A nice article this week from Trout Unlimited’s coordinator, Toner Mitchell, in New Mexico. I especially like how it talks about A) the improvements beavers make to streams B) A flow device installed by fish and game and C) The way that when people have their minds made up one way about beavers they simply DON’T SEE anything else other than what they expect.

Voices from the River: Beavers as tools

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.

Since this stream is in the coldest corner of New Mexico, anchor ice is common. I was pleased to see the latest work of the beaver population, knowing that their ponds would provide winter refuge for fish. But I was there to see the leveling device (beaver deceiver) installed by the New Mexico Game and Fish department to mitigate the legitimate though misplaced concern of downstream irrigators, who felt that the beavers were holding back valuable water from ranches and farms. The deceiver was working as intended, sending water downstream while limiting the pond’s depth and expanse so as not to inundate an adjacent parking lot.

Isn’t that a lovely start to an article? I only had to look up one phrase (anchor ice) so I can now tell you it refers to ice underwater attached to the bottom of the pond – this makes it a lot easier for the stream to freeze solid. In fact streams lacking anchor ice almost never do. You can see how the freezing would create an insurmountable problem for baby trout, and how a beaver swimming back and forth through the water every day and breaking holes in the ice over and over would help.

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.

The beaver is a keystone species, generally defined as an organism that exerts an outsized influence on the function and even formation of an ecosystem. Beaver dams capture peak flows, prolong spring runoff, while supporting and extending baseflows with water stored in riparian aquifers. Their deep ponds concentrate nutrients and macroinvertebrates; they provide shelter and security for trout, especially in winter.

The disgruntled fly shop owner hypothesized that his favorite run-turned-hated-beaver-pond might have warmed too much to harbor the trout it once did and, along with possibly consuming too much oxygen, accumulated silt may have buried insect production. For what little it’s worth, I’ve personally witnessed few instances where beavers have negatively impacted trout. I don’t doubt that it happens, certainly not in this case, but I think such stories should be viewed in the broader context of watershed health. Consider how many of our highest quality fisheries (and grazing pastures) were literally made by beavers. They cleared trees to build their dams, which filled with trapped sediment and forced channel migration across floodplains. Over time, floodplains expanded and thickened thanks to further beaver-induced sediment deposition. This long process created thick, spongy meadows, essentially grass-skinned reservoirs feeding streams with cooled groundwater.

Remember when you were a kid and there was a particular food you hated? Allow me to tell something from my 10 years as a day care teacher and 25 years in the child psychology field. You would contort your face with disgust, plug your nose and close your eyes and if your parents made you take a bite you would gag uncontrollably. I’ve long believed that even if, in those critical moments where you couldn’t see, your dad switched out the broccoli for chocolate cake or whatever, you would still wretch when taking a bite. Because everything you might try in that state of mind tastes horrid.

And every stream with beavers in it when you didn’t want them in the first place is horrible.

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.

And where they don’t live, we must imitate them; thanks to conservation groups in New Mexico, including the Truchas Chapter of TU, imitating beavers may soon become the hottest trend in stream restoration. Volunteer-made beaver dam analogs (BDAs) employ natural materials and are designed to pass water, trap sediment, and raise riparian water tables. Combined with willow and cottonwood plantings—which provide stream shading and future beaver food—BDAs create true beaver habitat and often attract the real animals to continue this important work. As a wise man I know once said, “In times of flood, prepare for drought. In drought, prepare for flood.”

I’m not sure, but I think this guy may have been a beaver in a previous life.

Ahh what a lovely summary of beaver benefits. And also a nice description of beaver disbelief. Well done, Toner! I have to finish this find read with a classic photo from Rusty’s visit to Tulocay creek last night. It has been so long since I saw a beaver up close I felt a little pang looking at those eyebrows! Ahh vibrassa!