California Watershed Assessment Manual, Volume II – Environmental IndicatorsDraft
1.Environmental Indicators
Environmental indicators present scientifically-based information on the status of, and trends in, conditions in the natural and human environments. One definition of an environmental indicator is a discreet measure of one aspect of environmental quality that can be used alone or in combination with other indicators to deliver a message or tell a story related to the overall environmental health of an ecosystem. (Chesapeake Bay Program, 2002). Good indicators convey complex information in a concise, easily understood format, and have a significance extending beyond that directly associated with the measure from which they are derived. They can be used in a variety of ways, including helping to evaluate the effectiveness of existing environmental programs and serving as an educational and informational tool for the public at large. Indicators can be used to monitor the environmental response to human actions (e.g., restoration or regulatory actions), to provide information needed to establish restoration and other goals, and to inform and involve the public in achieving environmental goals. They can be used to help guide programs and policies of the state or local government or other agency, as part of an adaptive management cycle.
Need for Indicators
The need for environmental performance evaluation systems to facilitate adaptive management has been recognized for quite some time and has recently resulted in a variety of indicator frameworks, methodologies, and initial assessments, at regional (e.g., State of the Sound 2004, Puget Sound Action Team) and national scales (e.g. Young and Sanzone, 2002, Heinz Center, 2003a&b). Numerous articles and national reports contain guidance for development of regional indicator suites that support large-scale restoration programs (Harwell 1998; Karr 1998; 2000; EPA, 2000; 2002). The overall goal of any such indicator system is to develop a quantitative measure of environmental or ecosystem health to evaluate program effectiveness.
There are many possible indicators of environmental condition, the effects of human actions, and the effectiveness of adaptive management. When data is available for a period of years, changes over time can be detected that can be used to understand how natural and human systems are being altered. This information can then be used to modify programs or activities that use an adaptive management approach.
Questions You Can Address Using Indicators
The following are the types of question you can answer using an indicator-based approach.
What is the condition of the watershed?
What is the condition of specific sub-watersheds?
What is the condition of specific parts of the ecosystem?
How well are management actions performing?
How well are water quality management actions performing?
How well are restoration actions performing?
How well are permitting actions/restrictions performing?
How are conditions changing over time?
How are specific parts of the system changing over time?
How are specific parts of the ecosystem responding to particular management actions over time?
How responsive are management actions to ecosystem changes over time?
This chapter discusses the various issues associated with selecting candidate indicators, testing these indicators for their utility in your system, analyzing data appropriately, and aggregating indicators into an evaluation and reporting index. The material is intended to introduce the field to allow you to engage in the global process of developing indicators.
The first third of the chapter introduces concepts important for developing environmental indicators. The second third describes a process for developing these indicators. The final third includes a description of combining indicators into an “index” of watershed condition or management effectiveness.
A.Background
Environmental indicators were originally developed to meet two goals. One is to reliably “measure” environmental condition over time, a continuing or periodic assessment process to report to the public changes in the conditions of natural resources. The second intent of indicators is to help guide management activities. The indicators you choose or adopt should be linked to the types of questions you are addressing in your assessment, or that you anticipate someone might need to answer in the future. Most indicator systems try to both measure natural processes and conditions and the influence of human actions.
Although California does not yet have a comprehensive environmental indicator program, there have been statewide and regional efforts to characterize ecosystem condition. Within California, two major reports have been released (California Dept. of Forestry’s Forest and Range Assessment, 2003; Cal/EPA and Resources Agency joint report Environmental Protection Indicators for California, 2002) that describe conditions for certain parts of the state. There have also been numerous smaller indicator reports at regional levels Some include the Santa Clara Basin Watershed Management Initiative, and the Southern California Environmental Report Card. At a national level, the US EPA’s State of the Environment (2002) and the HeinzCenter’s State of the Nation’s Ecosystems (2002b) are two of the major reports released in the last 5 years describing certain environmental conditions and ways these conditions can be assessed.
1.Overview of the Indicator Development Process
A process with statewide utility is described here for developing a watershed or regional-scale indicator system for evaluating the performance of natural systems and human actions to modify or respond to the system. The indicator system is usually composed of individual indicators that can be used collectively to analyze overall program effectiveness. Other parts of Volume II describe individual indicators and metrics for parts of watershed functioning. The methods described here don’t deal so much with the specific indicators you might choose for your system as with how you can develop and analyze the indicators, as well as how you could combine them into an index.
A variety of possible ways exist to implement indicator systems to evaluate programmatic and ecosystem performance in California’s watersheds. In this chapter we discuss possible frameworks for your indicator system. It is likely that individual indicators can be selected from existing project and monitoring data sets that you or others have in the watershed. Using the process laid out here, these indicators can be brought together into a single, statistically-robust suite of watershed or regional indicators. These can then be incorporated into a reporting model appropriate for multiple geographic and management scales over time (years to decades).
The process of indicator development usually involves two key steps: identification of key issues or question and the selection of indicators that provide insight into the issue.
i.Issue Identification
The process of developing the indicator system often begins with identifying the issues or topics that are important to the stakeholders, by a combination of experts and stakeholders. Frequently these issues are the focus of management activities, be it educational programs, restoration activities, or regulations by a government department or agency. Often this process can be facilitated by the use of a conceptual model showing the attributes and processes of concern in the watershed and the influences among these attributes and concerns.
ii.Conceptual Models
Conceptual models are developed to describe hypothesized or actual cause-and-effect relationships between key factors in the watershed. The detail in the conceptual models can be used to summarize the key issues in the watershed. Frequently the information in conceptual models is quite complex and the major issues don’t necessarily jump off the page. However, there are usually certain classes of topics or unifying themes that reflect the key issues. For example, many of the details in a conceptual model describe conditions or processes of concern. By reviewing the details, you will be able to identify broad themes that reflect the issues of concern. Likewise, human activities that impact the watershed can be grouped as “stressors”. The effects of the stressors are also likely to be represented in the conceptual model as well as efforts to respond to these stressors and conditions – the human response such as restoration efforts or new ordinances or guidelines.
The diagram in Figure 1 was developed by scientists Reid and Zeimer at the USFS Pacific Northwest research station in Arcata. The boxes are a mixture of management concern (disappearing salmon), management actions (logging, grazing), ecosystem attributes (high water temperature), and ecosystem processes (habitat change). This picture that tells a thousand words is a valuable addition to the field and is the kind of diagram that is often developed to represent the ecosystem and the management concerns about the system. Another conceptual modeling way of expressing some of these system attributes and management concerns might result in similar conclusions and probably should. In some fields there are competing conceptual models for how systems are functioning and this competition leads to research to investigate the difference. Ultimately, what is most important about the conceptual model is that it accurately represents enough of the system to inform development of research or to inform management decision-making and that it is understandable to relevant stakeholders.
A short guide to conceptual modeling is included as an appendix to this chapter.
iii.Selection of Candidate Indicators
The next step will be to develop a set of candidate indicators, based in part on the conceptual model, and find out if there are data available for these indicators that can be used to track changes over time. If data are lacking, then additional monitoring might be need; as well as an assessment of how much effort will be required to collect and statistically analyze data. Finally, the way in which the results will be reported, disseminated, and used to inform decisions should be considered so the indicators can be used as a guide for future actions. This could take the form of a scorecard similar to the one used in the Chesapeake Bay ( or as reports focused on systems or programs that are readily-understood by a wide range of interested parties. An accepted method in indicator science is to develop categories of indicators that can be used to develop an accurate picture of the conditions in the watershed. Each of the categories contains the indicators that describe a certain aspect of the watershed (e.g., land use). Multiple categories reflect the broad range of issues and conditions in watersheds. Although it might not be practical to collect data on all of these categories, it is worthwhile to at least review them and consider for which category you could develop indicators. For example, data on natural disturbances might not be easy to come by so developing an indicator for this category might not be possible. Yet, to gain a complete understanding of a watershed, information on all the watershed’s attributes is needed.
Most indicators are selected because they meet a set of frequently used criteria. Of course, the first and foremost criteria are the availability of data. If data is available, additional criteria can be evaluated, including:
- “Representativeness”, i.e., the indicator reflects or represents the ecosystem attributes that are of interest
- Decision Support, i.e., it can be used to evaluate the ecological performance of management actions and other investments,
- Understandable, i.e., it is reported in a format that can be used and understood by a wide variety of stakeholders and implementing agencies
- Detects changes over time, i.e., it reports on trends over time by taking into account the spatial and temporal scales relevant to condition assessment and/or management decision-making;
- Utilizes metrics that can be collected in a cost-effective way.
In addition, there are additional characteristics of indicator systems that are highly desirable. These include: a) a statistical analysis of the data to evaluate changes over time; b) a description of uncertainty and error; c) the use of a mathematical system that is consistent with the nature of the responses of particular indicators (e.g., non-linear) to environmental gradients (e.g., temperature fluctuations).
Indicators that meet these criteria can then be developed and analyzed to make up an indicator set. In some cases, metrics are developed that reflect many indicators in a single number.
2.Using Environmental Indicators in Watershed Assessment
Developing a set of watershed indicators grows directly out of a watershed assessment. It is a natural way to convey the information in your assessment in a concise and understandable format. For the stakeholders involved in the watershed council or organization that performed the watershed assessment, a set of watershed indicators permits the group to track status and trends for key watershed issues. It is a practical way to evaluate current and past conditions and influences in the watershed. For the public, a watershed indicators report is a useful tool to convey important information. The report can help raise awareness about the watershed in a way that has broad appeal. Whereas many people wouldn’t consider reading a complete watershed assessment, an attractive indicators report usually receives great interest. Finally, a watershed indicators report is a useful way to communicate with decision makers. Using assessment data for indicator development can be a valuable way to help decision makers interpret often complex information. Indicators will be useful for those who might be making or applying rules or regulations to protect the environment. It will enable them to evaluate the effectiveness of their policies and/or the need for new policies or rules.
The following simple questions about how you will use indicators in watershed assessment and management should help with choosing indicators:
What are you trying to measure with indicators?
Are you concerned more about natural processes, or the impact of human actions on natural processes?
What time scale are you interested in?
Are there existing indicators that others have used in the same watershed that you could replicate or continue?
Who are the other parties that may be interested in these indicators and who could assist with investigating them now or in the future?
Do you have the financial or community resources to investigate indicators?
Once you have decided that a particular indicator approach is appropriate, you can think about how the data you would collect would fit into a continuing assessment or periodic assessment. Because of the level of effort usually required to develop and investigate indicators at a watershed scale, there should be a clear connection between watershed assessment and adaptive management needs and the indicators and indicator analysis approach chosen. For example, along the NorthCoast, the persistence of salmon populations and the impacts of land uses on salmon populations are priorities. In this case, there are indicators that are directly tied to assessing fish populations (e.g., change in age class structure, number of out-migrants, number of redds), others that relate to fish habitat components (e.g., presence or abundance of large riparian trees, pool depth and number, large wood recruitment, water temperature), and still others that relate to influences of human actions (e.g., surface or ground water withdrawals, land use, presence/abundance of large riparian trees, sources and loads of fine sediment inputs) would be useful. The indicators could conceivably be useful for measuring the effects of restoration programs, scientific investigations of ecosystem processes and flux, and regulatory decision-making. It is also possible that particular programs might require specific indicators or types of indicators. For example, indicators of the well-being of riparian plant communities would be direct measures of the success of restoration projects or as a regulated retention requirement for logging.
3.Challenges and Issues Related to Choosing Indicators
As you think about candidate indicators and begin selecting them for us in the watershed, the following issues should be considered to make sure the indicators are effective in meeting your needs.
i.Scales and Geographic Extent
There are multiple scales in your watershed that must be addressed to evaluate management action effectively. One is the geographic scaling of issues from the project or action site to the landscape level for cumulative benefit evaluations (aka, “look-back” exercises). The other is the “conceptual model”-based scaling from the mechanism of action to the ultimate performance goal level. These two scaling processes obviously overlap with each other, but are not identical.
Through the rigorous application of conceptual models and statistical analysis, you can develop a system to appropriately deal with geographic and conceptual scales. In some cases, certain indicators will be significant across only one of these scales and will be positioned in the hierarchical system to reflect this. For example, in the area of water quality, mercury concentrations in fish are of concern throughout the Bay-Delta watershed because of impacts on human health and special-status species throughout the system. In contrast, remediation of abandoned mine lands or reduction of methylation processes to eventually reduce mercury in fish (through currently undefined mechanisms) are measured at the site of action. Hence, sportfish body burdens of mercury may be an appropriate Bay-Delta watershed-wide “endpoint” indicator but additional intermediate indicators are required to link actions at the site level to the desired endpoint. The linkage between site-specific action and ultimate end points, such as anadromous fish population responses or mercury body burden targets, can only be established with the appropriate metrics that can be aggregated to provide the appropriate weight of evidence and missing metrics identified that are required to link cause and effect at the appropriate level of certainty. The presumed relative importance of limiting factors can thereby be tested.
Consider classifying indicators selected earlier according to the appropriate geographic scale at which changes can be detected (e.g., the sub-watershed scale for natural fire return intervals) and how changes at individual sites can be aggregated to greater geographic scales (e.g., from the reach to river scale). The advantage of doing this is that you will have a reminder for how particular indicator data can be used and you can check your assumptions about scale later in the process of collecting and analyzing data. Also consider following the geographic classification step with a second classification according to the position of the indicator in ecosystem conceptual models and whether the indicator is for management goals (e.g., improved salmon escapement), effects of types of actions on ecosystem (e.g., improved Delta-wide wetland performance as habitat), mechanisms of action (e.g., increased redd establishment with gravel and flow augmentation). This step will help clarify what you expect to measure with data collection and who you will involve in reporting and evaluating the significance of any changes detected.