Ozark Hill Prairie Research Natural Area

[photo:] Ozark Hill Prairie RNA.  Photo by Lucy Tyrrell, USDA Froest Service.

The RNA contains relatively undisturbed examples of hill prairie, dry upland forest, dry-mesic upland forest, and mesic upland forest natural community types. The RNA includes the major part of the Ozark Hill Prairies Natural Area, which is significant because of its very high quality loess hill-prairie natural community and the presence of the uncommon timber rattlesnake (Crotalis horridus). The southern blazing star (Liatris squarrulosa) has been found within the RNA and will be probably be listed as a State Endangered Species in the near future.

Ecological Information

Physical and Climatic Conditions

Nearest weather station, with distance and direction from RNA:
Climatological information is taken from the collection station at Anna, IL, which has records dating from 1951. The station is located 10.8 miles (17.4 km) to the northeast of the RNA.
Annual precipitation (type, seasonal distribution) :
The annual precipitation averages approximately 45 inches (114 cm), and ranges between 30 and 70 inches (76.2-177 cm). Precipitation is fairly evenly distributed throughout the year. Average annual snowfall is about 9 inches (22.8 cm), but in one-third of the winters, average annual snowfall is less than 5 inches (12.7 cm).
Maximum and minimum temperatures:
July is normally the warmest month, with temperatures averaging 90 °F. January is normally the coldest month. Although similar temperatures may occur in February, the cold spells are usually of shorter duration. Below zero temperatures occur about twice in 5 years.
Relief is great, with the ridge top rising over 400 feet (121.9 m) above the valley of Ripple Hollow.
Geology and Soils:
he RNA is on the high bluffs that form the east wall of the Mississippi River valley in southern Illinois. It sits on a narrow, northerly-trending, main ridge with long lateral ridges in all directions. Closely-spaced and steep-sided canyons extend from floodplains to the crest. Massive gray limestone of the Devonian Bailey Formation forms the bedrock, and Devonian chert of the Grassy Knob Formation underlies the upper slopes. Thick deposits of silty loess dating from the Pleistocene are found on the ridges and to a lesser extent on the slopes. Most of the soils on the narrow ridge crests are Alford silt, with Elsah silt loam in the valleys.
Aquatic Features:
Drainage from the RNA is into the Mississippi River, via Ripple Hollow on the eastern side of the ridge and via Clear Creek Ditch and Dongola and Happy Hollows on the western side of the ridge. The drainage pattern is grossly reticulate, with dendritic tributary patterns in the lateral valleys. There is a suggestion that springs may be present, associated with the Bailey limestone,

Ecological Classification & Inventory

Ozark Highlands (222 A)
Mississippi River Alluvial Plain (222Ao)
Plant Communities:
Indian grass-little bluestem: Loess hill prairie natural community
Indian grass-big bluestem: Loess hill prairie
Little bluestem-Indian grass: Loess hill prairie
Big bluestem-Little bluestem- Indian grass: Loess hill prairie
White oak-post oak-black oak: Dry mesic upland forest
White oak-black oak-hickories: Dry mesic upland forest
Red oak-white oak-tuliptree: mesic ravine forest
Beech-sugar maple-sweetgum: mesic ravine forest
Grasses/forbs/saplings: successional field
SAF Cover Types (list acres): Kuchler Types (list acres):
40 Post oak-blackjack oak (25) 91 oak-hickory forest (315)
52 White oak-black oak-northern red oak (290) 93 beech-maple forest (10)
59 Yellow-poplar-white oak- red oak (190)
94 Mixed mesophytic forest (190)
60 Beech-sugar maple (10)  
64 Sassafras-persimmon (20)  
Common Shrub Species:
Flowering dogwood (Cornus florida), redbud (Cercis canadensis), spicebush (Lindera benzoin), pawpaw (Asimina triloba).
Common Herbaceous Species:
Big bluestem (Andropogon gerardii), Indian grass (Sorghastrum nutans), prairie rosin-weed (Silphium integrifolium), basal-leaved rosin-weed (S. terebinthinaceum), Virginia lespedeza (Lespedeza virginica), common poison ivy (Toxicodendron radicans), bent trillium (Trillium flexipes), violets (Viola spp.), wild ginger (Asarum canadense), bloodroot (Sanguinaria canadensis), Dutchman’s breeches (Dicentra cucullaria), Canada columbine (Aquilegia canadensis), Christmas-fern (Polystichum acrostichoides), bracken fern (Pteridium aquilinum), walking fern (Asplenium rhizophyllum).
Common Mammal Species:
White-tailed deer (Odocoileus virginianus), coyote (Canis latrans), gray fox (Urocyon cinereoargenteus), raccoon (Procyon lotor), Virginia opossum (Didelphis virginiana), gray squirrel (Sciurus carolinensis), bobcat (Lynx rufus).
Common Bird Species:
Pileated woodpecker (Dryocopus pileatus), common turkey (Meleagris gallopavo).

Related Reports and Publications

Adams, Eric D. 1995. Vegetation Analysis and Examination of Beta Diversity at Burke Branch and Ozark Hill Prairies Research Natural Areas in the Shawnee national Forest, Illinois, OR: Southern Illinois University at Carbondale.156 p. M.S. thesis.

Hutchinson, Max D. 1987. Establishment record for the Ozark Hill Prairie Research Natural Area within the Shawnee National Forest, Alexander County, Illinois. (pdf) Unpublished report on file at the Northern Research Station, Rhinelander, and the Shawnee Supervisor's office, Harrisburg, IL. 67 pages with appendices.

McCall, Robin K. 1995.  Microclimatic influence on spatial heterogeneity and photosynthesis in Sorghastrum nutans (L.) Nash. and Helianthus divaricatus L. on southern Illinois loess hill prairies. A Masters Thesis from Department of Plant Biology, Southern Illinois University - Carbondale, Illinois. 83 pp. Manuscript on file at the Northern Research Station, Rhinelander, Wisconsin.

Last Modified: May 6, 2021