In the fall of 2011 I was attending Feather River College here in my hometown of Quincy, CA. One of my classes was Sierra Nevada Natural History, and one of our field trips was to nearby Spanish Creek for the purpose of surveying beaver activity on the creek. In the recent years up to that time beavers had made a comeback on Spanish Creek. For decades preceding that time the beaver had been effectively extirpated from the area. Local cattle ranchers and some sports fisher-people did not like beavers at all; beavers’ natural work produced flooded grazing and hay pastures, blocked irrigation ditches, left trees across cattle and stream-side paths, spoiled favorite fishing holes and were considered a grievous nuisance pest, a rodent worse than rats. Solution? Get rid of ‘em. And we nearly did. But not entirely.
The Daily Bucket is a nature refuge. We amicably discuss animals, weather, climate, soil, plants, waters and note life’s patterns.
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Note that in the above block “we… note life’s patterns.” One thing I have noted around here is that the beaver doesn’t seem to be around anymore, or at least not close by. Back in 2011 when my college class went to check out what the beavers were up to on Spanish Creek we were able to see and survey three active beaver dams in about a half-mile stretch of the creek immediately adjacent to the college. My title photo shows what is left today of one of them. Downstream of that dam is a bare remnant of another.
There is no trace of the third dam, which I describe below.
From my field notes of September 13, 2011:
Bracketed passages added for clarity.
Walked downstream. Found [one] dam and channel in bank mud approximately 150 yards upstream of [location reference].
Partial (old?) dam approximately 1000 yards from 1st dam, but [there is] evidence of this year’s work (leaves still on alder [branches in the dam]).
3rd dam: Very recent work. Lots of fresh chew all around. This dam has backed water up sixteen to thirty inches above stream bed. [This dam] spans the stream completely bank to bank. Highway bridge not yet in sight but I can see the top of a light pole at the baseball field [which is right there at the highway bridge].
[We measured the dam to be] sixty-seven feet across.
I included in my field notes a rough sketch of the dam from a “bird’s-eye” view. The dam was S-shaped and had a slight gap in it at its far bank terminus, known as an “end run”.
Back to the present. In my outdoor walks and bicycle rides I have talked to several local people who claim to have seen beaver (and otter!) not only in Spanish Creek but also in some of the very smaller creeks which are very close to my apartment. Indeed there is plenty of beaver sign (colloquially known as “beavage”); lots and lots of small and large willow, alder, and cottonwood trees having been gnawed down by beavers. But none of it recent. So, where have the beaver gone? And why?
According to beaverinstitute.org
Since beavers prefer not to travel far from the water, eventually they exhaust their woody food supply. When this happens the beavers will move to a new location. Then their dams develop leaks and the ponds drain out. The rich pond sediment gives rise to a lush, grassy meadow. Eventually shrubs and trees become established, and after 10 -15 years there is enough woody vegetation to attract new beavers and the process starts over. This natural beaver cycle creates a repeating series of successional habitats that support biodiversity.
Maybe that’s the reason. Maybe they just used up their immediate food supply and have just moved to a different location. I hope that’s it. I hope they will be coming back to my neighborhood in the near future. We could certainly benefit by it.
Beaver Institute:
When beavers open the forest canopy by damming streams and cutting down trees they create new ecological niches and transition zone habitats where various species thrive. Many of our threatened and endangered species require these vanishing habitats at some stages of their lives. Beaver activity creates “Mosaic Habitats” (a mix of habitats), even as they continue to disappear elsewhere from development, negatively impacting species that are declining in numbers, such as turtles, bats, and grouse. So while killing trees in and around a beaver pond appears destructive, these dead trees actually create critical habitats for honeybees, wood ducks, swallows, herons, and others, and also allow grasses, sedges, bushes and saplings to grow on the perimeter of the pond. These plants provide habitat variety, food and cover for foraging animals.
Opening the tree canopy creates valuable land-based habitats, and it also allows sunlight reach the water where it triggers an explosion of aquatic biological activity. Algae and aquatic plants grow in the sun-drenched, nutrient rich water. This organic material supports microscopic organisms, which are eaten by a variety of invertebrates. These become food for fish, birds and mammals. An entire food chain is created which is why beaver ponds become magnets for wildlife. The biodiversity that exists due to beaver activity makes beavers our prototypical Keystone species and nature’s ecosystem engineers. Each Keystone species is critically important for biodiversity, yet there is another Keystone species that relies on beavers, salmon! More beavers mean more salmon, and more salmon mean even more biodiversity! Scientific research by Pollock, Wheaton, Kemp, and many others shows that streams with beaver dams actually produce larger and more numerous native trout and salmon. It turns out that beaver dams create ponds that serve as ideal nurseries for juvenile fish by creating complex edge habitat, increasing the invertebrate and insect food supply, putting beneficial woody debris in the water, reducing fish energy needs by providing slow water refuge, and increasing winter survival of salmonids. It is believed that having more beaver ponds could help some salmon be taken off the threatened species list!
I had hoped to get better photographs for this diary but I found the going to be difficult along this stretch of Spanish Creek. The trees and brush have grown dense and quite tangled along the stream banks. But in closing I’d like to include a couple of photos of this wonderful creature’s natural engineering abilities. Quite the logger the beaver is.
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Now It's Your Turn
What have you noted happening in your area or travels? As usual post your observations as well as their general location in the comments.
Thank you.