Connecting the environment of the ancient past with the natural and cultural history of yesterday and today.



Ecosystems of the Falls of the Ohio

A view up river toward the Falls

A view from Clark's Point

The information in this section on the natural communities was taken from the display case focusing on the natural communities of the park which is located in the Interpretive Center.

Plant species names and photos listed below can be found here.

 Terrestrial Natural Communities

A view of the outer fossil beds from a helicopter.

A view of rocky ledges and sand bar ecosystems

Sandbar Community

The most notable sandbar is located below the fixed weir dam under the Conrail Railroad Bridge.  Spring floods annually leave fresh blankets of sand, and as these islands grow the natural community changes.  The dominant plants found in the sandbar environments include:  common cocklebur (Xanthium strumarium), umbrella sedge (Cyperus spp.*), and sandbar willow (Salix exigua = S. interior), which stabilizes sand with its extensive root system allowing the establishment of more perennial plants and eventually larger trees like cottonwood (Populus deltoids), sycamore (Platanus occidentalis), and river birch (Betula nigra)

* These sedges are very difficult to distinguish at the species level.

Mud Bank Community

Fine sediment settles out of the water and forms a mud bank in places where the river’s current slows down or is cut off by an obstruction.  Mud banks occur in a number of places at the Falls, and one may be seen just northwest of the fossil beds below the Interpretive Center.  Characteristic plants of the mud bank consist of lamb’s quarters (Chenopodium album), sessile toothcup (Ammannia robusta), giant ragweed

(Ambrosia trifida), nodding-bur marigold (Bidens cernua), frog fruit (Phyla lanceolata), jimsonweed (Datura stramonium), late-flowering boneset (Eupatorium serotinum), umbrella sedge (Cyperus esculentus), smartweed (Polygonum hydropiper), and horse nettle (Solanum carolinense). 

Animals that are commonly found in this community are raccoons (Procyon lotor), opossums (Didelphis marsupialis), beavers (Castor canadensis), ring-billed gull (Larus delawarensis), Caspian tern (Sterna caspia) in the summer months, killdeer (Charadrius vociferous), and spiny soft-shelled turtles (Trionyx spinifer spinifer).


Woodland Community

The woodland communities are located on the sand and gravel terraces of the park that normally flood for short periods about 1-2 times per year.  Much of the Buttonbush Woods (near the GRC home site) possess the woodland community as well.  This environment is filled with an abundance of flora and fauna.  The dominate trees include:  cottonwood (Populus deltoides), box elder (Acer negundo), silver maple (Acer saccharinum), American elm (Ulmus americana), black willow (Salix nigra), black walnut (Juglans nigra), black locust (Robinia pseudacacia), green ash (Fraxinus pennsylvanica), and sycamore (Platanus occidentalis).  Trees growing at the highest terraces of the woodland community include:  mulberry (Morus alba), red maple (Acer rubrum), osage orange (Maclura pomifera), black cherry (Prunus serotina), and hackberry (Celtis occidentalis).  The bottomland forest is dominated by poison ivy (Toxicodendron radicans) and several types of grapes.  Also common is the Virginia creeper (Parthenocissus quinquefolia), bristly greenbrier (Smilax hispida), trumpet creeper (Campsis radicans), Canada moonseed (Menispermum canadense), wild ginger (Asarium canadense), Solomon’s seal (Polygonatum biflorum), Jerusalem artichoke (Helianthus tuberosus), and the buttonbush (Cephalanthus occidentalis).  The invasive Japanese honeysuckle (Lonicera japonica) is quickly becoming the dominant vine in many local bottomlands. 

Many animals make the woodland community their home, and some examples are the raccoon (Procyon lotor), opossum (Didelphis marsupialis), groundhog (Marmota monax), muskrat (Ondatra zibethicus), red fox (Vulpes vulpes), white-tailed deer (Odocoileus virginianus), squirrels (Sciurus carolinensis), eastern cottontail rabbit (Sylvilagus floridanus), eastern chipmunk (Tamias striatus), deer mouse (Peromyscus maniculatus), and numerous snakes, frogs, and birds.  In fact, of the more than 262 species of birds at the Falls, the majority of them use the forest for food and shelter.  


Pocket Prairie Community

This very unique habitat has developed on the north central section of Goose Island, which is technically not within the boundaries of the park, but it is being included in this report since all of the communities affect one another.  It is concentrated in patches where deep potholes in the bedrock have trapped enough soil for plants to grow.  The soil is tightly bound by an extensive root system of typical prairie grasses that prevent the soil from washing away during spring flooding.  The most common of this prairie grass is big bluestem (Andropogon gerardii), but little bluestem (Schizachyrium scoparium), switch grass (Panicum virgatum), barnyard grass (Echinochloa muricata), and witchgrass (Panicum capillare) are also commonly found in this environment.  Several types of flowers grow in this habitat including:  nodding-bur marigold (Bidens cernua), obedient plant (Physostegia virginiana), Indian hemp (Apocynum cannabinum), and late-flowering boneset (Eupatorium serotinum).  Occasionally stunted ward willow (Salix caroliniana) and sycamore (Platanus occidentalis) will grow in the deeper potholes. 

The killdeer (Charadrius vociferous), lesser yellowlegs (Tringa flavipes), and numerous sandpipers make this community their home.


Aquatic Natural Communities  

Winter view of the Falls river ecosystem

Winter view of the river ecosystem

River (Low-gradient Large River Community)

The Ohio River borders a significant amount of the park.  The vegetation consists mostly of aquatic algae such as the green filamentous Cladophora that forms long wavy, bright green strands in the shallow waterways.  The Falls of the Ohio has the highest diversity of fish species in the Ohio River because the upper and lower fish populations combine here.  Some of the most abundant fish include the emerald shiner (Notropis atherinoides), gizzard shad (Dorosoma cepedianum), freshwater drum (Aplodinotus grunniens), sauger (Stizostedion canadense), striped bass (Morone saxatilis), common carp (Cyprinus carpio), buffaloes (Ictiobus species), and paddlefish (Polyodon spathula).  It is interesting to note that the Falls of the Ohio is one of the few places along the Ohio River where the paddlefish can lay their eggs because these fish need to lay their eggs in a shallow area that has constantly running water, which is exactly what you get at the Falls. 

Birds such as the Canada goose (Branta canadensis), canvasback (Aythya valisineria), blue-winged teal (Anas discors), lesser scaup (Aythya affinis), hooded merganser (Lophodytes cucullatus), pied-billed grebe (Podilymbus podiceps), turkey vulture (Cathartes aura), black vulture (Coragyps atratus), great blue heron (Ardea herodias), black-crowned night heron (Nycticorax nycticorax), belted kingfisher (Ceryle alcyon), and the double-crested cormorant (Phalacrocorax auritus) are commonly found in this habitat.  There are 14 species of freshwater mussels found just 10 miles below the falls including numerous Quadrula species, the pink heelsplitter (Potamilus alatus), the zebra mussel (Dreissena polymorpha), and the introduced Asian clam (Corbicula fluminea).


Marsh (Wetland Community)

The largest and most developed marsh is on Goose Island located below the fixed weir dam.  Smaller marsh areas are found near seeps and springs in the sandbar below the Conrail Railroad Bridge and along the river at the Clark Home site.  A marsh community is also found in the Buttonbush Woods.  Most of the Buttonbush Woods property is a swampy, low area.  These marshes have standing water or slow-moving water present throughout summer months when surrounding areas have dried up.  Plants that are characteristic of this environment include:  water willow (Justicia americana), common arrowhead (Sagittaria latifolia), Virginia bugleweed (Lycopus virginicus), primrose willow (Ludwigia peploides), nodding smartweed (Polygonum lapathifolium), nodding-bur marigold (Bidens cernua), and small bulrush (Scirpus atrovirens).  Scattered areas of non-native purple loosestrife (Lythrum salicaria) and garden loosestrife (Lysimachia vulgaris) add color to the landscape along with large pink blossoms of the swamp rose mallow (Hibiscus moscheutos).  Commonly entangling itself over large patches of vegetation, dodder (Cuscuta gronovii) is also found in this habitat. 

This environment is the primary habitat for migrating waterfowl.  Birds commonly found in this area the same birds found in the river community listed above.  A colony of beavers (Castor canadensis) is established on the Goose Island marsh along with muskrats (Ondatra zibethicus) and reptiles like the midland water snake (Nerodia sipedon pleuralis).  Amphibians include the common southern leopard frog (Rana sphenocephala utricularia) and the minute cricket frog (Acris species).


Geologic Communities

A view of rock ledge and gravel bar ecosystems.

A view of rock ledge and gravel bar ecosystems

Rocky Ledges (Limestone Cliff Community)

The most expansive habitat at the Falls is comprised of rocky ledges/cliffs and bare limestone bedrock where very few plants grow.  This area is mostly located along the banks of the river where the limestone is exposed.  The dominant plants of this area are trumpet creeper (Campsis radicans), occasional poison ivy (Toxicodendron radicans), water hemlock (Cicuta maculata), Virginia creeper (Parthenocissus quinquefolia) and the indigo bush (Amorpha fruticosa).  In some areas, the cracks and potholes often contain enough soil to support hoary tick trefoil (Desmodium canescens), lady's thumb (Polygonum persicaria) and beggar ticks (Bidens frondosa)

Animals of this habitat include the eastern chipmunk (Tamias striatus), eastern woodrat (Neotoma floridana, killdeer (Charadrius vociferous), herring gull (Larus argentatus), and lesser yellowlegs (Tringa flavipes).  The peregrine falcon (Falco peregrinus) is also commonly seen in this community feeding on small shore birds.


Gravel Bar (Gravel Wash Community)

The major gravel bar at the Falls comprises the first terrace above the limestone cliffs below and to the west of the Interpretive Center.  Gravel at the Falls was scattered from glacial till along the river, and it was deposited on bars where the river made a bend.  Now protected by the surrounding fixed weir dam, the gravel bar habitat has become more permanently established as open woodland.  The gravel bars at the Falls are sparsely covered with cottonwood (Populus deltoids), sycamore (Platanus occidentalis), black willow (Salix nigra), silver maple (Acer saccharinum), elderberry (Sambucus canadensis), black locust (Robinia pseudacacia), white mulberry (Morus alba), American elm (Ulmus americana), and slippery elm (Ulmus rubra).  The under story is relatively bare and dominated by common ragweed (Ambrosia artemisiifolia), smartweed (Polygonum hydropiper), clearweed (Boehmeria cylindrica), mist flower (Eupatorium coelestinum), wild golden glow (Rudbeckia laciniata), wild cucumber (Sicyos angulatus), and various sedges.  Vines like the riverbank grape (Vitis riparia), wild potato (Ipomoea pandurata), red morning glory (Ipomoea coccinea), and trumpet creeper (Campsis radicans) often form a leafy carpet. 

The animals found in this habitat are the same as the adjacent woodland.       

The Classification of Ecological Communities      

Indiana's Endangered & Threatened Wildlife web site  

Indiana's Species of Greatest Conservation Need (PDF)              

Created July 19, 2010, Updated April 6, 2011.