Establishment of the RNA

The 3,645 acre Lost Water Canyon RNA was established in 1994. In 2004 it was reduced to 2,809 acres to accommodate the Pryor Mountain Wild Horse Range (PMWHR), a loss of 836 acres or 23%. This included a disturbing reduction from 650 acres to only 155 acres of the "subalpine grassland vegetation type" represented in the RNA - a loss of 495 acres or 76% of the 1994 designation.

The following is composed of quotations excerpted from Custer National Forest documents used to designate the Lost Water Canyon RNA. The bold headings have been added.

What is an RNA?

Research Natural Areas are part of a national network of ecological areas designated in perpetuity for research and education and/or to maintain biological diversity on National Forest System lands. Principal goals of the RNA system are to provide for long-term natural ecosystems as sources of baseline data, against which the effects of human activities in similar environments can be measured, to provide sites for education and research on natural processes in undisturbed ecosystems, and to provide gene pool reserves for a full array of plant and animal species, including both common and rare, within naturally functioning environments.

Why Lost Water Canyon?

The Pryor Mountains are a floristically rich, isolated mountain range composed primarily of limestone, and surrounded by lower elevation areas of the Northern Great Plains and Bighorn Basin. Within this setting the RNA encompasses essentially an entire watershed largely defined by a steep-walled limestone canyon nearly one mile across and about six miles long. A wide elevation gradient of nearly 3,500 feet occurs in the RNA, and habitats range from subalpine forest and grassland communities to montane Douglas-fir forests to low-elevation riparian areas.

The area spans a wide range of environments, ranging from a wind-swept subalpine plateau, to montane conifer forest, to riparian areas dominated by deciduous species. Much of the canyon is bordered by limestone cliffs and scree slopes. Lost Water Creek is intermittent except for about one mile in the central part of the canyon. There, mossy springs and seeps supply enough water to maintain a small stream.

Lost Water Canyon RNA serves as a baseline area for monitoring long-term ecological changes, especially in those communities dominated by Douglas-fir, found near its eastern limit, and in subalpine grasslands. The RNA serves as a nearly intact watershed for study of limestone bedrock hydrology. The RNA also provides a protected site for long-term monitoring of a large population of the regionally endemic and sensitive plant species, Shoshonea pulvinata, known only from the Pryor and Beartooth Mountains and portions of northwestern Wyoming.

A large population of approximately 1500 plants of shoshonea (Shoshonea pulvinata), a Forest Service sensitive species, is known from the area. This species, a regional endemic and the sole species of its genus, is also designated as a Category 2 candidate for federal listing as a threatened species by the US Fish and Wildlife Service. Shoshonea is known in only three locations in Montana. Fewer than twelve locations globally are known for this species.

According to the Forest Service Manual Section 4063 - RESEARCH NATURAL AREAS.

Definitions.
1. Research Natural Area. "A physical or biological unit in which current natural conditions are maintained insofar as possible. These conditions are ordinarily achieved by allowing natural physical and biological processes to prevail without human intervention.”

Objectives. The objectives of establishing research natural areas are to:


1. Preserve a wide spectrum of pristine representative areas that typify important forest, shrubland, grassland, alpine, aquatic, geological, and similar natural situations that have special or unique characteristics of scientific interest and importance that, in combination, form a national network of ecological areas for research, education, and maintenance of biological diversity.

2. Preserve and maintain genetic diversity.


3. Protect against serious environmental disruptions.


4. Serve as reference areas for the study of succession.


5. Provide onsite and extension educational activities.

6. Serve as baseline areas for measuring long-term ecological changes.


7. Serve as control areas for comparing results from manipulative research.


8. Monitor effects of resource management techniques and practices.