Riparian Landscapes - Mountains and Plains: The Ecology of Wyoming Landscapes - page 59

Fig. 4.14. trees falling across streams create debris jams
that provide habitat for fish and other organisms. Here,
Mullen creek in the Medicine Bow Mountains is flanked by

engelmann spruce, subalpine fir, and thinleaf alder. eleva-
tion 8,500 feet.

zone narrows, and gully erosion continues as long as
the flows are rapid and unobstructed. Such flows pro-
vide less opportunity for the benefits of bank storage.
ironically, erosion along lowland streams is some-
times of sufficient concern that landowners resort to
constructing dams themselves, which is far more costly
than the problems caused by beaver. As one Wyoming
rancher noted, “Beavers can be a pain in the neck when
you get too many in the wrong place. on the other
hand, how are we going to get that erosion stopped if
we don't use beaver? they work pretty cheap, and i've
never seen a lazy one yet.” 23
the role of beavers in preventing erosion and creat-
ing habitat has long been recognized. it was therefore
natural for land managers to consider transplanting
beaver to severely eroded gullies. in one case, in south-
western Wyoming, the transplanted beavers had diffi-
culty building and maintaining dams made from the
plant material that was available, namely, greasewood
and sagebrush. 24 A Bureau of Land Management biolo-
gist, Bruce Smith, wondered whether the beaver would

be more successful if other construction materials were
provided. He cut several aspen trees in the distant foot-
hills and transported them to near the transplanted bea-
ver. Several days later a dam was being constructed, and
within 2 years much of the gully behind the dam was
filled. With the rising water level, sagebrush and grease-
wood became less common, while meadow grasses and
willows became dominant. this experiment involved
working with beavers and has been repeated success-
fully in several locations. initially it was natural to look
for aspen to assist the beavers, but riparian ecologists
have learned that even old tires wired together can
serve as a stabilizing framework around which beavers
can build new dams. once the tires are in place, the
beavers finish and maintain the project using readily
available shrubs. 25
Significantly, gullies are not a new landscape feature
created by human activities. As noted in chapter 2, gul-
lies are frequently mentioned in journals written in the
1800s. Some could have resulted from excessive bison
grazing or beaver trapping by the first fur traders, or