North America's largest rodent is also nature's most amazing engineer. Beavers (Castor canadensis) are a keystone species, their presence or lack there of has a major impact on an ecosystem. They are one of only a few species, other than humans, that are capable of changing an entire ecosystem in order to benefit their own needs. They can take a small trickle of a stream in a desert and turn it into an oasis, not only for themselves, but for many other plant, animal and insect species.
In addition to creating a diverse wetland habitat they also improve water quality downstream. When they dam up a stream to create an environment to suit their own needs, they are creating much needed wetlands which are nature's sponges and filters. Their dams slow down the flow of water which allows time for sediment to settle out of the water and helps with erosion control resulting in cleaner water and healthier banks downstream.
For these reasons having a family of beavers on your property can be an amazing benefit, but as with any human/wildlife interaction it can have its problems too. Depending on how close your house is to a stream, pond or basin flooding could be an issue. If you tear down their dam they will only come back more determined than ever. If you put a hole in the damn or take down a part of it, the sound of flowing water will trigger them to fix it. One solution is to put a pipe called a "limiter" above and below the dam. The pipe will allow water to slowly and quietly flow through the dam while still keeping enough water behind it for their lodge, protection, food cache and to maintain the new ecosystem. This will require the use of a professional.
Beavers also have a talent for clear cutting expensive, landscaped trees. Willow, aspen, birch and maple trees are among their favorites. Depending on how close your house or other structures are to large trees, falling trees can be another concern. A solution to these probems is to pick which trees you want to save and wrap a 3-4 ft. barrier of galvenized welded wire around the tree leaving enough space between the fence and the tree so that the beavers cannot reach it. This will prevent them from girdling or cutting down your valued trees while leaving others for them to use for building and food supplies. Beavers are not very good climbers so fencing in your yard is another option.
If a happy medium cannot be reached and you are adamant about wanting beavers off of your property, call a professional trapper who will humanely catch and release them into a different stream system several miles away. There is no need to resort to fatal measures. Make sure to call a professional and do not attempt to do it yourself because beavers are not small, weighing in at up to 60 pounds, and can be aggressive when threatened.
With a little patience and a little work, humans and wildlife can live peaceful lives together. For a good look at a beaver dam, lodge and the wetland ecosystem they create, visit the Beaver Marsh in the Cuyahoga Valley National Park.
For additional information:
Nature: Leave It to Beavers (Documentary)
National Geographic: Nature's Engineers, Beavers (Documentary)
Blog Author: Kelly, Urban Conservationist