Part 2

But the relentlessly rising sea of the past 10,000 years has belittled drought, fire, hurricane, and frost as it slowly inundated this land 3 inches each hundred years. In compensation, the mangrove forest adds peat and rises with the sea. The sawgrass marshes retreat, and the mangrove ecosystem prevails essentially unchanged.

Florida Bay and the Coastal Prairie

When you reach Flamingo, a former fishing village and now a center for visitor services and accommodations, you will be on the shore of Florida Bay. Here is an environment rich in variety of animal life, where porpoises play, the American crocodile makes its last stand, and the great white heron, once feared doomed to extinction, holds its own. The abundance of game fish in the bay has given it a reputation as one of the best sport-fishing grounds on the east coast.

The bay’s approximately 100 keys (low-lying islets) were built up by mangroves and provide foothold for other plants hardy enough to withstand the salty environment and the sometimes violent winds. The keys are also a breeding ground for water birds, ospreys, and bald eagles.

Florida Bay, larger than some of our States, is so shallow that at low tide some of it is out of water; its greatest depth is about 9 feet. The shallows and mudflats attract great numbers of wading birds, which feed upon the abundant life sheltered in the seaweeds—a plant-and-animal community nourished by nutrients carried in the waters flowing from the glades and mangroves.

To the west beyond Flamingo is Cape Sable. This near-island includes the finest of the park’s beaches and much of the coastal prairie ecosystem. A fringe of coconut palms along the beach could be the remnants of early attempts at a plantation on the cape that did not survive the hurricanes; or it could be the result of the sprouting of coconuts carried by currents from Caribbean plantations and washed up on the cape. For a time, casuarina trees (called “Australian pines”), which became established on Cape Sable after Hurricane Donna, seemed to threaten the ecology of the beach. But these invaders were mostly removed in 1971, and now appear to be under control.

Examine the “sand” of this beach. You will discover that it is not quartz grains—but mostly minute shell fragments. Entire shells of the warm-water molluscs that live offshore also wash up on the beach. There are also artifacts that speak of Indian activity in this area in past centuries, curled centers of conch shells from which the pre-Columbian Indians fashioned tools, and numerous pieces of pottery (potsherds). Both shells and potsherds tempt the collector. Shelling—that is, the collecting of _dead_ shells, for noncommercial purposes—is permitted. But Federal law prohibits the removal of even a fragment of pottery—for these are invaluable Indian relics, essential to continuing scientific investigation of the human history of the region.

FLORIDA BAY 1 RED-MANGROVE 2 BLACK-MANGROVE 3 WHITE-MANGROVE 4 BUTTONWOOD 5 CABBAGE PALMETTO 6 HURRICANE-KILLED BLACK-MANGROVES 7 FIG 8 POISONWOOD CROCODILE GREAT WHITE HERON REDDIS EGRET COCONUT PALM SUCCULENTS GRASSES SEDGES WATERWAY MARL PRAIRIE

Back from the narrow beach is a drier zone of grasses and other low-growing vegetation. Some of the plants of this zone, such as the railroad vine, are so salt-tolerant that in places they grow almost to the water’s edge. (No plant that is extremely sensitive to salty soil could survive on Cape Sable.) Beyond the grassy zone is a zone of hardwoods (buttonwood, gumbo-limbo, Jamaica dogwood), cactuses, yucca, and other plants forming a transition from beach to coastal prairie.

Birds provide much of the visual excitement of the beach community, just as they do in other parts of the park. Sandpipers, pelicans, gulls, egrets, ospreys, and bald eagles use it and the bordering waters for feeding, nesting, and resting. Mammals, notably raccoons, stalk the beach in search of food. And the big loggerhead turtle depends on it for nesting. In late spring and early summer the female loggerhead hauls herself up on the beach and digs a hole above hightide mark. There she deposits about 100 ping-pong balls—which should hatch out into baby loggerheads. Unfortunately for this marine reptile, however, most of them meet another fate. Hardly has the female turtle covered the eggs with sand and started back toward the water, than they are dug up and devoured by raccoons and other predators. These conditions created such high mortality of the turtles that the National Park Service has adopted special protective measures—removing some of the raccoons and erecting wire barriers around turtle nests. These measures have been effective, but continued surveillance is required if the loggerhead is not to disappear from Florida.

An abundance of raccoons and other predators is not the only threat to survival of the loggerhead turtle. A major factor in its decline is the serious depletion of its nesting habitat. Park visitors are prohibited from interfering with these reptiles. Cape Sable beach is today virtually the only wild beach in South Florida, thanks to its inclusion in Everglades National Park. At present, visitors can reach it only by boat. But it would be foolhardy to take it for granted that the beach will remain unspoiled. Its potential as an attraction is such that someone not ecologically aware might believe that access for motorists would be an improvement. Roads, however, would bring increased pressure on the ecosystem by large numbers of visitors, and demands for further development, for lodging, meals, and other services seem always to go with automobiles. With continued protection from such encroachments, Cape Sable Beach will remain a unique wilderness resource and will not become just another recreational facility.

Merging with the beach is the coastal prairie, an ecosystem supporting red and black mangroves, grasses, and other plants tolerant of the very salty environment. Hardwood hammocks have developed here on Indian shell mounds, but the trees are stunted by the saline soils. Though there is no lack of water on the cape, much of the region appears arid because hurricane-lashed tides have deposited soils of marl and debris so salt-laden that only sparse vegetation develops.

Big Cypress Swamp

To the west of the great fresh-water marsh called the everglades, lying almost entirely outside the park, is an ecosystem vitally linked to the park. Big Cypress Swamp is a vast, shallow basin that includes practically all of Collier County. It is commonly called “The Big Cypress”—not because of the size of its trees, but because of its extent. Most of the baldcypresses (which are not true cypresses) are small trees, growing in open to dense stands throughout the area. The swamp is watered by about 50 inches of annual rainfall, the runoff from which flows as a sheet and in sloughs south and west to meet the coastal strip of mangroves and low sand dunes.

Big Cypress is speckled with low limestone outcrops, cut with shallow sloughs 1 to 2 feet deep, and dotted with ponds and wet prairies. As in the everglades, fire and water maintain the character of the plantlife in this swampy realm of sunlight and shadow. Also as in the everglades, a difference of a few inches in elevation creates different communities. Tropical hardwood hammocks grow on rocky outcrops. In the depressions arise bayheads and clumps of pond apple, pop ash, and willow. The larger baldcypress trees grow in shallow sloughs, which are usually surrounded by prairies of sawgrass and maiden cane growing on slightly higher land. Although the several different plant communities resemble those in the glades, they support slightly different plants, because of the sandy soil (there being more quartz in the limestone under Big Cypress than in the park).

These baldcypresses, many measuring 3 to 6 feet in diameter, were heavily lumbered from 1930 to 1950. Today, few giant trees survive, but a sizable stand exists on the Norris Tract—so named for its conservation-minded donor—which forms the nucleus of Corkscrew Swamp Sanctuary. Here, protected by the National Audubon Society, are baldcypresses 130 feet tall; some have a girth of 25 feet! A boardwalk more than one-half mile long enables you to enjoy the beauty of this wild preserve without getting your feet wet.

WET PRAIRIE TROPICAL HARDWOOD HAMMOCK WET PRAIRIE 1 SOUTH FLORIDA SLASH PINE 2 BALDCYPRESS 3 POP ASH 4 ROYAL PALM AIR PLANT

Large stands of baldcypress, called “strands,” support small communities such as ponds, prairies, and tropical hammocks. One such hammock is famous for the finest stand of royal palms remaining in south Florida. The largest cypress strand—the Fakahatchee—extends some 23 miles north and south a few miles east of Naples.

Big Cypress Swamp is the home of wild turkey, bobcat, deer, and an occasional Florida panther. The fish-eating otter plays in its waterways. Most of the birds found in the everglades also are found in the trees and waterways of Big Cypress, because the swamp has an abundance of food. The area is so rich in wildlife and edible plants that the Seminole Indians formerly lived entirely off its products.

The eastern edge of the big swamp and its importance to Everglades National Park came to worldwide attention in 1969 when it was selected as the site for the proposed Miami International Jetport. According to plans, this was to be the biggest airport in the world, covering 39 square miles and handling 65 million passengers a year. Millions of persons were expected to make their home in and around the jetport. Such a threat to the national park, into which the waters of Big Cypress partly drain, provoked protest letters from all over the world. Most writers objected on the grounds that Everglades belongs to all and that a jetport here would seal the doom of the park. Congress acted in 1974 by establishing Big Cypress National Preserve to help protect the water supply to Everglades National Park.

PLANT-AND-ANIMAL COMMUNITIES

To know Everglades, you must become acquainted with some of its diverse communities. The physical conditions determining the existence of a particular community may seem subtle—just a few inches difference in elevation, or an accumulation of peat in a depression in the limestone bedrock, for example. But often, the change in your surroundings as you step from one community to another is startling—for it is abrupt and complete. In Everglades, the dividing line between two habitats may separate an almost entirely different association of plants and animals.

Use the trails that have been laid out to help you see the communities. They make access easy for you; the rest is up to you. Be observant: notice the stemlike root of a saw-palmetto in a damp pothole of the pineland; look closely at the periphyton that plays such an important role in the glades food chain. Note the difference in feeding methods of wading birds; each species has its own niche in the habitat. Most of all, get into the habit of thinking of each animal, each plant, as a member of the closely woven web of life that makes up an integrated community.

Tropical Hardwood Hammock

Generally, in south Florida, hardwood hammocks develop only in areas protected from fire, flood, and saline waters. The land must be high enough (1 to 3 feet above surrounding levels) to stand above the water that covers the glades much of the year. The roots of the trees must be out of the water and must have adequate aeration. In the park, these conditions prevail on the limestone “ridge” (elevation of which ranges from 3 to 7 feet above sea level) and some spots in the glades region. On the limestone ridge, in areas bypassed by fires for a long period, hammocks have developed. Pines grow in the surrounding areas, where repeated fires have held back the hardwoods.

The moats that tend to form around glades hammocks, as acids from decaying plant materials dissolve the limestone, hold water even during the dry season; the moats thus act as barriers protecting the hammock vegetation from glades fires.

When the white man took over southern Florida, these hammocks were luxuriant jungle islands dominated by towering tropical hardwoods and palms. Stumps and logs on the floors of some of the remaining hammocks, attesting to the enormous size of some of the earlier trees, are sad reminders of the former grandeur of the hammocks. While most of south Florida’s hammocks have been destroyed, you can still see some fine ones protected in the park. At Royal Palm Hammock, near park headquarters, Gumbo Limbo Trail winds through a dim, dense forest with welcome coolness on a hot day.

Stepping into a jungle hammock from either the sunbathed glades or the open pine forest is a sudden, dramatic change. The contrast when you enter Gumbo Limbo Trail immediately after walking the Anhinga Trail is striking. While the watery world of Anhinga is dominated by a noisy profusion of wildlife, the environment of Gumbo Limbo will seem to be a mere tangle of vegetation. But the jungle hammock, too, has its community of animals—even though you may notice none but mosquitoes. Many of its denizens are nocturnal in their habits, but if you remain alert you will observe birds, invertebrates, and perhaps a lizard.

The trees that envelop you as you walk on Gumbo Limbo Trail are mostly tropical species; of the dominant trees, only the live oak (which grows as far north as Virginia) can be considered non-tropical. Under oaks and tropical bustics, poisonwood, mastics, and gumbo-limbos grow small trees such as tetrazygia, rough-leaf velvetseed, and wild coffee, a multitude of mosses and ferns, and only a few species of shade-tolerant flowering plants. Orchids and air plants burst like sun stars from limbs, trunks, and fallen logs. Twining among them all, the woody vines called lianas enhance the jungle atmosphere. Adding a final touch are the royal palms that here and there tower over the hardwood canopy—occasionally reaching 125 feet.

PINELAND SOUTH FLORIDA SLASH PINE BUSTIC GUMBO-LIMBO SOLUTION HOLE POND APPLE AIR PLANTS (ORCHIDS, BROMELIADS) ROYAL PALM LIVE OAK MASTIC VINES PINELAND SAW-PALMETTO

The limestone rock that underlies the entire park is porous and soluble; consequently the floor of the hammock is pitted with solution holes dissolved by the acid from decaying vegetation. Soil and peat accumulating in the water-filled bottom of one of these holes supports a plant community of its own: perhaps a pond apple, surrounded by ferns and mosses (including some varieties that seem to be limited to this pothole environment).

A dead, decaying log on the ground may support another miniature plant community—a carpet of mosses, ferns, and other small plants that thrive in such moist situations.

Strangest of the hammock plants is the strangler fig, which first gets a foothold in the rough bark of a live oak, cabbage palm, or other tree. It then sends roots down to the ground, entwining about the host tree as it grows, and eventually killing it. On the Gumbo Limbo Trail you will see a strangler fig that grew in this manner and was enmeshed by another strangler fig—which now is threatened by a third fig that already has gained a foothold in its branches.

Best known of the glades hammocks is Mahogany Hammock. A boardwalk trail in this lush, junglelike tree island leads past the giant mahogany tree for which the hammock was named—now, because of Hurricane Donna, a dismembered giant. This fine tree island was explored only after the park was established.

An array of large and small vertebrate animals, mostly representative of the Temperate Zone, populates these tropical hardwood jungles: raccoons and opossums, many varieties of birds, snakes and lizards, tree frogs, even bobcats and the rare Florida panther, or cougar. Not surprisingly, invertebrates—including insects and snails—abound in this luxuriant plant community. The tropical influence is evident in the presence of invertebrates such as tree snails of the genus _Liguus_, known outside of Florida only in Hispaniola and Cuba.

Cypress Head

Standing out conspicuously on the glades landscape are tall, domelike tree islands of baldcypress. Unlike hammocks, which occupy elevations, cypress heads, or domes, occupy depressions in the limestone bedrock—areas that remain as ponds or wet places during seasons when the glades dry up. Water-loving cypresses need only a thin accumulation of peat and soil to begin their growth in these depressions or in smaller solution holes in the limestone.

BALDCYPRESS ALLIGATOR HOLE (often in middle of cypress head) SAWGRASS

Though most conifers retain their needles all year, baldcypresses shed their foliage in winter. The fallen needles decay, forming acids that dissolve the limestone further; thus these trees tend to enlarge their own ponds. Since the pond is deeper in the middle, and the accumulation of peat is greater there, the taller trees grow in the center of the head, with the smaller ones toward the edge. Hence the characteristic dome-shaped profile.

Usually when fire sweeps the glades, the baldcypresses, occupying low, wet spots, are not injured. But with extended drought, the water disappears and the peat may burn for months, killing all the baldcypresses.

The cypress heads sometimes serve as alligator holes, where the big reptiles and other aquatic animals are able to survive dry periods. As you drive along the park road, stop and examine these tree islands through your binoculars; they are favored haunts of many of the park’s larger wading birds. Look for herons, egrets, wood storks, and white ibis, which visit these swampy habitats to feed on the abundant aquatic life.

Bald eagles find the tops of the tallest cypresses advantageous perches from which to scan the marsh. And at night certain of the cypress heads are “buzzard roosts”—resting areas for gatherings of hundreds of turkey vultures.

Bayhead

ALLIGATOR FLAG COCOPLUM SWAMP HOLLY CABBAGE PALMETTO REDBAY SWEETBAY SAWGRASS WILLOW ORCHIDS AND BROMELIADS

Many of the tree islands in the fresh-water glades are of the type called bayhead. Growing in depressions in the limestone or from beds of peat built up on the bedrock, these plant communities contain a variety of trees, including swamp holly, redbay, sweetbay, wax myrtle, and cocoplum. Some of them, on the fringes of the brackish zone, are marked by clumps of graceful paurotis palms growing at their edges.

Like the hardwood hammocks in the pinelands, bayheads are prevented from taking over the entire glades ecosystem by the dry-season fires that sweep the region at irregular intervals. The fires do not always affect the bayheads. A moat, formed by the dissolving action of acids from decaying plant materials on the limestone, may surround the tree island, providing some protection from fire. Wildlife concentrates in these moats during the dry season. Birds congregate here to harvest the fish, snails, and other aquatic life—and occasionally themselves fall prey to lurking alligators.

Willow Head

Willows pioneer new territories and create an environment that enables other plants to gain a foothold. Their windblown seeds usually root in sunny land opened by fire and agriculture. Since these trees require a great quantity of water, the solution holes in the glades are favorable sites. Seedlings grow, leaves fall, and stems and twigs die and drop—contributing to the formation of peat. When this builds up close to or above the surface of the water, it provides a habitat for other trees such as sweet bay and cocoplum; with enough of these the willow head changes character and becomes a bayhead.

Years ago, when alligators were plentiful, they weeded the willow-bordered solution holes, keeping them open. Consequently, the willow heads were typically donut-shaped. Today, however, alligators are scarce and many of the willow heads have no ’gators. The solution holes fill with muck and peat; relatively tall willows rise out of the deep, peat-filled centers, with increasingly smaller ones toward the less fertile edges, and the willow heads take on the characteristic dome-shaped profile but not nearly the height of the cypress domes. They have a clumpy, brushy appearance, seeming to grow right out of the marsh without trunks.

SPATTERDOCK COASTAL PLAIN WILLOW CATTAIL DRY SEASON WATER LEVEL

Willow heads that do have alligator holes have a seasonal concentration of aquatic animals and the birds and mammals that prey upon them. They rarely support orchids or bromeliads, for the bark of the southern willow is too smooth to provide anchorage for the seedlings of these plants.

During drought periods willow heads, like bayheads, are vulnerable to the fires that sometimes burn over the glades.

Web of Life in the Marsh

Around the stems and other underwater parts of the glades plants are cylindrical masses of yellowish-green _periphyton_. So incredibly abundant are these masses of living material that in late summer the water appears as though clogged with mossy-looking sausages and floating pancakes. Largely algae, but containing perhaps 100 different organisms, the periphyton supports a complex web of glades life. It is the beginning of many food chains in the fresh-water marsh. The larvae of mosquitoes and other invertebrates, larval frogs (tadpoles) and salamanders, and other small, free-swimming creatures feed upon the tiny plants and minute animals living in the masses of periphyton. These periphyton feeders are in turn fed upon by small fish, frogs, and other vertebrates, which are food for big fish, birds, mammals, and reptiles; most of these larger creatures are preyed upon by the alligator.

The periphyton is perhaps most important for its role in maintaining the physical environment of the marsh. The water flowing over the limestone of the glades is hard with calcium. The algae remove this calcium and convert it to marl (_see_ glossary), which precipitates to the bottom. Sawgrass is rooted in this marl; accumulated dead sawgrass forms peat; other marsh plants, including willows and the trees of the bayheads, spring up from the peat. Acid from the peat and from decaying plant matter of the tree islands dissolves some of the marl and underlying bedrock—and the cycle is complete.

Every plant, every animal, every physical element is involved in this web of life—as soil builder, predator, plant-eater, scavenger, agent of decay, or converter of energy and raw materials into food. Damage to or removal of any of these components—pollution of the water, lowering of the water table, elimination of a predator, or any interference in the energy cycle—could destroy the glades as we know them.