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Research Natural Area

Brunsweiler River and Mineral Lake

[photo:] The Brunsweiler River was designated as a Wild River by the state of Wisconsin in 2009. Photo by Steven SpickermanState: Wisconsin

County: Ashland

Forest: Chequamegon

District: Great Divide

Established: 2014

Acres: 962 acres

Description: Brunsweiler River and Mineral Lake Research Natural Area (RNA) occurs on a dramatic bedrock dominated landscape with high quality aquatic resources, old growth upland forest remnants, and rare plant and animal occurrences. It is large in size and connected to other protected areas with a similar lack of recent disturbance. This unique area contains a stretch of the Brunsweiler River, designated as a Wild River by the state of Wisconsin since 2009. Primary features include a large block of northern mesic forest, northern hardwood swamp, northern sedge meadow, shaded and open cliffs, and a scenic gorge carved by the Brunsweiler River. The site harbors rare plants and animals with conifers growing on undisturbed cliffs that may represent an ancient forest.

Ecological Information

Physical and Climatic Conditions:

Nearest weather station, with distance and direction from RNA: The Mellen 4 NE weather station is 8 miles east of the RNA.

Annual precipitation (type, seasonal distribution): Annual precipitation averages 33.4 inches (84.7 cm), 63.8% of which falls between April and September. Average seasonal snowfall is 102.2 inches (2,591 cm).

Maximum and minimum temperatures:  Temperatures average 56.3° F between April and September and between October and March temperatures average 22.6° F. Daily maximum temperatures average 50.3° F and daily minimum temperatures average 28.6° F.

Elevation: Elevations range from 1,340 feet (408 meters) to 1,510 feet (460 meters) above sea level.

Geology and Soils: The majority of the RNA has bedrock between 50 feet and 5 feet below the land surface. Geomorphologic processes include till deposition and water erosion. Most of the RNA contains hilly to steep well drained soils that correspond to the Gogebic-Michigamme-Rock outcrop complex. Areas of moderately well drained soils are found intermingled with well drained soils. Prominent bedrock outcrops are common. The soils are typically characterized by fine sand or very fine sandy loam surface over bedrock. An estimate of 2-10 percent of the surface area is bedrock outcrops.

Aquatic Features: The 225-acre (91 ha) Mineral Lake is a soft water drainage lake. Draining the west central section of the county, the Brunsweiler River has several natural glacial lakes along its course and feeders. Its principal water tributaries are Spider Creek, Hell Hole Creek, Camp Six Creek, and several other unnamed feeder streams.

Ecological Classification & Inventory

Section: Southern Superior Uplands (212J)

Subsection(s): Gogebic/Penokee Iron Range (212Jb) and Venegar Moraines (212Jc)

Landtype Association(s): Gogebic/Penokee Iron Range (Jc01) and Valhalla/Marinesco Moraines (Jc05)

Plant Communities:

Community Type
Kotar Habitat
US National
Vegetation Classification
Northern wet-mesic forest TMC hemlock, yellow birch Tsuga canadensis - (Betula alleghaniensis) Forest CEGL002598
Northern mesic forest ATM hemlock, sugar maple, yellow birch Tsuga canadensis - Acer saccharum - Betula alleghaniensis Forest CEGL005044
Northern mesic forest AOCa Sugar maple, yellow birch, basswood (the most common community in RNA) Acer saccharum - Betula alleghaniensis - (Tilia americana) Forest CEGL002457
Acer saccharum - Fraxinus americana - Tilia americana / Acer spicatum / Caulophyllum thalictroides Forest CEGL005008
Northern sedge meadow
small areas
  Carex stricta, Carex oligosperma, forbs Carex stricta - Carex spp. Herbaceous Vegetation CEGL002258 or Calamagrostis canadensis - Eupatorium maculatum Herbaceous Vegetation CEGL005174
Bracken grassland   bracken fern, grasses, forbs Pinus strobus - Populus tremuloides - (Acer rubrum) / Pteridium aquilinum Forest CEGL005563
these are small frost pockets within this association
Northern mesic forest ATM/ATD quaking aspen (succeeding to mixed hardwood forest) Populus tremuloides - Betula papyrifera / Acer saccharum - Mixed Hardwoods Forest
Talus Forest TMC yellow birch, mountain maple, white cedar Thuja occidentalis - Betula alleghaniensis Forest CEGL002450
Northern wet forest   black ash, white cedar, hemlock Fraxinus nigra - Mixed Hardwoods - Conifers / Cornus sericea / Carex spp. Forest CEGL002105
Northern hardwood swamp   black ash, yellow birch, red maple similar to above
Dry Cliff
(open, xeric, vertical cliff)
  lichen, red pine, white pine Igneous - Metamorphic Northern Dry Cliff Sparse Vegetation CEGL002300
Moist Cliff
(shaded, wet, vertical cliff)
  hemlock, white cedar, Polypodium vulgare, Dryopteris spp. Tsuga canadensis - (Betula alleghaniensis) Forest CEGL002598
Shrub Carr   willow/red-osier dogwood/meadow sweet Salix sericea Shrubland CEGL006305
Open bog   leatherleaf, Labrador tea, bog laurel Chamaedaphne calyculata - Ledum groenlandicum - Kalmia polifolia Bog Dwarf-shrubland CEGL005278
Northern sedge meadow   (blue joint grass/tussock sedge) Calamagrostis canadensis - Eupatorium maculatum Herbaceous Vegetation CEGL005174
Ephemeral ponds   mostly unvegetated (Carex spp, Sium suave) undetermined
River   Sparganium, Nuphar, Sagittaria Nymphaea odorata - Nuphar variegata Herbaceous Vegetation CEGL002562 (CEGL006086)


Common Fauna: Fauna typical of mesic northern forest and riverine communities is expected in the RNA.

Common Fish Species: Walleye, musky, and smallmouth bass are the most common species found in Mineral Lake, followed by largemouth bass, white sucker, bluegill, black crappie, yellow perch, and rock bass. Several small minnow species (Iowa Darter and Johnny Darter) are also found in Mineral Lake. Between Mineral and Beaverdam lakes, the Brunsweiler River supports a warmwater fish community that includes species that are found in Mineral Lake as well as additional species of minnows. 

Common Shrub Species: American fly honeysuckle (Lonicera canadensis) is the dominant shrub. Leatherwood (Dirca palustris), Canada yew (Taxus canadensis), and alternate-leaved dogwood (Cornus alternifolia) are also present. 

Common Herbaceous Species: Common herbaceous plants include club-moss (Lycopodium, Huperzia spp.), sessile-leaved bellwort (Uvularia sessilifolia), large-flowered trillium (Trillium grandiflorum), rosy twisted stalk (Streptopus lanceolatus), dutchman’s breeches (Dicentra cucullaria), baneberry species (Actaea sp), Aralia species, mountain wood sorrel (Oxalis montana), and three-leaved goldthread (Coptis trifolia).

Complete Plant List:  Brunsweiler River and Mineral Lake Plant List

Potential Research Topics: Potential research topics could focus on the rare plants found in the RNA, old northern white cedar (Thuja occidentalis) and Canada yew (Taxus canadensis) growing on protected cliff faces, unique geologic features, or stream ecology. Surveys of taxa not yet recorded include amphibians, reptiles, invertebrates, bats, and other mammals.

Related Website:

Brunsweiler River and Mineral Lake Natural Areas Program 

Related Reports and Publications:

Brzeskiewicz, Marjory.  2013.  Establishment Record for Brunsweiler River and Mineral Lake Research Natural Area.  Chequamegon-Nicolet National Forest, Great Divide District, Ashland County, Wisconsin.    44 pp.

Crow, T.R.; Cleland, D.T.; Donner-Wright, D.M.; Gustafson, E.J.; Lytle, D.E.; Parker, L.R.; Probst, J.; Schulte, L.A.; Sturtevant, B.R.; Zollner, P.A. 2006. Managing midwestern landscapes using ecological principles. In Chen, J.; Saunders, S.C.; Brosofske, K.D.; Crow, T.R. eds. Linking ecology to landscape hierarchies. Nova Sciences Publishers, New York. p. 251-281.

Curtis, J. T. 1959. Vegetation of Wisconsin. University of Wisconsin Press, Madison WI.
Fields, D.M.  1997.  Chequamegon-Nicolet National Forest Research Natural Area Evaluation Report: Bear Creek.  Unpublished Forest Service report on file in Park Falls Headquarters.

Kotar, J.; Kovach, J.; Burger, T.  2002.  A Guide to Forest Communities and Habitats of Northern Wisconsin (2nd edition).  Madison: University of Wisconsin, Department of Forest Ecology and Management.

NGDC. National Geographic Data Committee. 2012. National Vegetation Classification Standard (NVCS). Available online: Accessed 2012.

Vora, R. S. 1997. Developing programs to monitor ecosystem health and effectiveness of management practices on Lakes States National Forests, USA. Biol. Conserv. 80:289-302

Last Modified: February 23, 2017