Jon and I spent all day joking about the nasty “invasive mergansers” – sometimes very unpleasant things stay with you for a while. Luckily for us, this morning provides an antidote. Written by in the glossy magazine “Anthropocene”. Don’t you wonder what the stats would say about our single family of beavers?
The tremendous benefits provided by just one beaver family
People already know that beavers are keystone species whose activities shape landscapes in broadly beneficial ways. If such descriptions sound a bit abstract, though, consider the observations of scientists who followed the activities of a single beaver pair living in the British countryside.
In a study published in the journal Earth Surface Processes and Landforms, researchers led by hydrologist Richard Brazier of the University of Exeter describe their measurements of sediment composition and water quality in ponds built by the beavers, who were released in 2011 as part of a species reintroduction effort. Beavers were extirpated from the British Isles about 400 years ago.
The beavers’ enclosure, roughly the size of three (American) football fields and situated on a stream below a farm, originally contained one small pond. Since their arrival the beavers have built 12 more ponds. Their enclosure is now a wetland mosaic regulated by dams and canals, and the ponds are slowly filling with sediment — 101 tons of it to date, estimate Brazier’s team.
Remind me to send Dr. Brazier a thank you note. His careful research has produced such helpful results that actually benefit from the extirpation of beaver for 400 years. Come to think of it, maybe I should send a thank you note to the entire United Kingdom, since there “should we or shouldn’t we” drama has helped move the beaver conversation forward in so many ways.
Some of that sediment was generated by the beavers’ own digging. The vast majority, though, is eroded soil from the adjacent farmland. Altogether the sediments contain 16 tons of carbon — representing, were every last ounce of it sequestered permanently, the average yearly carbon emissions of six British citizens.
Carbon aside, the beavers’ wetlands also filtered out one ton of nitrogen, which becomes a pollutant when released at high concentrations into riversheds, and prevented that eroded soil from becoming lost. A 2009 report estimated that agricultural soil erosion in the United Kingdom annually costs £45 million — $60 million in U.S. dollars — in damage. Beavers might offset that, suggest Brazier and colleagues, adding yet another line to the flood-controlling, biodiversity-promoting, recreation-enhancing ledger of their services.
Given the accomplishments of just one pair observed by Brazier’s team, the landscape-scale possibilities are enormous. Beavers can “deliver significant geomorphic modifications and result in changes to nutrient and sediment fluxes,” write the researchers, “limiting negative downstream impact” of agricultural pollution. To put it another way: beavers could help clean up our messes. The same applies to the rest of Eurasia, where beavers were eradicated from much of their historical range, and also North America, where their populations are now perhaps one-tenth of pre-colonial levels.
Nice work Brandan! That’s one fine summary of some very delicious research. What a great way to start the day off right. Not only can beavers fix what ails us, they can do so cheaply and efficiently on a massive scale. You would think everyone would be fighting over who gets them first, like the last Elmo doll at a Christmas sale.
Now if you haven’t already, and you live in California, go vote! Be careful of that jungle primary too.
I grew up in Pawlet. I grew up fishing the Mettowee, the Otter Creek, the Poultney, the Castleton, and the Battenkill rivers. A lot has changed in those rivers since I was a kid. The fishing has declined drastically! I’ve heard of a few plans that the state is thinking about doing to change things around. I think that the plans that I have heard are a waste of time and money.
I recently visited a tailwater stream known for its capacity to produce lots of brown trout, some of them quite large. The reservoir feeding this stream is operated exclusively for downstream agricultural users, the result of which is that the fishery is also renowned for its poor conditions in winter, when dam releases are curtailed and the stream becomes a thin vein of shallow puddles, trickles, and exposed spawning redds.
My next stop was a nearby fly shop. I proudly reported my observations to the proprietor, who proceeded to give me an earful. The stretch of stream occupied by the beavers had always been a money spot for his guides and their clients. Until, that is, the beavers took up residence. The pond had since become a bugless sucker hole devoid of trout, and though he acknowledged the positive impact of the beaver impoundment on riparian storage and late season flows, the shop owner judged the local beavers as a net detriment to the fishery. Beavers are either good or bad, he opined, never both.
To hedge against drought, we must lift and spread water tables and reconnect streams with their floodplains, especially in headwater regions. Reconnected floodplains will also enable our streams to de-energize high-intensity precipitation events, particularly important in this era of common wildfire. Where beavers live, we must make them welcome, as they are the cheapest and most efficient means of restoring the greatest acreage of watershed in the shortest timeframe. They work around the clock and accept food as payment; no matter how hard we try, we will never find a better deal than that.
The skull and the castor sacs really isn’t enough. You need the penis too. Those damn male beavers, having all those baby beavers. (?) Plus it’s fun for the kids. You never know what you’re going to get until you open it up!
