Research Proposals: Lupita Sanchez, Nels Holmberg, Jenny Morrison
 

Johnson’s Shut-Ins State Park

Johnson's Shut-Ins State Park  is one of Missouri's 45 state parks and is located in the "Ozark Natural Division" region of the state (Thom and Wilson 1980; reprint in Pioneer Forest handout) (click here to see location in Missouri). Heralded by many as the most scenic of Missouri's state parks, Johnson's Shut-Ins contains many features that characterize the Ozark mountains, including deep canyon-like gorges and fast-flowing streams, oak-hickory-pine forests, igneous glades, and rocky talus slopes. The state park gets its name from the gorges created by the East Fork Black River as it works its way through volcanic rocks that date back to 1.5 billion years ago. These rocks are exceptionally hard and result in areas where the river accumulates in deep pools behind a narrow rock opening. The park is approx. 1038 ha (2490 acres) but is connected to the adjacent East Fork Wild Area and Taum Sauk Mountain State Park. Taum Sauk Mountain is the highest point in Missouri at approx. 540m (1772 feet). At this site, we will get a chance to see and explore igneous glades and walk over certainly some of the oldest exposed rocks in North America along the East Fork Black River.

This region of Missouri remained unglaciated and is part of an ancient uplifted area that for hundreds of millions of years has been gradually becoming exposed due to stream action. The oldest rocks date back to 1.5 billion years ago and arose from the earth's crust through volcanic activity. An inland sea once covered the region during the Paleozoic. Sediment accumulated in the inland sea and solidified into horizontal layers of sandstone, limestone and dolomite. Following retreat of the inland seas, the Ozark area experienced several later periods of uplifting. These horizontal rock layers are being carved downward and exposed by the rivers that drain the area. During glaciation periods, forests more typical of northern forests predominated in the Ozarks. Another important time period occurred approximately 5000-8000 years ago, when maximum temperatures occurred throughout North America; it was during this period that prairies penetrated eastward into areas that are now covered by deciduous forests. This is likely the period that western prairie and desert species colonized the Ozarks and were most abundant; relict populations can be found in Missouri glades.

The Ozarks are interesting biologically as they represent the farthest eastward extension of the eastern deciduous forests. On the western border is the beginning of prairies that extend to the Rocky Mountains and from Texas to Canada. The northern border represents the south boundary of past glaciers, and to the south one encounters the hot, bottomland forests of the southeast. Consequently, relict plants and animals congregate in some of the diverse Ozark habitats. For example, northern plant relicts occur in cool hollows, southern swamp species in sinkhole bogs, and western desert species occur on glades. Moreover, the region has a number of endemic species, including at least 38 endemic plant species and numerous endemic fish (approx. 14 species) and salamander species (see Pioneer Forest Introduction).

Active management is occurring at Johnson's Shut-Ins State Park by the Department of Natural Resources. There is a general feeling among DNR people and biologists (although we will discuss this) that the forests were much more open in presettlement times (see Batek et al. 1999 in course reprints). However, due to fire suppression, canopies have closed and many herbaceous species, including endemic wildflowers are less abundant today. Much of the East Fork Wild Area undergoes prescribed burns every 3 years during the late winter in an attempt to open the understory and canopy and stimulate regeneration of some of these more light demanding species. The last burn occurred in March 2000. In addition, many of Missouri's glades (see below) are being invaded by woody plants, primarily red cedar (Juniperus virginiana), and through fire and removal of red cedar, state park biologists are hoping to recover the glade habitats. Johnson's Shut-Ins and the adjacent protected areas reside in one of Missouri's most important lead mining areas (note the town names as we drive south). A lead smelting plant is only 8 km to the southeast and emissions from this plant have reportedly resulted in the premature deaths of trees on nearby mountaintops. In addition, lead likely runs off from the tailing ponds and ends up in adjacent waterways and in the soil. Lead mining is a difficult subject politically because of its economic importance in the state, and in fact there appear to have been few studies of its ecological impact in the area.

Fens

At Johnson’s Shut-Ins we will also visit a fen. Fens are wetland communities where soils are saturated from the upwelling of mineral-rich groundwater, creating spring rivulets and ooze areas. The fen at Johnson’s Shut-Ins is found within the floodplain of East Fork Black River and is partially a seep forest and calcerous fen. Seep forests are infrequently found in Missouri. Dominant trees include red maple, green ash, slippery elm and honey locust. Two rare plants are found here along with other notable wetland species including closed gentian, silky willow and an uncommon variety of southern blue flag.

Missouri Glades: General Information (see course reprints)

Glades generally are dry rocky barrens dominated by herbaceous vegetation. Glades occur primarily on south- and west-facing slopes, and are usually surrounded by forests (Nelson and Ladd 1980). In general, glades are characterized by having bedrock at or near the surface. They tend to be located on relatively moderate to steep slopes. Soil cover, if present, is very thin (< 50 cm thick). Soil features, together with exposure, result in extremely xeric conditions, especially during the growing season.

Maintenance of glade habitats is thought to be primarily due to drought, animal activity, exposure, aspect, and topography (Steyermark 1959, Nelson and Ladd 1980). In particular, Nelson and Ladd (1980) in an examination of glade occurrence in Missouri found that (1) resistance to weathering and (2) active erosion on moderate to steep slopes were essential for glade formation. However, in order to prevent succession to woody vegetation, invading woody plants must be removed through burning or some other mechanical method (Baskin and Baskin 2000).

Most of Missouri glades occur in the unglaciated regions of the state on 6 substrate types (dolomite, limestone, sandstone, chert, igneous rock, shale) (Nelson and Ladd 1980, Thom and Wilson 1980). These different substrate types result in distinctive plant communities because of the different physical and chemical properties of the substrate (Nelson and Ladd 1980). In fact, substrate type appears more important in predicting plant distribution patterns than geographic location. On limestone and dolomite glades, Baskin and Baskin (2000) report that little bluestem (Schizachyrium scoparium) is the dominant plant species. The Missouri Department of Natural Resources report that approximately 415 species of vascular plants, including 45 woody species, occur on undisturbed Missouri glades. Plants found in glade habitats have many characteristics typically found for plants growing in extreme environments. For example, many plants have thick, succulent leaves. Several have compact growth forms and reduced leaf areas. Trees on the glade edges (or on the glades themselves) frequently have stunted and gnarled growth.

Some of Missouri's animals reach their greatest abundance or are only found on the rocky glades of Missouri (e.g., Eastern Collared Lizard Crotaphytus collaris collaris, Painted Bunting Passerina ciris). The disjunct nature of glade habitats result in potentially interesting population studies on these organisms (e.g., work by Anne Gerber, Alan Templeton, Owen Sexton and others at Washington University). Although recent prescribed fires have led to exchange of individuals (e.g., Collared lizards) among formerly isolated populations.

Sources:

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