Once upon a time, not long ago, there were some beavers swimming and chewing happily in the Owens Valley River in southern california. Hardly anyone noticed that their dams created habitat for numerous waterfowl – the felled trees made homes for obligate nesters, and chewing produced coppicing with dense bushy regrowth that migratory and song birds preferred. One tireless audubon advocate noticed that their ponds flooded some cottonwoods which were the homes of these remarkable birds.
That advocate wrote in the Eastern Sierra Newsletter:
It is important that the Los Angeles Department of Water and Power and the California Department of Fish and Game address this critical issue sooner and not later. Audubon members are urged to contact the Inyo County Board of Supervisors, the California Department of Fish and Game in Bishop and the Los Angeles Department of Water and Power in Bishop to urge them to begin controlling beaver numbers along the lower Owens River in the Lone Pine area (and elsewhere in the southern valley?). The threat to the Great Blue Herons due to girdling or drowning of nesting trees is real and will worsen.
It seems Michael Prather’s warning was the ‘shot heard round LA’ – or at least provided an excellent excuse for the reflexive decision to kill beavers. Los Angeles Water & Power was only too happy to dress up their beaver killin’ in a feathered Audubon suit, and decide without debate that the beavers in an entire range should be killed to protect the birds. Never mind that this was all done 10 years ago with disastrous and well documented results.
‘‘Beavers Will Die So Birds Can Survive.’’ This headline ran in the local Riverside, California, newspaper in January 1999 (Farwell 1999a). It marked the beginning of an effort by the management of the Southwestern Riverside County Multi-Species Reserve to eliminate beavers with the purpose of protecting songbird habitat.
concluding
Observations at Lake Skinner produced insufficient data to demonstrate that beavers harmed habitat for either least Bell’s vireo or southwestern willow flycatcher. In general, vegetation ‘‘managed’’ by beavers favors songbirds, both by providing nesting opportunities and boosting insect populations as a food base, some examples of which are summarized by Mu ller-Schwarze and Sun (2003).
Environ Manage (2007) 39:460-471: Management by Assertion: Beavers and Songbirds at Lake Skinner (Riverside County, California)
Travis Longcore , Catherine Rich & Dietland Muller-Schwarze
Alright, maybe beavers are good for little tiny birds, but Mr. Prather was worried about majestic blue herons. What about them? Funny thing, here’s an interesting paper put forward by Fish & Game in New Hampshire. Click on the link to read the highlighted sections which demonstrate the herons often nest in flooded dead trees of beaver ponds, and are in fact dependent on them.
Great Blue Heron (and beaver dependence) Kelly JR New Hampshire Fish and Game
Well, maybe those New England herons are different? How do we know that beavers are good for this specific habitat in this specific waterway? It’s not like there’s an technical study done on this exact location to assess the impact of beavers in Owens valley.
Oh.
Beaver ponds generally provide unique and valuable habitat for many species of wildlife. Increased structural complexity and high interspersion of unique plant communities and habitat features are important factors influencing wildlife species presence and abundance. High breeding bird density, bird species richness and diversity, and total breeding bird biomass are typically associated with beaver ponds.
Well sure, there may be some incidental good that beavers do for an area, but its the conclusion of the report that really matters. I’m sure that the department of water and power wouldn’t have made the decision to kill all the beavers if the report they commissioned had recommended something else.
Although beaver activity has resulted in the removal of much willow and other shrub and woody vegetation and the dams create favorable tule conditions and reduce fish spawning habitat, they also provide important fish rearing habitat, mesic meadows, and promote the growth of other riparian species. It is most likely that the physical removal of beaver dams will result in more adverse environmental impacts than environmental benefits.
It is our conclusion that beaver dams should be left as they are, allow the natural forces associated with future out-of-channel and base flows to remove or incorporate them into the riverine ecosystem, but focus on controlling the number of beaver by reach through trapping as the management strategy.
Wow.
So a commissioned report advised keeping a healthy population of beavers, beaver dams have been proven to benefit birds including the great blue heron, and Mr. Prather is still able to say “eek beaver!” and provide environmental cover for a species genocide campaign that not a single reporter can be bothered to question.
Are we surprised?
(Many thanks to RL for finding the articles that made ashes of the Owens valley beaver killing argument.)
