An American crocodile is swimming in the swamp. The Everglades is a complex system composed of subtropical wetlands, lakes and rivers, covering an area of over 4,000 square miles (65,438+00,000 square kilometers) from Lake Oktobee to the southern tip of Florida. However, according to the Florida Museum of Natural History, the Everglades has shrunk to less than half of its original size due to development. Although it is sometimes considered as a huge swamp, technically speaking, the Everglades is a shallow river with very slow flow. Because this river is dominated by grass-sawed swamps, it is traditionally called the "River of Grass". In fact, the native Americans living in this area call it Pahayokee, which means "water of grass". The subtropical climate in this area is characterized by hot and humid summers and mild winters. According to the World Wildlife Fund (WWF), about 80% of the rainfall occurs in summer.

The Everglades has a variety of habitats and is home to unique wildlife, including nearly 70 endangered species, such as manatees, American crocodiles, turtles, and according to Marvin's notes, Florida leopards and various birds. The Everglades National Park was built in 1947, which protected 20% of the southern part of the original Everglades. It is a UNESCO World Heritage Site, UNESCO International Biosphere Reserve and Ramsar Wetland of international importance.

Ecosystem The Everglades contains several different ecosystems. These areas include:

Coastal lowlands or coastal grasslands are located on the west coast of the Everglades, just inland of mudflats in florida bay. These lowlands are formed by inland sediment movement during tropical storms and hurricanes. There are many salt-tolerant shrubs and plants in this area, such as succulent plants and other low-growing desert-like plants.

Freshwater swamp is a deep swamp river, which is the main flow direction of the everglades. According to the National Park Service (NPS), these waterways move about 65,438+000 feet (30 meters) every day. The two main swamps in the Everglades are Shark River silt, also known as "Qingcao River", and the smaller Taylor silt, which is located in the east. Both flow into florida bay.

Freshwater marl grassland is located in the east and west of the everglades, and there is a deep gap in the boundary. Marl is a thin calcareous soil at the top of limestone bedrock, and it is chalky soil composed of calcium carbonate. Although these grasslands look similar to swamps, freshwater swamp grasslands have shallow water and short mowing time. These grasslands are characterized by low-growth vegetation and epiphytes-a mixture of bacteria, algae, debris and microorganisms-which are important food sources for tadpoles, fish and invertebrates. According to nuclear energy resources, the everglades

According to the University of Florida, the marine environment includes coral reefs, estuaries, mangroves, seagrass beds and bays. Water from the Everglades eventually flows into the Gulf of Mexico in the southwest and south florida bay. According to NPS, florida bay is the largest body of water in the Everglades National Park, with an area of over 800 square miles (2,072 square kilometers). Florida bay consists of a series of shallow water basins,

Pine forests are usually rooted in limestone in southern Florida. A healthy pine forest needs fire to help clear the fast-growing hardwoods, which will block the sun from shining on the pine seedlings. According to the National Park Service of the United States, the Everglades National Park conducts regular fire prevention to simulate natural fire patterns and maintain the health of pine trees.

Mangrove is a kind of tree with strong salt tolerance, which can thrive in rivers, rivers and tidal waters where fresh water and salt water are mixed. The most common are red forest, black mangrove and white mangrove. The largest panther in everglades national park. 1967, when the panther was listed as a federal endangered species, the defenders of the wildlife protection non-profit organization claimed that only 12 to 20 animals existed, which was limited to a small breeding population in Florida. Today, there are about 100 to 180 adult and sub-adult leopards living in southern Florida, which only accounts for about 5% of the historical range. Other common swamp mammals include skunks, raccoons, white-tailed deer, opossums, red foxes and eastern cotton-tailed bobcats.

The Everglades is famous for its many reptiles, including crocodiles, crocodiles and 27 kinds of snakes. Marine animals include West Indian manatees and bottlenose dolphins.

The main problem of invasive species wetland is invasive species. These animal and plant species from other parts of the world can take advantage of the imbalance in this area, which is mainly due to the changes in natural water flow and wildfire patterns, according to the Northwest Forest Foundation. In addition, many invasive animals thrive in swamps because they have no natural enemies to control their numbers.

Non-native plants have invaded about 6.5438+700,000 acres (690,000 hectares) of everglades. According to the National Wildlife Fund, the invaders include Brazilian pepper trees, China privet trees, broad-leaved trees and old world climbing ferns.

One of the most famous invasive animals is the Burmese python, which may have escaped into the everglades after the hurricane destroyed the local breeding facilities. The destructive power of these snakes to the natural ecosystem is amazing. They greatly reduced the number of most small mammals in the Everglades National Park and even preyed on crocodiles. To make matters worse, these snakes are very mysterious and hard to find.

According to the Northwest Forest Foundation, other invasive animals include the Cuban tree frog, which preys on smaller local frogs, and the Nile monitor lizard, which is a large lizard that eats crocodile eggs and burrowing owls.

The everglades used to be very big. They are a complex system composed of rain-fed wetlands, lakes and rivers, covering an area of nearly 3 million acres (1.2000 hectares). However, since the19th century, human beings have been using land reclamation for agricultural and urban development, and changing the landscape of the everglades by establishing flood control structures and changing roads. As a result, the area of the everglades has been greatly reduced. From 65438 to 0947, Marjory Stoneman Douglas published her masterpiece The Everglades: A River of Grass, which aroused people's attention to this area and aroused people's awareness of protection. Soon after,1947 65438+February 6, * * set aside 1.5 million acres (600,000 hectares) as the Everglades National Park. However, according to the data of Boeggering Wetland Museum and Wildlife Foundation, the area of the Everglades is still half that of 65,438+000 years ago.

Fixed on a tree island in the swamp shark river swamp. (Pablo Ruiz, Florida International University) Drainage and Algae Problems For thousands of years, when the water level of Lake Okichoby became too high, it would naturally overflow into the Glass River and flow all the way to florida bay. However, at the end of 19, people began to drain water from the land, mainly to turn the wetland into a sugar factory. Families and businesses will soon follow suit and drain water for their own purposes.

1928, a category 5 hurricane called "Okhobi" hit the area. This is one of the deadliest disasters in American history, killing 2500 people. The storm surge on the lake covered hundreds of miles of land. In order to prevent similar disasters from happening again, a huge herbert hoover Dam was built to contain the water from Lake Okichoby. Because the natural water flow to the Everglades is blocked now, canals have been built. When the water level becomes dangerous, the excess water will be discharged to two coasts in Florida. Unfortunately, once the everglades no longer accept normal lake water, the area becomes drier.

One of the main problems in discharging the water from Lake Okichoby into the ocean is that the lake has a high content of nutrient phosphorus, which is a key component of fertilizer. Excessive supply of phosphorus to algae may lead to large-scale algae proliferation that is harmful to the environment.

Larry Brand, a professor of marine biology and ecology at Rosenstiel College, told Field Science: "When the water from sugarcane fields flows south through the swamp and enters florida bay, we will see blue-green algae blooms in florida bay during the rainy season." He studied the algae bloom in the coastal waters downstream of the Everglades.

"We found cyanobacteria blooms in the estuary of Saint Lucia and the South Indus lagoon (IRL). When Okeechobe Lake released a lot of nutritious water, Brand said:

Cyanobacteria are bacteria that get energy through photosynthesis. They are the only photosynthetic prokaryotes that can produce oxygen.

"We saw the same thing when keechobee's water was discharged westward into the caloosahache River." The high nutrition of Lake O comes from years of withdrawal from sugarcane fields in the south and various pastures and agriculture along the Kishi Nobusuke River in the north.

Additional resources

National Park Service: Everglades