The
Louisiana Swamp and its wildlife
Where
the Mississippi River flows through Louisiana to the Gulf
of Mexico, it forms a large area of swamps. A variety of plants,
birds, and mammals inhabit this rich wetland environment.
Vegetation
In
the Rockies the tree line (the highest altitude at which
trees will grow) ranges from 2,500 feet in the icy Yukon
territory to 1 2,000 feet in more temperate New Mex-ico.
just below those areas that are covered permanently with
snow, the forests are made up of pine, spruce, and fir trees.
At lower elevations they also include birch, beech, and
cherry trees.
>Knee-high
willows cover much of the Arctic Rockies, and mature willows
and cottonwoods grow beside streams. Above the tree line,
lichen, saxifrage, columbine, larkspur, and other alpine
plants abound.
Reptiles
Once
quite rare, the alligator is returning in numbers now
that hunting it is illegal. The alliga-tor lays its eggs
in a nest of mud and grass. The mother helps the young
out of the nest after they hatch.
Other
reptiles include venomous snakes such as the cop-perhead
and cottonmouth, as well as harmless water snakes. The
snapping turtle and map turtle (named for markings on
its shell that resemble a map) also live in the marshes.
Am-phibians are also numerous, including several frog
species.
Mammals
The raccoon
is very skilled at catching fish, crayfish, frogs, and salamanders.
The American mink has a similar diet, with the addition of
birds and mice. Its larger cousin, the river otter, is a rare
sight.
Other
large predatory mammals such as the bobcat and cougar are
also elusive. The black bear is even rarer. It has been saved
from extinction in Louisiana only by the introduction of cubs
from Minnesota into the area.
The muskrat,
a large rodent, builds a lodge like the beaver's out of reeds
and twigs above the water line, with an entrance below water
level. A similar animal from South America, the coypu, or
nutria, escaped from fur farms in the area and is now flourishing.
In the
swamps, the white-tailed deer has larger hoofs than normal
to cope with muddy ground. The cypress swamp is also home
to the flying squirrel that glides from tree to tree.
In the
forests surrounding the swamp lives the common opossum-one
of only a few marsupials (mammals whose young develop inside
the mother's pouch) to live outside Australia.
Aquatic
Aniamals
The coastal
marshes of Louisi-ana are important nurseries for shrimp, channel
bass, and sea trout, which breed and mature here before swim-ming
out to open sea.
Moving
inland through the salt and freshwater marshes, the species
change with the water salinity (salt level), since fish, crabs,
oysters, and shrimp all prefer different conditions. The aquatic
animals of the swamps provide a rich food supply for predators,
including humans. Crayfish are considered a local delicacy,
although supplies are dwindling. Fishermen also catch freshwater
fish such as channel catfish and bluegill.
Birds
The "Mississippi
Flyway" is a huge migration route that passes through the open
marshes of Louisiana. In win-ter, a half million blue and snow
geese fly in from Arctic breeding grounds. Other win-tering
species include the Canada goose, mallard, ring-necked duck,
pintail, and shoveler.
Summer
migrants include the snowy egret, green her-on, Louisiana
heron, ibis, roseate spoonbill, least bit-tern, and darter.
Smaller species such as warblers and hummingbirds spend the
summer in the woods, while other birds just stop over in the
swamps on their way farther north.
Plants
The bayous
meander through cypress swamps where trees such as bald cypress
and tupelo gum support other plants: tree orchids, ferns, and
Spanish moss.
Insect-eating
plants such as the sundew and pitcher plant live underneath
the trees. The water hyacinth, a species from South America,
grows rapidly and can clog bayous.
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