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- For information on Wisconsin's Ecological Landscapes, contact:
- Andy Stoltman
Southwest Savanna Ecological Landscape
Landscape at a Glance
|Physical & Biotic Environment|
1,950 square miles (1,248,126 acres); 3.5% of the land area of Wisconsin.
Typical of southern Wisconsin; the mean growing season is 153 days, mean annual temperature is 45.6 deg. F, mean annual precipitation is 35.2, and mean annual snowfall is 39.9 inches. However, the Southwest Savanna has the fourth longest growing season, the most precipitation, the third lowest snowfall, and second warmest January low temperature among Ecological Landscapes in the state. The climate tends to be warmer in the southwestern part of the state, which affects the ecology of the Southwest Savanna and also makes it suitable for most agricultural uses. 80% of this Ecological Landscape is devoted to row crops, small grains, and pastures.
The Southwest Savanna Landscape is underlain by sedimentary bedrock, especially dolomites and sandstones.
Geology & Landforms
The Southwest Savanna is part of Wisconsin's Driftless Area, a region that has not been glaciated for at least the last 2.4 million years. The topography is characterized by broad, open ridgetops, deep valleys, and steep, wooded slopes.
Soils on hilltops are silt loams mostly silt loams. In some areas soils are shallow, with bedrock or stony red clay subsoil very close to or at the surface. In other locales the ridgetops have a deep cap of loess-derived silt loam (these are the most productive agricultural soils). Valley soils include alluvial sands, loams, and occasionally, peats.
The drainage patterns of streams in the Southwest Savanna are dendritic, which is a pattern characteristic of unglaciated regions but absent or uncommon in most of Wisconsin. Flowing waters include warmwater rivers and streams, coldwater streams, and springs. Natural Lakes are virtually absent, though there are a few associated with the floodplains of the larger rivers. Natural lakes are rare but there are a few in the floodplains of the larger rivers, such as the Pecatonica. Impoundments and reservoirs have been constructed on some rivers and streams, and check dams have been built in ravines to hold storm and snow runoff.
Agricultural crops (corn, soybeans, small grains, hay) cover 70% of this Ecological Landscape, with lesser amounts of grassland (mostly pasture), forest, and residential areas. The major forest types are oak-hickory and maple-basswood. Prairie remnants of varying quality persist in a few places, mostly on rocky hilltops or slopes that are too steep to farm. Some pastures have never been plowed, and those that historically supported prairie may retain remnants of the former prairie flora. Pastures with scattered open-grown oaks still exist in some areas, mimicking oak savanna structure. A complement of native plants persists in some of these pastured savannas.
(based on data from Iowa, Grant, Lafayette, and Green counties)
123,899, 2.2% of the state total
39 persons/ sq. mile
Per Capita Income
Important Economic Sectors
Retail trade (15.2%); government (14.0); agriculture, fishing & hunting (13.8%); and manufacturing (non-wood) (9.1%) were the most important sectors in 2007 reflecting high dependence on retail trade, government and agriculture. Agriculture and residential development have the largest impact on the natural resources in the Ecological Landscape at this time.
About 96.5% of the land in the Southwest Savanna is privately owned while 3.5% belongs to state, county, or municipal governments. State-owned lands include Parks, Wildlife Areas, Fisheries Areas, Natural Areas, and one Recreation Area. These include Belmont Mound, New Glarus Woods, and Yellowstone Lake State Parks; part of Blue Mounds State Park; Browntown-Cadiz Springs State Recreation Area; Hardscrabble Prairie State Natural Area; Mount Vernon Creek State Fishery Area; and Yellowstone Lake State Wildlife Area. A map showing public land ownership (county, state, and federal) and private lands enrolled in the Forest Tax Programs in this Ecological Landscape can be found at the end of this chapter.
Other Notable Ownerships
The Wisconsin Chapter of The Nature Conservancy has several active projects here, including Thomson Memorial Prairie and Barneveld Prairie. Three chapters of The Prairie Enthusiasts (Southwest Wisconsin, Empire-Sauk, and Prairie Bluff) have been very active in this Ecological Landscape and have at least 10 projects underway in the Southwest Savanna. Pheasants Forever and the National Wild Turkey Federation are also very active in this Ecological Landscape.
|Considerations for Planning & Management|
The need for partnerships between government agencies, NGOs, and private individuals are critical as less than 1% of the Ecological Landscape is publicly owned. Coordinated management of large areas will be difficult because of ownership patterns and the prevalence of intensively used agricultural land. Remnant prairies and savannas are small and often isolated, but in a few areas there are opportunities to develop partnerships that will accommodate a mix of active cropland, pasture, conservation reserve program lands, and reserves that feature high quality prairie and savanna remnants or other habitats known to be especially important to rare or otherwise sensitive species, including streams. The Southwest Wisconsin Grassland and Stream Conservation Area, a cooperative project involving many public and private partners, encompasses one of the best locations to accomplish this and is an excellent place in which to focus some of the grassland protection efforts at larger scales.
Species of Greatest Conservation Need
The following species are listed according to their probability of occurring in the Southwest Savanna Ecological Landscape, based on the findings in the Wisconsin Wildlife Action Plan.
|Bell's Vireo||Vireo bellii||3|
|Brown Thrasher||Toxostoma rufum||3|
|Eastern Meadowlark||Sturnella magna||3|
|Field Sparrow||Spizella pusilla||3|
|Grasshopper Sparrow||Ammodramus savannarum||3|
|Henslow's Sparrow||Ammodramus henslowii||3|
|Northern Bobwhite||Colinus virginianus||3|
|Red-headed Woodpecker||Melanerpes erythrocephalus||3|
|Short-eared Owl||Asio flammeus||3|
|Upland Sandpiper||Bartramia longicauda||3|
|Vesper Sparrow||Pooecetes gramineus||3|
|Western Meadowlark||Sturnella neglecta||3|
|Willow Flycatcher||Empidonax traillii||3|
|American Golden Plover||Pluvialis dominica||2|
|Black-billed Cuckoo||Coccyzus erythropthalmus||2|
|Blue-winged Teal||Anas discors||2|
|Blue-winged Warbler||Vermivora pinus||2|
|Buff-breasted Sandpiper||Tryngites subruficollis||2|
|Loggerhead Shrike||Lanius ludovicianus||2|
|Northern Harrier||Circus cyaneus||2|
|Rusty Blackbird||Euphagus carolinus||2|
|Solitary Sandpiper||Tringa solitaria||2|
|Wood Thrush||Hylocichla mustelina||2|
|Yellow-billed Cuckoo||Coccyzus americanus||2|
|Acadian Flycatcher||Empidonax virescens||1|
|American Woodcock||Scolopax minor||1|
|Bald Eagle||Haliaeetus leucocephalus||1|
|Barn Owl||Tyto alba||1|
|Black-throated Blue Warbler||Dendroica caerulescens||1|
|Horned Grebe||Podiceps auritus||1|
|Hudsonian Godwit||Limosa haemastica||1|
|Least Flycatcher||Empidonax minimus||1|
|Lesser Scaup||Aythya affinis||1|
|Marbled Godwit||Limosa fedoa||1|
|Red-shouldered Hawk||Buteo lineatus||1|
|Short-billed Dowitcher||Limnodromus griseus||1|
|Slender Madtom||Noturus exilis||3|
|Gravel Chub||Erimystax x-punctatus||2|
|Ozark Minnow||Notropis nubilus||2|
|Black Buffalo||Ictiobus niger||1|
|Redside Dace||Clinostomus elongatus||1|
|Reptiles and Amphibians||Score|
|Blanding's Turtle||Emydoidea blandingii||3|
|Northern Cricket Frog||Acris crepitans||3|
|Ornate Box Turtle||Terrapene ornata||3|
|Pickerel Frog||Rana palustris||3|
|Prairie Ringneck Snake||Diadophis punctatus arnyi||3|
|Yellow-bellied Racer||Coluber constrictor||3|
|Bull Snake||Pituophis catenifer||2|
|Timber Rattlesnake||Crotalus horridus||2|
|Gray Ratsnake||Pantherophis spiloides||1|
|Eastern Red Bat||Lasiurus borealis||2|
|Franklin's Ground Squirrel||Spermophilus franklinii||2|
|Northern Long-eared Bat||Myotis septentrionalis||2|
|Prairie Vole||Microtus ochrogaster||2|
|Woodland Vole||Microtus pinetorum||2|
|Hoary Bat||Lasiurus cinereus||1|
|Silver-haired Bat||Lasionycteris noctivagans||1|
|Water Shrew||Sorex palustris||1|
|White-tailed Jackrabbit||Lepus townsendii||1|
Natural community management opportunities
The Southwest Savanna Ecological Landscape contains opportunities to manage for the following natural communities, based on the findings in the Wildlife Action Plan (originally presented by the Ecosystem Management Team).
|Natural Community Type||Opportunity|
|Southern Dry Forest||Important|
|Southern Dry-mesic Forest||Important|
|Southern Mesic Forest||Important|
|Southern Sedge Meadow||Present|
Description of Terms Used to Define Opportunities for Protection, Restoration and/or Management of Natural Communities by Ecological Landscapes
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.
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.
The natural community occurs in the Ecological Landscape, but better management opportunities appear to exist in other parts of the state.
General management opportunities 1
The Southwest Savanna was once dominated by fire-dependant natural communities representing the continuum of prairie, oak savanna, oak woodland and oak forest. Now dominated mostly by agricultural lands, and with less than one percent in public ownership, this landscape still offers good opportunities to maintain expansive grassland and savanna habitats through public / private partnerships. Restoration and management of the entire continuum of fire-dependent natural communities native to southern Wisconsin is possible here.
This is arguably Wisconsin's best ecological landscape to manage grasslands at large scales. Native grasslands are rare here, as they are throughout the upper Midwest. However, some of the scattered remnants support rare plants, invertebrates, herptiles, birds and other animals. In addition, abundant surrogate grasslands can provide the scale needed by area-sensitive species and in some cases can connect isolated prairie patches. Large areas of surrogate grasslands can buffer prairie and savanna remnants from more intensively managed land, and there are sometimes opportunities to embed remnants within large acreages of CRP, fallow agricultural land, pasture, or cropland. The surrogate grasslands may also provide missing environmental gradients of soil types, soil moisture, slope and aspect, which may be needed for the vegetation to adapt to long-term environmental changes.
The Wisconsin Natural Resources Board recently approved a project that will protect and restore grassland and stream habitats in this Ecological Landscape: the "Southwest Wisconsin Grasslands and Streams Conservation Area." The project boundary encompasses high-priority grasslands, prairies, savanna remnants and watersheds across parts of southern Iowa, northern Lafayette, southwest Dane and far northwestern Green counties. This project represents major habitat management opportunities via numerous private-public partnerships.
Extensive areas of grazed but never plowed oak savanna occur at several locations in the Southwest Savanna. Survey needs include the identification of prairie remnants, unplowed prairie and savanna pastures and other sites with diverse native flora. Floristically diverse remnants adjoining or embedded within extensive surrogate grasslands will offer the best restoration and management opportunities.
Rivers and streams here afford opportunities to manage and conserve native aquatic species and their habitats as well as recreational opportunities. The identification of aquatic habitats known to support sensitive species provides a starting point on which to focus restoration and protection efforts. Some sites will offer good opportunities to merge terrestrial and aquatic conservation projects.
Miscellaneous management opportunities in the Southwest Savanna include scattered hardwood forests, conifer relicts, springs and spring runs and rare species populations. At some sites there are good opportunities to maintain, restore and manage these features, including restoration of oak forests that are succeeding to more shade and browse-tolerant species. Conifer relicts could be mapped and monitored. The long-term viability of these relicts, especially Hemlock Relicts, is unknown and needs further investigation.
1. The text presented here is a summarized version of a longer section developed for the Ecological Landscapes of Wisconsin Handbook.
Southwest Savanna maps
Printable maps from the Ecological Landscapes of Wisconsin Handbook. These maps are in PDF format and will open in a new window.
- Finley's Vegetation of the Mid-1800s
- Land Cover of the Mid-1800's
- Landtype Associations (LTAs)
- Public Land Ownership, Easements and Private Land Enrolled in Forest Tax Programs
- Ecologically Significant Places
- Exceptional and Outstanding Resource Waters and 303(d) Degraded Waters (2010 Update)
- WISCLAND Land Cover (1992)
- Soil Regions
- Relative Tree Density in the Mid-1800s
- Population Density, Cities, and Transportation
Also see the statewide maps from the Ecological Landscapes Handbook.
Southwest Savanna Landtype Associations
Landtype Associations (LTAs) are units of the National Hierarchical Framework of Ecological Units (NHFEU), a hierarchical ecological land classification system. LTAs are much smaller than Ecological Landscapes, ranging in size from 10,000 and 300,000 acres. In Wisconsin, they are usually based on glacial features like individual moraines or outwash plains. LTAs can be very useful for planning at finer scales within an Ecological Landscape.
The following are the LTAs associated with the Southwest Savanna Ecological Landscape. The Southwest Savanna LTA map can be used to locate these LTAs. Clicking on an LTA in the list below will open a data table for that LTA in PDF format. Descriptions are included, where available.