Corals of the Devonian and Silurian seas, 375 to 425 million years ago. Many corals were colonial but some were solitary.

Brachiopods - These shells are among the most common fossils found in Iowa. Brachiopods lived inside the protective cover of two hinged shells, attached to the floor of warm, shallow seas that once covered the state. These eastern Iowa specimens are about 375 million years old (Devonian).

 

Gastropods - Shells of marine animals are often preserved as fossils. This coiled shell from Winneshiek County was inhabited by a snail. The sluggish, bottom-dwelling mollusk scavenged or grazed the ancient sea floor about 440 million years ago (Ordovician).

 

Stromatoporoid - "Stroms" are extinct organisms related to sponges. They constructed skeletons of lime and lived in various shaped colonies that resembled layered mats, branches, and rounded masses. This Floyd County specimen, with its prominent nodes, lived 370 million years ago (Devonian) .

 

Crinoids - Often called "sea lilies," crinoids are actually animals related to starfish. This 350 million-year-old (Mississippian) specimen from Marshall County shows the arms, which in life would filter sea water for food particles.

 

Trilobites - Trilobites are an extinct group of bottom-dwelling, hard-shelled arthropods that scavenged the sea floor. These Scott County specimens are 375 million years old (Devonian).

 

Cephalopods - These squid-like animals lived in chambered shells and propelled themselves by ejecting water from a tube near their head.. These straight-shelled cephalopods , from Marion County are 300 million years old (Pennsylvanian). The coiled cephalopod is a 365 million-year-old (Devonian) specimen from Butler County, and a distant relative of the chambered nautilus seen in today's oceans.

 

Fishes - This jaw belonged to a 2 to 3 ft-long placoderm, a primitive fish partly covered by bony plates that gave it an armored appearance. The black color of this 375 million-year-old (Devonian) specimen from Black Hawk County results from mineralization of the fossil bone.

 

Fossilized plants - These black fossil seeds are from Scott County. They grew at the end of a frond on a fern-like tree about 300 million years ago (Pennsylvanian).

Fossilized plants - The fossil foliage of seed ferns (small fossils) was found in Dallas County, and the scale-tree (Lepidodendron, large fossil) in Muscatine County. About 310 million years ago, these plants were common in the coastal swamps that produced Iowa's coal deposits (Pennsylvanian).

 

Fossilized mammals - Tooth shapes of these 15,000 year-old molars indicate mastodons browsed tree branches, while mammoths grazed grasses. Fossils of these extinct Ice Age (Pleistocene) creatures resembling elephants have been widely found across Iowa.

 

The Megafauna of the Pleistocene

Mammoths

Mastodons

Giant Beaver

Saber-toothed tiger

Giant ground sloth

Camels

Horses

Prairie Communities - only 30,000 of Iowa’s original 30,000,000 acres of prairie remain!

Wet Prairies - characterized by more available moisture than supplied by precipitation

Species include sedges , New England aster , bluejoint reedgrass, marsh muhly grass, yellow stargrass, cowbane, common mountain mint, prairie cordgrass, purple meadow rue, blueflag iris, swamp saxifrage and bottle gentian

Mesic Prairies - Species include: big bluestem and prairie dropseed (dominant among the grasses), little bluestem, wetter sites include sedges, wild strawberry, sawtooth sunflower and common mountain mint, grayhead prairie coneflower, Canada goldenrod, heath aster, meadow bedstraw, golden alexanders. Other common species are Scribner’s panic grass, leadplant, sky-blue aster, false sunflower, Indian grass, showy sunflower and golden alexanders.

Dry Prairies - occur on the upper slopes of high-relief prairie landscapes or on sites with rapidly permeable soil over coarse substrates that are above the water table.

Dry-mesic - little bluestem, big bluestem, needlegrass, prairie dropseed, Indiangrass, sideoats grama, Schribner’s panic grass, leadplant, heath aster, yellow puccoon, prairie coriopsis, showy sunflower, prairie wild rose, prairie goldenrod

Loess Hills (dry prairie) - plains muhly grass, sideoats, grama, sand dropseed, yucca, great-flowered beardtongue, skeleton weed, scarlet guara, sand lily, red three-awn, stiffstem flax

Gravel hill prairie - found on the steep upper slopes of the moraines associated with the Des Moines lobe. Species may included: little bluestem, plains muhly grass, blue grama grass, hairy grama grass, needlegrass leadplant, prairie goldenrod, stiff goldenrod, old-field goldenrod, fleabane, aromatic aster, blazing star

Sand prairie - Species include little bluestem, erect dayflower, fameflower, purple milkwort, pink milkwort, knotgrass, sand dropseed, rough blazing star and evening primrose.

Spruce and pine trees dominated Iowa’s landscape during/following the advance of glaciers.

By 9000 years ago species such as oak, elm, maple and basswood were more common than conifers.

Before settlement Iowa had about 5-6 million acres of forest. As of 1974 only about 1.5 million acres were left.

Recent data suggest that 0.4 million acres have been added to Iowa’s forests since the mid-70s.

Iowa’s Forest Communities:

Oak-hickory

Common species include: white oak, red oak,black oak, chinkapin oak, bur oak,, northern pin oak, shagbark hickory, white ash, black cherry and bigtooth aspen. Understory trees include:

Understory continued - ironwood, chokecherry, hackberry, red mulberry, serviceberry, American and slippery elms and saplings of overstory trees. Shrubs include: nannyberry, prickly ash, prickly gooseberry, American hazelnut, Smooth sumac, gray and red-osier dogwoods.

 

Oak-basswood - Common species include: red oak, basswood (American linden), sugar maple, black maple; also bitternut hickory, black walnut, white oak, shagbark hickory, white ash, black ash. Understory is sparse but may include: ironwood, American hornbeam, slippery elm, black cherry. Shrubs include: wahoo, blackberry, bladdernut, serviceberry, dogwoods and witch hazel.

 

Bottomland hardwoods - Common species include: silver maple, green ash, hackberry, black walnut, cottonwood and river birch. Also: Kentucky coffee-tree, honey locust, black willow, peachleaf willow, bitternut hickory, shellbark hickory, pin oak, rock elm, butternut, black ash, pecan, shingle oak, swamp white oak and pawpaw.

Understory/shrubs/vines species include: wahoo, indigo bush, buttonbush, chokecherrry, elderberry, dogwoods, grapes, Virginia creeper, poison ivy.

Riparian - Common species include: cottonwood, silver maple, box elder, river birch, sandbar willow, black willow, peachleaf willow and some bottomland hardwoods. Understory species include: other willows (silky, rigid and prairie), wahoo, elderberry.

Northern conifer and hardwoods - Common species: oak-basswood overstory, white pine, balsam fir, paper birch, yellow birch, and mountain maple. Other species: quaking aspen, bigtooth aspen, black ash. Common shrubs: speckled alder, Canada yew, highbush cranberry and red-osier dogwood. Herbs/ground layer vegetation: red baneberry, spikenard, northern bush honeysuckle, leatherwood, wild lily-of-the-valley, genseng,

Northern conifers and hardwoods continued - slender rock fern.

Oak-cedar glade - Common species: chinkapin oak, eastern red cedar. Shrubs/ground-layer vegetation: downy serviceberry, columbine, hops, moonseed, black snake-root, bladder fern, starry campion, sassafras, goldenrods, pye-weeds, flowering spurge, false sunflower, crownbeard and ironweed.

Iowa probably had 2-3 million acres of wetlands in north-central Iowa.

The 1850 Federal Swamp Land Act granted 1,196,392 acres of public domain wetlands to the state of Iowa for "swamp reclamation".

The drainage of wetlands proceeded rapidly; only 110,000 acres of wetlands remain today.

Next to prairie habitat, this is the most threatened group of habitats in Iowa. Current threats include:

Continued tiling/drainage of wetlands.

River channelization/dredging

Pollution of surface/ground waters

Development

Types of wetlands in Iowa:

Palustrine wetlands: nontidal wetlands covering areas less than 20 acres with water up to 6.6 feet deep.

Type I - Seasonally flooded basins - common species: smartweek, wild millet, fall panicum, sedges, beggar-ticks, ragweed and barnyard grass

Type II - Freshwater meadows - common species: prairie cordgrass, reed canary grass, common reed, manna grass, sedges, rushes and mints.

Type III - Inland shallow water - common species include: grasses, bulrushes, spikerushes, cattails, arrowheads, giant bur reed, smartweeds, sedges

Type IV - Deep freshwater marshes - common species: cattails, bulrushes, reeds, spikerushes, bur reeds, pondweeds, water milfoils, coontails, waterlilies and duckweeds.

Fens/hanging bogs - Unique species include: large arrow grass, hooded ladies’tresses, yellow-lipped ladies’ tresses, small white lady’s slipper, small fringed gentian, Northern bog orchid, grass-of-Parnassus.

Lacustrine wetlands - found in shallow protected areas of lakes larger than 20 acres with the deepest water exceeding 6.6 feet. Typically found along the shores of lakes.

Riparian wetlands - wetlands contained within the flood plain/channel areas of riverine systems. Include oxbows, backwater marshes, overflow bottomlands.

Amphibians - 5 species listed in Iowa (see attached list in your notes)

Birds - 11 species listed in Iowa

Fishes - 18 species listed in Iowa

Mammals - 8 species

Reptiles - 15 species

Butterflies - 7 species

Mussels - 14 species

Snails - 9 species

Plants - 154 species

Introduced fishes:

Carp Species

Common Carp (Cyprinus carpio) - Introduced into Iowa waters about 100 years ago. Carp were originally brought over from Europe where they were a prized food fish.. They are extremely tolerant of poor water quality, which has contributed to its spread.. The aggravation of bottom sediments caused by feeding carp reduces visibility for predatory fish and limits light penetration for plant growth.

Bighead carp (The bighead carp is a plankton eater (microscopic algae) native to Asia. They were introduced into the Mississippi River when private hatchery ponds were washed out in the state of Missouri. They quickly began spawning in the Mississippi and populations spread to other Iowa Rivers. These carp have also been found in the Chariton, Iowa, and Des Moines Rivers. In fact, bighead carp were quite numerous in the Chariton River below Rathbun Dam. They may compete with paddlefish for plankton.

 

Zebra Mussels - (Dreissena polymorpha) are small clam shells (1/2 - 2 inches) which attach to any solid object with tufts of fiber called "byssal threads." They are native to the Caspian Sea region of Asia, and were introduced into North America in the mid 1980's via transoceanic ships that discharged ballast water into Lake St. Claire, near Detroit.

 

Exotic plants - This is an almost impossible topic to deal with in a lecture. We have hundreds of introduced species many of which are now nuisances or cause environmental damage. Some prominent concerns in Iowa are:

Purple loosestrife

Purple loosestrife - Purple loosestrife (Lythrum salicaria) is a wetland plant from Europe and Asia. It was introduced into the east coast of North America in the 1800s. First spreading along roads, canals, and drainage ditches, then later distributed as an ornamental garden plant, this exotic plant species is in 40 states, Iowa included, and in all Canadian border provinces.

Purple loosestrife invades marshes and lakeshores, replacing cattails and other wetland plants. In some locations, natural cattail marshes have been completely overtaken by loosestrife. The plant forms dense, impenetrable stands that are unsuitable as cover, food, or nesting sites for a wide range of native wetland animals including ducks, geese, rails, bitterns, muskrats, frogs, toads, and turtles.

 

Eurasian watermilfoil - Eurasian Watermilfoil (Myriophyllum spicatum) was accidentally introduced to North America from Europe.. It reached the Midwestern states between the 1950's and the 1980's. It was established in Iowa in 1992, in Hancock County's Crystal Lake. By 1993, the 260-acre lake was taken over by the plant, and was rendered virtually unusable from mid-July until fall.

Watermilfoil continued - It has since been reported in St. Benedict pond, Walnut Creek Marsh, County Pond, Wilson Grove Pond, and Snyder Bend Lake (see map below). To date, all infestations in interior waterbodies have been successfully eradicated with the exception of Wilson Grove Pond and Synder Bend, which are scheduled for eradication in the spring of 1997, and the Mississippi River.

Loess Hills

Neal Smith National Wildlife Refuge

Upper Mississippi Wildlife and Fish Refuge

Yellow River State Forest

Shimek State Forest

Hayden Prairie

White Pine Hollow

Iowa Preserve System (including preserves managed by the Nature Conservancy; County management at many)

National Wildlife Refuges/State Wildlife Areas

Prairies, Forests and Wetlands: The Restoration of Natural Landscape Communities in Iowa, Janette R. Thompson, University of Iowa Press, 1992.

Wildflowers of Iowa Woodlands, Runkel and Bull, Iowa State University Press, 1987.

Wildflowers and other Plants of Iowa’s Wetlands, Runkel and Roosa, 1999

An Illustrated Guide to Iowa Prairie Plants, Paul Christiansen, University of Iowa Press, 1999.

Key to the trees of Iowa: http://www.extension.iastate.edu/pages/tree/

The Vascular Plants of Iowa: An Annotated Checklist and Natural History, Lawrence J.Eilers, Dean M. Roosa, University of Iowa Press, 1994.