Beaver Reintroduction in the Absaroka-Beartooth Wilderness

Absaroka-Beartooth Wilderness

Greater Yellowstone Ecosystem

(1,475 sq. miles)

Release Areas

Eagle CreekHellroaring Creek

Buffalo Creek Slough Creek Stillwater River

Project Origin

Abundant habitat devoid of beaver

(Early 1980’s)

Wilderness Reintroduction Requirements

•Positive affect

•Unable to recolonize

•Sufficient habitat

•Extirpation by humans

•Historically present – currently absent

Preparatory Documents

•Minimum tool – Wilderness character•NEPA – Effects and public input•BA & BE – Protected species

An Ecosystem Engineer

Riparian habitat enhancement

Colonization potential

Sufficient Habitat

20 miles: 1st-3rd order streams

Human role

Beaver abundant until 1950’s

Beaver absent in 1985- but evidence of past occupancy

Cause of demise:

•Trapping

•Tuleremia

•Willow decline

West Fork Cabin – symbol of a trapping era

A source for beaver– damage complaint

System for delivery

Relocation constraints :- Family groups- Early fall release

130 relocated – 40 at primary release sites

Trapping curtailed

What can we learn?

Management actions as investigations

1986-2010 Annual structure inventories

DamsLodgesBank LodgesCaches

Inventory Example: Frenchy’s Meadow

Quantification of Physical Variables

• Stream sinuosity

• Stream width and depth

• Sandbar distance

• Willow canopy

• Distance to confluence

Results 1986-2010:

• Carrying capacity reached – year 2000

• Colonies = 1.33/ km

• Willow and standing water >15%

Carrying Capacity Model:

Colony success correlated with: - Greater stream sinuosity and depth- Less distance to secondary channel- Fewer gravel bars

Colony success not correlated with: - Willow canopy