Wisconsin State Natural Areas Program
Avoca Prairie and Savanna (No. 68)

Overview

Location

Within the Lower Wisconsin State Riverway, Iowa County. T8N-R1E, Sections 1, 2, 3, 12. T8N-R2E, Sections 5-8. T9N-R1E, Sections 34, 35, 36. 1885 acres.

Access

From Avoca, go east on State Highway 133 1.5 miles, then north on Hay Road, across Marsh Creek, 0.8 miles to a mowed parking area in the southeast corner of the prairie. If the Marsh Creek crossing is impassable due to high water, vehicles must park in the lot south of the creek. The site is also accessible by canoe from the Wisconsin River.

Description

Description

Located on an extensive outwash sand terrace along the Wisconsin River, Avoca Prairie and Savanna contains the largest natural tallgrass prairie east of the Mississippi River. Frequent flooding has created braided stream topography characterized by low, sandy ridges interspersed with small linear wetlands giving a local relief of 4 feet. The moist prairie and wetland swales contain more than 200 species of vascular plants including large numbers of rattlesnake master, Michigan lily, prairie blazing-star, and two rare species – tall nut-rush (Scleria triglomerata) and prairie Indian plantain (Arnoglossum plantagineum). Big blue-stem, prairie cord grass, Indian grass, and sedges dominate the wet areas while little blue-stem, prairie drop-seed, and June grass are common on the drier ridges. Permanent and ephemeral swales contain aquatic species such as sweet-flag, yellow water buttercup, and common bur-reed. Some of the showy species include sweet grass, white wild indigo, flowering spurge, prairie smoke, bottle gentian, cardinal flower, and swamp candles. Oak openings, with large open-grown black and bur oaks, are an outstanding feature of this natural area looking much as they did during the original land survey of 1833. Even today, from many points on the prairie, the same presettlement character has been preserved, with completely natural vistas still accessible in all directions. Avoca is also home to rare animals including red-shouldered hawk (Buteo lineatus), northern harrier (Circus cyaneus), short-eared owl (Asio flammeus), and Blanding’s turtle (Emydoidea blandingii). Avoca Prairie and Savanna is owned by the DNR and was designated a State Natural Area in 1968.

Maps

The WDNR'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. Therefore, while the majority of SNAs are open to the public, access may vary accordingly. 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 land owner 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.

• Guidebook Map [PDF, 79 KB]
• Detailed Map [PDF, 207 KB]
• Line Map [PDF, 51 KB]

Objectives

Site Objectives

Manage the site as a reserve for prairie, oak opening and floodplain forest, as an aquatic reserve and wetland protection site, and as an ecological reference area. Allow for a shifting mosaic of dry-mesic to wet-mesic prairie, southern sedge meadow, shrub-carr and oak opening. Natural processes (especially fluctuating water levels) and prescribed fire will determine the structure of the native communities represented here. Provide opportunities for research and education on the highest quality native prairies and oak openings.

Management Approach

The ecological characteristics of the site will be primarily shaped by an intensive fire management program. The native prairie and wetland species are managed actively through tree/shrub control using tree harvest, brushing and especially fire to mimic natural disturbance patterns. Occasional fire-tolerant oaks and native shrubs such as meadowsweet may be retained at low densities. The native dominant savanna tree species (primarily oaks) are managed passively. However, some thinning of the canopy, understory manipulation and shrub control via harvest, brushing or fire may be needed to mimic natural disturbance patterns. The mostly passive canopy management and understory manipulation will determine the ecological characteristics of the oak opening. The native floodplain forest species are managed passively, which allows nature to determine their ecological characteristics. Prescribed fire, however, will be allowed to pass through the floodplain forest, though consumption of fuel here will not be facilitated, other than to secure fire breaks. Other allowable activities throughout the site include control of invasive plants and animals, augmentation of native savanna species after careful review, maintenance of existing facilities, and access to suppress wildfires.

Site-Specific Considerations

• Although removal of hazardous trees from over and near trails and field lanes is an allowed activity, manipulation/removal of vegetation and soil disturbance should be minimized to the extent possible.
• An access lane with a ford across a backwater lake is maintained to Department standards.
• A decades-long tradition of visitors driving on the prairie has caused extensive environmental degradation to portions of the site. Reclamation activities are addressing this chronic problem.

Activities

Please come prepared for your visit. Amenities vary from site to site with most SNAs being primitive and without facilities. See Guidelines for Visitation for details.

Allowable Activities

Most DNR-owned SNAs allow:

• Hiking
• Hunting
• Fishing
• Trapping
• Skiing

Some exceptions apply. Properties closed to the public or closed to specific use, such as hunting, will be posted.

***For non-DNR-owned SNAs: Additional use guidelines may apply. Please verify any use restrictions with the landowner or contact the SNA Program. Landowners may require additional permits or restrict the number of hunters at a given SNA to provide a quality hunting experience. SNA landowners can be found at the bottom of each SNA description page.

Prohibited Activities

• Horseback riding
• Rock climbing
• Vehicles, including bicycles, ATVs, aircraft, and snowmobiles except on trails and roadways designated for their use
• Collecting of plants (including fruits, nuts, or edible plant parts), animals, fungi, rocks, minerals, fossils, archaeological artifacts, soil, downed wood, or any other natural material, alive or dead

Please note that a permit is required for scientific collection and research on State Natural Areas. For more information, contact Thomas Meyer, State Natural Areas Program Specialist.

For more information on rules governing state-owned SNAs and other state lands, please consult Wisconsin's Administrative Code Chapter NR 45 (exit DNR)