Wednesday, June 02, 2010

Beaver Engineers

The staff at the Audubon Center at Francis Beidler Forest continues to monitor the changes in the swamp that beavers (Castor canadensis) are creating via their water-management engineering.

As many of the animals in the swamp are adapted to the wetland ecosystem, water is a critical component of their life cycles. Though the dam is not tall it is effectively slowing the flow of water.  The upstream side of the dam appears bright green in the video as duckweed has taken hold in the non-flowing water.  The downstream side of the dam is brown exposed swamp bottom with little water outside of the deepest channels.  Obviously, animals that live in water (fish, crayfish, mussels) will continue to thrive in the pool of water created by the beaver dam.  These same prey items will be fewer in number on the downstream side of the dam, so predators will move their hunting efforts to the upstream side of the dam.  The numerous crayfish parts indicate that hunting is good for the Raccoons (Procyon lotor) and Barred Owls (Strix varia), while tracks from Yellow-crowned Night Herons (Nyctanassa violacea) and scat from River Otters (Lutra canadensis) show that they too have discovered the bounty sustained by the beavers' water-management project.

While we were exploring the area around the dam, we flushed eight Wood Ducks (Aix sponsa) that were resting in the quiet backwater and spotted a Greenish Rat Snake (Elaphe obsoleta x quadrivittata) moving rapidly across the weed-covered water.

We will definitely be making this one of the stops during summer camp, which begins next week!

Images and video by Mark Musselman

No comments: