Mutualistic Relationships Between Beavers and Other Species

A) Invertebrates:

-Beaver damming increases invertebrate abundance and changes the invertebrate assemblage in the surrounding habitat by increasing microhabitats

-Typical assemblages of aquatic invertebrates following beaver damming include predatory dragonflies, sludge worms, filtering mussels, midges, water beetles and chironomids

-Typical assemblages of terrestrial invertebrates in a beaver pond include fruit flies, weevils, leaf beetles and bark beetles

-Aquatic invertebrates provide a good food source for fish, while both aquatic and terrestrial invertebrate species provide protein- and calcium-rich food for birds

B) Birds:

-Beaver ponds create important feeding, breeding, wintering and migration habitats for waterfowl and other water bird species (wood ducks in particular for southern Ontario regions)

-The ponds and aquatic vegetation associated with beaver habitats provide courtship areas, nesting cover and travel lanes for birds

-The cutting of trees around beaver habitat during initial colonization opens the forest canopy and improves habitat for edge and woodland species like wild turkey and numerous songbird species

-Dead and decaying trees in flooded beaver ponds may provide nesting and feeding sites for woodpeckers, and when the woodpeckers abandon their nests (because they use a different nest each breeding season) they become used by other birds like flycatchers, tree swallows, tits, wood ducks, owls and kestrels

-Herons, kingfishers, cormorants and egrets use beaver ponds as foraging grounds

C) Mammals:

-Beaver dams increase prey and foraging resources for semi-aquatic mammal species like the North American mink, muskrats, water voles and otters

-Terrestrial mammals like elk, deer and moose benefit from beaver activity through increases in vegetation (bark and branches of felled trees, riparian vegetation)

-Beaver dams also create habitats for mice, gophers, rabbits and hares

-Increases in fish abundance also creates an optimal foraging area for different bear species in the summer

D) Fish:

-Beaver damming improves the habitat for fish species by improving water quality, reducing erosion and reducing seasonal fluctuations in flow

-The increased water levels caused by damming may also improve overwinter fish survival, or create an important winter habitat for fish lacking deep pools, by providing cover and resting habitat and reducing temperature fluctuations

-For salmon, beaver dams maintain the clean gravel required for spawning through reductions in flow rate and decreasing in the silt load in the water

-Fish species including brown trout, sockeye salmon, brook charr, minnows and rainbow trout have been found to be larger in beaver ponds

E) Amphibians and Reptiles:

-Frogs, toads and tailed amphibians (like salamanders) often use the shallow waters of beaver ponds to breed and lay eggs

-This is important because amphibians are becoming increasingly threatened due to habitat degradation, pollution and climate change, and it is crucial that breeding areas be preserved

-Turtles and water snakes may utilize beaver ponds because the habitat provides shallow, slow-moving water with abundant vegetation and soft organic substrates that these species prefer

The Different Animals That Benefit from Beaver Dams