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|Everglades National Park|
Everglades National Park is one of the largest and most well-known of America's national parks. It was also the first of America's parks to be preserved not for its scenic wonders (although these certainly exist) but because of the magnificence of its biological resources. Currently covering 1,506,539 acres, it is the third largest national park in the contiguous 48 states, smaller only than Death Valley and Yellowstone NationalParks.
The Everglades is located on the extreme southern section of the Florida peninsula, about 20 miles east of Biscayne National Park. Although many visitors are unprepared for Everglades' attractions which are quite different the spectacular geographical characteristics of many western parks, the features are subtle but fascinating. The park encompasses sawgrass marshes, hardwood hammocks, mangrove swamps, lakes, and Florida Bay. It is know for its animal life including the famous alligators, the largest concentration of wading birds on the American continent, 14 threatened or endangered species. The park preserves one of the world's truly unique ecosystems.
It is apparent that the Everglades have been inhabited for over 10,000 years, perhaps even 20,000. By 4,000 years ago the area with its ample food supplies-fish, shellfish, plants, and land animals--supported a substantial population. Europeans first appeared on the scene in 1513 when Ponce de Leon explored portions of the Florida peninsula. On a later visit he was killed in the area by a Calusa arrow. When the Spanish arrived in the 1500's, two primary groups of Indians, the Calusas and the Tequestas--lived in the area. Population estimates range between about 5,000 and 20,000. The Tequestas were fishermen, while the Calusa ate shellfish, clams, and oysters. However, the Indian population was largely eliminated by the diseases introduced by the Spanish explorers, such as tuberculosis, influenza, and polio.
After the initial Spanish attempts at conquest, the south Florida area returned to isolation for 300 years. After 1700, Indians of the Creek Confederacy from Georgia and other areas north of Florida migrated into the areas vacated by the extermination of the previous inhabitants. These Indians came to be known as Seminoles ("free man" in an Indian language), but they were largely eliminated and eventually forcibly moved as a result of the Seminole Wars (1835-1842, 1855-1859) which followed the acquisition of Florida by the United States in 1821. Whites begin to settle the coastal areas of the present park in the 1880's and 1890's. Piioneers supported themselves with a combination of farming, fishing, hunting, and hunting of birds for their plumage.
For potential visitors, ParkVision recommends "Story Behind the Scenery" guides and "Trails Ilustrated" maps.
However, threats to the integrity of the Everglades ecosystem became a reality with the arrival of people. Many birds were hunted to the brink of extinction for their plumage. The sheet flow "river of grass" which forms the basis for the existence of the glades came under attack as Floridians began to divert the waters flowing south from Lake Okeechobee to control floods and provide water to the burgeoning population. In the early 1900's Governor Napolean Bonaparte Broward campaigned on promises to drain the wetlands. In 1909 the Everglades Drainage District completed the Miami Canal connecting Lake Okeechobee to the Miami area, and additional channeling projects were completed by the Army Corps of Engineers. A dam on the south rim of the lake itself was completed in 1930. Later, the Tamiami Trail road which runs east and west through the Everglades was completed, interrupting the flow of water to the south.
During this period the characteristics of the glades began to attract attention. In 1832 J. J. Audubon visited and observed and studied the amazing concentration of birds. The Audobon Society later spearheaded efforts to save the bird populations from the ravages of hunters. In 1901 this effort culminated in a law prohibiting hunting of many of the area's birds (except for game birds).This effort was highlighted in 1905 when one of the Audobon wardens, Guy Bradley, who was charged with prevention of bird poaching, was murdered by a hunters. Eventually, interest in preservation of parts of the glades began to develop. In 1916 the Paradise Key area was established as Royal Palm State Park, a result of effort by the Florida Federation of Women's clubs.
However, threats to the resources of the park continued to mount, as a result of oil drilling, lumbering, and other activities. These threats generated interest in preservation of the natural wonders. National Park Service Director Stephen Mather advocated a national park for the Everglades in 1923. In 1929, the Florida legislature created the Tropical Everglades National Park Association under the leadership of landscape architect Ernest Coe to investigate the possibility of establishment of a national park. Coe's tireless efforts resulted on May 20, 1934 in the passage of a bill authorizing creation of the park, and although the boundaries of the park were to enclose 2 million acres no land was to be actually acquired for 5 years. In fact, land acquisition was further delayed until after World War II when the park was finally dedicated on December 6, 1947 by President Truman in a ceremony at Everglades City. It was the first park to be founded to protect primarily biological resources.
Despite creation of the park, threats to the Everglades environment have continued. Water supplies and quality remain a problem, and in the 1960's an enormous airport on the eastern border of the park, planned to cover 39 square miles, was planned. This plan was opposed by environmental groups and finally abandoned. In 1962 water suppolies to the Everglades was seriously diminished when the water flowing under the Tamiami Trail was restricted through only 4 water control gates. Water was on occasion shut off completely; among other casualties of this action, half of the existing alligator population was lost.
In 1971 Congress mandated a minimum flow of water into the park. And, in 1974, the Big Cypress National Preserve was created. This area had been part of the original authorization in 1934 but had not actually been included in the park when it was officially created.In 1979, an additional 107,600 acres was added to the park.
However, the Everglades has often been called the most endangered national park. Water supplies and the natural flow and cycle are still problems. Diminished flows of water from the north have increased the intrusion of salt water into the southern section of the park near the coast. The water which does flow into the park is somewhat polluted by agricultural runoff. Very high levels of mercury have been detected in the park's fish. The park is under serious stress from three major sources--the increasing domination of non-native plants, water quantity, and water quality.
To many people the name "Everglades" conjures up images of a deep, dark swamp. And while swamps exist in the Everglades, particularly in the Big Cypress National Preserve, most of the land area of the park is quite different from that. Very different types of land and vegetation can be found in the park, often dependent on how high the land lies and where differences of a few feet have substantial effects.
Sawgress Marsh The heart of the Everglades is the vast sawgrass marshes, the largest of its kind in the world. Prior to the engineering efforts of the human residents of Florida, these marshes were once part of a huge, shallow river 50 miles wide and 120 miles long running from Lake Okeechobee in the north to Florida Bay in the south. Noted naturalist and defender of the Everglades Marjorie Stoneman Douglas appropriately termed these areas the "River of Grass." This river was created from overflowing water from the lake running slowly--on the order of a foot or so a minute--across the slightly inclined floor of south Florida. From a geological perspective, this environment and the Everglades themselves are quite young, perhaps 5000 years.
There are two seasons in the Everglades--the dry season, from about November through April, and the wet season, from May until October when an average of 53 and even 100 inches of rain might fall. Approximately 60 inches of rain falls during the wet season and the limestone base of the sawgrass areas are covered by water. The sheet of water which flows through the Everglades results from overflow from Lake Okechobee in the north after the summer rains.
However, the "River of Grass" from Lake Okeechobee through the Everglades no longer flows freely. Over the past 60 years it has been interrupted by 1400 miles of canals, levees, and spillways, designed to control flooding and provide water to the ever increasing population of south Florida. The current park embraces only about 1/10 of the original Everglades area.
Surprisingly, to some, the sawgrass marshes are not soft, but have a porous but extremely hard limestone bottom. It is quite possible to walk across these prairies even during the wet season without sinking.
The sawgrass plant itself is actually a sedge, one of the oldest green plants on earth. It's low requirements for nutrients makes it well adapted for the Everglades environment. The leaves of the sawgrass plant have serrated edges which can easily cut a person if he or she runs a hand along the plant in the wrong direction. During the wet season the roots of the plant are completely covered by water; in the dry season the marshes are occasionally devastated by fire. Periodic fire is actually helpful, as it eliminates dead, matted sawgrass which otherwise accumulates.
The sawgrass marsh is the emblem of the Everglades, in some ways calling to mind the African savanna. But there is no real equivalent to the sawgrass marshes and the sheet flow anywhere in the world; the ecosystem is unique. Marjory Stoneman Douglas, in her famous book Everglades: River of Grass, wrote in 1947 that "there are no other Everglades in the world."
Pine Forest The highest areas of the park, which lie several feet above the low areas, are covered by forests of slash pine and plants like the saw palmetto which grows in the mulch of fallen pine needles. These are called "pinelands" or "pine flatwoods." The term "slash pine" is derived from the old practice of slashing their bark to get sap to make turpentine. Other pines which are found in these areas include longleaf pine, southern Florida slash pine, and pond pine. The floor of these forests is rough, rugged, and rocky.
At one time much of the eastern border of the park was covered by these forests, as they ran in a band about 4-5 miles wide some 50 miles to the south from Ft. Lauderdale. The Miami and Ft. Lauderdale areas used to be part of these pinelands.The only remaining portion of this forest is that which exists in the park.
The land in the Everglades is very flat (the highest point is only 8 feet!) and the wetlands are quite shallow, so elevations of even a few feet make a considerable difference in the character of the land and the vegetation which grows on it. Pinelands are located on the highest points which are rarely covered with water where there are pockets of fertile soil laying on the limestone base.
Fires which periodically sweep park areas are necessary for the survival of the pine forests, clearing undergrowth and promoting growth. Without fire, pineland areas will become overgrown, rather than open, and eventually dominated by hardwood trees. The slash pine itself has a corky bark which is quite resistant to fire. Hurricanes, however, can be a different matter. Hurricane Andrew's powerful winds snapped the trunks of about 30% of the parks pines in 1992.
The pine forests are rich with vegetation, supporting fully half the plant species in the park. Within the pine forests, based on the limestone floor, solution holes can be found. Alligators used to live in these pockets sin the limestone, but there isn't usually enough water anymore to support them.
Hardwood Hammocks Few trees grow within the sawgrass marshes themselves since their roots would be covered by water during a significant portion of the year. However, within the marsh are places where the limestone is just a couple of feet higher, high enough to permit hardwood trees like mahogany, gumbo limbo, cocoa palm, and other plants to grow. These areas, which may range from an acre or so to hundreds of acres, remain dry year round. The hammock creates ins own protective environment, often cooler than the surrounding glades.
The leaves cast off by the hammocks trees mix with rainwater to form an acidic solution, dissolving limestone downstream from the hammock, surrounding the hammock with a moat which provides additional protection in the event of fire.
Because they are dry the hammocks served as places for the Indians of the glades to live. They also grew crops in the soil of the hammock; the word "hammock" may be derived from the Indian term for "garden place." The damp shade, however, also provides a wonderful environment for the mosquitoes which can often be found there in great numbers.
One of the most well-known of the hammocks is Mahogany Hammock, below.
The interior of the hammock is dark and thick with vegetation, the floor spongy with rotting leaves. Mahogany Hammock also features a .3 mile boardwalk nature trail (left) which allows the visitor to experience the interior of a hammock.
Mahogany Hammock happens to contain America's largest mahogany tree, a portion of which is seen below. Many of these trees have been logged for the superior quality and durability of their wood.
So many trees have been destroyed by fire, hurricanes, and logging that they no longer reseed naturally, and therefore are likely eventually to disappear. This is considered a natural occurrence and thus will be allowed to happen.
Mangrove Swamp In areas near the coast where the salt water of the gulf and Florida Bay meets the fresh water traveling from Lake Okechobee is realm of the mangrove trees. These trees prefer brackish water, and are responsible for creation of much new land because their roots and trunks trap organic material in the water. Mangrove swamps cover more than 500 square miles in the park.
The photograph below shows Buttonwood Canal through the mangrove groves. This channel was built by the National Park Service and was somewhat controversial as it allow salt water from Florida Bay to enter Coot Pond and Whitewater Bay.
Coastal Prairie One other type of landform found in the extreme southern section of the park is the coastal prairie, shown below. These areas contain meadows and woodlands of buttonwood, gumbo limbo, hardwoods of other types, yucca, and grasses.
Another photograph of coastal prairie lands, just north of Eco Pond in the Flamingo area, is shown below.
If there is any animal which is synonymous with a national park it is surely the American alligator and the Everglades. The largest of about 50 reptile species in the Everglades, this animal can be found in many places throughout the park in large numbers.
This reptile is a remnant of the Mesozoic era (245-65 million years ago). It is America's largest reptile, reaching as much as 16 feet in length for males and 8-9 feet for females. The largest gator ever measured was a 19 foot 2 inch monster in 1890, although it is rare to find one today greater than 14 feet. In the wild, male alligators may live about 30-35 years.
The name alligator originated in the Spanish "el lagento"--the lizard. The alligator is surprisingly mobile, able to cover as much as 5 miles a day across land if necessary. A large bull alligator may patrol a territory of as much as 5 square miles.
Although many people are quite frightened of alligators they generally do not attack human beings as they are intimidated by the human's vertical stance. The alligator can be discriminated from its relative the crocodile by the u-shape of its snout and the impossibility of seeing bottom teeth when its mouth is closed. The jaw is hinged, allowing it to open its mouth very wide and ingest a large piece of food.
Of course, the teeth are among the most impressive features of the 'gator. It has 400 teeth each in its upper and lower jaws, and it is able to regenerate new teeth after old ones fall out. All of the teeth are sharp--it possesses no molars at all. The strength of the jaws is awesome--as much as 3000 pounds per square inch.
The alligator does not have to eat frequently, sometimes taking a meal only once or twice a week, and it can survive up to six months without feeding. Typically, the gator feed between dusk and dawn. When it does eat it generally catches wading birds, waterfowl, turtles, raccoons, other small animals, fish such as the gar, and even poisonous snakes. Typically, an alligator meal may be 20% of its current weight. When it takes a larger animal, it may grab the animal and use its strength to drown it. The alligator depends on quick, strong muscles and lightning quick movements to catch its prey. In the picture below a wood stork shares a portion of Taylor Slough with a gator.
The alligator also functions as the engineer of the glades, providing a valuable function by finding low points in the limestone bases and using its snout, tail, and feet to enlarge the hole and clear out mud and vegetation from the water there to form "gator holes." During the dry season these pools provide water resources for many animals in the glades. As such the alligator is a "keystone species"--it affects the existence of other organisms in key ways.
The alligator prefers ambient temperatures between about 89 and 95 degrees but will tolerate temperatures as low as 39 degrees. The animal prefers fresh water but can tolerate brackish and salt waters. Alligators are able to stay submerged for as long as 45 minutes, even longer in cooler weather. Gators which live along channels and canals utilize "gator slides" (as below) to exit and reenter the water.
When born the alligator hatchlings are only 10 inches long. They grow about 1 foot a year for about 10 years. Although powerful when older, baby alligators may be eaten by great blue herons, egrets, otters, and raccoons. Not surprisingly, once an alligator reaches 6 feet in length it's relatively free from predation.
The alligator's streamlined shape, powerful tail, and eyes set on the top of its head. Its ears, which are very sensitive, are located behind the eyes, covered by a small flap. Thus, the alligators major sensory organs lie just above the surface of the water when it is partially submerged, as in the picture below.
No matter how many alligators may appear on the front of golf shirts, the alligator's skin is black, not green. The dark color enables the cold blooded animal to absorb the sun's heat and warm its body. The hide contains hundreds of rectangular scales as well as bony plates, called scutes. Its distinctive "armor-plated" skin which it depends on for defense is made of keratin, similar to human fingernails.
But the skin of the alligator (particular the non-plated areas on the underside of the neck and stomach) was once responsible for the near extinction of the animal, as they were hunted to produce alligator purses, boots, and other goods. Hunting began in 1855, and it is estimated that at least 10 million hides were processed between 1870 and 1965. Hunters (and later poachers) would hunt the animals at night and fire at the reflection of torches in the alligator's eyes. Hunting of these creatures occurred from the mid-1880's until the 1960's but of course is no longer permitted in the park. Although the alligator once existed in far greater numbers in the glades, the alligator population has recovered nicely and it is no longer classified as an endangered species, although the disappearance of alligator habitat continues to cause concern for the long term well-being of the species.
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