BCNA Ecosystem Plan – North and South St. Vrain ECAs

(This is the third in a series of articles that explores the evolution of the Ecosystem Plan and the current status of the core preserves and habitat connectors.)

The largest foothills to montane Environmental Conservation Areas (ECAs) are centered on the North St. Vrain and South St. Vrain Canyons. At 34,500 acres and 21,800 acres respectively, they represent some of the finest roadless foothill habitat along the Front Range. Both areas contain old-growth ponderosa pine forests, elk winter concentration areas, golden eagle nest sites, and good habitat for mountain lion and black bear. The North St. Vrain is a bighorn sheep concentration area, a designated Wild Trout Stream, and contains a sizeable population of the rare plant Larimer aletes. Both ECAs contain imperiled plant communities comprised of foothill grass and shrub species that have been degraded over much of the West. 

During the mid-1980s conservation efforts focused on protecting these areas from additional degradation. A proposal to place a dam and reservoir along the North St. Vrain between North and South Sheep Mountains spearheaded an effort, largely through the work of BCNA’s Mike Figgs, to recognize the ecological importance of the canyon and to stop the potential of any new main stem dams on the creek. 

With this accomplished, BCNA worked towards protection of private lands within these areas. A major early success was convincing The Nature Conservancy to purchase Sheep Mountain Ranch, located in the heart of the North St. Vrain Canyon, until federal funds were found so the Forest Service could purchase the property. The 700-acre Riverside Ranch, located west of Coffintop Mountain, was deeded to Boulder County Open Space after the property owner transferred the development rights to a more acceptable receiving area. The Boulder County Land Trust was actively talking with a number of the large ranch owners in both of the canyons. In the end, Boulder County Open Space purchased conservation easements or outright fee title to these lands. Conservation easements were purchased on the Trevarton Ranch, located west of North Foothills Highway, and the Lillian Trevarton Ranch east of Meeker Park. The final pieces were the purchases of the Hall Ranch and Heil Valley Ranch. With these acquisitions, the lower portions of the North St. Vrain and South St. Vrain ECAs were protected. Boulder County has continued to fill in the gaps in these ECAs through the purchase of conservation easements and fee title interest.

The update of the Arapaho and Roosevelt National Forest Plan helped increase the protection of these areas. Much of the North St. Vrain ECA was designated as a Research Natural Area, while the Coffintop area of the North St. Vrain and the Central Gulch portion of the South St. Vrain were designated as Core Area. These designations increase the level of protection awarded these special canyons of north-central Boulder County.   

- Dave Hallock

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