This section includes excerpts from “Best Practices for Integrating Ecosystem Services into Federal Decision Making” and an earlier version of this guidebook as well as new content.
In an ecosystem services assessment, conceptual diagrams—also known as means-ends diagrams—provide a systematic approach to connecting ecological conditions and societal benefits. They are composed of multiple causal chains, wherein each chain is a logical model that declares how ecological conditions (current, desired, or changed by a management action or policy) affect the provision of ecosystem services and benefits to various segments of society.
Causal chains are commonly used in ecological assessments but are slightly different when used in an ecosystem services assessment. As in an ecological assessment, they begin with either ecological conditions (e.g., current healthy wetland habitat) or the action or policy affecting those conditions (e.g., wetland restoration or invasive species removal). However, they end with effects on human well-being caused by changes in ecosystem services, rather than expected environmental changes or outcomes, which are common endpoints for ecological assessments. When connections to people are not made explicit, it is unclear whether and how each ecological change is related to changes in social benefits, and important changes to societal benefits may be left out of the analysis. For this reason, causal chains in an ecosystem services assessment extend to human well-being (Figure 1). As part of scoping, the causal chains embedded in conceptual diagrams may be preliminary best guesses requiring relatively little effort yet providing a comprehensive overview of all potentially significant services. More robust quantifiable causal chains are needed in the analysis.
Figure 1. Components of an ecosystem service causal chain
As mentioned above, causal chains used in conceptual diagrams can be used to evaluate current conditions, desired conditions, and/or changes caused by a management alternative. In an assessment of current or desired conditions, these diagrams reveal the services provided and help stakeholders and decision makers consider what services they may want to enhance or sustain when setting future objectives. In alternatives assessment, they display how management options will change the biophysical landscape (and related human behaviors) and show how those changes relate to the provision of ecosystem services and ultimately societal benefits. These alternatives can include individual changes in conditions at one site or comparisons of changes in condition for multiple sites or for combinations of actions that make up a management scenario or management plan. They also reflect changes in human behavior that may be expected as part of these ecosystem changes, such as increases in recreational visits (and hence benefits) that might be expected when relevant conditions improve at sites used for recreation. Causal chains can also be used to consider project options (e.g., funding wetlands restoration in Florida versus Minnesota) or policy choices, which are evaluated in terms of the actions they imply; for example, policies affecting incentive payments for protecting riparian zones would be evaluated in terms of the changes to those zones. Conceptual diagrams linked to alternatives will be the inputs for the analysis step.
Creating conceptual diagrams is one of many simultaneous and interactive scoping activities, the others being assessing current status and trends (both ecological and social) and identifying services, objectives, and alternatives (Figure 2). Stakeholders can be engaged in all these activities. For example, by identifying services they care about, stakeholders can provide information directly relevant to the development of causal chains and conceptual diagrams. Conceptual diagrams can also serve as communications tools with stakeholders. For example, resource managers often think about outcomes in terms of ecological conditions alone—healthy long-leaf pine forest, fire-resilient riparian ecosystems, or hydrologically functional wetlands. Unlike managers, stakeholders may be apt to think about concrete experiences and opportunities when thinking about changes to their surroundings: areas available for fishing, trails open for hiking, water available for irrigation, risk of flood or fire to personal property. In other words, stakeholders think in terms of ecosystem services, though they may not use that term, whereas resource managers may think in terms of the conditions that lead to those services.
Figure 2. Simultaneous and interactive scoping activities initiate the decision process
* While less formal, perhaps narrative, causal chains can be used in the scoping process as part of conceptual diagrams, it will be necessary to fully flesh out causal chains incorporating indicators and models for quantification during the analysis.
At the end of the scoping process, practitioners should have a conceptual diagram, built around causal chains, for current conditions and for each proposed action or option. These causal chains may include some draft indicators but can be made into measurement models with specific indicators and data later in the analysis process.
Developing conceptual diagrams is a critical step to ensure that ecosystem services assessments are relevant, comprehensive, and transparent. Conveniently, they do not require particular software or technological expertise to develop. Rather, practitioners should take adequate time to brainstorm with experts and stakeholders about possible interactions and impacts and then refine them over time to capture the suite of interactions and impacts as completely as possible. This diagramming process can help identify how a policy or management action can affect multiple aspects of an ecosystem and how each of the impacts on an ecosystem can have multiple impacts on social benefits. For example, mechanical thinning of forests is used to reduce the risk of catastrophic wildfire. Thinning affects forest structure, which changes not only the intensity of fires but also species habitat, risk of pest and pathogen outbreaks, and forest carbon storage. Each of these ecological changes can then be followed down individual causal chain branches of the conceptual diagram to one or more ecosystem services and anticipated human benefits (Figure 3). All possible impacts to valued services should be included in the diagram, even those likely difficult to measure or model or likely to have only minor effects on people. This transparency enables practitioners to explain to stakeholders why only select services are carried forward in further analysis and hopefully reduces accusations of forgetting or ignoring services. Because all impacts are included, this process will likely identify too many services to be meaningfully quantified in any ecosystem services assessment. Those effects likely to be most important to the decision—often those expected to have the largest impacts on human welfare—can be targeted for quantitative analysis (see “Selecting Ecosystem Services”). However, by identifying the full range of pathways through which actions can influence people regardless of jurisdiction, these diagrams can often provide important insights for decision making and present opportunities to identify necessary partners and stakeholders.
Figure 3. Conceptual diagram with causal chains for an ecosystem services assessment of a forest management alternative
Note: This conceptual map of simplified causal chains shows possible outcomes from forest fire management activities like mechanical thinning. Black text indicates an ecological assessment and indicators, red text indicates extension to an ecosystem services assessment, and blue text indicates measures of social benefit and value.
Once conceptual diagrams are developed, practitioners can select a suite of services for analysis and build quantifiable causal chains.
Best Practice Questions: Creating Conceptual Diagrams for Ecosystem Services Using Causal Chains
To follow best practice in considering current conditions and objectives, the assessor should be able to answer yes to this question:
- Have all services that people care about been included in the diagram (even if they will not all be included in the final analysis)?
To follow best practice in considering changes in conditions, the assessor should be able to answer yes to ALL of these questions:
- Have all effects of a policy, management decision, or program on ecological conditions been included?
- Have the changes in ecological conditions that lead to changes in the delivery of affected ecosystem services been included?
- Have the effects on individuals or groups from changes in the delivery of ecosystem services been included?
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