The
Everglades is a swampy area located in southern Florida.
The Indians called this the “River of Grass”
because it is a body of water fifty miles wide and six inches deep that
runs
from Lake Okeechobee to the Gulf of Mexico through prairies of sawgrass. This unique place is home to a diverse
population of plants and animals. For
the past one hundred years people have changed this natural system by
building
canals and levies to bring water to the cities and farms.
The water has been polluted by factories,
fertilizers and pesticides. There has been a severe change in water
flow to the
Everglades. Because of these changes
there is habitat and animal loss due to the lack of food and water.
To
protect this ecosystem, part of the Everglades was turned into a
national park
in 1947. The Everglades National Park is
located at the south tip of Florida. It
is shaped like a bird with its head pointing northeast and its wings
and body
covering the rest of Florida’s tip. The Everglades National Park covers
2,746
square miles or about one-fifth of the original area of the Everglades
swamp.
Because
of the dramatic changes in rainfall between the wet summer season and
the dry
winter season, survival in the Everglades is very difficult for plants
and
animals. In the summer, there is 100% humidity and 95 degree
temperatures most
of the time, with severe thunderstorms.
In summer the water covers wide areas, while in winter the edges
of the
Everglades dry up into smaller ponds.
Slight changes in elevation, water salinity (saltiness), and
soil create
entirely different landscapes, each with its own plants and animals.
During
the dry winter season, water levels drop and fish move to the deeper
pools. Birds, alligators, and other
predators concentrate around the pools to feed.
In spring, thunderstorms begin the rainy season and the pools of
water
turn into a landscape completely covered by water.
The wildlife disperses throughout the swamp
and the food chain is replenished.
Plants
and animals that live in the Everglades have adapted to these severe
conditions
over many thousands of years. When
humans change the cycle of water flow, many animals have great
difficulty
adapting fast enough. For example,
alligators build their nests at the high water level.
When more water is released into the
Everglades through the man-made channels and gates, the nests are
flooded and
destroyed.
There
are over 900 different types of plants. The northern part of the
Everglades is
a prairie covered by water with sawgrass growing up to 10 feet high. Some other plants in the northern area are
bald cypress, custard apples, wax myrtles, and willows.
The
“Pinelands” is dry, rugged terrain that sits on top of a limestone
ridge. The slash pine trees root in cracks
where the
soil collects in the bedrock. These pine
trees need fire to survive. The
pinelands have over 200 types of tropical plants. The “hardwood
hammocks” are
groups of hardwood trees that grow on land a few inches above the water. Acid from decaying plants dissolves the
limestone and creates a moat around the hammock trees, protecting them
from
fires.
The
Everglades is home to more than 600 different species of animals, not
including
over 60 types of mosquitos. Some are
alligators, crocodiles, deer, fish, panthers, pelicans, and snakes. Scientist think that if some animals in the
Everglades were studied, they could help humans cure diseases.
Some
of the endangered animals are the American crocodile, southern bald
eagle,
logger head turtle, snail kite, wood stork, and the red-cockaded
woodpecker. Due to the loss of their
habitat, the number of wading birds has been reduced by 90% in the last
100
years.
Humans
have changed the landscape, but you can still see the geological
landscape. During the Great Ice Age the
seas rose and fell as the glaciers formed and melted.
When water covered the land, silt, sand, and
particles of calcium settled to the
bottom of the sea and gradually cemented themselves into limestone. Since this happened at many different
times,
layer after layer of limestone created different elevations of land. These small differences in height eventually
lead to different regions of plant growth.
For instance, pine and hardwood forests grow at higher
elevations, while
sawgrass prairies cover the lower and wetter areas and mangrove trees
grow
along the coast. The elevation
differences are very small. No place in
the Everglades is more than 8 feet above sea level.
Thomas Carter
May, 2002