Guest essay by Eric Worrall
Climate scientists are worried a beaver boom may be helping to melt the Arctic ice.
Beavers gnawing away at the Arctic permafrost
by Alfred Wegener Institute
JUNE 30, 2020Alaska’s beavers are profiting from climate change, and spreading rapidly. In just a few years’ time, they have not only expanded into many tundra regions where they’d never been seen before; they’re also building more and more dams in their new homes, creating a host of new water bodies. This could accelerate the thawing of the permafrost soils, and therefore intensify climate change, as an International American-German research team reports in the journal Environmental Research Letters.
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This has already affected the water balance. Apparently, the rodents intentionally do their work in those parts of the landscape that they can most easily flood. To do so, sometimes they dam up small streams, and sometimes the outlets of existing lakes, which expand as a result. “But they especially prefer drained lake basins,” Benjamin Jones, lead author of the study, and Nitze report. In many cases, the bottoms of these former lakes are prime locations for beaver activity. “The animals have intuitively found that damming the outlet drainage channels at the sites of former lakes is an efficient way to create habitat. So a new lake is formed which degrades ice-rich permafrost in the basin, adding to the effect of increasing the depth of the engineered waterbody,” added Jones. These actions have their consequences: in the course of the 17-year timeframe studied, the overall water area in the Kotzebue region grew by 8.3 percent. And roughly two-thirds of that growth was due to the beavers.
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Read more: https://phys.org/news/2020-06-beavers-gnawing-arctic-permafrost.html
The abstract of the study;
Increase in beaver dams controls surface water and thermokarst dynamics in an Arctic tundra region, Baldwin Peninsula, northwestern Alaska
Benjamin M Jones1,6, Ken D Tape2, Jason A Clark2, Ingmar Nitze3, Guido Grosse3,4and Jeff Disbrow5
Published 30 June 2020 • © 2020 The Author(s). Published by IOP Publishing Ltd
Beavers are starting to colonize low arctic tundra regions in Alaska and Canada, which has implications for surface water changes and ice-rich permafrost degradation. In this study, we assessed the spatial and temporal dynamics of beaver dam building in relation to surface water dynamics and thermokarst landforms using sub-meter resolution satellite imagery acquired between 2002 and 2019 for two tundra areas in northwestern Alaska. In a 100 km2 study area near Kotzebue, the number of dams increased markedly from 2 to 98 between 2002 and 2019. In a 430 km2 study area encompassing the entire northern Baldwin Peninsula, the number of dams increased from 94 to 409 between 2010 and 2019, indicating a regional trend. Correlating data on beaver dam numbers with surface water area mapped for 12 individual years between 2002 and 2019 for the Kotzebue study area showed a significant positive correlation (R2 = 0.61; p < .003). Beaver-influenced waterbodies accounted for two-thirds of the 8.3% increase in total surface water area in the Kotzebue study area during the 17 year period. Beavers specifically targeted thermokarst landforms in their dam building activities. Flooding of drained thermokarst lake basins accounted for 68% of beaver-influenced surface water increases, damming of lake outlets accounted for 26%, and damming of beaded streams accounted for 6%. Surface water increases resulting from beaver dam building likely exacerbated permafrost degradation in the region, but dam failure also factored into the drainage of several thermokarst lakes in the northern Baldwin Peninsula study region, which could promote local permafrost aggradation in freshly exposed lake sediments. Our findings highlight that beaver-driven ecosystem engineering must be carefully considered when accounting for changes occurring in some permafrost regions, and in particular, regional surface water dynamics in low Arctic and Boreal landscapes.
Read more: https://iopscience.iop.org/article/10.1088/1748-9326/ab80f1
Let us hope scientists find a way to mitigate the damage done by the exploding beaver population before it is too late.
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In case there is not more beav info than anyone wanted….I have seen old beer cans incorporated into dams…whatever is available – the beav will involuntarily react to the sound of running water because wildlife people have planted a recording of running water in a beav dam and the beav tried to build the dam higher over the recording…maybe coyotes will control the beav, but what will control the coyotes?
Wolves. When they reintroduce wolves to an area one of the first things those wolves do is go control the coyote population, they are competition that can’t defend themselves against wolves. What controls wolves? Man but man can cut out the middle man and directly control both beavers and coyotes without reintroducing wolves. There just needs to be an incentive along with laws that allow controlling populations. Currently I can go out and shoot coyotes all day and all year long, no one will bat an eye or ask to see my license. For beavers I have to be mindful of regulations, permitting and seasons to take just one. Not my cup of tea so I’ve never done it.
I understand their population was decimated at one point and needed protection but they’re a rodent. They literally breed like rats and repopulate in a hurry. The nutria was imported into our area for their fur, when the fur market dropped they were released in the wild. Didn’t take long for them to spread all over the place and become a serious destructive nuisance. Just like the coyote above I can shoot them all year round with no licensing or regulations to follow needed. With the poplulation rebound and few trappers (low fur prices) they don’t need the same level of protection they’ve enjoyed.
So they took the joke “kill a beaver – save a tree” seriously this time.
They need to reintroduce French-Canadian trappers to the area. Are there any left, in perhaps zoos or trapper sanctuaries. And I admit I’m not sure, do they breed in captivity?
Beavers can create a disaster scenario, if left unchecked. A very good friend and employee of mine had his log home destroyed by the breech of a beaver dam about a 1000 feet elevation above his very rural lakefront home. Basically, the beaver built a dam at a small creek where the creek channel was constrained by a narrow rock canyon, with a large flat meadow before the creek drained down the mountain, nearly vertical. The beaver built up the dam about 11-12 feet over several years in an old logging block up above on a flat bench, and then a few years back at a large freshet snowmelt, the dam completely breeched instantly releasing about 100 acre feet of water which is about 4,356,000 cubic feet of water (33 million US gallons) which roared down the small creek channel picking up VW sized boulders all the way down. Not a lot of water in the scheme of things, but it was all at once. It is absolutely amazing the amount of damage even a relatively small amount of water can do.
They were having a family barbecue on their dock on the other side of their house and barely escaped with their lives. But their entire property was basically destroyed including their log home in less than 7 minutes of peak instantaneous flow, ripping out 3 foot diameter green Fir trees in the creek canyon. This created so much stress in his life, that he had a heart attack and died just last month, which I think a lot of that stress came from his loss of his home and property after a life time of hard work. So, the lesson here is to monitor beaver dams if there is any risk downstream from a beaver dam failure. Note to self…and RIP Ron.