Eager: Ben goldfarb’s 2018 book-A review by norm

In his 2018 book, EAGER, Ben Goldfarb shares surprising secrets about beavers.  Upon reading it recently, I was intrigued, especially by Chapter 8, Wolftopia. 

Why?  Because the chapter is all about the history of wolves, elk, and beaver in Yellowstone, where I served for 17 years as a resource manager and interpreter.  “Too many elk” was the issue I addressed upon my arrival, and the vegetational changes along Elk Creek documented by studies over time were prime examples of the effects of the extirpation of wolves.

Author Goldfarb takes us back to 1863 when traveler Walter DeLacy complained of numerous beaver dams frustrating his passage through the upper Madison drainage.  The Earl of Dunraven remarked that in 1874, streams along the upper Yellowstone were full of beaver.  In the 1920s, Syracuse University biologist Edward Warren spent two summers surveying the park’s beavers, concentrating on the northern elk range; every defile was jammed with dams and ponds.  In 1927, park naturalist Milton Skinner estimated the park’s beaver population at ten thousand.  But, by 1953 when graduate student Robert Jonas of Idaho State University replicated Warren’s reconnaissance, he found only ruins.  Why?

In 1914, Congress had assigned to the new Bureau of Biological Survey the job of destroying predators like wolves.  By 1926, the Survey and the Park Service had killed every park wolf.  Exploding elk populations devoured forage plants.  In i926, Edward Warren suggested that carnivore extermination had unleashed “what is probably an unnatural expansion of this beaver population.” But soon, elk devastated the beaver habitat, and by 1934, researchers reported a range of deplorable conditions.  In 1955, Bob Jonas wrote, “The serious reduction of the favorable beaver habitat within the park boundaries can be attributed primarily to the overpopulation of elk.”  Habitat for amphibians and birds was wiped out, and Elk Creek was cut down to bedrock.

Jonas was a friend and mentor to Dan Tyers, the son of a park naturalist. Tyers became a ranger on the Gallatin National Forest on Yellowstone’s north boundary, upstream from Elk Creek.  Inspired by Jonas, Tyers restored beavers to the Absaroka-Beartooth Wilderness from 1986 to 1999, providing a source for colonizers on several streams that flow into Yellowstone.

In 1995-96, 31 wolves were restored to the park. In 1996, park wolf biologist Doug Smith counted 49 beaver colonies park-wide. By 20007, his count was 127, with the spike concentrated in streams where Tyers had released beavers.

In the late 1990s, CSU ecologist David Cooper installed “flow velocity inhibitors,” a euphemism for dams, on a stream within an area fenced to exclude elk.  The dam mimicked beaver; the fence mimicked wolves.  The combination produced a vigorous growth of willows.  Wolves couldn’t recover willows on their own.  They required help from beavers.

Suzanne Fouty, a retired Forest Service hydrologist, was a graduate student at the University of Oregon when she studied how fencing out grazers changed the contours of streams.  Shortly she discovered that beavers were the most compelling narrative thread in her streams’ stories.  The beavers captured enough sediment to reconnect incised creeks to their surrounding valleys in a year.  She told Goldfarb, “When you take off grazing pressure from livestock, elk, and deer, you get a significant vegetation recovery.  But you don’t take the next step until you have beaver back in the system.”  She also remarked, “(W)e have to have wolves to have beaver, and we have to have beaver to have water.”