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Ecology
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- Overview
- The unique landscape of the "Driftless Area" has produced a tremendous
diversity of plant and animal life. The Mississippi River with its many islands, sloughs
and backwaters produce an abundance of habitat for aquatic vegetation and animals.
The Yellow River wetlands complex contains shallow waters and lowland forests ideal for
many forms of bird life. The terraces above the floodplain contain rich soil for walnut
trees.
The bluffs and hills along the river provide a corridor for migratory species along the
Mississippi Flyway. South-facing slopes receive more direct sunlight and are relatively
free of snow during the winter. Many of the ridge tops contain prairie remnants which are
once part of a greater expanse of grassland extending to the west.
North-facing slopes contain plants normally associated with areas to the north. Some
plants very likely arrived in the area during the time when much of the midwest was
covered by glaciers. The bluff country, which was missed by the ice, harbored plants from
the north which today continue to grow on cool north slopes.
- Habitats
River Bottoms
- While the Mississippi River channel is heavily used for navigation, it is also the home
of many species of mussels including the federally-designated endangered Higgin's eye
pearly mussel. For many years sedimentation and now the exotic zebra mussel may lead to a
further decline of these species. Some soft shelled turtles use the channel and are also
declining in numbers. Map and falls map turtles, painted turtles, and Blanding's turtle
use the quite backwaters.
 The backwaters are the home of
many of the most interesting animals in the region. The majestic bald eagles nest on
island and feed on fish from the river. Hundreds of bald eagles winter along this stretch
of the river. The threatened red-shouldered hawk nest in the wooded flood plain forests.
Several colonies of tree nesting areas, called rookeries, contain great blue heron, common
egrets and double-crested cormorants. The rookeries become very noisy places in spring
with the nests of young being fed by their parents.
The islands and backwater sloughs contain beaver, otter, muskrat and other furbearers. The
land of the Sny Magill Unit of Effigy Mounds National Monument not only contains many
mounds, but also an interesting riverbottom forest. Large swamp white oak, honey locust,
cottonwood and soft maple make up the canopy of this forest. Many song birds use this
habitat for nesting and as resting places during migration. The prothonotary and cerulean
warbler are two of the feathered jewels of the riverbottoms.
The Yellow River environment consists of slow-moving streams and shallow ponds. This
wetland is an important feeding and rest area for birds and also contains many types of
amphibians and reptiles. In early spring the chorus of frogs rises from the ponds and
continues through early summer as various species begin their ancient courtship ritual.
- Upland Forest
- Along the base of the bluffs is rich soil that supports stands of black walnuts. The
terrace along the Yellow River where the present visitor center is located very likely
contained a large stand of walnut when the mounds were built 2000 years ago. Much of this
land was logged and later cleared for farmland. Some large walnut trees are still found
behind the visitor center.
The wooded hills consist of red and white oak, sugar maple and basswood. Some ridgetops
have young aspen and shagbark and bitternut hickory growing on them today. The land that
the monument encompasses today had been logged several times prior to becoming a monument.
At one time, elk lived in the area of the present monument and were last found in the area
in the 1840s. The white-tailed deer is very common in the monument. Few people realize
that in the 1920s no deer were found in northeast Iowa. Unregulated hunting led to the
disappearance of the deer, which returned to become plentiful again and commonly sited in
the monument. Wolves were found in the area until the 1920s according to bounty record.
Today the coyote fills the niche of the wolf in this area. It is not uncommon to see
coyote in the area and to hear their eerie call in the night. Red fox are seen frequently
along roadsides and den in the monument. Gray and fox squirrels along with chipmunks, blue
jays, redheaded woodpeckers and wild turkey depend on acorns for food. Ruffed grouse can
be heard drumming in the spring from the wooded hills and are year round residents,
feeding on aspen buds during the winter.
Raccoons and wood ducks nest in hollow trees in the monument. The upland forest with its
many nut trees and berries provide excellent food for wildlife. Wildlife and birdwatching
are best in the early morning when wildlife is most active. Deer and other large animals
are also active just before dusk.
- Prairie
- Much of the prairie that was found when the monument was established in 1949 consisted
of small remnants called goat prairies. These prairie areas were on the rocky bluffs
overlooking the river valley "too steep to plow and only fit for a goat to
graze." The South Unit had an area of prairie which had been heavily grazed but never
plowed. In the 1980s, the resource manager at Effigy Mounds National Monument began a
program of prescribed burns to enhance the quality of the prairie vegetation.
The spring burning ritual tends to give the deep rooted prairie plants a survival
advantage over shallow rooted weeds. Woody plants are set back and sometimes killed by
burning. The prescribed burns are intended to recreate the conditions found on our
ridgetops before settlement. In the early 1990s a program of prairie restoration was
started to plant prairie vegetation in roadside ditches and in old fields in the North
Unit. Although the bison will not be a member of the living community of the monument's
prairies, many insects and birds will benefit greatly from the increased diversity of
plants found in the prairie environment.
Big bluestem, Indian Grass, switchgrass and little bluestem make up the predominate
grasses of the tall grass prairie. Butterfly weed, compass plant, blazing star and
black-eyed susans add color to the open grasslands. The prairie reaches its peak of height
and color in August and September. A trip to the prairie can be an unforgettable
experience. It reminds us of our heritage here in the midwest.
The ecology of the monument is dynamic, constantly changing from season to season and from
year to year. This process of change is called succession. The more we learn about the
monument's plant and animal life, the more interesting this area becomes.
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