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Swan River
Swan River
Swan River Oxbox map1
Preserve location
Swan River Oxbox map1
Location close-up

Swan River Oxbow Preserve - Swan Valley, Montana

The Preserve

Between the Swan Range to the east, and the Mission Mountains to the west, the Swan River flows through a beautiful valley. In 1986 The Nature Conservancy purchased 392 acres of this valley, creating the Swan River Oxbow Preserve. The preserve derives its name from a long, curving oxbow in which the Swan River used to flow. The oxbow is home to a variety of wetland communities, many species of birds and numerous rare plants including the threatened Howellia aquatilis. Historically, portions of this land served as a homestead site and supported such activities as farming, logging, grazing and even a muskrat farm. The Nature Conservancy is proud of the Swan River Oxbow Preserve and is committed to understanding and protecting the mosaic of plant communities, and the interaction of water, wildlife and land.

The Essential Element

Water is the key to understanding the Swan River Oxbow Preserve. Most of the preserve lies within a delta formed by the Swan River as it flows north to Swan Lake. The water table is high throughout the preserve due to the flooding of the river and a system of perennial springs and seeps along the eastern border of the preserve. Hydrologic studies show that the high quality water in the preserve originates as snowmelt from the Swan and Mission ranges. Water enters the preserve from different sources depending on the time of the year. In late spring and early summer, when the river is high, water flows through the river bed and charges the oxbow pond. In late summer through early spring, water from Lost Creek radiates into the limestone till beneath the preserve. Whether from the river or underground sources, this essential element feeds the meadows, marshes, forests and perennial springs of the preserve.

Wetland Communities

Water moving through the Swan River Oxbow Preserve supports an amazing variety of wetland communities. Spruce forest predominates along the southern boundary. A complex of sedge fen and birch carr communities lies adjacent to the spring system. To the west, cottonwood forest dominates the area around the aquatic oxbow. In addition, much of the northwest portion of the preserve is covered by marsh which is flooded throughout most of the growing season.

The Nature Conservancy has identified five rare plant populations and two rare lichens within the variety of wetland communities of the Swan River Oxbow. These discoveries inspired the Conservancy to protect these plants and the habitat each requires. Round-leafed pondweed (Potamogeton obtusifolious) grows in the oxbow and adjacent ponds. Northern bastard toadflax (Geocaulon lividum) inhabits the wet spruce forest. Buchler fern (Dryopteris cristata) is found where carr vegetation and spruce forest intermingle. Small yellow lady’s slipper (Cyprepedium calceolus) grows on the preserve.

Federally listed as a threatened species, water howellia (Howellia aquatilis) is especially significant. Howellia is thought to be extinct in California and Oregon and is threatened in Washington, Idaho and Montana. On the preserve howellia grows in the marshy areas next to the oxbow. An annual plant with white flowers, howellia requires very specific conditions for its survival. The plant has flaccid stems and must be submerged in water to grow and reproduce. Its seeds, however, will not germinate under water. Therefore, howellia only grows and reproduces in ponds that are flooded in the spring, but become dry by late summer or fall. Given these and other habitat requirements, howellia is sensitive to periods of prolonged climatic extremes. If conditions are too wet, the seeds will not germinate. In drought conditions the plant will not grow. Though howellia populations fluctuate with changes in the climate, it is estimated that the Swan River Oxbow Preserve supports approximately 5,000 plants, thanks in part to the different drying regimes found across the preserve. This population, however, is extremely sensitive to climatic change, soil conditions and disturbance.

Wildlife Habitat

The Swan River Oxbow Preserve is very important wildlife habitat. Grizzly bears use the preserve as a corridor between mountain ranges and feed on the thorn apples in the river valley. Bald eagles and osprey roost in the trees and feed along the river. Elk, moose and white-tailed deer may also be found on the preserve.

Various aquatic birds are drawn to the water systems of the preserve, including the common loon, mallard, cinnamon teal, ring-necked duck, common goldeneye and spotted sandpiper.

Since 1989 the Swan River Oxbow Preserve has been the site of a bird banding station. Under the Monitoring Avian Productivity and Survivorship program (MAPS), volunteers use mist nets to catch and band such neotropical migrants as the western tanager, Swainson’s thrush, red-eyed vireo and Lincoln’s sparrow. Through this research The Nature Conservancy hopes to contribute to the understanding of bird population trends worldwide.

Getting to the Preserve

The Swan River Oxbow Preserve is located 2.5 miles south of Swan Lake. From Highway 83 go west on Porcupine Road for 1/4 mile. A road on the right with a directional sign will lead you to a parking area and kiosk at the trail head.

Planning Your Visit

The Sally Tollefson Memorial Trail winds through the Swan River Oxbow Preserve. The trail was made possible by a gift from the Tollefson family and the combined efforts of The Nature Conservancy, U.S. Forest Service, the U.S. Fish and Wildlife Service and the Montana Conservation Corps.

· Protect yourself against mosquitoes in the spring and summer months.

· Also in the spring and early summer months bring hip boots or waders.

· Bring your bird and plant books, as there is much to see! And the plant identification plaques along the trail will help you.

· Do not travel alone through the preserve.

· Please stay on the trail. This is a sensitive area with special plant communities, an ongoing bird banding project and deep springholes.

· Warning: "Be Bear Aware" while hiking the trail. Please don’t hike the trail between mid-April and mid-June. These are the months when grizzly and black bears are most frequently in the area.

· Please report any bear activity (sightings, tracks, scat) to the U.S. Forest Service, Swan Lake District at (406) 837-5081.