1. Introduction to Vegetation Inventory, Assessment, and Monitoring
The purpose of this section is to explore steps in designing and conducting vegetation monitoring projects. Specific concepts and tools will complete the story in subsequent sections of this course.
2. Sampling Principles
This unit focuses on the principles of sampling: why we sample, the relationship between population parameters and sample statistics, accuracy and precision, types of error and their causes, and using confidence intervals to make inferences about populations. Very simply, we sample so that we can gather accurate and precise information about populations, and to make inferences about populations with confidence.
3. Sampling Design
This module focuses on the elements of sampling design. Sampling design encompasses all of the practical components of a sampling endeavor: where to sample, what to sample, and how to sample!
4. Monitoring Implementation, Data Quality, and Best Practices
Data management is fundamental to any type of data gathering activity. It is a process that includes many steps, each of which provide opportunities to introduce non-sampling errors related to human error. This module focuses on the best management practices that can be used to reduce or eliminate potential errors associated with data management.
5. Indicators, Methods, Descriptors, and Covariates
This section explores the distinctions between indicators and methods, introduces the concepts of site descriptors and covariates that are used to help classify and interpret monitoring data.
This module focuses on plant density: what it is, how it is measured, and how density data are used by land managers to inform resource management decisions. Very simply, density is defined as the number of individuals per unit area, and reflects the closeness of individuals.
This module focuses on plant frequency: what it is, how it is measured, and how frequency data are used by land managers to inform resource management decisions. Very simply, frequency measurements record the presence of species in quadrats or plots placed repeatedly across a stand of vegetation. Frequency reflects the probability of finding a species at any location in the vegetated area.
This module focuses on cover: what it is, how it is measured, and how cover data are used by land managers to inform resource management decisions.
9. Vegetation Height and Structure
This module focuses on vegetation structure: what structure represents, how it is measured, and how information about vegetation structure is used to inform resource management decisions. Very simply, vegetation structure refers to the three-dimensional arrangement of plants and plant materials on a site or across a landscape. Vegetation structure is primarily influenced by plant cover on horizontal and vertical planes.
10. Biomass and Production
This module focuses on plant biomass: what it is, how it is measured, and how biomass data are used by land managers to inform resource management decisions.
This module focuses on plant utilization: what it is, how it is measured, and how utilization data are used by land managers to inform resource management decisions.
12. Composition, Diversity, Similarity
This module focuses on plant community diversity: how it is described, how it is measured, and how diversity is interpreted by land managers to inform management decisions.
13. Remote Sensing for Vegetation Monitoring and Assessment
Remote sensing techniques offer many opportunities to inform, supplement, and sometimes replace traditional field-based aproaches to vegetation assessment and monitoring. This module explores ways in which remote sensing can be used in monitoring and provides example applications.
14. Assessment and Monitoring Programs
This module explores some established rangeland assessment and monitoring programs, describes their protocols, and discusses how the collected data are used in management decision making.
1.2: Monitoring Process and Management Objectives
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Monitoring: The Main Steps
The main steps involved in planning and implementing a monitoring protocol are:
Figure 1. The seven major steps of developing resource management objectives, monitoring methods and management strategies (originally published as Fig 2.1 in Elzinga et al., 1998).
These seven steps provide the basis for feedback loops and reviews that form the iterative process of adaptive management (Figure 1). Decisions formed early in the process may need to be revisited and objectives revised. Resource management objectives drive the monitoring approach. We may start with our observations and what we perceive about the situation on the ground. These observations then inform our decisions as we develop resource management objectives, which dictate what the management approach is, and then the monitoring program is designed to evaluate the efficacy of the management. By following this step-by-step approach we remain focused on ensuring that the monitoring activities are designed to provide the specific information needed to inform management decisions, and helps us avoid haphazardly “fishing” for relationships in the data related to the resource response.
Complete Background Tasks
The first step is often skipped with dire consequences. Before one starts dreaming up plans and creating a monitoring protocol it is important to know what information already exists. What information is on file? In an area you are managing there could be records of previous inventories, management decisions, implementation of vegetation management and structural improvements, changes in land ownership, etc. What are the overall management priorities? Identifying and documenting management priorities related to species of interest, conservation, or production-oriented goals is extremely important for land managers and future managers in order to justify management actions. What has been published on the topic? For example, if you are ranching in southeastern Oregon and cheatgrass is invading one of your pastures, you should “do your homework” by reading research and extension publications about how cheatgrass responds to different approaches to grazing management, and to inform yourself about potential options for cheatgrass control (Figure 2).
Figure 2. The Area Wide project in southeastern Oregon (http://www.ebipm.org/) is a collaborative group that promotes dialogue and discusses information with land managers facing issues with invasive exotic species, such as cheatgrass. Extension and research groups throughout the western US provide information of this nature for a variety of issues.
Setting Resource Management Objectives
When one knows the basic lay of the land, it is time to start honing in on a specific objective. This important step is called “defining the problem” or “setting objectives” and it is not usually as easy as it sounds. A monitoring objective must be stated clearly with a focus on specific attributes and directions of change. A monitoring objective like “I want to see if the plant community is changing” is not very useful. Specificity is needed. For example, “I want to determine if the herbaceous biomass and fine fuel load in an open ponderosa pine forest is maintained at a level below 1,000 kg/ha at the end of the growing season after mid-season grazing by cattle.”
The first step in setting resource management and monitoring objectives is developing an ecological model that describes what is and isn’t known about specific resources, the ecosystem in which they exist, and their interrelationships with management. These models help to then define what the broad, overreaching goals are for management: should the size of a particular species be increased or maintained? Do we want to have sustainable production? Which geographic regions are to be monitored and are certain sites at risk?
Then it is important to select an informative indicator to monitor. This could be the target species itself, which is a biotic component, or an abiotic aspect of the habitat in which the species occurs, such as soil stability. Once we have determined the nature of the indicator to be monitored, it is necessary to identify the sensitive attribute that is to be measured. Attributes can include plant density, cover, frequency and production. The choice of an appropriate attribute will vary depending on the particular species or area of concern; it should be sensitive to management changes and disturbances, inform management from a biologic and ecologic standpoint, and prove to be technically feasible and repeatable among different observers.
There are two main categories of resource management objectives. The first category involves monitoring the condition (or target/threshold) of the resource, where the current state is compared to a desired or undesired state and an absolute target is specified. For example: increase the number of individuals of Senna hirsuta in the Sycamore Canyon population to 3,000 individuals by 2015. The second category is to monitor change or trend over time. An example of this type of objective is: decrease the population size of Prosopis caldenia at the Aseguro Ranch site by 60% by 2020 (Figure 3). To see more examples of each objective category, reference chapter 4 in Measuring and Monitoring Plant Populations Elzinga et al. 1998.
Figure 3. Prosopis caldenia is a native tree species in the Caldenal region of central Argentina. However, in the past century these trees have extended their cover of the landscape outcompeting palatable grass species for light, a). A desirable savanna state, b), is the target goal of most ranchers and land managers in the area.
The next step is to specify the direction of change and the magnitude or quantity of change that you want to detect. For example, if our objective is to increase the population size of a target species in a particular management unit, and we select density as the attribute to monitor, how much increase do we want to see? Detecting small differences, such as a 5% increase may be difficult, whereas detecting a 20% increase may be more practical. Another consideration is whether we decide to monitor for relative change or absolute change. For example, if the current density is 4.0 plants/m2, we could state the desired increase in relative terms (30% increase) or in absolute terms (increase to 5.2 plants/m2).
Finally, the time period over which we expect to see a response to management needs to be clearly stated: within what time period should change be detected? This affects not only when to begin monitoring, but also incorporates how long we anticipate that we expect it may take to achieve the desired response. The length of monitoring period may depend on species biology and the practical time frame that is driven by management and planning.
All of these stages are then incorporated into the development and refinement of clearly stated resource management objectives. Finally, we will specify the anticipated response to management and carefully review the resource management objectives to ensure that they are aligned with current ecological understanding and that the objectives are feasible.
Another way to consider setting resource objectives in a natural resource management application is to follow the “SMART” approach that is frequently applied to business planning.
SMART objectives are:
- Specific – Objectives should specifically state what you want to achieve on the land you are managing.
- Measurable – It must be possible to measure whether you are meeting the objectives or not.
- Achievable – Are the objectives that you set achievable in your current setting? Consider environmental constraints, societal expectations, economic parameters, legal requirements, and technological limitations.
- Realistic – Set objectives that you can realistically achieve given the natural and management context of your situation.
- Time – Set a time horizon to meet management objectives.
Setting a monitoring objective is not an easy task as sometimes we see symptoms rather than identify the underlying problem. For example, we may be interested in productivity in a mountain meadow and our monitoring may reveal that production of grasses and forbs has decreased over the last decade. However, knowing this trend does not reveal the underlying cause. Multiple causes could create the trend, such as soil moisture becoming limited because of encroachment of conifer trees into the meadow coupled with several years of below average precipitation. When developing management objectives and management plans, it is important to remember that certain factors, such as weather, are difficult to predict and impossible to control. Therefore, management objectives should remain flexible in the event of circumstances outside the influence of management actions.
Design and Implement Management
After the resource management objectives have been clearly defined, the next step is to design the management approach. We may decide to maintain the current management if we feel that this management approach supports the resource management objectives. However, if we decide that we need to implement a different management approach in order to achieve the desired objectives, then we need to develop a management plan that incorporates the new management actions. For example, if our management objective is to increase cover of cool-season perennial grasses to 20% canopy cover in a pasture that is currently grazed year-round by cattle, we may decide to either reduce the stocking rate, defer grazing in the pasture until early summer, or both. Once a decision has been made on what management plan to use, then it is time to implement the plan!
Design Monitoring Methodology
When designing monitoring methodology it is important to remember that the data collected must be informative relative to the resource management goal and objectives. This is to say we need to be careful in selecting each component of the monitoring protocol, or sampling design. For example, we need to decide what level of monitoring to implement, which vegetative attribute(s) to measure, what type of sampling units, the number of sampling units, where to locate monitoring, when and how frequently we need to collect data: each are factors that should be considered in the context of the stated resource management objectives.
The level of monitoring specifies the intensity, or the amount of detail collected in monitoring effort. It may be possible to provide sufficient information with qualitative data such as taking repeated photographs at specific photo-points (photo monitoring), or visual ratings of plant abundance or utilization. Qualitative data can provide very useful information, but the utility of the data is somewhat limited because the data cannot be manipulated mathematically. For example, photo monitoring will clearly show yearly changes in plant cover or relative changes in the amount of bare ground, but you are limited to reporting that cover increased, you cannot quantify or report the actual cover values. Usually, more intensive forms of monitoring involve measurement, the collection of quantitative data. Monitoring protocols frequently incorporate collection of both quantitative and qualitative data. For example, we often photograph transects before collecting density, cover, or other type of quantitative data (Figure 4).
Figure 4. Line-point intercept measurements to calculate cover were conducted on this savanna ecosystem transect after the photo was taken.
Once the level of monitoring has been established, we need to specify all of the elements in the sampling protocol: 1) indicate what attribute or attributes will be measured, 2) determine what methods will be used to measure them, 3) define the sampling unit (e.g., is the sampling unit a single point of a transect of 50 points?) , 4) specify the dimensions of the sampling unit (e.g., size and shape of quadrats or plots, length of transect lines), 5) determine where the sampling units will be placed in the area of interest (e.g., we may selectively concentrate our sampling in key areas or we may use a random or stratified random approach to locating sampling units throughout the area of interest), 6) decide whether the sampling units will be permanent or temporary (if sampling units are permanent, we usually need to clearly mark and document the spot where the unit is placed so that it can be re-established in the exact location for subsequent measurement), 7) determine the number of sampling units that need to be measured, and determine when measurements are taken, and how frequently they need to be collected.
In addition, it is important to consider the level of skill and training needed to ensure that the data are accurately collected, and that the data collection techniques can be performed reliably by different observers. Finally, the monitoring plan needs to be clearly documented and reviewed to ensure that it will provide sufficient information specific to the resource objectives.
Implement Monitoring as a Pilot Study
Pilot studies are a critical step of every monitoring plan. Pilot studies are essentially a test-run of the monitoring plan, in which the protocol is implemented and the data are analyzed to determine the feasibility and practicality of the proposed approach. The pilot study enables us to identify potential problems associated with data collection, and to address these problems before dedicating substantial resources of time and money in the monitoring effort. Data from the pilot study should be used to decide whether assumptions of ecological models appear correct and if the sampling design is adequate to address the sampling objectives: do we have sufficient precision and statistical power to make correct inferences about the resource? Issues with equipment or technique can be taken care of relatively easily and troubleshooting of additional issues may be necessary. At this point it is good to reevaluate resource and time constraints and review the monitoring design with all groups involved in the monitoring project.
Once the monitoring plan has been field-tested in pilot studies and refined as needed, it is time to implement the monitoring plan by collecting the data! Remember to analyze data after each set of measurements and continuously evaluate the monitoring plan, recognizing that problems may appear along the way. It is very important to double check that data have been collected according to the plan and that information is complete.
Report and Use Results
Finally, all data should be interpreted and reported relative to the goals and objectives of resource management. Document the results in periodic reports to ensure that the information is available for others to use and informs them of the progress of the project. By completing a final analysis and report, we ensure that the adaptive management cycle is complete, and the results can be used to inform future management. Circulating this information around will assist other in their management plans and reduce redundancies in operations and efforts. Finally, it is critically important to ensure that the monitoring plan including a detailed description of the entire protocol is documented and stored or archived so that it can be retrieved or accessed for future reference.
The following questions are designed to test your knowledge and understanding of vegetation measurements for monitoring. These questions are for your own benefit: scores are not recorded.