LaPlatte River wetlands provide diverse, rare habitats

The LaPlatte River wetlands provides habitat to 22 different rare or threatened plants and animals. Photo by Boston Neary

Editor’s Note: Last week, we featured a story about The Vermont Natural Resource Council’s petition to reclassify Shelburne’s LaPlatte River Marsh Wetlands as class I wetlands, a status that would provide greater environmental protection than this area currently has. This week, we provide a more in-depth discussion of this area’s ecology.

The LaPlatte River Marsh, a landscape of sedges, swamps, and towering trees, is situated at the river’s entry into Lake Champlain. This wetlands area provides a unique blend of habitats to animals that live, feed, reproduce, and migrate here. The humans of the region, too, benefit from the important functions that this area plays in stormwater and pollution management.

The wetlands are a complex, connected system of communities, each containing different plants, soils, and hydrological features. “A community assemblage or wetland complex consists of multiple different wetland functions. Because they are interrelated, impacts in one part of the wetland may have ripple effects throughout the complex,” notes the LaPlatte Marsh Class I Petition, submitted by VNRC Policy and Water Program Director Jon Groveman to Wetlands Program Manager Laura Lapierre of the Vermont Wetlands Program. Part of the class I protection extends the wetlands buffer from 50 to 100 feet, which is particularly important as the habitat and its functions extend beyond this buffer, the petition notes.

The wetlands lie along the LaPlatte and its tributary, McCabe Brook, with water creating connections among its different communities, the petition notes. Many of the wetland communities are designated state-significant based on their rarity, viability, and integrity.

The different habitat types present, including marshes, forests, and open water, offer habitat and resources to various animals. LaPlatte River Marsh’s shaded areas, stable banks, and varied communities provide important spawning and feeding habitat for diverse fish species. Songbirds, waterfowl, hawks, owls, and osprey use the area for feeding, nesting, and other activities, as do mammals including beavers, muskrats, mink, and otters. Deer winter here. Vernal pools provide an important breeding location for amphibians, and reptiles including the uncommon wood turtle and map turtle are seen.

“The diverse assemblage of wetlands within the LaPlatte River Marsh wetland complex provides habitat to 22 different rare, threatened or endangered plant and animal populations,” according to the petition. “This includes 13 plant species, two fish species, four freshwater mussel species, and one each of an insect, bird and amphibian species.”

The communities comprising the wetlands include buttonbush swamp, a state-significant area that provides waterfowl habitat, per the LaPlatte Natural Communities Report prepared by Vermont Fish and Wildlife Department Community Ecologist Eric Sorenson, Vermont DEC Wetlands Scientist Charlie Hohn, and Shawler Conservation Planning independent contractor Avery Shawler (formerly of Middlebury College). Also present is a small area of red maple-black ash seepage swamp, where peat comprises part of the soil. Various marsh types are also found.

LaPlatte wetland forests include a 24-acre undisturbed lakeside floodplain forest, a significant community hosting various trees, shrubs, and ferns, according to the report. Also present is 62 acres of silver maple-sensitive fern riverine floodplain forest, as well as a mesic clayplain forest; agriculture has replaced most such forests in Vermont. Another small patch contains another state-significant floodplain forest.

A cliff-face delivers calcium, reducing the surrounding area’s acidity and creating a rare community on the floor below, the report notes. Along a little over a half-mile of LaPlatte River shoreline lies a river mud shore community, only exposed during low-water periods, when this state-significant community hosts herbaceous plants and provides shorebird feeding area.

Overall, the petition notes, “The Nature Conservancy has documented that this wetland provides habitat for 20 species of mammals, 60 species of birds, and 50 species of fish, reptiles and amphibians.” The petition also notes the crucial role of the area’s habitat for migrating waterfowl and other wildlife.

The wetlands also provide services to the surrounding human population. Per the petition, the wetlands provide physical space for floodwaters and brake their flow, while vegetation slows down and removes floodwater through evaporation and transpiration. The wetlands also capture and hold lake floodwaters when major storms occur, and act as a filter between water and pollution from surrounding land, a role likely formerly played by more extensive wetlands since infilled for agricultural use.

The wetlands’ site between land and lake places them at an important intersection of human and natural worlds. “This critical position at the southern tip of Shelburne Bay makes the health and functioning of this wetland complex inextricably linked to that of Lake Champlain,” the petition states. “This tie to the impaired waters and cultural resource of the Lake enhances the importance of this wetland complex and attests to the need for its conservation.”

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