Ecoregion

Beaverhead Mountains Section (M332E)

General Description

Birch Creek is a fed by approximately 52 springs that emanate in the valley bottom. The Fen is the result of the damming action of a basalt ridge that is oriented perpendicular to the valley. The combination of a very stable raised water table plus alkaline substrates provides habitat for many unique species and plant communities. 

Alkaline benches support temporarily saturated wetlands that are often dominated by Chrysothamnus nauseosus (rabbitbrush), and the graminoids Agropyron smithii (bluebunch wheatgrass), Distichlis stricta (inland saltgrass), and Elymus cinereus (basin wildrye). Chrysothamnus covers a large area and may occupy areas that historically supported the Sarcobatus vermiculatus/Elymus cinereus (greasewood/basin wildrye) community type.

Grasslands are also present on the alkaline benches and are dominated by Poa juncifolia (alkali bluegrass), Spartina gracilis (akali cordgrass), Muhlenbergia richardsonis (mat muhly), and Distichlis stricta. Adjacent swales and slightly lower microsites support stands of the Pentaphylloides floribunda/Deschampsia cespitosa (shrubby cinquefoil/tufted hairgrass) and Juncus balticus (Baltic rush) community types. Aquatic communities are dominated by Mimulus guttatus (seep monkeyflower) and Rorippa nasturtium aquaticum (watercress) at spring heads with Potamogeton vaginatus (sheathed pondweed), Ceratophyllum demersum (coon's tail) and lesser amounts of Ranunculus aquatilis (whitewater crowfoot) forming thick mats in stream channels. Emergent wetlands occur over small areas within a complex wetland mosaic with Carex simulata (short-beaked sedge) and Eleocharis pauciflora (fewflower spikerush) as the 

dominant community types. Carex simulata most frequently occurs adjacent to channels on highly organic soils that are saturated throughout the year. Eleocharis pauciflora communities generally occur on quakey, unstable, marl substrates. Deschampsia cespitosa was likely very widespread at Birch Creek in the past. Currently, however, only small remnant stands remain. Willows occur near the downstream end of Birch Creek Fen and are scattered along certain spring channels within the fen.

General Location

Birch Creek is located in east-central Idaho between the Lemhi Montains to the west and the Beaverhead Mountains of Montana to the east. The Fen is the headwaters of Birch Creek in the Birch Creek Valley just north of Lone Pine, Idaho. 

Highlights

Provides habitat for at least 9 plant species of concern and at least two snail species of concern.

Species of Concern

Birch Creek Fen provides habitat for nine special status plant species including one globally rare species (G1) that is endemic to the alkaline fens of east-central Idaho. Endemic snails are also known to occur at Birch Creek (Frest 1994). 

Major threats

The Upper Birch Creek watershed has very little development but it does receive a substantial amount of recreational use. This is primarily for camping, fishing, and hunting activities. Off-road vehicle users do pose a threat to the fen and stream channels. 

Commercial use of the area is primarily for season-long livestock grazing. Additionally the USFS holds a lease on a BLM tract where an outhouse, horsebarn, and small house are present at Kaufmann Guard Station. The BLM lease includes a 40 acre tract that is used for winter horse pasture. 

Native plant species that tend to increase with ground disturbing activities may be more of a threat to wetland and biodiversity values. Increasers includeThermopsis montanum (mountain thermopsis), Iris missouriensis (Rocky Mountain iris), and Chrysothamnus nauseousus. 

Major Science and Stewardship Activities

In 1995, The Nature Conservancy purchased 1,160 acres in the heart of the fen from a private rancher and transferred the majority of the land to the Bureau of Land Management (BLM). The Conservancy retained 80 acres, and together with the BLM, jointly manage the entire tract as a preserve. Cattle and vehicles have been excluded, overnight camping has been eliminated, border fences have been repaired, and signs have been posted regarding the significance of this area. Only foot travel is allowed.

Numerous studies have taken place at Birch Creek Fen to determine habitat needs of globally rare plant species (Moseley 1995, Mansfield and Miyasaki 1993, Moseley 1992).

More Information

For more information, please contact:
       The Nature Conservancy of Idaho
       Box 165
       Sun Valley, ID
       (208)726-3007 

or contact:
       Idaho Conservation Data Center
       600 South Walnut, P.O. Box 25
       Boise, ID
       (208)344-9273

or email:
       mjankovs@idfg.state.id.us

References

Frest, T. R. 1994. Southern Idaho springsnail sites. Data records from Deixis Consultants. Seattle, Washington. 46 pp.

Mansfield, D. H., and H. Miyasaki. 1993. Analysis of the habitat requirements of SENSITIVE INFORMATION Primula alcalina. Challenge Cost Share Project, Albertson College of Idaho and Salmon District, Bureau of Land Management. 84 pp.

Moseley, R. K. 1992. Ecological and floristic inventory of Birch Creek Fen, Lemhi and Clark Counties, Idaho. Cooperative Challenge Cost-share Project, Targhee National Forest, Salmon District BLM, and Idaho Conservation Data Center, Idaho Department of Fish and Game. 29 pp.

Moseley, R. K. 1995. Demographic monitoring of Primula alcalina (alkali primrose) SENSITIVE INFORMATION: 1991-1994. Conservation Data Center, Idaho Dept. of Fish and Game. 27 pp. plus appendices.