for centuries some wetlands, especially marshes and swamps, have
had a bad image Such areas harbored dreaded diseases during pioneer
times. Old World folklore told of the dark mystery of bogs. Who
would want such a feature on their land? Water has also been intensely
managed in the last 150 years. Illinoisans have extensively modified
the environment to make water go where they wanted. Wetlands have
been eliminated by drainage and filling. Rivers and streams have
been rerouted, deepened, and dammed to suit human purposes.
with an inkling of interest in nature need only visit a marsh or
a swamp on an April morning or evening to hear a remarkable concert
of songbirds or frogs. Or you could don waders
in November to visit a cattail marsh and see a diversity of waterfowl.
See Table 5.1 for information on the attributes of selected wetland
The term wetland has historically been defined
in many ways, confusing scientists and the public alike. In 1979
the U.S. Fish and Wildlife Service developed a classification system
to describe all water habitats in the U.S. The system, classifying
wetlands and deepwater habitats, was subsequently adopted by Illinois
Illinois water habitats are classified in three
- Rivers and streams-aquatic habitats contained within a channel
with water that moves permanently or intermittently.
- Lakes and reservoirs-permanent, deepwater impoundments and
natural lakes greater than twenty acres in size.
- Ponds, sedge meadows, marshes, forested wetlands, bogs, fens,
and othe r shallow or small habitats-permanent or temporary
wetlands partially or completely supporting aquatic plants;
bodies of water that are twenty acres or smaller in size.
The terms wetland and aquatic habitat are used
interchangeably in this chapter, with wetland being a generic term
for water habitat. Sedge meadows generally are dominated by a mixture
of sedge plants. These meadows are not permanently flooded but are
located in areas of frequently damp soil conditions. Marshes may
have permanent or seasonal water and usually contain both emergent
(growing in and above the water) and submergent (growing under the
water) herbaceous vegetation. Forested wetlands in Illinois are
known by such names as swamps, floodplain forests, and bottoms.
Most of our forested wetlands are composed of trees that can survive
short, frequent periods of flooding, such as silver maple, cottonwood,
and green ash. Southern Illinois, however, has a unique type of
forested wetland composed of stands of baldcypress and water tupelo,
which are noted for their ability to tolerate long periods of inundation.
While lake and river habitats are discussed in
this chapter, the primary focus is smaller aquatic habitats that
landowners can create and manage. Also addressed are the habitats
flanking rivers and streams (riparian habitat), which landowners
can significantly impact. Floodplain forests, which are also defined
as wetlands due to their periodic inundation, are discussed briefly,
but more specifics can be found in chapter 4.