The Changing Face of Nature
The Changing Face of Nature
by John Schwegman
Illinois' natural world is constantly changing as new species move in, some old ones die out
and some animals change their habits. Of course massive human induced changes such as land
clearing and draining and urban development are going on, but this column is about more subtle
changes brought about by plants and animals themselves.
The most conspicuous changes going on are those involving natural vegetation where whole
communities are taking on a different character.
Our oak woods are changing to sugar maple forests and our hill prairies are converting from
prairie grasses to shrubs and trees due to a lack of fire. Widespread landscape fires that maintained
these communities in the past are not compatible in much of our modern landscape.
Many bulrush and sedge marshes in northeastern Illinois are changing to cattail marshes
because of increased nutrients and fertility in their water. Others are being invaded by the introduced
exotic purple loosestrife plant and reed canary grass which replace the native sedges and flowers.
Whole forests are changing their character as their native wildflowers are replaced by exotic
plants like garlic mustard and dame's rocket. Prairies are being overrun by the exotic sweet clover
plant.
Conservation biologists are working to control these changes in managed natural areas, but
the overall landscape continues its face change.
At the species level, exotic animals like the zebra mussel are changing the nature of our rivers
and lake Michigan in a major way. Because of their massive numbers, they lower the oxygen levels
in the water and their filter-feeding consumes much of the microscopic food needed by hatchling
fishes and other creatures. They may kill out native mussels by attaching to them in such numbers
that they smother them.
Newly introduced fish, like the round goby of lake Michigan and the bighead carp in the
Mississippi River, may eventually trigger big changes in these aquatic habitats. The 2-inch-long
Chinese mystery snail that has recently established itself in the Illinois River drainage and Lake
Michigan is quite a change in nature just by its presence. Its impact on native snails may cause
further changes.
Exotic land animal introductions, like the house sparrow and starling, have been stabilized
for many years, and no new invasions are under way. However, our native wildlife continues to
change its range and abundance.
That pink-tinged "sparrow" that shows up at your bird feeder now is the house finch of
southwestern American deserts that has managed to get across the great plains and has now spread
widely in the east.
The coyote is now common throughout Illinois while it was not even present when I was
growing up in southern Illinois. With its increase, there has been a decline in the numbers of
woodchucks and red foxes in the state. Coyotes successfully prey on these mammals.
The giant Canada goose that was nearly exterminated early this century has adapted so well
to our lakes and ponds that it is now a common nester statewide. In urban areas it has become a pest.
Wild turkeys are now common almost statewide where they were absent within my memory,
and our deer herd is locally so abundant now that it changes the vegetation on large areas by over
browsing the trees and shrubs for food. This change of nature is greatest in urban areas where deer
numbers are difficult to control.
Native migrant birds are also changing their ways. White pelicans that normally just fly over
Illinois en route to nesting grounds in the northern Great Plains now sometimes stop for the summer
on the Mississippi River in northern Illinois.
Some snow geese, a species that once wintered only on the Gulf Coast of Texas and
Louisiana, now stop and spend the winter along major rivers of the southern half of Illinois. The
presence of these showy white geese over winter is a very conspicuous change in the face of nature.
The appearance of the striped mullet in the Mississippi and Ohio river waters of Illinois in
the last seven years represents another change in range for a native species. Normally a fish of
coastal salty waters, for some reason this fish has decided to move into fresh waters up the
Mississippi River. Since it reaches 3 feet in length, it will obviously be a conspicuous addition to
our fauna.
About 10 years ago, wild American holly trees began appearing in southern Illinois forests.
While this native tree of the south had been cultivated in the area for probably a century, it has
escaped to establish wild populations only in the past decade. Speculation would indicate that a
warming climate might be the cause of this change.
The changes in nature include behavior changes as well. One of the most noticeable of these
is the foraging of gulls on parking lots in the last few years. Gulls have learned that discarded french
fries and other food items can be found on these lots and now soar over them searching for food as
they once searched our rivers and lakes.
Someone familiar with the natural scene in Illinois just 40 years ago would be amazed to see
the changes that have occurred in nature since that time. Most of this change is due to human
activities like the introduction of species, habitat alterations and possibly global warming. One thing
seems sure; the changing face of nature will continue to change.
# # #
by John Schwegman
Illinois' natural world is constantly changing as new species move in, some old ones die out
and some animals change their habits. Of course massive human induced changes such as land
clearing and draining and urban development are going on, but this column is about more subtle
changes brought about by plants and animals themselves.
The most conspicuous changes going on are those involving natural vegetation where whole
communities are taking on a different character.
Our oak woods are changing to sugar maple forests and our hill prairies are converting from
prairie grasses to shrubs and trees due to a lack of fire. Widespread landscape fires that maintained
these communities in the past are not compatible in much of our modern landscape.
Many bulrush and sedge marshes in northeastern Illinois are changing to cattail marshes
because of increased nutrients and fertility in their water. Others are being invaded by the introduced
exotic purple loosestrife plant and reed canary grass which replace the native sedges and flowers.
Whole forests are changing their character as their native wildflowers are replaced by exotic
plants like garlic mustard and dame's rocket. Prairies are being overrun by the exotic sweet clover
plant.
Conservation biologists are working to control these changes in managed natural areas, but
the overall landscape continues its face change.
At the species level, exotic animals like the zebra mussel are changing the nature of our rivers
and lake Michigan in a major way. Because of their massive numbers, they lower the oxygen levels
in the water and their filter-feeding consumes much of the microscopic food needed by hatchling
fishes and other creatures. They may kill out native mussels by attaching to them in such numbers
that they smother them.
Newly introduced fish, like the round goby of lake Michigan and the bighead carp in the
Mississippi River, may eventually trigger big changes in these aquatic habitats. The 2-inch-long
Chinese mystery snail that has recently established itself in the Illinois River drainage and Lake
Michigan is quite a change in nature just by its presence. Its impact on native snails may cause
further changes.
Exotic land animal introductions, like the house sparrow and starling, have been stabilized
for many years, and no new invasions are under way. However, our native wildlife continues to
change its range and abundance.
That pink-tinged "sparrow" that shows up at your bird feeder now is the house finch of
southwestern American deserts that has managed to get across the great plains and has now spread
widely in the east.
The coyote is now common throughout Illinois while it was not even present when I was
growing up in southern Illinois. With its increase, there has been a decline in the numbers of
woodchucks and red foxes in the state. Coyotes successfully prey on these mammals.
The giant Canada goose that was nearly exterminated early this century has adapted so well
to our lakes and ponds that it is now a common nester statewide. In urban areas it has become a pest.
Wild turkeys are now common almost statewide where they were absent within my memory,
and our deer herd is locally so abundant now that it changes the vegetation on large areas by over
browsing the trees and shrubs for food. This change of nature is greatest in urban areas where deer
numbers are difficult to control.
Native migrant birds are also changing their ways. White pelicans that normally just fly over
Illinois en route to nesting grounds in the northern Great Plains now sometimes stop for the summer
on the Mississippi River in northern Illinois.
Some snow geese, a species that once wintered only on the Gulf Coast of Texas and
Louisiana, now stop and spend the winter along major rivers of the southern half of Illinois. The
presence of these showy white geese over winter is a very conspicuous change in the face of nature.
The appearance of the striped mullet in the Mississippi and Ohio river waters of Illinois in
the last seven years represents another change in range for a native species. Normally a fish of
coastal salty waters, for some reason this fish has decided to move into fresh waters up the
Mississippi River. Since it reaches 3 feet in length, it will obviously be a conspicuous addition to
our fauna.
About 10 years ago, wild American holly trees began appearing in southern Illinois forests.
While this native tree of the south had been cultivated in the area for probably a century, it has
escaped to establish wild populations only in the past decade. Speculation would indicate that a
warming climate might be the cause of this change.
The changes in nature include behavior changes as well. One of the most noticeable of these
is the foraging of gulls on parking lots in the last few years. Gulls have learned that discarded french
fries and other food items can be found on these lots and now soar over them searching for food as
they once searched our rivers and lakes.
Someone familiar with the natural scene in Illinois just 40 years ago would be amazed to see
the changes that have occurred in nature since that time. Most of this change is due to human
activities like the introduction of species, habitat alterations and possibly global warming. One thing
seems sure; the changing face of nature will continue to change.
# # #
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