A key step in managing any system is to be clear about what you are trying to accomplish. In particular, you need to be able to assess the current status of the system today, define specific future goals, and measure progress towards these goals. A useful analogy can be found in the medical field, where doctors define healthy individuals as having, among other things, a pulse rate and blood pressure within an appropriate range for their age and condition. If a patient is outside of the normal range, then the doctor can prescribe therapy and monitor the patient’s condition over time as they hopefully move towards a desired goal in the normal range.
This process of setting measurable goals is particularly challenging for conservation targets. Most targets are very complex systems that vary naturally over time, making it difficult to define or measure their health in a systematic and repeatable fashion. Viability assessment is a flexible and powerful methodology based on sound ecological principles that helps address the challenges of defining healthy targets and setting appropriate and measurable goals. The general purpose of conducting a viability assessment is to determine how you will measure the health of your conservation targets over time. It helps you determine how your target is doing today, what a healthy target would look like, and what status you would like to see in the future as a result of your project actions.
Oftentimes teams will not go through a formal viability assessment process. The process, however, can be very useful for helping you think about where your targets need to be in order for the overall biodiversity or resources at your site to be in good shape. We encourage you to go through at least an initial iteration of a viability assessment. This may require bringing in experts who can help guide you toward defining the impact you need to achieve.
Viability assessments rely on established principles of ecology and conservation science. The team should use available evidence on the target’s biology and ecology in an explicit, objective, consistent, and credible manner. If the needed information does not yet exist for the team to sufficiently understand the viability of the target to select strategies, the team should assess ways to generate needed information.
A viability assessment involves identifying key ecological attributes (KEAs) for each conservation target (see Box 1 for a list of viability assessment-related terms). These KEAs are aspects of a target’s biology or ecology that if present, define a healthy target and if missing or altered, would lead to the outright loss or extreme degradation of that target over time. For example, a key attribute for a freshwater stream target might be some aspect of water chemistry. If the water chemistry becomes sufficiently degraded, then the stream target is no longer viable. The team will need to consider how current and projected changes in climate affect the target’s viability in the selection of appropriate KEAs.
Although the viability assessment process can seem complex and overwhelming, it is merely a systematic process to use the best available evidence to define and measure the health of your conservation targets. In effect, if your indicators are in their acceptable range, then the KEAs of your targets are healthy. If your indicators are not in their acceptable range or are headed out of the acceptable range, then there are problems that need to be addressed.
The text for viability assessments borrows heavily from The Nature Conservancy’s Conservation Action Planning, currently called Conservation By Design.
How To
Assessing the viability of targets involves identifying their key ecological attributes, defining an indicator for each attribute, and establishing an acceptable range of variation and a current and desired future status for each indicator. As with many seemingly complicated tasks, if you take viability assessment one step at a time and work through it systematically, you will see that it is a logical and much more simple methodology to use than it appears on the surface. Following steps:
- Select a target and identify a limited number of key ecological attributes (KEAs)
- For each KEA, identify a limited number of measurable indicators
- For each indicator, determine an acceptable range of variation and rating scale
- For each indicator, define current and desired future status
- Record any assumptions
- Repeat for your other targets
- Review your viability assessments and adjust as necessary
Select a target and identify a limited set of key ecological attributes (KEAs)
With your team, select one of your conservation targets to assess – start with a relatively simple and straightforward target. There is an almost infinite number of attributes that could describe some characteristic of a target. You may start with brainstorming a long list, and then select a small number of critical attributes that if degraded, would seriously jeopardize the target’s ability to persist for more than a few decades.
In identifying your KEAs, it is important to ensure that your final selections are attributes of the target, rather than descriptions of threats to the target. For example, “compatible land use” is not a key ecological attribute for a forest target. Instead, the threat of incompatible land use affects actual key attributes such as connectivity, soil stability, or the hydrologic regime.
To identify KEAs, it is helpful to think about three categories - size, condition, and landscape context - that often collectively determine the health of a conservation target (Box 2)
Note: Not all categories apply to all conservation targets.
In our marine example, the team chose “Area of coral reef” and “Healthy populations of key reef species” as KEAs for coral reefs. Likewise, they chose “Population size of frigatebirds” as a KEA of seabirds (see table below for information recorded in Miradi).
For each KEA, identify a limited number of measurable indicators
KEAs are generally still too broad to measure in a cost-effective manner, so it is important to develop indicators to assess the attribute over time. For each KEA, the team should identify at least one indicator. In many cases the indicator can be the same as the KEA itself (e.g., an attribute of population size may have an indicator of the number of individuals in the population). If you cannot count this number directly, then you may need a proxy indicator – for example, for a fish population, you may use catch per unit effort using a specific technique at a given time of the year.
In other cases, however, developing an indicator will require a bit more thinking to find a way of measuring the KEA over time. For example, if your attribute is the water quality of a stream, it is not possible to measure every physical and chemical parameter. Instead, you would select a few representative parameters (e.g., water temperature and dissolved oxygen levels) that you feel can represent the overall water quality. You can also combine several measurable properties into a composite indicator or index.
Indicators frequently involve some type of quantitative assessment – such as number of acres, recruitment rate, age class sizes, percent of cover, or frequency of fire of a given intensity. Other indicators may involve measurable elements that are not numerical, such as the seasonality of fire or flooding. Indicators should be measurable, precise, consistent, and sensitive (Box 3).
In many cases, you may be able to measure a KEA using just a single indicator. However, sometimes there may be no single best indicator, in which case you may need to track several indicators to get a better picture of your target’s status. For example, field surveys and analyses of aerial photographs together may provide complementary information on forest tree composition that would be more accurate and reliable than either one could provide on its own.
For our marine reserve example, the team chose the indicators shown in Table 2 below:
For each indicator, determine an acceptable range of variation and rating scale
Most indicator values vary naturally over time, but we can define an acceptable range of variation. For example, the size of migratory fish population might go up and down on a year-to-year basis. As shown below, however, there is a difference between a population size that is within the acceptable range of variation and one that is under exceptional stress and thus falls outside the acceptable range.
For some indicators, this acceptable range is one-sided for example, it may be possible to have too little, but not too much of a particular kind of forest within a project area). For other indicators, the acceptable range is two-sided (for example, there can be too many or too few deer per hectare in the forest).
An acceptable range of variation for each KEA indicator is one that would allow the target to persist over time – a range in which we would say the indicator value falls into a Very Good or Good category (see the figure below for definitions of these criteria). If the indicator drops below or rises above this acceptable range, it is a degraded attribute that has Fair or Poor status. Your challenge is to specify – with the best available information – what would constitute an acceptable range of variation.
The rating reflects a team’s assumptions about what constitutes a “conserved” target versus one that is in need of management intervention. This rating scale is analogous with the established pulse rate and blood pressure ranges that a doctor uses to determine whether a patient’s circulatory system – and thus by extension the entire patient – is healthy. Although a team ideally would define all four classifications of the rating scale, often teams are only able to define one or two key classifications – for example the threshold between Fair and Good.
In our marine example, the team determined that there had to be at least 71% of appropriate areas covered by live coral reef and minimal bomb damage to the reefs in order to consider their coral reef target in good health (Table 3). Notice that the ratings for area are much more precise than those for degree of bomb damage. The team was also able to identify ranges of numbers of breeding pairs of Ruby Crested Puffins.
For each indicator, define current and desired future status
Your next task is to assess the current status rating and set the desired future status rating of each KEA indicator relative to your rating scale. The current status rating describes the indicator rating category of the KEA’s status today; the desired future status rating describes what you want the indicator status to be in the future. In most cases, you want the indicator to fall into the Very Good or Good categories. In some cases though, you might be at Fair or Poor and, for a variety of reasons, the best you can hope to achieve is maintaining the target status at Fair. The important point here is that you need to look at your viability assessment for each indicator and determine what category you want to achieve several years or even decades out. You should also consider the appropriate time frame for achieving the desired status, keeping in mind that some changes may require long time periods (50-100 years). If you know the actual current indicator status information, record it as well as the desired indicator rating category (e.g., if a Very Good size indicator rating is > 30,000 acres, and you know the current extent is 55,000 acres, then record the specific acreage, as well as a Very Good classification for that indicator).
Ideally, there is already strong evidence for identifying the KEA indicators of each target, a set of thresholds for the four rating classifications (Very Good, Good, Fair, and Poor), and the current and desired future status of each indicator. These thresholds should state clearly where the indicator being measured would fall within each level of the rating scale. The information needed to establish these benchmarks for each KEA indicator, however, is often inadequate. In these cases, project teams may need to rely on general ecological concepts, comparisons to other similar systems, well-informed expert opinion – or failing that, the team members’ best estimate of the benchmarks for the current assessment. Although you ideally want to get the categories right, you would not want to get so bogged down in this detail that you cannot move on to other equally important steps in the project planning process. With this in mind, you can consider the first pass as your initial thinking to be refined in an iterative process. For example, suppose a team is working on a project with a grassland target. They decide that one of the KEAs is fire regime and the indicator of fire regime is fire frequency. They know that the grassland is full of woody species and the grasses and forbs are not flowering well and they have not seen some grassland nesting bird species in a few years. As a result, they are pretty certain that the grassland needs to burn, but they do not know how frequently the grassland would burn in a natural state. So in their first pass, the team fills out the viability rating scale as follows:
This loosely defined, qualitative categorization may be sufficient for deciding on the management intervention and knowing if it is achieving the desired change in grasslands. Later, the team locates a local grassland expert. She tells them that fire should occur every 5-10 years to maintain the structure of this type of grassland. This additional information enables them to fill out the table as:
Reviewing the literature and consulting with experts, the team comes to realize, however, that it is not just the presence of fire anywhere on the site that matters, but that a sufficient portion of the site should burn on a regular interval. To this end, over a few years, the team does some more research about the frequency of fires, and they redefine their indicator and ratings as follows:
Record any assumptions
As you go through this process, make sure you write down any relevant issues or comments that emerge. In particular, you should note how you arrived at your viability assessments including references and experts consulted, data analyzed, assumptions made, your level of confidence in your assessments, and information needs.
Repeat for your other targets
Repeat the process outlined in this How-To section for your remaining targets.
Review your viability assessment and adjust as necessary
Review the results of the viability assessment for all of your targets and discuss with your team. Once you think about threats and the potential impacts of climate change on your targets, you may have to revisit some of your attributes or even your choice of targets. The end product should be a completed viability table. It is also important that teams periodically revisit and refine their classifications as more evidence is generated or becomes available.
Examples
In the example above, the project team has a grassland habitat target. They identify fire regime as a key attribute of the grasslands and % area with 5-10 year fire as an associated indicator. Based on expert input, the team assumes that a healthy frequency is to have fires every 5-10 years, with a sufficient portion of the site burning on a regular interval. If fires happen more or less often, the grassland will lose integrity over time, leading to serious system degradation.
For another example, in the following table, you can see the marine reserve team hopes to have parrotfish density at 10 per 100 square meters by 2035 (desired future status), and its most current measurement shows the density at 7. Likewise, the team hopes to see a dramatic recovery in spiny lobster populations, increasing from its current qualitative status of “few” to a future desired status of “lots” by 2035.
Exercise
- Identify a limited set of key ecological attributes (KEAs) for each target. Keep in mind the effects of changes in climate on the viability of targets in KEA selection.
- Develop indicators for each KEA.
- Determine an acceptable range of variation and rating scale for each indicator.
- Determine current and desired future status of each indicator. Record any assumptions or important background information.
- If you are missing any information to adequately define the viability of your targets, discuss and describe the implications of selecting and implementing strategies without this information and how you intend to manage risk by addressing information needs.
- Write a short paragraph about your impression of the process of conducting a viability analysis. Include any challenges you had or anything you found to be useful.