New Residents at Cordova Creek
Overview of Cordova Creek in July 2018
If you have recently strolled through Cordova Creek, you may (or maybe not) have noticed new additions to the creek – beaver dams! On the one hand, this is an exciting indicator of the successful naturalization of the area, as native species continue to utilize the site and make it their home! Though beavers provide numerous ecological benefits –like increasing biodiversity, preventing downstream flooding, and minimizing pollutants – they can also simultaneously cause problems in urban environments, commonly referred to as human-wildlife conflict.
Our CivicSpark Fellow Cassie has worked diligently to find a solution to balance the needs of the beaver with the successful establishment of the creek.
Left: Beaver dam creating a pond ecosystem Right: The pond leveler installed and managing pond dimensions
As the ubiquitous population of North American beavers (Castor canadensis) has steadily recovered from historic depletion, it has become increasingly apparent that these aquatic mammals can fundamentally modify existing hydrologic regimes. Due to this ability to change their environment, beavers have earned the status and nickname of ecosystem engineers. In natural environments, their engineering abilities can be incredibly beneficial.
However, the initial dam on Cordova Creek had detrimental impacts on the newly naturalized site. The beaver dam caused nearby banks to submerge, which in turn caused the drowning of young plants and it began to overflow across the trail. Additionally, the beaver removed cottonwood trees, young willows, and many yards of irrigation which cascaded into many more plant problems.
Though the damage caused by the beaver was not easy to ignore, we recognized that it would be unreasonable to get mad at a beaver for simply doing what beavers do. Thus, we brainstormed ways to live peacefully with the beaver, while continuing to maintain the site in its early years of establishment. Through the help of Sacramento-Yolo Mosquito & Vector Control District, a pond leveler was installed on the creek. The pond leveler is a pipe that goes through the dam to allow a certain amount of water to pass through the dam whilst maintaining a pond environment for the beaver.
Additionally, through the help of Soil Born Farms, their summer high school interns spent a morning on Cordova Creek assisting in wrapping vulnerable cottonwood trees with fencing to protect the trees from beaver herbivory. Cottonwood trees have slower growth rates compared to willows which will naturally recover faster from beaver herbivory. Now that the cottonwoods will have a chance to grow, they will be able to provide some shade to the many walkers, runners, and cyclists enjoying the trail.
Left: Student interns prepare to wrap a cottonwood tree Right: Student interns pose and smile after wrapping 15 cottonwood trees
As Cordova Creek continues to establish itself, we look forward to welcoming new wildlife residents to the neighborhood and finding innovative ways to resolve any more human-wildlife conflicts that may arise.