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For information on State Natural Areas, contact:
Thomas Meyer
Natural areas conservation biologist

Wisconsin State Natural Areas Program Mary Lake (No. 264)

State Natural Area program graphic

Overview

Location

Vilas County. T44N-R5E, Section 32 NW¼. 44 acres.

Description

Description

The 3-acre Mary Lake is one of very few known meromictic lakes in Wisconsin. Meromixis, the permanent thermal stratification of the water, results from the lake having an extremely small surface area in comparison to its depth. Mary Lake has a small 3-acre surface area but is disproportionately very deep - 67 feet. Due to the extreme relative depth in relation to surface area, watershed soils, and its protection from surrounding uplands, Mary Lake never "turns over" and circulates as the water temperature changes in the spring and fall as is typical of most other Wisconsin lakes. Instead, the lake stays stratified creating unusual chemical and biological layers. Internationally known to limnologists, extensive research has been conducted on the physical, biological, and chemical properties of the lake since the 1920's. Mary Lake is second in a chain of five interconnected lakes and is primarily fed by land runoff and inflow from a small stream that connects Mary Lake to nearby Lake Rose. Mary Lake is nestled in a small basin and surrounded by dense forest, which helps shelter the lake from wind action. The surrounding forest is primarily second-growth northern hardwood forest, swamp hardwoods, and swamp conifers. Dominant species include white cedar, spruce, white pine, and balsam fir. Mary Lake is owned by the DNR and was designated a State Natural Area in 1999.

Access

Driving directions

From the intersection of County Highways J and W south of Winchester, go west on Highway J 1.6 miles, then go north on S. Turtle Lake Road 2.8 miles into Winchester. Go north on Beaver Lake Road and continue on Old County "O" about 2.4 miles, then go west on Adelade Road 0.3 mile to an access road.

Ownership

Mary Lake is owned by:

  • WDNR

Maps

The DNR's state natural areas program is comprised of lands owned by the state, private conservation organizations, municipalities, other governmental agencies, educational institutions and private individuals. While the majority of SNAs are open to the public, access may vary according to individual ownership policies. Public use restrictions may apply due to public safety, or to protect endangered or threatened species or unique natural features. Lands may be temporarily closed due to specific management activities. Users are encouraged to contact the landowner for more specific details.

The data shown on these maps have been obtained from various sources, and are of varying age, reliability, and resolution. The data may contain errors or omissions and should not be interpreted as a legal representation of legal ownership boundaries.

Management

Site objectives

Manage the site as a meromictic lake, as an aquatic reserve, and as an ecological reference area. Natural processes will determine the structure of the lake and surrounding forest. Provide opportunities for research and education on the highest quality native ecosystems.

Management approach

The native species are managed passively, which allows nature to determine the ecological characteristics of the site. Exceptions include control of invasive plants and animals, maintenance of existing facilities, and access to suppress fires. Salvage of trees after a major wind event is not considered compatible with management objectives.

Site-specific considerations

  • Roadside easement area and utility corridor may be managed sporadically by township and utility.
  • Ditches may be plugged with woody materials during dry ditch periods to restrict flow of different water into Mary Lake.

Recreation

Very few State Natural Areas have public facilities, but nearly all are open for a variety of recreational activities as indicated below. Generally, there are no picnic areas, restrooms, or other developments. Parking lots or designated parking areas are noted on individual SNA pages and maps. Trails, if present, are typically undesignated footpaths. If a developed trail is present, it will normally be noted on the SNA map and/or under the "Access" tab. A compass and topographic map or a GPS unit are useful tools for exploring larger, isolated SNAs.

Allowable activities

In general, the activities listed below are allowed on all DNR-owned SNA lands. Exceptions to this list of public uses, such as SNAs closed to hunting, are noted under the "Access" tab above and posted with signs on site.

  • Hiking
  • Fishing
  • Cross country skiing
  • Hunting
  • Trapping

Prohibited activities

  • Horseback riding
  • Rock climbing
  • Vehicles, including bicycles, ATVs, aircraft, and snowmobiles except on trails and roadways designated for their use
  • Collecting of animals, non-edible fungi, rocks, minerals, fossils, archaeological artifacts, soil, downed wood, or any other natural material, alive or dead. Collecting for scientific research requires a permit issued by the DNR
  • Collecting of plants including seeds, roots or other non-edible parts of herbaceous plants such as wildflowers or grasses
  • Camping and campfires
  • Geocaching

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For rules governing state-owned SNAs and other state lands, please consult Chapter NR 45 Wis. Admin. Code [exit DNR]

Last revised: Friday, November 14, 2014