Everglades may not be our largest national park (that honor belongs to
Wrangell-St. Elias in Alaska), but it is certainly the wettest. During
and after the rainy season, when not only the mangrove swamp but also
the sawgrass prairie is under water, most of the park abounds in fish
and other water life, and even the white-tailed deer leads a
semi-aquatic existence.
Despite the fact that it is low, flat, and largely under water,
Everglades is a park of many environments: shallow, key-dotted Florida
Bay; the coastal prairie; the vast mangrove forest and its mysterious
waterways; cypress swamps; the true everglades—an extensive freshwater
marsh dotted with tree islands and occasional ponds; and the driest
zone, the pine-and-hammock rockland.
The watery expanse we call “everglades,” from which the park gets its
name, lies only partly within the park boundaries. Originally this river
flowed, unobstructed though very slowly, southward from Lake Okeechobee
more than 100 miles to Florida Bay. It is hardly recognizable as a
river, for it is 50 miles wide and averages only about 6 inches deep,
and it creeps rather than flows. Its source, the area around Lake
Okeechobee, is only about 15 feet above sea level, and the riverbed
slopes southward only 2 or 3 inches to the mile.
As you can see by the maps on pages 2 and 3, the works of man have
greatly altered the drainage patterns and the natural values of south
Florida, and you can imagine how this has affected the supply of
water—the park’s lifeblood.
The park’s array of plants and animals is a blend of tropical species,
most of which made their way across the water from the Caribbean
islands, and species from the Temperate Zone, which embraces all of
Florida. All of these inhabitants exist here through adaptation to the
region’s peculiar cycles of flood, drought, and fire and by virtue of
subtle variations in temperature, altitude, and soil.
[Illustration: HISTORIC DRAINAGE PATTERNS OF SOUTH FLORIDA]
[Illustration: DRAINAGE PATTERNS OF SOUTH FLORIDA TODAY]
[Illustration: PLANT COMMUNITIES OF EVERGLADES NATIONAL PARK
The horizontal distance represented on this diagram, from the Pineland
to Florida Bay, is 15 miles. With a greatly exaggerated vertical scale,
the difference between the greatest elevation of the pine ridge and the
bottom of the Florida Bay marl bed is only 14 feet.]
FLORIDA BAY (SALT WATER)
MUD BANK
KEY
COASTAL PRAIRIE
MANGROVE SWAMP (BRACKISH)
BUTTONWOOD LEVEE
TREE-ISLAND GLADES (FRESH WATER)
BAYHEAD
CYPRESS HEAD
WILLOW HEAD
HARDWOOD HAMMOCK
PINE AND HAMMOCK RIDGE
Underlying the entire park is porous limestone (_see_ glossary), which
was deposited ages ago in warm seas that covered the southern part of
today’s Florida peninsula. Over this limestone only a thin mantle of
marl and peat provides soil for rooting plants.
Some of the park’s ecosystems (_see_ glossary) are extremely complex.
For example, a single jungle hammock of a dozen acres may contain, along
with giant live oaks and other plants from the Temperate Zone, many
kinds of tropical hardwood trees; a profusion of vines, mosses, ferns,
orchids, and air plants; and a great variety of vertebrate and
invertebrate animals, from tree snails to the white-tailed deer.