Rare animals
Find rare and non-game animals.
Rare plants
Learn about plants on the Natural Heritage Working List.
Rare lichens
Discover Wisconsin's lichens.
Natural communities
Explore Wisconsin's natural communities.
Other features
Discover unique resources.
Contact information
For information on Wisconsin's natural communities, contact:
Ryan O'Connor
Natural Heritage Inventory Ecologist

Warmwater rivers


General natural community overview

Warmwater rivers are flowing waters with maximum water temperatures typically greater than 25 degrees Celsius. They usually have watershed areas greater than 500 square miles and mean annual flow rates of more than 200 cubic feet per second. Warmwater rivers occur statewide and include very large rivers such as the Mississippi, Wisconsin, Chippewa, Fox, Wolf, and Rock, as well as smaller rivers such as the Sugar, Baraboo, Milwaukee, Flambeau, and Yellow. A rich fish fauna, dominated by warmwater species in the Cyprinidae, Catostomidae, Ictaluridae, Centrarchidae, and Percidae families, occurs in these rivers.

Natural, periodic flood flows, most often driven by spring snow melt and rains, are important to the health of floodplain forests and wetlands, and to the maintenance of self-sustaining populations of wetland-spawning fish like walleye and northern pike. The aquatic life dependent upon these rivers and their floodwaters also support a variety of mammalian and avian species. Free-flowing, undammed rivers are a critical factor in the existence and perpetuation of widely distributed populations of certain species, especially sturgeon and several mollusk species that require a far-ranging fish host to complete their life cycle. Dams established for a variety of purposes (power generation, navigation, flood control, and recreation) caused noticeable declines in some mollusks by blocking the movement of their fish hosts.

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

Hairy-necked Tiger BeetleCicindela hirticollis hirticollis3
Sandy Stream Tiger BeetleEllipsoptera macra3
A Predaceous Diving BeetleLioporeus triangularis2
A Predaceous Diving BeetleNeoporus hybridus2
A Riffle BeetleStenelmis quadrimaculata2
A Riffle BeetleStenelmis musgravei2
A Riffle BeetleStenelmis fuscata2
A Riffle BeetleStenelmis antennalis2
Douglas Stenelmis Riffle BeetleStenelmis douglasensis2
Knobel's Riffle BeetleStenelmis knobeli2

Black-crowned Night-HeronNycticorax nycticorax2
Great EgretArdea alba2
Yellow-crowned Night-HeronNyctanassa violacea2
American Black DuckAnas rubripes1
Common NighthawkChordeiles minor1
Peregrine FalconFalco peregrinus1
Purple MartinProgne subis1
Red-shouldered HawkButeo lineatus1

A Humpless Casemaker CaddisflyBrachycentrus lateralis2

Dragonflies and damselfliesScore
Extra-striped SnaketailOphiogomphus anomalus3
Royal River CruiserMacromia taeniolata3
Smoky RubyspotHetaerina titia3
St. Croix SnaketailOphiogomphus susbehcha3
Slaty SkimmerLibellula incesta2
Double-striped BluetEnallagma basidens1
Pronghorn ClubtailGomphus graslinellus1
Sioux (Sand) SnaketailOphiogomphus smithi1

Black BuffaloIctiobus niger3
Black RedhorseMoxostoma duquesnei3
Blue SuckerCycleptus elongatus3
Bluntnose DarterEtheostoma chlorosoma3
Crystal DarterCrystallaria asprella3
Gilt DarterPercina evides3
Gravel ChubErimystax x-punctatus3
Lake SturgeonAcipenser fulvescens3
Mud DarterEtheostoma asprigene3
PaddlefishPolyodon spathula3
Redfin ShinerLythrurus umbratilis3
River RedhorseMoxostoma carinatum3
Shoal ChubMacrhybopsis hyostoma3
GoldeyeHiodon alosoides2
Pallid ShinerHybopsis amnis2
Starhead TopminnowFundulus dispar2
American EelAnguilla rostrata1
Lake ChubsuckerErimyzon sucetta1
Least DarterEtheostoma microperca1
Skipjack HerringAlosa chrysochloris1

Grasshoppers and alliesScore
Seaside GrasshopperTrimerotropis maritima2
Gladston's Spur-throat GrasshopperMelanoplus gladstoni1

Big Brown BatEptesicus fuscus3
Eastern PipistrellePerimyotis subflavus3
Little Brown BatMyotis lucifugus3
Northern Long-eared BatMyotis septentrionalis2
Silver-haired BatLasionycteris noctivagans2
Water ShrewSorex palustris1

A Common Burrower MayflyPentagenia vittigera3
A Flat-headed MayflySpinadis simplex3
Fox Small Square-gilled MayflyCercobrachys fox3
Pecatonica River MayflyAcanthametropus pecatonica3
Wisconsin Small Square-gilled MayflyCercobrachys lilliei3
A Brush-legged MayflyHomoeoneuria ammophila2
A Flat-headed MayflyMacdunnoa persimplex2
A Small Minnow MayflyParacloeodes minutus2
Winnebago Small Square-gilled MayflyCercobrachys winnebago2
A Cleft-footed Minnow MayflyMetretopus borealis1
A Flat-headed MayflyMaccaffertium pulchellum1
A Spiny Crawler MayflyDrunella cornuta1
A Spiny Crawler MayflyEurylophella aestiva1
American Sand Burrowing MayflyDolania americana1

Mussels and clamsScore
BuckhornTritogonia verrucosa3
ButterflyEllipsaria lineolata3
EbonyshellFusconaia ebena3
Elephant EarElliptio crassidens3
ElktoeAlasmidonta marginata3
FawnsfootTruncilla donaciformis3
Flat FloaterAnodonta suborbiculata3
Higgins EyeLampsilis higginsii3
MapleleafQuadrula quadrula3
MonkeyfaceQuadrula metanevra3
Purple WartybackCyclonaias tuberculata3
Rock PocketbookArcidens confragosus3
SheepnosePlethobasus cyphyus3
SnuffboxEpioblasma triquetra3
SpectaclecaseCumberlandia monodonta3
WartybackQuadrula nodulata3
WashboardMegalonaias nervosa3
Winged MapleleafQuadrula fragosa3
Yellow & Slough SandshellsLampsilis teres3
EllipseVenustaconcha ellipsiformis2
Salamander MusselSimpsonaias ambigua2
Slippershell MusselAlasmidonta viridis2

QueensnakeRegina septemvittata3
Smooth SoftshellApalone mutica3
Wood TurtleGlyptemys insculpta3
Blanding's TurtleEmydoidea blandingii2
Eastern MassasaugaSistrurus catenatus2
Plains GartersnakeThamnophis radix1

A Common StoneflyAttaneuria ruralis2

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
Callitriche hermaphroditica Autumnal Water-starwort 2
Nuphar advena Yellow Water Lily 2
Sagittaria montevidensis ssp. calycina Long-lobed Arrowhead 3
Stuckenia filiformis ssp. occidentalis Slender Pondweed 3


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

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




Slackwater Cove, Black River, Jackson County.

Photo by Eric Epstein.


Slough in the lower Wolf River floodplain, Outagamie County.

Photo by Eric Epstein.


Large silver maples along the Sugar River. The understory is dominated by the invasive reed canary grass.

Photo by Drew Feldkirchner.


The Peshtigo River near Spring Rapids. Water flow is controlled by the dam upstream.

Photo by Drew Feldkirchner.


Lower Chippewa River, Dunn County.

Photo by W.A. Smith.

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: Wednesday, June 16, 2021