Rat Lake Swamp – Popple River Headwaters Research Natural Area

Rat Creek, north of FR 2409; Photo by Steve Janke 1996, USDA Forest Service.

Eagle River-Florence
The most important features of Rat Lake Swamp - Popple River Headwaters RNA include an extensive wetland complex of black spruce-tamarack (Picea mariana- Larix laricina) and northern white cedar (Thuja occidentalis) swamp that provides good interior forest habitat for a number of rare plants and animals. Embedded in these wetlands are drumlinoid hills topped with good quality hardwood stands.    The southern portion borders a section of the Popple River flowing through conifer swamp as well as uplands.  The north end contains Rat Lake, a muck-bottomed hard-water seepage lake with a well-developed bog mat, surrounded by an old-growth eastern hemlock and hardwood forest containing a large component of super-canopy white pine (Pinus strobus).  The RNA supports numerous orchid species, and rare birds and plants.

Ecological Information

Physical and Climatic Conditions

Nearest weather station, with distance and direction from RNA:
Laona 6 SW (station no. 474582)  is about 22 mi (35 km) south of the RNA.
Annual precipitation (type, seasonal distribution) :
Annual precipitation averages 32 inches (81 cm), 62% of which falls between April and September. Average seasonal snowfall is 73.5 inches (187 cm).
Maximum and minimum temperatures:
Daily summertime temperatures average 47.6° F; average daily maximum temperatures average 49.5° F. Average temperature in the winter is 23.2° F; average daily minimum temperatures average 29.3° F.
Elevations range from 1,570 feet (479 m) to 1,660 feet (488 m) MSL.
Geology and Soils:
Bedrock of the RNA includes igneous, metamorphic, and volcanic rock. Bedrock is between 50 and 5 feet of the land surface. Geomorphologic processes include till deposition and glacial meltwater deposition. Several prominent glacial eskers rise 50 feet (15 m) or more above the surrounding level wetlands.
The soils of Rat Lake Swamp-Popple River Headwaters RNA are heterogeneous and include the Padus, Carbondale, Goodman, and Stambaugh series.
Aquatic Features:
This RNA protects an important headwater area of the Popple River, a designated State Wild River and a Class IIA and III trout stream.  Rat Lake in the northwest corner of the RNA is a shallow, 47-acre bog lake with wetlands surrounding most of its shoreline. Rat Creek is a slow-moving shallow creek that drains from Rat Lake south about three miles (5 km) into the Popple River on the southern boundary of the RNA. Several spring ponds occur in this extensive wetland community.

Ecological Classification & Inventory

Laurentian Mixed Forest Province, Northern Highland (212X)
Brule and Paint Rivers Drumlinized Ground Moraine (Xc)
Land Type Association(s):
Iron River/Argonne Drumlins (Xc01) and Argonne Outwash Plains (Xc02)
Plant Communities:

Curtis Community Type

Kotar Habitat Types

Dominant Species Initial US National Vegetation Classification

Northern mesic forest


eastern hemlock, sugar maple, yellow birch

Tsuga canadensis - Acer saccharum - Betula alleghaniensis Forest; CEGL005044

Northern mesic forest


sugar maple, basswood

Acer saccharum - Betula alleghaniensis - (Tilia americana) Forest; CEGL002457

Northern mesic forest


eastern hemlock, northern white cedar

Tsuga canadensis - (Betula alleghaniensis) Forest; CEGL002598 or CEGL005003

Northern wet-mesic forest


black ash, red maple

Acer rubrum - Fraxinus spp. - Betula papyrifera / Cornus canadensis Forest; CEGL002071

Northern wet-mesic forest


white cedar, balsam fir

Thuja occidentalis / Sphagnum; CEGL006007

Northern wet-mesic forest

TMC - wet

hemlock, white cedar

Tsuga canadensis - Betula alleghaniensis Saturated Forest; CEGL005003

Northern wet forest


black spruce, tamarack

Picea mariana - (Larix laricina) / Ledum groenlandicum / Sphagnum spp. Forest; CEGL005271

Alder thicket


speckled alder

Alnus incana Swamp Shrubland; CEGL002381

Open bog


leatherleaf, Labrador tea, bog laurel

Chamaedaphne calyculata - Ledum groenlandicum - Kalmia polifolia Bog Dwarf-shrubland; CEGL005278

Northern sedge meadow


Carex spp

Eastern North American Wet Meadow Group; G112

Lake shallow, hard-water, seepage bog lake -Rat Lake


not surveyed

not delineated

Stream- slow, hard, cold -Rat Creek


not surveyed

not delineated

River- slow, medium hard-water , cold -Popple River


not surveyed

not delineated

Complete Plant List

Common Shrub Species:
The shrub layer is poorly developed, with American fly honeysuckle (Lonicera canadensis) the most common.
Common Herbaceous Species:
The ground flora is well-developed, particularly on the drumlin tops, and includes lycopods (Lycopodium and Huperzia spp), wild sarsaparilla (Aralia nudicaulis), rosy twisted-stalk (Streptopus lanceolatus v. longipes), northern beech fern (Thelypteris phegopteris), yellow bluebead lily (Clintonia borealis), and mountain wood-sorrel (Oxalis montana).  Richer soils support wild ginger (Asarum canadense), bloodroot (Sanguinaria canadensis), blue cohosh (Caulophyllum thalictroides), and three species of the genus Botrychium.   Most notable are the numerous rare plants, including the state-endangered little goblin moonwort (Botrychium mormo) and good populations of orchid species present within the RNA.  A sedge-sphagnum-ericad mat is also well-developed and botanically rich; including numerous ericaceous species, orchids, sedges, and insectivorous plants.
Common Fauna:
Fish of the Popple River include brook trout (Salvelinus fontinalis), fifteen species of forage fish, and black bullhead (Ameiurus melas).  In addition to numerous song birds, waterfowl commonly observed include mallard (Anas platyrhynchos), American black duck (Anas rubripes), and common merganser (Mergus merganser).
Potential Research Topics:
Topics for study include wetland ecology, climate change, peatlands, rare plants, amphibians, bryophytes, and insects. 

Related link: Wisconsin State Natural Areas Program Rat Lake Swamp and Popple River

Related Reports and Publications

Anderson, Craig; Ayers, L.; Bergeson, T.  2006.  Biodiversity in selected natural communities related to global climate change, annual summary for 2006 submitted to Wisconsin Focus on Energy Environmental Research Program.  20 pp.

Brzeskiewicz, Marjory.  2014.  Establishment Record for Rat Lake Swamp- Popple River Headwaters Research Natural Area.  Chequamegon-Nicolet National Forest, Eagle River Ranger District, Forest County, Wisconsin.   45 pp.

Curtis, J. T. 1959. Vegetation of Wisconsin.  University of Wisconsin Press, Madison WI.

Howe, R.W.; Wolf, A.T. 2003. A Checklist of Birds in the Chequamegon-Nicolet National Forest. USDA Forest Service Publication, Park Falls, WI.

Howe, R.W.; Roberts, L.J. 2005. Sixteen Years of Habitat-based Bird Monitoring in the Nicolet National Forest. Pages 963-973 in Ralph, C.J. and T.D. Rich, editors. 2005. Bird Conservation Implementation and Integration in the Americas: Proceedings of the Third International Partners in Flight Conference. 2002 March 20-24; Asilomar, California, Volume 2. Gen. Tech. Rep. PSW-GTR-191. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; 643 p.

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: http://usnvc.org/explore-classification/ Accessed 2012.

Schulte, L.A.; Pidgeon, A.M.; Mladenoff, D.J. 2005. One-hundred-fifty years of change -in forest bird breeding habitat: Historical and current estimates of species distributions. Conservation Biology 19:144-156.

Last Modified: August 20, 2021