Wetlands

Water with grass and plants surrounded by trees and a lush green field.
Wetland area in Mallows Bay Park. Photo: McIntosh/NOAA

Beaver activity in the sanctuary creates unique wetland habitat. In a cycle that lasts many years, they will move up and down the streams that flow into the sanctuary and create dams, flooding different areas and drying out others. The nontidal wetlands that form behind the dams support floating aquatic plants, including spatterdock, white water lily, duckweed, and pondweed. Pickerelweed, rice cutgrass, sedges, and cattails often border the areas of open water behind beaver dams. These wetlands provide habitat, regulate the flow of water, and help prevent flooding and erosion.

Labeled illustration of a freshwater wetland ecosystem that shows beavers with a dam and lodge, as well as surrounding wetland plants.
Illustration of ecosystem components for freshwater wetland habitat. Image: Jing Graber/NOAA