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How to Monitor Wetland Rehabilitation Projects

The speed at which the plant community establishes itself in your wetland can be one of the most rewarding as well as easiest changes to track. Plants colonizing the site can be used as a measure of progress toward achieving restoration goals. As water levels stabilize and the plants become established, birds, amphibians, and mammals will make greater use of the wetland.

Take Photos. Set up one or several permanent photo points on your site where you can view a large portion of the wetland. Use of a landmark or stake can help you maintain photo consistency. Take photos before construction, immediately after construction and, at a minimum, annually thereafter in the same season. For more detail, take a photo from each point each season. Carefully label the photos with the date and exact location.

Map Invasive Plants. Monitoring for invasive plants is critical to the health of your wetland. In particular, look for reed canary grass and purple loosestrife. Both plant species aggressively invade a wetland after a disturbance. Immediately remove any invasive plants before they become a larger problem. These plants can be effectively eliminated if discovered and treated early in the process.

Revisit Your Project Goals and Objectives. Refer to your original goals and "vision" plan to evaluate your restoration. Many sites take several to many years before beginning to achieve the vision. Upon project completion, and for subsequent years, review the site map you drew before construction. Draw a new map outlining major plant community types, areas dominated by open water, cattails, sedges, grasses, shrubs or trees. Compare this to your project goal, and use it over time to plan additional site management activities, if needed.

Inspect the Plantings. Keep close watch over any plantings. This is particularly critical in the first year when plants are growing root systems and are under stress, but many perennial plants may need this for up to three years. Wilting plants may need mulch or water. You can expect a certain percentage of loss, and may want to fill in gaps where plants or rootstock did not survive. Rapidly growing "colonizer" plant species may quickly dominate a site and overwhelm your other plantings.

Notice Bare Ground. In the first year of restoration you may notice spots with little vegetative cover. These should fill in by the second year. If these areas remain without vegetation for several years, especially if they are not flooded, then it may indicate poor soil in that area. You may need to bring in topsoil from elsewhere on your site and re-seed the area with appropriate species.

Measure Water Depths. During site construction, place permanent marks at 1-foor intervals on lengths of hollow and uncapped PVC piping driven into the ground at several points in the wetland. Three pipes set in a line over an area anticipated to be covered with water will provide a good range. This will allow you to record the post-construction depth of the water at each point over the years. Measure and record the amount of water from the ground surface to the height of the water. If you have the time and interest, take a reading every other week during the spring, summer, and early fall. Even infrequent data collection can be important, however. You may observe seasonal or annual fluctuations that are normal to wetlands, or you may document that your site has a hydrologic problem that you may need to discuss with a wetland specialist or hydrologist.

Authored by Esther Lev, Executive Director, The Wetlands Conservancy (2009)