Pioneer Forest

Site: Pioneer Forest, Salem, MO
Date: Sept. 9-10
Time: Leave UMSL parking lot 7:30 AM; return Sunday, 6 PM
Focus: Ozark ecosystems, especially aquatic
What to bring: LUNCH for Saturday; binoculars, sweater, raingear, personal field equipment (notebook, hand lens, field guides, compass), extra set of dry clothes and shoes (Sat and Sun field problems in the water), insect repellant, shorts, hiking boots or appropriate footwear, towel, bathing suit (optional), tapes, computers (optional), sleeping bag(mattresses available)

Our first trip takes us to the heart of the Ozarks in south-central Missouri. The Ozarks extend from southern Missouri outside St. Louis through northern Arkansas to the Oklahoma plains near Tulsa. The total area encompasses approximately 140,800 square kilometers and is bordered by five major rivers: the Mississippi, the Missouri, the Osage, the Neosho, and the Arkansas. The Ozarks, which have a peak elevation of approximately 540 m in Missouri, are the only extensive highland area between the Applachian mountain chain in the east and the Rockies in the west. The most prevalent habitat is deciduous forest consisting of oak, hickory, and pine. The region, however, is dissected with ridges and hollows that have been shaped by rivers and streams that have cut through the bedrock.

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. The last period of glaciation occurred about 18,000 to 20,000 years ago, with the glacial retreat beginning about 16,500 years ago. 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 westward 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 (e.g., river birch) or alongside creek beds (.g., beech), southern swamp species (e.g., water tupelo, buttonbush) in sinkhole bogs, and western desert species (e.g., desert scorpions, collared lizards) 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. Overall approximately 43 mammals, including 13 bats, 3500 plants, and over 160 species of fish occur in the Ozarks. Some mammals, such as elk, bison, and mountain lion are now locally extinct, whereas others (bear, deer) have recovered once dwindling populations. There has been at least one unconfirmed sighting in recent years of mountain lions in the Ozarks.

Ozark Forests: General Information (see course reprints)

Within the Ozarks, tree species composition is dominated by oaks (Quercus sp.), and hickories (Carya sp.). The area, however, varies greatly in moisture, soil conditions, and exposure. As a consequence one can encounter many different tree species including Acer, Betula, Platanus, Juniperus, Pinus, Cercis, among others. For example, north- and east-facing slopes appear to be dominated by Quercus alba, Q. velutina, Q. rubra, Q. muehlenbergii, Carya ovata, C. tomentosa, C. cordiformis; south- and west-facing slopes tend to be dominated by a different set of oaks and hickories which include Quercus marilandica, Q. stellata, Q. falcata, as well as Missouri's only native pine, Pinus echinata. The understory layer tends to be more open than that found in more mesic eastern forests, but along streams and in protected valleys the understory can be quite dense. As Zimmerman and Wagner (1979) point out in their studies of vegetation composition in Tyson Forest, a research area owned by Washington University, local environmental conditions are likely primary determinants of species composition in these areas.

In general, winter temperatures are not too severe, although cold pockets can occur. January temperatures range between 29^oF and 50^oF and snowfall is relatively light (i.e., generally from 10 to 20 cm per year). Summer temperatures can exceed 100^oF, but average July temperatures range between 64^oF and 92^oF. Annual precipitation is approximately 100 to 120 cm rain.

Human impacts in the region have been great, and nearly all of the forest is regrowth following logging and past agricultural use. Much of the area was logged during the second half of the 19^th century when railroad construction was proceeding and industry needed logs for "ties". During the early part of the 20^th century, most of the remaining land was dominated by scrubby trees and agriculture. Following the droughts of the 1930's, many of the failing farms were bought out and the area became part of the National Forest system.
 

Missouri Glades: General Information

We will not visit any Missouri glades on this trip, but it will be a Amust see@ when we return to the Ozarks on later trips. Glades hold many of Missouri=s endemic species and are the site of a number of research projects by biologists at UMSL and Washington Unviersity (e.g., on-going studies by Drs. Carol Kelly, Owen Sexton, and Alan Templeton, among others).

Glades 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.

Most of Missouri glades occur in the unglaciated regions of the state (see Fig. 1) 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; see reprint box). In fact, substrate type appears more important in predicting plant distribution patterns than geographic location (see folder in Biol. Conf. Rm for some characteristic plants found on each substrate). 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.
 

Pioneer Forest

Pioneer Forest is an extensive tract of oak-hickory forest that is privately owned and under natural forest management for timber since the 1950's (see accompanying brochure on Pioneer Forest). Our future trips to the Ozarks will be centered around the forest habitats. On this field trip, we will focus on exploring the Ozark streams and rivers, but some of you will likely get into the forest. Streams are characterized by such factors as gradient, flow volume, flow constancy, velocity of current, clarity of water, presence of pools or riffles, type of bottom (e.g., rocky, sandy, etc.). In general, Ozark waterways are characterized by clear waters, chert gravel bottoms, and relatively moderate to steep gradients. Ozark streams typically have pool habitats interspersed with riffles. Typical aquatic plants include water cress (Nasturtium; especially at mouths of springs), water willow (Justicia; riffles and rocky shores), yellow pond lily (Nuphar; rocky shores), coontail (Ceratophyllum; pools), water milfoil (Myriophyllum; pools) and pond weeds (Potamogeton; pools).

The fish diversity is quite high, in fact, one of the richest fish communities in the US. Bill Resetarits (formerly at UM-St. Louis) once found greater than 56 species of fish in a single sample from the Meramec River. In addition to the relatively high species diversity, many fish are endemic (14) to the Ozark region (e.g., Niangua darter Etheostoma nianguae, ozark madtom Noturus albater). Minnows (Cyprinidae; 22 species) and darters (Percidae; 17 species) predominate in Ozark streams.

In recent years, the construction of hydroelectric facilities and flood control projects, as well as gravel mining, have strongly affected the fish populations of these waterways. Most of the unique Missouri fishes disappear in these areas, and more widespread fishes move into the disturbed areas. In addition, in these newly created reservoirs, certain game fishes have been introduced (e.g., muskellunge, northern pike, and striped bass).
 

Literature Cited

Angermeier, P. L., and I. J. Schlosser. 1989. Species-area relationships for stream fishes. Ecology 70:1450-1462.

Greller, A. M. 1988. Deciduous forest. Pp. 287-316 in M. G. Barbour and W. D. Billings, eds., North American terrestrial vegetation. Cambridge Univ. Press, Cambridge.

Johnson, T. R. 1987. The amphibians and reptiles of Missouri. Missouri Dept. of Conservation, Jefferson City.

Karr, J. R. 1991. Biological integrity: a long-neglected aspect of water resource management. Ecological Applications 1:66-84.

Karr, J. R., L. A. Toth, and D. R. Dudley. 1985. Fish communities of midwestern rivers: a history of degradation. BioScience 35:90-95.

Nelson, P. and D. Ladd. 1980. Preliminary report on the identification, distribution, and classification of Missouri glades. Pp. 59-76 in Proc. Seventh No. American Prairie Conference.

Pflieger, W. L. 1975. Fishes of Missouri. Missouri Dept. Conservation, Jefferson City, MO.

Robbins, M. B., and D. A. Easterla. 1992. Birds of Missouri: their distribution and abundance. Univ. Missouri Press, Columbia.

Schlosser, I. J. 1982. Fish community structure and function along two habitat gradients in a headwater stream. Ecological Monographs 52:395-414.

Schlosser, I. J. 1982. Trophic structure, reproductive success, and growth rate of fishes in a natural and modified headwater stream. Can. J. Fisheries & Aquatic Sciences 39:968-978.

Steyermark, J. A. 1959. Vegetational history of the Ozark forest. Univ. Missouri Studies XXXI, Columbia. 138 pp.

Steyermark, J. A. 1963. Flora of Missouri. Iowa State University Press, Ames.

Zimmerman, M., and Wagner, W. L. 1979. A description of the woody vegetation of oak-hickory forest in the Northern Ozark highlands. Bull. Torrey Botanical Club 106:117-122.

Schedule
 

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