Identify Priority Sites for Wetland Conservation and/or Restoration
Once your community has an updated local wetland map, identifying priority wetland sites for conservation and/or restoration is an important step to guide decisions about how to target wetland programs, funding, and local regulations. This step is especially useful for communities with extensive wetland resources who wish to accommodate future growth while protecting the most sensitive or valuable lands. It is recommended that communities include prioritization of wetlands as part of broader-scale conservation and/or restoration planning efforts. This may include watershed plans, regional green infrastructure assessments, wildlife action plans, and habitat conservation plans.
This analysis can also be conducted as part of a service provided by the U.S. Fish and Wildlife Service (FWS), its primary cooperator, Virginia Tech’s Conservation Management Institute, or an organization or firm with experience in these techniques. This service generates an historical assessment of pre-settlement wetland types, acreage, functions and general trends; a watershed characterization of current wetland status and functions; and an identification of potential wetland restoration sites. Costs for these services vary with the type and density of wetlands in a geographic area, the amount of historic loss, the age of the NWI data, and the availability of digital data sources (e.g., land use/cover and soils).
The criteria used to prioritize sites for conservation and restoration is different, but the overall process is the same:
Note that if the process of updating your wetland maps has resulted in a new map of ‘potential wetlands,’ there are three options for dealing with these sites in the ranking exercise: 1) field-verify all potential wetlands before including them in the ranking; 2) rank these sites separately; or 3) leave these sites out of the ranking entirely, and evaluate them on a case-by-case basis over time as resources become available to conduct field verifications.
Step 1. Identify potential sites for conservation/restoration from local wetland maps
To identify potential sites for wetland conservation, we suggest that communities begin by using their local wetland maps and making a preliminary assessment of wetland function to identify specific wetlands that have high or moderate potential to provide the functions of interest to the community (e.g., flood control, shoreline protection). The preliminary assessment of wetland function assigns wetland functions to wetlands in the community by adding abiotic and landscape feature descriptors through a desktop GIS exercise. While field assessments of individual wetlands are necessary to more accurately evaluate wetland functions, a remote sensing approach to estimate wetland function provides a cost-effective way to rapidly identify priority sites for conservation and/or restoration. It is considered preliminary because on-the-ground conditions can affect wetland functions and these must be evaluated in the field (see Step 3).
Potential sites for wetland restoration include former wetlands or existing degraded wetlands. These can be identified using maps of historic wetlands, and local wetland maps using a method described by Tiner (2005). Potential restoration sites include:
Former wetlands with:
Degraded wetlands that are:
The results of this step are maps of potential wetland conservation and restoration sites.
Step 2. Rank sites based on specific criteria derived from mapping
Because not all potential sites identified in Step 1 can actually be conserved or restored due to cost and other factors, ranking criteria are used to prioritize sites. Communities should develop wetland ranking criteria that reflect local goals, regulatory requirements, community interest, and/or wetland characteristics. In general, ranking criteria that relate to environmental benefits, feasibility and community benefits of the proposed project, as well as development pressure on individual sites should be considered. Table 3.1 provides some example ranking criteria for wetland conservation and restoration sites.
Of the criteria listed in Table 3.1, at a minimum, communities should evaluate vulnerability to impacts from development and include this as a major factor for ranking conservation sites so that those valuable wetlands with a high likelihood of being developed can be protected if possible. A spreadsheet is helpful for this ranking exercise, and communities can determine how to score each criterion and assign each a different weight if desired.
The ranking results in a list and map of sites that are the highest priorities for conservation and/or restoration. For communities with limited funds for wetland protection, this ranking can serve as the basis for a local wetland conservation or restoration program. However, because the ranking is primarily based on mapping data, it is also helpful to visit the top priority sites in the field to verify wetland presence, further evaluate function and collect additional data to refine the ranking. Therefore, communities with additional resources may wish to continue on to Steps 3 and 4.
Step 3. Evaluate top sites (or all sites) in the field to collect more detailed site information
Field assessments can be used to confirm the assumptions made in Steps 1 and 2 about the presence, function, and condition of individual wetlands. Site visits can also be used to further evaluate restoration feasibility. For example, site evaluation for restoration potential can tell you whether the causes of impacts are known and controllable, whether the hydrology is suitable for restoration, and give you a sense of the complexity of the proposed restoration project.
Given the complexity of most wetland assessment methods and the expertise and time needed to conduct them, it may not be realistic to assess all potential wetland conservation and restoration sites in the field. This is where the ranking in Step 2 comes in handy to help narrow down the number of sites that are field-assessed.
Step 4. Revise ranking to reflect field conditions
Results of field assessments should be used to update the spreadsheet ranking and maps of priority wetland conservation and restoration sites. This may mean deleting sites from the list that have since been developed, or that do not concur with the initial functional assessment. It could also include adding criteria to the ranking and re-ranking the sites based on new, more detailed, information collected in the field.
Additional guidance for this Step of the WARPT is provided in the following 3 sub steps:
After identifying priority wetlands for protection and restoration, the next step is to protect wetlands locally using regulatory or voluntary measures.