Monitoring efforts are generally designed to detect or measure change. Developing a monitoring plan for coral reef management includes setting objectives, selecting variables, establishing thresholds and triggers, choosing monitoring methods and deciding on a sampling design. A monitoring plan can also help managers determine what type of a monitoring program should be implemented. Responsive and participatory monitoring are two common types of monitoring programs used by coral reef managers. See the steps below for more details on key components of all monitoring plans.
Having a clear set of objectives is essential for designing monitoring plans. Managers should decide what information is required to support their management goals. Is the priority simply to detect any change in the ecosystem? Is the priority to track the condition of species or communities that are ecologically/economically important, understand the cause of ecological change, or measure the effectiveness of a management action? The purpose of a monitoring plan will guide the selection of variables that need to be included.
The most cost effective monitoring plans focus on variables that indicate trends in system characteristics that are of interest to managers, and that can trigger management responses. Monitoring programs designed to detect and track change can help managers determine trends in important ecosystem components (populations, species, communities, water quality) and processes (such as recruitment, ocean currents, growth rates).
However, it is usually not feasible to monitor every variable of interest or anticipate all changes that could be important to management. Managers will often select variables that are ecologically or economically important, such as variables that are resilience indicators, or that can indicate the effectiveness of management actions. Variables included in monitoring programs can relate to species/community biology and ecology (coral cover and fish abundance or coral and fish diversity and richness) and/or can describe the physical-chemical environment (temperature, salinity, nutrient concentrations, flow rates).
If an objective of the monitoring program is to understand the drivers of ecological change, then a monitoring program might also measure levels of known or suspected stressors like pesticide concentrations, sedimentation rates, and fishing effort. Another important consideration when selecting variables is whether there is a need to compare the results of the monitoring program to other programs or submit the results to regional or global databases. In these instances, managers will want to align the selection of variables with those used in other relevant programs. Variables should only be selected that can be reliably measured or assessed within local time and resource constraints. In some cases, this consideration will drive the method chosen as well as the variables (see Monitoring Methods below).
Thresholds and Triggers
To be effective for management, the results from monitoring programs should be compared to values that represent thresholds of ecological or social concern. When monitoring results indicate that thresholds have been reached or crossed, appropriate management responses may be triggered. These can include increased vigilance, commissioning of targeted research, communicating with stakeholders, or taking action to reduce stressors by management interventions. In some instances the threshold may be as simple as presence of an impact (e.g., bleaching or coral disease). Managers may want to set multiple thresholds for many variables; i.e., different severity levels of impacts or effects on coral condition will trigger different types and levels of management response.
Many monitoring programs are designed by researchers to address scientific questions or for detecting change in a broad range of variables. These can provide useful information to managers as long as the scientists have a clear understanding of the changes that concern managers. Managers and scientists engaging in these discussions can maximize the value of the monitoring programs not overseen by managers.
There are many publications that describe coral reef monitoring methods (see Resources below), and it is easy to get overwhelmed by the range of choices. The methods selected need to provide a robust and reliable assessment or the selected variables. The selected methods also need to be appropriate to the capacity, resource constraints, and operational conditions of the people and institutions undertaking the monitoring.
Different methods can produce results that can be compared among monitoring programs, as long as the methods are robust and appropriate to the variable. For example, different measures of the percentage of coral reef substrate made up by corals (coral cover) can be compared whether they are made using point-intercept or quadrat-based methods. See the many comprehensive manuals on monitoring (Resources, below) for further assistance in selecting methods.
The type and location of the sites chosen for a monitoring program will be determined by the objectives of the monitoring program and the resources available. Managers can consider whether control sites are necessary, for example, if the objective is to detect or measure changes caused by local stressors (such as a coastal development). If detecting broader or system-wide trends is important, then sites should be chosen that are representative of different habitats within the area.
Sometimes there is a tendency to select ‘pretty’ sites where coral and fish abundance and diversity is greater than at most of the sites in the area. These sites can be included, but should not be the focus or the only sites, as this can lead to a bias towards negative trends; abundance is more likely to decline if the starting point is high. Managers may want to include stakeholders and community members in monitoring programs, so accessibility should be considered when selecting sites.
After developing a plan based on the above steps, it is important to consider the resources and needs available to implement the monitoring plan including financial, technical expertise, and capacity. A monitoring plan is an important tool and can help a manager think through various aspects of monitoring design that might not have been considered otherwise including the design of long-term monitoring programs.