The Everglades is a natural area of wet grasslands in southern Florida. It covers the southern part of a large drainage area in the Neotropical region. The system starts near Orlando with the Kissimmee River, which flows into the large but shallow Lake Okeechobee. During the wet season, water from the lake forms a slow-moving river that is 60 miles wide and over 100 miles long. This river flows southward across a limestone shelf to Florida Bay at the southern end of the state. The Everglades has many different weather patterns, including frequent flooding during the wet season and dry conditions during the dry season. In the 20th century, the Everglades lost much of its habitat and suffered environmental damage.
People have lived in southern Florida for about 15,000 years. Before European settlers arrived, the area was home to the Calusa and Tequesta tribes. After Spanish colonization, both tribes declined over the next two centuries. The Seminole, who were mostly Creek people from the north, moved into the Everglades in the early 19th century after being forced there during the Seminole Wars. They adapted to the region and resisted being removed by the United States Army.
In 1848, people who wanted to build plantations first suggested draining the Everglades, but no work began until 1882. Canals were built throughout the first half of the 20th century, which helped grow the economy and led to more land development. In 1947, Congress created the Central and Southern Florida Flood Control Project, which built 1,400 miles of canals, levees, and water control systems. During this time, the Miami area grew, and water from the Everglades was directed to cities. Parts of the Everglades were turned into farmland, with sugarcane as the main crop. About half of the original Everglades has been developed for agriculture or urban use.
In the 1970s, conservation groups began to focus on protecting the Everglades. UNESCO and the Ramsar Convention named the Everglades a Wetland Area of Global Importance. A plan to build a large airport near Everglades National Park was stopped after an environmental study showed it would harm the South Florida ecosystem. In the 1980s, restoration efforts began, such as removing a canal that had changed the path of the Kissimmee River. However, challenges related to development and sustainability continue. Poor water quality in Lake Okeechobee has been linked to problems in South Florida’s cities. In 2000, Congress approved the Comprehensive Everglades Restoration Plan, the most expensive and detailed environmental restoration project in history. However, the plan faced political challenges during its implementation.
Names
The first written mention of the Everglades appeared on Spanish maps created by mapmakers who had never seen the area. They gave the unknown region between Florida’s Gulf and Atlantic coasts the name Laguna del Espíritu Santo, which means "Lake of the Holy Spirit." This area was shown on maps for many years, even though no one had explored it. In 1811, writer James Grant Forbes wrote, "The Indians describe [the Southern points] as hard to enter; and the [British] surveyors, wreckers, and coasters did not have the tools to explore beyond the coastline or the mouths of rivers."
British surveyor John Gerard de Brahm, who mapped Florida’s coast in 1773, called the area "River Glades." The name "Everglades" first appeared on a map in 1823, though it was sometimes spelled "Ever Glades" as late as 1851. The Seminole people call the region Pahokee, which means "Grassy Water." A U.S. military map from 1839 labeled the area "Pa-hai-okee," even though it had earlier been called "Ever Glades" during the Second Seminole War.
In 2007, geographers Ary J. Lamme and Raymond K. Oldakowski found that the "Glades" has become a distinct region with a common name in Florida. It includes the interior areas and southernmost part of the Gulf Coast in South Florida, mostly matching the Everglades itself. It is one of the least populated areas in the state.
Geology
The geology of South Florida, along with a warm and wet climate, creates conditions that are good for a large marshland ecosystem. Layers of rock and soil that let water pass through easily affect the weather, climate, and water movement in South Florida. The rock under the Everglades can be explained by the history of the area. The land under Florida was once part of the African region of a large landmass called Gondwana. About 300 million years ago, North America joined with Africa, connecting Florida to North America. Volcanic activity on Florida’s eastern side covered the existing rock with new rock formed from volcanic material. Around 180 million years ago, the land began to pull apart, separating North America from Gondwana. When Florida was part of Africa, it was above water, but during the cooler Jurassic Period, the Florida Platform became a shallow ocean where rock layers formed. During the Cretaceous Period, most of Florida was underwater, with different depths. The area has been covered by seawater at least seven times since the bedrock formed.
Changing sea levels pressed together layers of calcium carbonate, sand, and shells. These layers formed permeable limestone between 25 million and 70 million years ago, creating the Floridan aquifer, which is the main source of fresh water for northern Florida. However, this aquifer is covered by layers of rock that do not let water pass through easily from Lake Okeechobee to the southern tip of Florida.
Five rock layers form the surface of southern Florida: the Tamiami Formation, Caloosahatchee Formation, Anastasia Formation, Miami Limestone, and Fort Thompson Formation. The Tamiami Formation is made of light-colored sand and quartz, 150 feet thick. It is named after the Tamiami Trail, which runs through the Big Cypress Swamp, and lies under the southern part of the Everglades. Between the Tamiami Formation and Lake Okeechobee is the Caloosahatchee Formation, named after the river over it. This layer is less permeable and made of sandy shell marl, clay, and sand. Water under this layer is usually very rich in minerals. Both the Tamiami and Caloosahatchee Formations formed during the Pliocene Epoch.
Surrounding Lake Okeechobee is the Fort Thompson Formation, made of dense limestone, shells, and sand. Rainwater is less likely to erode this rock to form small sinkholes. This layer is generally impermeable. Under Palm Beach County is the Anastasia Formation, made of shelly limestone, coquina, and sand from a former mangrove or salt marsh. This layer is more permeable and has many small holes. The Fort Thompson and Anastasia Formations, along with the Miami Limestone and another layer, formed during the Sangamonian interglacial period.
The Miami Limestone and Fort Thompson Formation have the most influence on the Everglades. The Miami Limestone has two types: the Miami Oolite, made of tiny, egg-shaped shells around sand or shell fragments, and another type made of fossilized bryozoan organisms. This rock is very porous and stores water during dry seasons in the Everglades. Its chemical makeup also affects the plants and animals in the area. The Miami Oolite also slows water flow from the Everglades to the ocean near Fort Lauderdale and Coot Bay.
The cities of Miami, Fort Lauderdale, and West Palm Beach sit on a raised area called the Miami Rock Ridge, a leftover oolite shoal on top of the Anastasia Formation. Along the western edge of the Big Cypress Swamp is the Immokolee Ridge, a slight rise of compressed sand that divides water flow between the Caloosahatchee River and the Big Cypress. These rises create a basin that directs water from Lake Okeechobee toward the southwest. Under the Miami Limestone and Fort Thompson Formation is the Biscayne Aquifer, a surface water layer that supplies fresh water to Miami. Rainfall and stored water in the Everglades refill this aquifer directly.
During the Pleistocene, about 17,000 years ago, rising sea levels slowed water flow from Lake Okeechobee, creating the Everglades. This slower flow led to the buildup of nearly 18 feet of peat, evidence of widespread flooding by about 5,000 years ago.
The Everglades’ flooding is fed by rivers like the Kissimmee, Caloosahatchee, Miami, Myakka, and Peace Rivers. The Kissimmee River flows directly into Lake Okeechobee, a large but shallow lake covering 730 square miles with an average depth of 9 feet. Soil in the Everglades shows that peat forms in areas flooded year-round, while calcium deposits form where flooding is shorter. Calcium deposits appear where more limestone is exposed.
The area from Orlando to the tip of Florida was once a single drainage system. When rainfall overwhelmed Lake Okeechobee and the Kissimmee River’s floodplain, water flowed southwest into Florida Bay. Before urban and agricultural development, the Everglades began at the southern edge of Lake Okeechobee and stretched about 100 miles to the Gulf of Mexico. The limestone shelf is wide and slightly sloped, unlike most rivers with narrow, deep channels. The slope from Lake Okeechobee to Florida Bay is about 2 inches per mile, creating a 60-mile-wide river that moves about half a mile per day. This slow movement of water, called sheetflow, gives the Everglades its nickname, "River of Grass." Water from Lake Okeechobee may take months or years to reach Florida Bay. The slow sheetflow stores water in porous limestone between wet seasons. Over 5,000 years, the movement of water has shaped the land and ecosystems in South Florida. Water movement defines plant communities and how animals adapt to their habitats and food sources.
Climate
The climate of South Florida is part of a large area where subtropical and tropical climates meet. This region experiences two main seasons: a dry season in winter, from November to April, and a wet season in summer, from May to October. About 70% of the yearly rainfall happens during the wet season, often in short but heavy tropical rains. The dry season has little rain, and the air is usually dry with low humidity. At times, the dry season can be very hot, leading to wildfires and water restrictions.
In South Florida and the Everglades, temperatures do not change much throughout the year. The difference between the warmest and coolest monthly averages is less than 20°F (11°C), ranging from about 65°F (18°C) in January to 83°F (28°C) in July. During the wet summer months, temperatures often go above 90°F (32°C) inland, but are cooler near the coast because of wind from the Gulf of Mexico and the Atlantic Ocean. In the dry winter months, temperatures average between 70°F and 79°F (21°C and 26°C). Freezing temperatures are rare, and cities like Miami and Naples rarely experience frost. However, once every few years, temperatures may drop to between 30°F and 40°F (−1°C and 4°C). The plant hardiness zones for this area are 10a in the north, with minimum temperatures of 30°F to 35°F (−1°C to 2°C), and 10b in the south, with minimum temperatures of 35°F to 40°F (2°C to 4°C). On average, the region receives about 62 inches (160 cm) of rainfall yearly, with the Eastern Coastal Ridge receiving the most and the area around Lake Okeechobee receiving about 48 inches (120 cm).
The Everglades are unique because they depend mostly on the atmosphere for water. Evapotranspiration, which is the process of water evaporating from the ground and being released by plants, is the main way water leaves the region. During normal years, this process removes about 40 inches (100 cm) of water yearly. During droughts, it can remove more than 50 inches (130 cm), which is more than the amount of rain that falls. Solar energy causes water to evaporate from the ground or plants, and wind carries it to other areas that are part of the Everglades watershed. Evapotranspiration provides about 70–90% of the water that enters undeveloped wetlands in the Everglades.
During the wet season, rainfall is mostly caused by air mass thunderstorms and wind patterns from the Bermuda High. Hot daytime temperatures make warm, moist air rise, creating afternoon thunderstorms typical of tropical climates. In South Florida and the Everglades, thunderstorms usually happen around 2:00 pm. In late summer (August and September), rainfall is highest because tropical storms and low-pressure systems add to daily rain. Sometimes, these systems grow into severe tropical cyclones that cause damage when they hit the area. On average, one tropical storm hits South Florida each year, and a major hurricane occurs about once every ten years. Between 1871 and 1981, 138 tropical cyclones affected the Everglades. Strong winds from these storms help spread plant seeds and support ecosystems like mangrove forests and coral reefs. Large changes in rainfall, along with droughts and tropical cyclones, are natural parts of the water system in the Everglades.
Formative and sustaining processes
The Everglades are a system of ecosystems that depend on each other. Marjory Stoneman Douglas called the area a "River of Grass" in 1947, but this name only describes part of the system. Before drainage, the Everglades covered about 4,000 square miles (10,000 km²) and included marshes, prairies, and other wetlands. The edges between different ecosystems are hard to see or notice. These ecosystems can change over time, growing, shrinking, or disappearing within years or decades. Geology, climate, and how often fires happen help shape and change the ecosystems in the Everglades.
Water is the most important force in the Everglades, shaping the land, plants, and animals in South Florida. About 21,000 years ago, ice sheets melted, and sea levels rose. This caused parts of Florida to be covered by water and raised the water table. Fresh water soaked into the limestone beneath the Everglades, eroding it and creating springs and sinkholes. The fresh water allowed new plants to grow and helped form thunderstorms through evaporation.
As rain continued to fall, the slightly acidic rainwater dissolved the limestone. As the limestone wore away, groundwater came to the surface, creating a large wetland. Although the Everglades look flat, the limestone created small valleys and plateaus. These slight changes in the land affect how water flows and what plants can grow.
The limestone bedrock beneath the Everglades influences the hydroperiod, or how long an area stays flooded each year. Areas that were underwater longer have longer hydroperiods. More water is stored in the porous limestone and ooids than in older rocks that were above sea level. A hydroperiod of ten months or more supports sawgrass growth, while shorter hydroperiods of six months or less support periphyton, a mix of algae and tiny organisms. There are only two soil types in the Everglades: peat and marl. Peat builds up in areas with long hydroperiods over many years from decaying plants. In areas where periphyton grows, the soil becomes marl, which has more calcium.
Early farming near Lake Okeechobee was successful, but the nutrients in the peat were quickly used up. A process called soil subsidence happens when peat is exposed to oxygen. Underwater, bacteria break down sawgrass slowly without oxygen. When water was drained in the 1920s, bacteria interacted with oxygen, breaking down peat into carbon dioxide and water. Some settlers burned peat to clear land. Homes built on early farms sometimes needed to be raised on stilts as the peat sank. In some areas, the soil lost about 8 feet (2.4 meters) of depth.
Fire plays a natural role in maintaining the Everglades. Most fires are caused by lightning during the wet season. These fires mainly affect the surface, helping certain plants grow. Sawgrass burns above water, but its roots stay safe. Fire in sawgrass marshes prevents larger plants like bushes and trees from growing and helps release nutrients from dead plants faster than decomposition. During the wet season, fires burn dead plant matter and the tips of grasses and trees. In the dry season, fires may burn peat deeply, damaging root systems. Water and rain help control where fires spread. It takes about 225 years for one foot (0.3 meters) of peat to form, but in some areas, peat is less dense than it should be for the Everglades' 5,000-year history. Scientists believe fire caused this. Fire also explains the dark color of Everglades muck. Layers of charcoal in the peat show the region had severe fires for years, but this trend has decreased since around 940 BC.
Ecosystems
The Everglades contain several ecosystems, and the lines between them are often unclear or not present. The main part of the Everglades is the sawgrass marsh. This area, known as the "true Everglades" or "the Glades," is a wide, shallow river about 100 miles (160 km) long and 60 miles (97 km) wide. It stretches from Lake Okeechobee to Florida Bay. Before drainage efforts began in 1905, this slow-moving water covered nearly one-third of the lower Florida peninsula. Sawgrass grows well in this water but may die if the water becomes too deep and blocks oxygen from reaching its roots. It is also weak after fires. The marsh stays flooded for at least nine months, sometimes longer. Areas with dense sawgrass have few other plants or animals, but alligators often nest there. In areas with more open space, periphyton grows. Periphyton supports insect and amphibian larvae, which are food for birds, fish, and reptiles. It also removes calcium from water, helping form the calcitic marl soil.
Sloughs, which are free-flowing water channels, form between sawgrass prairies. Sloughs are about 3 feet (0.91 m) deeper than sawgrass marshes and may remain flooded for at least 11 months a year, sometimes for several years. Turtles, alligators, snakes, and fish live in sloughs, feeding on aquatic insects. Submerged and floating plants like bladderwort (Utricularia), waterlily (Nymphaeaceae), and spatterdock (Nuphar lutea) grow here. Major sloughs include the Shark River Slough, which flows into Florida Bay, the Lostmans River Slough near The Big Cypress, and Taylor Slough in the eastern Everglades.
Wet prairies are slightly higher than sawgrass marshes but have more plant variety. They are covered in water for three to seven months a year, with water averaging 4 inches (10 cm) deep. When flooded, the marl soil supports many water plants. Deep pits called solution holes, where limestone has worn away, may stay flooded even when the prairies are dry. These holes support crayfish, snails, and amphibian larvae, which feed young birds. Wet prairies often lie between sloughs and sawgrass marshes.
Alligators have adapted to wet prairies by digging ponds in low areas. These ponds remain filled during dry seasons and provide water for animals during droughts. Alligators then eat some of the animals that visit these ponds.
Small islands of trees, called tropical hardwood hammocks, grow on land 1 to 3 feet (0.30 to 0.91 m) above sloughs and prairies. They range from one to ten acres (4,000 to 40,000 m²) and appear in freshwater sloughs, sawgrass prairies, or pinelands. Hammocks grow on slightly raised limestone plateaus or land untouched by deep peat fires. They include subtropical and hardwood trees like Southern live oak (Quercus virginiana), gumbo limbo (Bursera simaruba), royal palm (Roystonea), and bustic (Dipholis salicifolia). Sharp saw palmettos (Serenoa repens) grow near the base, making hammocks hard for people to enter but ideal for small animals. Water flows around hammocks, creating moats. Hammocks take decades or centuries to recover after fires, and the moats protect the trees. Trees in hammocks rarely grow taller than 55 feet (17 m) due to frost, lightning, or wind.
The driest part of the Everglades is the pineland (also called pine rockland) ecosystem, located in the highest areas with little or no water. Some areas may have flooded solution holes or puddles for a few months. The main feature of pinelands is the South Florida slash pine (Pinus elliottii). Pinelands depend on fire to survive. Pine needles on the sandy floor are highly flammable, but the trees’ thick bark protects them from heat. Fire clears competing plants and opens pine cones to release seeds. Without fire, pinelands can turn into hardwood hammocks. Fire-resistant plants like saw palmetto (Serenoa repens), cabbage palm (Sabal palmetto), and West Indian lilac (Tetrazygia bicolor) grow in the understory. Herbs, with two dozen species, also thrive here, using tubers to regrow after fires.
Before urban development, pine rocklands covered about 161,660 acres (654.2 km²) in Miami-Dade County. Within Everglades National Park, 19,840 acres (80.3 km²) are protected, but only 1,780 acres (7.2 km²) remained outside the park in 1990. Misunderstanding the role of fire caused pine forests to shrink, as natural fires were stopped and pine rocklands became hardwood hammocks. Prescribed fires are used in Everglades National Park every three to seven years to maintain pine rocklands.
Cypress swamps are found throughout the Everglades, with the largest covering most of Collier County. The Big Cypress Swamp, located west of sawgrass prairies and sloughs, is called "The Big Cypress." This name refers to its size, not the height of its trees. The swamp covers about 1,200 square miles (3,100 km²), but its hydrologic boundary is over 2,400 square miles (6,200 km²). The Big Cypress sits on bedrock with thin limestone layers, which contain quartz, creating sandy soil that supports different plants. The swamp receives about 55 inches (140 cm) of water during the wet season.
Although The Big Cypress is the largest cypress swamp in South Florida, smaller cypress swamps exist near the Atlantic Coastal Ridge, between Lake Okeechobee and the Eastern flatwoods, and in sawgrass marshes
History
Humans arrived in the Florida peninsula about 15,000 years ago. Paleo-Indians likely came to Florida by following large animals, such as giant sloths, saber-toothed cats, and spectacled bears. They found a dry landscape that supported plants and animals adapted to desert conditions. However, 6,500 years ago, climate changes made the area wetter. Large animals became extinct in Florida, and the Paleo-Indians slowly adapted and became the Archaic peoples. They adjusted to the environment and made tools using resources available in their area. During the Late Archaic period, the climate became wetter again. Around 3000 BCE, rising water levels allowed the population and cultural activity to grow. Florida Indians developed into three distinct but similar cultures named after nearby water bodies: Okeechobee, Caloosahatchee, and Glades.
From the Glades peoples, two major nations emerged: the Calusa and the Tequesta. The Calusa was the largest and most powerful group in South Florida. It controlled about 50 villages along Florida’s west coast, near Lake Okeechobee, and the Florida Keys. Most Calusa villages were located at river mouths or on islands. The Calusa were hunter-gatherers who relied on small animals, fish, turtles, alligators, shellfish, and plants for food. Their tools were often made of bone or teeth, and sharpened reeds were used for hunting or fighting. They used bows and arrows, atlatls, and spears as weapons. Canoes helped them travel, and they often used them to move through the Everglades, though they rarely lived there. Canoe trips to Cuba were also common.
At the start of the Spanish occupation, the Calusa population was estimated to be between 4,000 and 7,000. Over time, their power and numbers declined, and by 1697, their population was about 1,000. In the early 18th century, the Calusa faced attacks from the Yamasee tribe to the north. They sought refuge in Cuba, but many died of illness. Later, they were relocated to the Florida Keys.
The Tequesta were the second-largest group in South Florida. They lived in the southeastern part of the lower peninsula, in what are now Dade and Broward counties. Like the Calusa, the Tequesta built villages near river mouths. Their main village was likely on the Miami River or Little River. Spanish accounts described the Tequesta as feared by sailors, who believed they harmed shipwreck survivors. As European presence grew, Native Americans from the Keys and other areas traveled more frequently to Cuba. Cuban officials allowed Native Americans from the Florida Keys to move to Cuba in 1704. Spanish priests tried to establish missions in 1743, but noted that the Tequesta were being attacked by a neighboring tribe. When only 30 members remained, they were moved to Havana. By 1770, a British surveyor found many deserted villages where the Tequesta had lived. By 1820, Native Americans in Florida were often called “Seminoles.”
After the Calusa and Tequesta declined, Native Americans in southern Florida were referred to as “Spanish Indians” in the 1740s, likely because of their friendly relations with Spain. The Creek tribe invaded Florida and absorbed the remnants of earlier societies into the Creek Confederacy. These groups joined with other Native American remnants to form the Seminole, a new tribe, through a process of forming a new group. The Seminole originally settled in the northern part of Florida. At the same time, escaped slaves and free Black people moved to Florida, where Spain promised freedom and weapons to those who converted to Catholicism and pledged loyalty to Spain. These African Americans created communities near the Seminole and became known as the Black Seminoles. The two groups worked together as allies.
In 1817, Andrew Jackson invaded Florida to speed up its annexation by the United States, an event known as the First Seminole War. After Florida became a U.S. territory in 1821, conflicts between settlers and the Seminole increased as settlers tried to take
Restoration
The International Union for Conservation of Nature (IUCN) World Heritage Outlook reported that the Everglades National Park 2020 Conservation Outlook is "Critical." Current trends are described as "deteriorating," with "very high threat" to the ecosystem’s health. Some ecological features that have been lost cannot be restored because they developed over decades or centuries. The remaining ecological features are important to protect because they support Florida and have unique properties not found elsewhere in the world. These features are also valuable for scientific research.
Major causes of the decline include poor water quality (pollution from nutrients), reduced water flow, improper water distribution, and timing; invasive species; climate change (such as rising sea levels); ocean acidification; and hurricanes. Other challenges include slow progress in planning and laws related to restoration. Projects in other parts of Florida, such as the Tamami Trail and water storage near Lake Okeechobee, have not received enough attention but are needed to prevent further damage. A study by Almeida et al. (2022) showed how water movement affects soil microbes and how this can help restore the Everglades. Soil samples were collected in 2018 from tree islands in Loxahatchee. An experiment found that soil with microbes had a 52% higher germination rate for plants compared to soil without microbes. This study highlights the role of microbes in plant growth and restoration.
Some Everglades restoration projects have been completed, but important plans remain unfinished. Earlier plans overestimated the benefits of these projects, and new projects due by 2027 lack enough funding to address these issues.
Recent changes in park policies have improved management of visitor activities, efforts to control invasive species, and funding for park projects. However, support from local, state, and federal groups has not matched the need for conservation.
The Central and Southern Florida Flood Control Project straightened the Kissimmee River, a 90-mile river, to create land for farming. This caused harm to wildlife, leading to calls for restoration. The first part of the river was restored in 1986, and full restoration was planned by 2000. The Kissimmee River Restoration project, approved in 1992, is expected to cost $578 million to restore 22 miles of the river. As of 2017, the project was "more than halfway complete," with a new completion date of 2020.
In 1986, a large algal bloom appeared in Lake Okeechobee, and cattails began replacing sawgrass in the Loxahatchee National Wildlife Refuge. Scientists found that phosphorus from fertilizer in the Everglades Agricultural Area (EAA) entered the lake through canals. This changed the soil and allowed cattails to grow densely, harming wildlife and reducing oxygen in the water.
At the same time, high levels of mercury were found in local fish, leading to warnings for fishermen. Mercury from power plants and incinerators entered the air and fell as rain or dust. Bacteria in the Everglades turned mercury into methylmercury, which built up in the food chain. Stricter rules on emissions reduced mercury levels but did not eliminate the problem.
Recent studies showed how seasonal changes in Lake Okeechobee affect cyanobacteria blooms, including the toxin-producing Microcystis aeruginosa. These blooms produce microcystin, a harmful toxin for humans and animals. The study found that cyanobacteria concentrate in different parts of the lake during different seasons and can spread to estuaries, worsening water quality.
Salinity also affects water quality. A study by Wilson et al. (2018) found that rising sea levels and saltwater intrusion reduce wetland health. When water levels dropped below the soil, carbon production increased threefold. After two years, plant life in brackish water areas decreased significantly. The study concluded that high carbon levels and loss of plant roots contribute to peat soil collapse in coastal Everglades.
The Everglades Forever Act, introduced by Governor Lawton Chiles in 1994, aimed to reduce phosphorus in waterways. The South Florida Water Management District (SFWMD) and Florida Department of Environmental Protection (DEP) were tasked with keeping phosphorus levels below 10 parts per billion (ppb). Stormwater Treatment Areas (STAs) near sugarcane fields use lime rock and peat to filter water, successfully reducing phosphorus levels from 80 ppb to 10 ppb.
South Florida, a key area for trade and travel between the U.S., the Caribbean, and South America, is especially vulnerable to invasive species.
Plane crashes
Three airplanes have crashed in the Everglades:
- Northwest Orient Airlines Flight 705 on February 12, 1963. All 43 people on board died.
- Eastern Air Lines Flight 401 on December 29, 1972. The plane crashed in the Florida Everglades, resulting in 101 deaths and 75 people surviving. The cause was mistakes made by the pilots.
- ValuJet Flight 592 on May 11, 1996. The plane crashed in the Everglades, killing all 110 people on board. The cause was a fire that started in the cargo area during the flight.