Ecosystem engineering is by definition an interdisciplinary concept, tying together geomorphology (the study of physical processes and forms in rivers) and ecology. Two researchers at Umeå University in Sweden that bridge these disciplines, a fluvial geomorphologist, Dr. Lina Polvi, and a landscape ecologist, Dr. Judith Sarneel, examined the available literature and summarized the range of ecosystem engineers that are found in river environments in their review recently published in WIREs Water.

An important aspect of this work was to determine where various ecosystem engineers have the most impact, in terms of three geomorphic factors—channel width, sediment size and the relative stability of the channel. For example, rivers affected by beaver dams can become more complex and change from being single-thread meandering channels to more complex multi-thread systems. However, although the beaver can be found throughout a river system from very narrow to very wide channels, they will only engineer by building dams and truly alter the river’s form in narrow- to intermediate-sized channels.

This sounds basically like beavers always make a difference but in the right shape streams they make a bigger difference. Fair enough. The article goes on to talk about other kinds of ecosystem engineers and how one should be careful to only put in native ones. Really? Somebody is STILL researching this? They talk about macrophytes as engineers of streams  to which I say HRMMPH! When has anyone ever had a macrophyte festival?

Beavers are sooo much better,

I like this letter to the editor in the Register-Guard much better for obvious reasons,

Beavers important to ecosystems

I appreciated the Jan. 11 article bringing attention to the U.S. Department of Agriculture’s Wildlife Services’ illicit killing of Oregon’s beavers. During the 1990s, I conducted a research project on the then-state-endangered river otter population in the Colorado Rocky Mountains. Because beavers occupied many of the same sites as otters in my 40-mile stretch of watershed, I documented their behaviors as well.

Through my research — and that of many others throughout the country — good river otter habitat is often equated to be a consequence of beaver activity. In fact, through complex science, these ecosystem engineers provide habitat for many other species as well: plants, invertebrates, amphibians, reptiles, birds, mammals, and fish — including Oregon’s beloved salmon. Results from research conducted in Oregon, Alaska and British Columbia show that juvenile salmon have higher survival rates in streams with beaver ponds.

Beavers should be revered for their contribution to sustainable ecosystems, not killed to justify an agency’s existence. Two long-time beaver researchers, Bruce Schulte and Dietland Müller-Schwarze, expressed it well: “Given the flexibility of beaver behavior, perhaps we would be better to manage human activity, to use preventive measures to avoid problems with beavers, and to reap the benefits of living with beavers.”

Judith K. Berg. EUGENE OR

HOW much do we LOVE Judith? What a wonderful letter!  Of course ideal otter habitat is the result of beaver work. And ideal salmon habitat and blue heron habitat too. Judith is the author of the very successful book  “The Otter Spirit” which has won several awards, I’m thinking she deserves an award for her letters to the editor too, because “Beavers should be revered, not killed” is a mighty fine sentence.

She is definitely a member of Worth A Dam in spirit! Thanks, Judith.