The Lower Slade Brook Natural Area has been forested for at least the last 100 years, and now hosts many kinds of wildlife, including fisher, deer, fox, and coyote. Black bear and moose follow Slade Brook in their travels between Moose Mountain and the Connecticut River.
Biologists have found 232 species of plants and three primary plant community types here. The hardwood forest seep on the river terrace slope occurs in small patches along the stream, surrounded on drier land by hemlock-beech-oak-pine forest. Farther above the stream is a hemlock-beech-northern hardwoods forest.
The Slade Brook forest, close to the Connecticut River, is a rich migratory stop-over and feeding site for birds traveling up the river valley in spring, and also for resident nesting birds. Thirty-five species of birds have been documented here. Among them is the Louisiana Waterthrush, an uncommon bird that requires forested habitats with open streams. Listen for its musical song, a series of descending notes ending in a warble.