The effort to reintroduce fishers into Olympic National Park
continues to be an exciting good-news story, but the implications
may be even greater than they seem at first glance.
We must wait to see whether the males and females among the 40
or more fishers will find each other. But biologists say there’s a
good chance they will, and researchers may discover some dens with
kits either this spring or maybe next year.
I had the privilege of seeing five fishers released yesterday
near Staircase Ranger Station in Olympic National Park. These were
the first animals to be released on the east side of the mountains.
For a description of their rapid escape into the woods, see my
story and watch the video in
today’s Kitsap Sun.
While on the outing, I talked to Jasmine Minbashian of
Conservation Northwest about the potential for unexpected results
from this experiment. As an example, she wondered about the
potential of a trophic cascade, such as seen in Yellowstone Park
after the introduction of wolves. In a chain of events, the wolves
have done a great favor for fish in the national park.
Wolves not only eat elk at times, but their presence frightens
away these animals that love to eat the shoots of aspen trees.
Without the elk browsing continuously, the aspens grow into dense
vegetation that can provide shade, cover and insects — all to the
benefits of fish and other creatures.
Chris Conway of the New
York Times does a nice job explaining this in a brief story
from Aug. 5, 2007. For a little longer version, see Science
Daily, which points out:
Prior to the re-introduction of wolves, scientists found there
were many small sprouting shoots of these important tree species,
and numbers of large trees 70 years old or more — but practically
nothing in between. High populations of grazing ungulates,
primarily elk, had grazed on the small tree shoots at leisure and
with little fear of attack.
But the ecological damage, researchers say, went far beyond just
trees. The loss of trees and shrubs opened the door to significant
stream erosion. Beaver dams declined. Food webs broke down, and the
chain of effects rippled through birds, insects, fish and other
plant and animal species.
For more information about trophic cascades, go to the Web site
of Oregon State
University, where this issue is being studied in depth.
As for Olympic National Park, the extermination of wolves on the
peninsula may have had a cascading effect on species that depend on
cottonwood and bigleaf maples. The Fall 2008 issue of
Island Geoscience (PDF 732 kb) tells it this way:
In 1890, members of the Press Expedition found the banks of the
upper Quinault River “so dense with underbrush as to be almost
impenetrable,” they wrote at the time. Logs jammed the rivers,
dense tree canopies shaded and cooled the streams, and trout and
salmon thrived, along with hundreds of species of plants and
animals.
“Today, you go through the same area and instead of dense
vegetation that you have to fight through, it’s a park-like stand
of predominantly big trees,” said Bill Ripple, a co-author of the
study and forestry professor at Oregon State University. “It’s just
a different world.”
“Our study shows that there has been almost no recruitment of
new cottonwood and bigleaf maple trees since the wolves
disappeared, and also likely impacts on streamside shrubs, which
are very important for river stability,” said Robert Beschta, lead
author of the study and professor emeritus of forest hydrology at
OSU. “Decreases in woody plant communities allow river banks to
rapidly erode and river channels to widen.”
Efforts to reintroduce wolves to the Olympic Peninsula are on
hold for the time being. But we have a lot to think about. What we
can learn from the fisher may be much more than the idea that we
should have a few more of the furry animals running around.
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