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Contact information
For information on Wisconsin's natural communities, contact:
Ryan O'Connor
Natural Heritage Inventory Ecologist

Lake--Large, Shallow, Hard - Very Hard (marl), Drainage


General natural community overview

Lakes that are Large (>10 acres), Shallow (< 18 feet), Hard or Very Hard (alkalinity >50ppm and >100 ppm often causing a 'marl' or turquoise color), and Drainage (have both an inlet and outlet, and the main water source is from streams).

Similar to soft water shallow drainage lakes, the submergent community of this lake type is often dominated by coon-tail (Ceratophyllum demersum), water-milfoils (Myriophyllum spp.), common waterweed (Elodea canadensis), and naiads (Najas spp.). However, muskgrasses (Chara spp.) that thrive in hard water are some of the most abundant species of aquatic plant in this lake type. Floating lilies (Nymphaea odorata and Nuphar variegata) occur near the shoreline in most examples. Fish species in headwater drainage lakes include northern pike, golden shiner, blacknose shiner, blackchin shiner, black bullhead, yellow bullhead, bluegill, largemouth bass, black crappie, and Johnny darter. Lowland drainage lakes within this type have the same fish associates, plus brook silverside, though the Johnny darter does not favor lakes that are very hard.

Rare animals

Species of Greatest Conservation Need

Wisconsin Wildlife Action Plan graphic

The following Species of Greatest Conservation Need are listed according to their level of association with the natural community type, based on the findings in Wisconsin's 2015 Wildlife Action Plan.

Scores: 3 = high association, 2 = moderate association, and 1 = low association. See the key to association scores for complete definitions.

Blanchard's Cricket FrogAcris blanchardi3
Mink FrogLithobates septentrionalis3
Pickerel FrogLithobates palustris2

A Crawling Water BeetleHaliplus apostolicus2
A Predaceous Diving BeetleLiodessus obscurellus2
A Riffle BeetleStenelmis quadrimaculata2
Robust Dubiraphian Riffle BeetleDubiraphia robusta2

Black TernChlidonias niger2
Common GoldeneyeBucephala clangula2
Purple MartinProgne subis2
Common TernSterna hirundo1
Forster's TernSterna forsteri1

Dragonflies and damselfliesScore
Alkali BluetEnallagma clausum3
Lake EmeraldSomatochlora cingulata3
Lilypad ForktailIschnura kellicotti3
Mottled DarnerAeshna clepsydra3
Pronghorn ClubtailGomphus graslinellus3
Slaty SkimmerLibellula incesta3
Spatterdock DarnerRhionaeschna mutata3
Unicorn ClubtailArigomphus villosipes3
Spangled SkimmerLibellula cyanea2
Double-striped BluetEnallagma basidens1

Lake SturgeonAcipenser fulvescens3
Pugnose ShinerNotropis anogenus3
Lake ChubsuckerErimyzon sucetta2
Least DarterEtheostoma microperca2
Longear SunfishLepomis megalotis2
Starhead TopminnowFundulus dispar2
Redfin ShinerLythrurus umbratilis1

Big Brown BatEptesicus fuscus3
Little Brown BatMyotis lucifugus3
Northern Long-eared BatMyotis septentrionalis2
Silver-haired BatLasionycteris noctivagans2
Eastern PipistrellePerimyotis subflavus1
Water ShrewSorex palustris1

Blanding's TurtleEmydoidea blandingii3
Eastern RibbonsnakeThamnophis sauritus1

Please see Section 2. Approach and Methods of the Wildlife Action Plan to learn how this information was developed.

Rare plants

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

Scores: 3 = "significantly associated," 2 = "moderately associated," and 1 = "minimally associated."
Scientific Name Common Name Score
Eleocharis robbinsii Robbins' Spike-rush 1
Nuphar microphylla Small Yellow Pond Lily 2
Schoenoplectus torreyi Torrey's Bulrush 1
Utricularia resupinata Northeastern Bladderwort 1


The following Ecological Landscapes have the best opportunities to manage for , based on the Ecological Landscapes of Wisconsin Handbook.

Ecological LandscapeOpportunity
North Central ForestMajor
Central Sand HillsImportant

Major (3 on map)
A major opportunity for sustaining the natural community in the Ecological Landscape exists, either because many significant occurrences of the natural community have been recorded in the landscape or major restoration activities are likely to be successful maintaining the community's composition, structure, and ecological function over a longer period of time.

Important (2 on map)
Although the natural community does not occur extensively or commonly in the Ecological Landscape, one to several occurrences do occur and are important in sustaining the community in the state. In some cases, important opportunities may exist because the natural community may be restricted to just one or a few Ecological Landscapes within the state and there may be a lack of opportunities elsewhere.

Present (1 on map)
The natural community occurs in the Ecological Landscape, but better management opportunities appear to exist in other parts of the state.


Wisconsin Wildlife Action Plan graphic

What are conservation actions?

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.

Threats/issues and conservations actions for natural communities




Mud Lake, marsh, sedge meadow, cedar swamp. Northeastern Door Peninsula, north of Baileys Harbor.

Photo by Mike Mossman.


Photo by Paul Skawinski.

Note: photos are provided to illustrate various examples of natural community types. A single photograph cannot represent the range of variability inherent in a given community type. Some of these photos explicitly illustrate unusual and distinctive community variants. The community photo galleries are a work in progress that we will expand and improve in the future.

Last revised: Tuesday, August 30, 2022