Superior Coastal Plain Landscape

Map showing the Superior Coastal Plain Ecological Landscape

General Description

The Superior Coastal Plain is Wisconsin's northernmost Ecological Landscape, bordered on the north by southwestern Lake Superior and on the south by the Northwest Sands, the Northwest Lowlands, and the North Central Forest. The climate is strongly influenced by Lake Superior, resulting in cooler summers, warmer winters, and greater precipitation compared to more inland locations. Exposed coastal areas are subject to significant disturbance from windstorms, waves, ice, currents, and periodic water level fluctuations. These disturbance regimes play a significant role in determining both the landform and vegetation characteristics of the shoreline ecosystems. The major landform in this Ecological Landscape is a nearly level plain of lacustrine clays that slopes gently northward toward Lake Superior. The clay plain is separated into two disjunct segments by the comparatively rugged Bayfield Peninsula. An archipelago of sandstone-cored islands, the Apostles, occurs in Lake Superior just north and east of the Bayfield Peninsula. Wave carved sandstone cliffs bracket stretches of the Peninsula and also occur along the margins of several of the islands. Sand spits are a striking feature of the Lake Superior shoreline, typically separating the waters of the lake from inland lagoons and wetlands. The spits support rare and highly threatened natural communities such as beaches, dunes, interdunal wetlands, and pine barrens, and these in turn are inhabited by specially adapted plants and animals. The mouths of many of the streams entering Lake Superior are submerged, creating freshwater estuaries. A ridge of volcanic igneous rock, primarily basalt, forms the southern boundary of portions of this Ecological Landscape.

Vegetation

Historically the Superior Coastal Plain was almost entirely forested. A distinctive mixture of white pine, white spruce, balsam fir, paper birch, balsam poplar, trembling aspen, and white cedar occurred on the lacustrine clays. White pine was strongly dominant in some areas, according to mid-nineteenth century notes left by surveyors of the US General Land Office. Mesic to dry-mesic forests of northern hardwoods or hemlock hardwoods were more prevalent on the glacial tills of the Bayfield Peninsula and throughout the Apostle Islands. Large peatlands occurred along the Lake Superior shoreline, often associated with drowned river mouths and well-developed sand spits. The most extensive of these wetland complexes were on the Bad and St. Louis rivers. A few large peatlands also occurred at inland sites, such as Bibon Swamp, in the upper White River drainage, and Sultz Swamp on the northern Bayfield Peninsula. The present clay plain forest has been fragmented by agricultural use, and today approximately one-third of this landscape is non-forested. Most of the open land is in grass cover, having been cleared and then subsequently pastured or plowed. Aspen and birch forests occupy about 40% of the total land area, having increased in prominence over the boreal conifers. On the Bayfield Peninsula, second-growth northern hardwood forests are interspersed among extensive early successional aspen stands. Older forest successional stages are now rare throughout the Superior Clay Plain.

Hydrologic Features

The larger rivers include the St. Louis, Nemadji, Bad, White, Amnicon, Flag, Sand, Raspberry, and Sioux. Smaller streams flowing across the clay plain typically occupy short, relatively straight, steep-sided valleys before emptying into Lake Superior. Other streams originate in the higher elevations of the Bayfield Peninsula and follow meandering courses toward the lake. Inland lakes are rare. Many wetlands still persist, and, collectively, they constitute a regionally significant reservoir of rare plants and animals, intact natural communities, and natural processes. All watersheds have been ranked for groundwater pollution by Wisconsin DNR, and groundwater conditions are among the cleanest in the state. Most watersheds in this Ecological Landscape have not been ranked for watershed, stream, or lake pollution.

Land Use

The total land area for the Superior Coastal Plain Ecological Landscape is approximately 906,000 acres, of which 57% is classified as timberland. Publicly owned lands make up about one-fifth of the area; about half of them are county forest, and the remainder are state or federally managed. Two tribal reservations of the Lake Superior Ojibwa -- Red Cliff and Bad River -- are situated along Lake Superior.

Socioeconomics

Socioeconomic data are summarized based on county-level approximations of the Ecological Landscape (referred to as a "region"). Economic data are available only on a political unit basis with counties as the smallest unit. The counties included in this socioeconomic region are Ashland, Bayfield and Douglas ("Superior Coastal Plain Region"). Recreation is an important contributor to the economy of the Superior Coastal Plain Region. The number of state parks, forests and recreation areas, as well as acreage of federal lands, is quite high. Forest products and processing industries contribute about 9% to the total industrial output of the region. Agriculture is not a major contributor to the economy. This region not only has the third lowest percent of farmland acreage, but the second lowest market value per acre of products sold, and the third lowest per acre production of both milk and corn. (Farmland is defined as all land under farm ownership, which includes cropland, pastureland, and woodland.) It has seen the greatest decrease in both farm numbers and acreage in agricultural land since 1970, and still ranks as one of the regions with highest agricultural land sales. The Superior Coastal Plain Region has one of the lowest population densities and growth rates (1970-2000) of all the regions in the state. The population density of the region (19 persons/sq. mile) is only about one-fifth that of the state as a whole (96 persons/sq. mile). Although there are few minorities, this region has the largest percentage of Native Americans. Economically, the counties of the Superior Coastal Plain are not very prosperous. Not only are the per capita income and average wage relatively low, but this region has the highest poverty rates for both adults and children and the second highest rate of unemployment of all the regions. The counties in the Superior Coastal Plain are highly dependent on the service and government job sectors with one of the lowest percentages of manufacturing jobs.

For any questions regarding the maps presented on this site or the "DNR Ecological Landscapes of Wisconsin" handbook, please contact Jeff Schimpff at Jeff.Schimpff@wisconsin.gov. Suggested Citation for Handbook: Wisconsin Department of Natural Resources. In Prep. DRAFT Ecological Landscapes of Wisconsin. State of Wisconsin, Dept. of Nat. Resources, Handbook. 1805.1. Madison, WI.

Last Revised: Thursday February 08 2006