, siting those uses requires trade-offs. New analyses and tools are being developed that allow decisionmakers to transparently and quantitatively assess trade-offs among competing goals, objectives, and uses (e.g., White et al. 2012, Lester et al. 2013).
The ESSIM assessment (DFO 2005) goes beyond the four ecological principles and includes more complex ecosystem considerations, including (a) characterizing current ecological and social conditions, such as the interactive and cumulative nature of human impacts; (b) identifying representative, important, and sensitive areas on the basis of species and habitat diversity and the naturalness of ecological communities; and (c) assessing the threats, likely impacts, and factors that influence ecosystem health and productivity, such as climate change and ecosystem resilience. This comprehensive assessment framework, which is one of the most advanced frameworks developed, serves as a basis for subsequent planning and regulatory decisionmaking, not only within the DFO but across the broader ocean resource management community.
The NOAA IEA framework has drawn attention as a leading example of a comprehensive, ecosystem-based assessment. The IEA framework (Levin et al. 2008) is intended to help resource managers gather and analyze relevant biophysical and socioeconomic information across sectors and scales before making substantive decisions (deReynier et al. 2010). At a finer scale, the IEA framework can help managers and decisionmakers transparently identify ecological attributes that maintain ecosystem structure and functioning, assess human uses in the planning area and their likely impacts on ecological attributes, and evaluate management alternatives that reflect planning objectives and EBM principles. To date, the framework has mainly been used in the fisheries management context (Levin and Schwing 2011); however, it is beginning to be applied in multisector planning in places such as Puget Sound (Ruckelshaus et al. 2009, Tallis et al. 2010, Levin and Wells 2013). The IEA framework consists of the following five components, which are discussed in more detail below (figure 1): (1) scoping, (2) identifying indicators and reference levels, (3) performing risk analyses, (4) evaluating management strategies, and (5) monitoring and evaluating progress toward management goals.
The goal of the first step of an IEA—scoping—is to provide a general overview of the system, including the relevant ecological, social, and political issues and interests. Understanding how these components of the system overlap allows ecosystem stressors and management drivers to be identified. Ecosystem management or planning objectives are often identified in the scoping phase, which helps structure the rest of the IEA process. In the second step, indicators are identified that reflect how the ecosystem is changing as a whole and provide a metric for assessing progress toward management or planning objectives. Indicator selection can be difficult because of the complexity of ecological systems and the interests of coastal communities. Criteria for selecting indicators (Rice and Rochet 2005) and computer simulation approaches to evaluate indicator performance can help constrain the indicator selection process. The third step—risk analysis—involves understanding the risks to the chosen indicators from human or natural processes. Uncertainties in the system are incorporated into the IEA framework at this stage, along with an analysis of susceptibility (i.e., exposure to an impact) and resilience (i.e., the ability to recover from impact) of each indicator. A full analysis of all indicators is conducted once the individual indicators are selected. The final two steps—management strategy evaluation and monitoring and evaluation of progress—require an adaptive approach to assess the thoroughness of scoping, the effectiveness of the indicators, and the level of understanding and certainty of the risk associated with the indicators. The trade-offs associated with management alternatives are also evaluated at this step, and triggers for evaluation and adaptation are established.
The IEA framework is one of the most developed and widely implemented assessment methodologies to date. The framework is being or has been used in a number of locations, including Kona, Hawaii, the California Current, the Bering Sea, the Aleutian Islands, the Gulf of Alaska, the Northeastern US Continental Shelf, the Gulf of Mexico (see www.noaa.gov/iea), and the North Sea (ICES 2011).
Incorporating ecological principles and ecosystem vulnerability into the IEA framework
The existing IEA framework supports the inclusion of the ecological principles during the scoping, indicator development, and risk assessment steps. By expanding the framework to explicitly incorporate ecological principles and ecosystem vulnerability (figure 1), the IEA framework can be modified to capture the full scope of ecological principles and ecosystem vulnerability in order to enhance its consistency with the goals of the US ocean policy, as well as other ocean planning and conservation processes.
In addition to identifying management drivers and specific stressors on the ecosystem, scoping can be expanded to incorporate the approach taken in the Australia Bioregional Assessment and the California MLPA Initiative to map the distribution of species and habitats of interest, populations of key species, and possible connectivity corridors (figure 1). In the current IEA framework, the status of many of these biophysical attributes is assessed (figure 2), but the framework does not include a mapping component. Mapping efforts could be taken a step further to include the overlap between human impacts and biophysical attributes. This preliminary phase—scoping—which includes both mapping and assessment, helps define the appropriate planning scale, identify the concerns relevant to each region, and set management goals and objectives.
The indicator selection process should result in a suite of indicators that are relevant to management and consistent with the goals and objectives established in the scoping step. To the extent that this is possible, indicators—either single or composite metrics—can be developed that are consistent with the ecological principles (e.g., species diversity, abundance of top predators), cumulative impacts (e.g., water quality), and climate change effects (e.g., abundance of novel species) (figure 1). Indicators that reflect the ecological principles and ecosystem vulnerability are also often consistent with existing agency mandates and management regulations (Erickson et al. 2012). Although many of the indicators currently used in the IEA process are consistent with ecological principles (e.g., species diversity, habitat condition; figure 2), indicators that reflect changes in the ecosystem due to cumulative impacts and climate change have not yet been incorporated into the IEA framework.
Risk analyses that determine the probability of an indicator's serving as an effective proxy for evaluating management strategies could be expanded to incorporate cumulative impacts and climate change to more fully assess the probability that an indicator will remain in or reach an undesirable state (figure 1). As an example, the risk analysis used for the DFO's ESSIM assessment incorporates cumulative impacts and focuses risk assessment on ecologically and biologically significant areas (i.e., areas with valued ecological or biological attributes; DFO 2005).
Management strategy evaluation requires a careful weighing of the options and trade-offs associated with different management options. The ecological principles and ecosystem vulnerability concepts can be used to help structure these evaluations and weigh the trade-offs. For example, one management strategy may have a negative effect on habitat diversity and top predators, whereas another may have a negative effect on species diversity but may reduce the overall cumulative impact. Relating the ecological principles to management strategies can help managers devise decision rules that aid in selecting the preferred management option. Similarly, the ecological principles can be used as a guide to develop thresholds for each indicator that inform monitoring and evaluation efforts. Monitoring and evaluation require an adaptive approach to evaluate the thoroughness of the scoping analysis, the effectiveness of indicators, and the progress toward achieving management or planning objectives.
Although the IEA framework already incorporates a number of the ecological principles, our proposed additions focus the development of objectives, indicators, and thresholds on the fundamental attributes of the biophysical system and expand the consideration of ecosystem vulnerability. The current IEA framework lends itself to these additions while maintaining its utility across multiple spatial scales, management applications, and planning processes. Approaches used in the other three comprehensive ecosystem assessments provide examples of how these additional components can be incorporated into the IEA framework.
Modifying the IEA framework to more explicitly incorporate the ecological principles and concepts of ecosystem vulnerability not only helps make it more consistent with US ocean planning and management policies, but it also makes the framework more widely applicable for resource managers who are trying to incorporate EBM principles into their day-to-day decisions. In the United States, many of the components of an IEA are required by federal and state agencies as part of the environmental review process—for example, under the National Environmental Policy Act (NEPA) or state equivalents—that accompanies agency planning, permitting, and development activities. IEAs could help standardize the type of information that multiple agencies use during a project review process and could serve as major components of programmatic environmental impact statements under NEPA, providing a necessary factual and analytical foundation for any future project-level decisions.
Challenges associated with IEAs
Conducting such a comprehensive assessment does not come without significant challenges (box 2). For IEAs in particular, data and expertise may be seen as barriers to implementation. In planning regions with limited data or resources, it may not be possible to complete all five steps of an IEA. Under such conditions, the components of the framework can be prioritized in three phases to help practitioners identify the most important types of data and information that should be gathered in a planning or other decisionmaking process (figure 3). Phase 1—including the steps of scoping and identifying indicators and reference levels—is focused on biophysical and human-use data that are often available, albeit distributed across agencies and academic institutions. These data can form the backbone of management decisions by visually documenting where resources and activities are located, where they overlap, and where potential conflicts exist. With an understanding of the distribution of ecological attributes and human activities, management objectives can then be developed, and indicators—ideally, representative of the ecological principles—can be chosen that are consistent with management goals and objectives, much like the assessments in the MLPA regional profiles.
There are a number of challenges associated with conducting comprehensive ecosystem assessments, including high costs, limited expertise, interagency communication, and high uncertainty. The ecosystem assessments described in this article are all designed to be conducted at regional or larger scales. In many instances, some data relevant to the assessment are available, but data analysis and model generation are time-consuming activities that require personnel with specific expertise. In many planning situations, however, staff with time and experience or the funds to hire additional necessary personnel may not be available. Novel partnerships—such as collaborative research projects and public–private partnerships—among government, industry, and academia can help reduce the burden of these costs.
Conducting comprehensive ecosystem assessments requires communication among multiple agencies, stakeholders, and decisionmakers. Although interagency communication is required by some legal mandates (e.g., the California Environmental Quality Act), there is no protocol for structuring communication during the assessment process. Effective communication can help reduce the time and cost of assessments by creating transparency around planning and management objectives and through data coordination and sharing.
By the nature of their structure, comprehensive ecosystem assessments contain uncertainties that are difficult to address. For example, indicators are selected as part of many assessments. These indicators are chosen using the best available information but are sometimes not good measures of ecosystem-level change because of unknown complex interactions in the ecosystem. However, assessment frameworks help make areas of uncertainty more transparent, allowing management alternatives to incorporate an appropriate level of precaution on the basis of the sensitivity of the system and the level of impact.
Phase 2, which is focused on the risk assessment step, includes more in-depth analyses that can be used to tell a comprehensive story of ecosystems within the planning region. These analyses typically require more expertise and expert knowledge that link impacts on biophysical attributes, including the cumulative effects of multiple activities.
Finally, phase 3, including management strategy evaluation and monitoring and evaluation of progress requires more-specialized analyses for developing thresholds, understanding trade-offs, and evaluating the success of management strategies. Completing all three phases is the ultimate goal of the IEA, but management can be improved by focusing on phase 1 if resources are limited. A full IEA, in which all three phases are completed, provides a more-detailed analysis and synthesis that can help managers and decisionmakers develop robust management alternatives that can actually be achieved.
All five steps of the IEA should be based on the best available science and data in order to adequately enable managers to interpret and apply the ecological principles, incorporate EBM approaches, evaluate the degree of uncertainty and risk, and acknowledge and incorporate regional context and values during the planning process. IEAs should be closely tied to ecological monitoring activities to ensure assessments are updated on a regular basis. Monitoring and evaluating the IEA over time is important for assessing the progress of the ecosystem toward management goals and objectives. When used in combination with decision support tools (box 3), the results of an IEA can help improve transparency in planning and adaptive management processes, can facilitate the use of science in ocean decisionmaking, and can enhance the effectiveness of nascent and forthcoming ocean planning and management efforts of all types.
Major technological advances have been made in decision support tools (DSTs) over the last 5 years, and they are being used more frequently in spatial planning processes to help users visualize complex and multifaceted scenarios that are challenging to fully understand intuitively. Used properly, DSTs can help planners and managers (a) save time, energy, and resources; (b) guide users through the difficult steps of the decisionmaking process; (c) reduce requirements for human expertise; (d) help users explore a wider range of alternatives; and (e) increase the understanding of the requirements and limitations of multiple human activities (Coleman et al. 2011). The main functions of DSTs range from data visualization (e.g., the US National Oceanic and Atmospheric Administration's Multipurpose Marine Cadastre) to scenario development and analysis (e.g., InVEST) and stakeholder engagement (e.g., MarineMap; see below). A more thorough description of DST functions and features can be found in Coleman and colleagues (2011). In the context of ecosystem assessments, DSTs can help organize information, explore management alternatives, and assess the trade-offs associated with different planning scenarios. For example, in the California Marine Life Protection Act (MLPA) process, multiple DSTs were used throughout the planning process, including a tool called MarineMap, which greatly aided the stakeholder process by reducing misunderstandings and creating alliances. MarineMap is a mapping interface that allows users to draw proposed MPA networks, to evaluate the design against the MLPA objectives, and to share their proposals with others. Similarly, the DST Atlantis has been used extensively in the integrated ecosystem assessment context to help users quantitatively evaluate the outcomes of multiple management scenarios (Fulton et al. 2011).
Emerging scientific analyses and models
Successful ocean planning processes require significant investment in personnel, stakeholder engagement, and data processing. A number of emerging tools (box 3), analyses, and models are aimed at making data visualization, trade-off analyses, and impact assessments more efficient and robust. Below, we highlight emerging scientific analyses and models that can help planners and managers move through the steps of the recommended enhanced IEA process, with a focus on the more difficult components. The three advances highlighted below are specific to ecosystem vulnerability, cumulative impacts, and climate change, because they are likely to be the most difficult components to operationalize in the modified IEA framework.
Ecosystem vulnerability assessments.
Assessing ecosystem vulnerability is a major challenge for scientists and resource managers. Numerous types and combinations of stressors that occur in marine ecosystems and each habitat or species may be differentially vulnerable to the same stressor. Expert survey techniques have recently been developed to calculate quantitative vulnerability scores for ecosystems on global (Halpern et al. 2007) and regional scales (Teck et al. 2010). In data-limited cases, generating expert-derived vulnerability scores is a step forward and advances our understanding of how current and future activities may interact with ecosystems and whether those interactions are positive or negative.
Assessing vulnerability as part of an ecosystem-based approach to ocean and coastal management may allow resource managers to proactively manage marine resources and human uses by identifying and prioritizing the necessary actions for managing stressors that pose the greatest threat to all ecosystems, comparing the level of threat from the same stressor between two or more ecosystems, and comparing multiple threats to a given ecosystem. Compatibility matrices can be developed from this information that provide a simplified chart denoting whether a specific use is compatible with a specific ecosystem feature (MOMP 2009).
Advances in cumulative impact assessments.
Cumulative impact assessments are a required component of the federal environmental review process in the United States under NEPA and under many state analogs of NEPA. Unfortunately, these cumulative impact analyses are rarely comprehensive, and the analysis undertaken is often not sufficiently descriptive (from the scientific perspective and sometimes also from the legal perspective) of the full scope of impacts that are occurring at ecologically meaningful scales (MacDonald 2000). There are a number of hurdles to achieving more-effective and scientifically valid cumulative impact assessments, including a better understanding of how to assess the impacts of stressors on species, habitats, and the ecosystem; evaluating impacts on appropriate scales; accounting for interactions among stressors; and creating a baseline against which additional impacts can be measured. Growing recognition from scientists and a greater demand from resource managers has fueled efforts to develop a systematic approach to accounting for cumulative impacts in marine ecosystems.
Cumulative impact maps based on ecosystem vulnerability and ecosystem stressor footprints that depict existing total cumulative impact load have been developed for the global ocean (Halpern et al. 2008) and for an increasing number of ocean regions (Halpern et al. 2009, Selkoe et al. 2009, Ban et al. 2010). Developing methods to quantify the total impact from multiple activities within a given area is an important advancement in understanding how future user–ecosystem interactions are likely to develop on the basis of current and historical levels of impact in an area. By recognizing what the major stressors are, where they occur, where multiple stressors overlap, and what activities cause them, it is possible to develop more-effective strategies for quantifying and limiting the number and rate of co-occurrence of stressors that are of particular concern for important or vulnerable ecosystems or those commanding particular interest among decisionmakers (Jankowski et al. 2001).
Advances in climate change impact assessments.
The impacts of climate change and increased carbon dioxide, including sea level rise, warmer ocean temperatures, altered storm frequency and intensity, and ocean acidification, are already documented in coastal communities around the world (Feely et al. 2008, Fabry et al. 2009), which highlights the immediate need to develop comprehensive approaches to incorporate the likely effects of these changes into management decisions. A number of states and countries are developing creative solutions for climate change planning, adaptation, and mitigation (CANRA 2009, COA 2010).
For example, the states of New York and Connecticut have engaged in climate adaptation planning with the aid of The Nature Conservancy's Coastal Resilience tool. This approach brings together census data, storm surge predictions, and sea level rise forecasts to help managers and planners visualize how coastal inundation will affect their populations and how natural ecosystems can help buffer communities from those impacts (http://coastalresilience.org). In Australia, researchers are analyzing sea surface temperature data to develop a map of the Great Barrier Reef that depicts where temperatures are changing rapidly and where they are changing slowly. This analysis is being used to inform the designation of additional MPAs in areas that will potentially be less affected by increases in ocean temperature (Ban et al. 2012). In addition, shellfish growers along the West Coast of the United States are experiencing ocean acidification conditions that were not predicted to manifest until 2050 (Feely et al. 2008). In order to protect their industry from collapse, many hatcheries are installing carbon chemistry monitoring systems to help them determine when it is safe to draw seawater into their facilities. These emerging analyses and tools allow managers and planners to address and respond to current trends and future predictions of ecosystem change, which can, in turn, increase the ability of resource managers to evaluate how user–ecosystem interactions are likely to play out over longer time frames and under changing conditions.
The ultimate goal of EBM and many proactive spatial planning processes is resilient ecosystems (McLeod and Leslie 2009). Healthy ecosystems have a natural capacity to absorb and recover from many disturbances, but their ability to recover from or withstand disturbances is finite. Conducting comprehensive ecosystem assessments that incorporate ecological principles and ecosystem vulnerability allows the drivers of ecosystem resilience to be incorporated into management decisions through the synthesis of vulnerability, cumulative impacts, and climate change, as well as the identification of stressors that drive ecosystem change and metrics that are most useful for avoiding ecological surprises.
Data, methods, and models are continually being collected and developed to increase the feasibility of undertaking IEAs. The IEA framework provides resource managers with a broader perspective on how their decisions affect whole ecosystems, rather than a single species. The framework can be used to advance understanding of the interconnectedness of ecological components to identify management alternatives; assess the compatibility of uses and the ecosystem; and evaluate trade-offs among ecological, economic, and social objectives. This enhanced EBM approach better reflects the growing scientific understanding of links within and between ecosystems; the relationships among ecosystem functioning, ecosystem service provision, and human well-being; and the importance of acknowledging humanity's role in structuring ecosystems and actively selecting management actions.
We have not provided specific instructions for how the IEA framework should be operationalized because implementation will vary greatly, depending on the context of the management process. The revised IEA framework does, however, provide a standardized format for incorporating ecological principles, concepts of ecosystem vulnerability, and other EBM principles into spatial planning processes that builds on the ongoing management efforts of governmental agencies worldwide. This globally applicable framework also draws on ocean planning efforts that have been developed for multiple geographic regions around the world by combining their strengths and explicitly including complex ecosystem analyses in the framework. Incorporating comprehensive ecosystem assessments into ocean planning and conservation can help resource managers address the problems associated with single-sector, short-term management decisions. They can also help move resource management and spatial planning toward more coordinated, ecosystem-based approaches that use the best available science, are cognizant of the relationship between human impacts and marine resources, and promote sustainability of resources and ocean health.
This work was supported by the David and Lucile Packard Foundation and the Gordon and Betty Moore Foundation. We thank three anonymous reviewers for helpful comments that improved the manuscript.