in other words
may7
2020
9
A Word From the Watershed: Happy Beaver, Happy Watershed continued from page 8
Thankfully, beaver have recov-
ered. Populations are estimated around
15 million, and although that’s nowhere
near the estimated 400 million pre-colo-
nization, it’s enough for the species to be
considered stable.
Drain The Swamp? Maybe Not
Here in the 21 st century, we are
beginning to understand the significant
impact beaver had on the North Ameri-
can landscape 300 years ago. Streams
and rivers were backed up and impound-
ed all over the place. Water filled the
valleys and the beaver reigned supreme
from atop lofty lodges. Rather than rush-
ing, babbling streams neatly confined to
a trench-like bed, one would have seen
dam after dam holding and pooling wa-
ter, giving way to wetlands, marshes,
and bogs, and connecting floodplains to
waterways.
If I’m honest, from my human
perspective, it sounds awful. It sounds
like mosquitoes and snakes and nowhere
dry for days. But that perspective is a
naïve one. The reality is that the slog and
swamp-like muck is actually a cradle of
life, a refuge for biodiversity.
In the United States, only 2%
of land is wetland, and yet wetlands ac-
count for 80% of our biodiversity. Thou-
sands of species depend on wetland
habitat: fish, birds, mammals, reptiles,
amphibians, insects, and plants. Beaver
are a keystone species because they cre-
ate habitat used by so many others and
without them, some species collapse en-
tirely. Encouraging beaver to colonize
our waterways can increase the riparian
footprint and vegetation, cause a season-
Beaver Dam Analogue, Trask Consulting, Inc.
al stream to become perennial, capture
pollution, sediment, carbon and nitro-
gen, lessen flood devastation, and retain
cool water during summer.
“Let The Rodent Do The Work”
Here in our corner of Oregon,
the UNWC wants to encourage beaver
to resume their dam building and habi-
tat creating as a way to bolster Coho
salmon rearing, spawning, and juvenile
survival, and there is hope that beaver
activity could increase the Upper Ne-
halem’s resiliency to climate change. To
this end the UNWC and Steve Trask of
Trask Consulting, Inc. began the Beaver
Dam Analogue Pilot Project in 2018.
Last month Trask released the Upper
Nehalem BDA Pilot Project Year 2 Post
Implementation Monitoring report with
promising results.
A BDA is essentially a fake bea-
ver dam, intended to lure beaver into a
constructive attitude. Formed by a line
of posts driven into the stream bed with
branches woven between them, these
playgrounds often come complete with
food caches and newly planted willow
stakes for grazing.
In August 2018, 27 BDAs were
installed in four of the Nehalem’s tribu-
taries: Buster Creek, Bear Creek, Rock
Creek, and Lousignont Creek. Then, one
year later in August 2019, an addition-
al 30 BDAs were installed along Deer
Creek, Walker Creek, and upper Fish-
hawk Creek above the Lake. The chosen
BDA sites are legacy beaver sites, but
showed no signs of beaver activity at the
time of installation.
In the new 2020 report, 15 out
of 57 BDA sites were colonized by bea-
ver with an additional 30 natural beaver
dams constructed between the BDAs.
This has added over 30,000 square
feet of pool surface area and greatly
increased the Coho salmon rearing po-
tential. Some BDAs not colonized by
beaver held back water and increased
pool surface area well for the first win-
ter, but are no substitute for active ro-
dent maintenance and by year two they
are beginning to fail. Overall the project
appears to be successful and monitoring
will continue into 2021 to assess lon-
ger term impacts.
Because of this success, the
UNWC has definite plans to strategi-
cally encourage the expansion of beaver
colonies throughout the watershed along
designated anchor habitat reaches in
cooperation with interested landowners
and engaged managers.
If you want to learn more about
beaver, the UNWC, or to view the 2020
BDA Pilot Project report, visit our web-
site at unwc.nehalem.org.