The Impact of South Florida’s Coastal Ecosystem

Abstract

This paper explores the impact the coastal ecosystem has on South Florida. Research was conducted using the internet and “The Everglades Handbook: Understanding the Ecosystem,” Lodge, T.E. This paper will take you through the historical and current significance of the coastal ecosystem to South Florida. How we have gotten to where we are today, the impact of human interference with the coastal ecosystem and the effects it has on the Everglades and what can happen in the future to the coastal ecosystem if we continue to destroy our coastal ecosystem, and ways we can start today to help prevent further destruction. South Florida’s coastline is divided into four ecological areas such as sandy beaches, mangrove and salt marshes, shallow bays, and the Florida reef tract. Each ecological area plays its important role in the coastal ecosystem. Lastly, we will break down the entire South Florida coastal ecosystem and marine ecosystem into 10 sub regions and describe the current ecological status of each sub region in South Florida.

Most people come to South Florida to enjoy our beautiful sandy beaches and the vast marine life. To most people it is a vacation site, to Floridians it’s home and about protecting and saving our Coastal Ecosystem. The coastal ecosystem of South Florida can be best described by dividing it into four ecological areas. There are sandy beaches, salt and mangrove marshes, shallow bays, and reef tracts. South Florida is not only appealing to tourists, people who live here vacation all the time to other Florida destinations. Having such a beautiful ocean and all the marine life South Florida is feeling the effects of human activities and our coastal ecosystem has some serious alterations. The population here in South Florida just continues to grow and industries are trying to keep up and continuously growing new developments. Currently the South Florida coastal ecosystem can be divided into about 10 sub regions, and the current ecological status of each will play their own role. The history of the South Florida coastal ecosystem is important to understand because this will help us see where we are headed and how we can impose change to better our environment. Lastly, the prediction of prospects into the future under alternative scenarios both protective and neglected will be discussed.

South Florida’s coastal ecosystem has four ecological areas; sandy beaches, mangrove and salt marshes, shallow bays, and the Florida reef tract. Florida is described as a peninsula, having water around ¾ of the state. The sandy beaches run down the Atlantic coast, down and around the tip of Key Bicayne, and continues up along the Gulf Coast. These sandy coastlines are constantly changing due to the onshore wind-generated wave action from the ocean with a current drifting southward. Typically, there is sand that is found in the pocket beaches, or as we know them as inlets, where you will find beaches that are mostly composed of calcium carbonate. The cause of the calcium carbonate comes from the limestone that is found along the lower mainland and also near the Keys. More so along the Gulf Coast you can find beaches that are more shelly and has silica sand (Pregram, 2018). South Florida is not only known for its beaches, but also for the number of severe storms each year.

There is a hurricane season from June through the end of November, where the most severe storms will occur. As a result, to these storms, the shell and quartz sand over a marl base are constantly formed and rearranged, the sand would appear to be white and soft and found mostly along the Gulf Coast. Due to the Atlantic beaches containing littoral sands, this sand is compared to dessert sand, because of its low diversity of marine animals and plants living there. Thus, the type of marine invertebrates and fishes found here are the burrowing type, such as, sea urchins, burrowing snails, crabs, and flat fish. The most common biological feature of the sandy coast northward from Key Biscayne is the massive worm reefs. These reefs can be found building up on the rocky platforms along the coast. The reef plays a significant role in providing protection for a host of fish and marine invertebrates (Pregram, 2018). Resting above sea level are dunes, these are a result from the shifting of sand and home to many plants. Plants are more commonly found here that have a strong root system, as a result from these systems these plants can act as a holdfast against the shifting sand (Kurz, 1942).

As we continue to move through these ecological areas we get into the mangrove and salt marshes, which are found forming a crescent shape around the southern tip of Florida. As a part of the Everglades National Park and the most southern tip in Florida is what is known as Cape Sable. Here is where you will find the greatest mangrove development. It has been proven that here are deep estuaries and mangroves are able to penetrate freshwater marshes (Pregram, 2018). Mangroves form small to moderate size islands known as, Tree Islands. This plays a significant role in the creation of the mangrove flats, which are developed along the mainland and the sediment is at its deepest. These flats thene turn into large strands along the tidal riverbanks that have a higher elevation than the center of the flats, due to the uneven elevation this causes breaks in the in the banks and will allow frequent flooding. With the hurricanes in Florida, debris and mud have been deposited along an old shoreline creating a low embankment called “Buttonwood Embankment.”

You can find these embankments along the shoreline of Florida Bay continuing to the North and Watson Rivers. There are different types of mangroves and some may require different needs to survive. For example you have the black and white mangroves, both that are dependent on periodic saltwater inundation. Lastly, you have the red mangrove, which is the dominant mangrove species, partly because the can grow in salt or fresh water. Due to the red mangrove having such a high tolerance for the freshwater, it can extend furthest inland (Pregram, 2018). Next you have your marl prairies that contain salt-tolerant ground, these prairies are constantly dealing with changes within the salinity and allow for saltwort, glasswort, sea blite, water hemp, sea daisy, and cordgrasses to grow. These plants contain a tolerance to these salinity changes and therefore are able to grow and develop.

Semitropical environments like Shallow bays, are important in supporting a variety of biological communities. The most common place to find these shallow bays are along the inlets between the Florida keys and are interconnected by narrow channels through shallow mudbanks. These communities are rely on the distribution of sediment, salinity, and the tidal flow. Tree island or “Ten Thousand Islands,” are along the southwest coast that contain numerous oyster bars creating a pattern of protected backwaters. Mangroves will continuously cover intertidal bars and will connect adjacent islands. Over time they will deposit tough fibers of what is known as peat and you will start to see the growth of oyster bars. Eventually these oyster bars will have a decline in growth and will cause restriction of the tidal flow (Pregram, 2018).

The Florida reef tract consists of a series of banks and channels parallel to the keys. Two major reefs that are present in the Florida reef tract are patch reefs and outer reefs. The patch reefs grow in the back of the reef zone where the water is calmer, and the silt accumulates. Patch reefs often have a halo of white sand around their perimeter caused largely by the browsing of the black-spine sea urchins on the adjacent grasses (Ogden and others, 1973). The outer reefs are formed from the seaward edge of the reef tract platform and contain more than 500 recorded species, providing a haven for fish, crustaceans, mollusks, worms, and sea urchins. They have an environment that is most stable in temperature and salinity and contains the clearest waters. This is important because most reef corals require photosynthetic algae living in their soft tissues which can only be found in the clear water (Pregram, 2018).

Research has shown the human interaction has a major impact on the current and historical significance of the coastal ecosystem. Due to these human interactions and development in the region alterations in the Florida Bay has had to deal with distress of seagrass die-offs, algal blooms, and a decline in sponge and shellfish. Research has proven from the study of pre-1900 and post-1900 has many similarities, however, because of the rapid growth in the human population many human developments have caused fluctuations to the natural pattern of salinity. Studies show that prior to 1900, the natural hydrologic system had variations of salinity, from faunal indicators swinging back and forth between 15-20% of the mean. Around 1910 the construction of the Flagler Railroad link to the faunal distributions. This railroad was built between 1905 and 1912 and the impact on it had on Florida Bay was significant because it cut off the flow of water that was between the Atlantic Ocean and the Gulf of Mexico (Henkel, 2013).

Going back to the 1970’s, the environmental history of South Florida’s coastal ecosystem starts with the construction of Dade County’s International Airport. This airport serves the tourist industry which provided nearly $2.1 billion dollars to the economy (Davis, 1972). A debate against the Port Authority came about when they agreed to build a jet training facility located on the Big Cypress Swamp which is approximately 6 miles north of the Everglades National Park. This sparked a committee to report, also known as the “Leopold Report,” that this proposed jetport would lead to drainage of the Big Cypress Swamp. It never dawned on anyone at the time that this drainage was going to cause permanent alterations of the South Florida ecosystem. Some concerns that were brought to the attention of these committees were for the protection for the Everglades National Park, now with the increased interest in public acquisition of the Big Cypress Swamp, and uncontrolled urban growth. Being so long ago, no one realized the impact South Florida was about to face with this drainage. Now we understand what is happening here in South Florida, and we are now aware that climate change has a huge impact on the polar ice caps that are melting and causing our sea level to rise. With the rise in sea level we are experiencing salt and fresh water mixing. However, the committee did find that because of the incompatibility of the surrounding ecology this report analyzed the function of the ecosystem and the plans for this jet training facility was to be relocated (Service, n.d.).

South Florida coastal ecosystem surrounds approximately 26,000 square miles of the 19 southernmost counties. To further elaborate, the South Florida coastal ecosystem region can be broken down into about 10 sub regions such as; Kissimmee River, Lake Okeechobee, Lake Wales Ridge, Peace River/Charlotte Harbor, Upper East Coast, Lower East Coast, Caloosahatchee River, Everglades, Big Cypress, and Florida Keys, including Biscayne Bay, and the lower southwest estuaries (Service, n.d.). To begin the Kissimmee River, originate in Orland and ends at Lake Okeechobee. The Kissimmee River is flat and contains hilltop and slopes, located along this river are high pines, and on the sandy coastal and more interior sites are the flatwoods. You can also find along the river hardwood forests, dry prairies, forested wetlands, and marshes (Service, n.d.).

Next is the largest lake found in all of Florida known as Lake Okeechobee. This lake was formed by a broad and shallow depression causing a circular shape in the bedrock. Originally Lake Okeechobee was the main source for the flow of Everglades. The lake sustained the Everglades and provided nourishment for the Florida bay and coastal estuaries. Today Lake Okeechobee has been re-engineered and contains major vegetative communities outside the lake. Predominantly outside the lake are freshwater marshes and some wetlands with small fragments of the pond apple forest. Had it been known that such a huge vegetative community would be dependent on this lake the draining of these freshwater lakes may have not occurred, and we wouldn’t be dealing with its effects on our agriculture (Service, n.d.).

The sea level has gone up and down, as a result the Upper east coast sub region was formed. This sub region can be characterized by three zones; (1) Atlantic Coastal Ridge, (2) Eastern Valley, and (3) Osceola Plain. Along the upper east coast, the vegetative community is made up of coastal dunes, coastal strand, maritime forest, hardwood hammock, and pine flatwoods. A more urbanized area in Florida is a sub region known as Lower East Coast. Here is where you have 30% of Florida’s residents. The ecological communities that are found here are your beach dunes, maritime and tropical hardwood hammocks, pine Rocklands, mangrove swamps, coastal saltmarshes, freshwater marsh, and wet prairie (Ronald L. Myers, 1990).

Located on the South West coast of Florida in the Lee County district is he Caloosahatchee River sub region. This river is shallow and extends from Lake Okeechobee to San Carlos Bay and contains three water control structures: Moore Haven Lock, Ortona Lock, and Franklin Lock. The predominant ecological communities found in this sub region are pine flatwoods, scrubby flatwoods, coastal strand, freshwater marshes, mangroves, and seagrasses (Service, n.d.).

The Everglades is unique with its diverse habitats containing both temperate and tropical flora. Historically the Everglades consisted of dense wetlands that covered an area approximately 40 miles wide, by 99 miles long. Rockland communities are found in the Everglades’ uplands. For example, you would see here the Rockland pine forests and the tropical hardwood hammocks. Also located in the Everglades are the freshwater communities, these can be categorized by marshes, prairies, ponds, and sloughs. With the length and location of the Everglades on Florida’s peninsula, the periphyton community occurs within the freshwater communities and serves as an important element to the base of the food chain (Service, n.d.).

Big Cypress has two watersheds: The Corkscrew Swamp and the Big Cypress Swamp, with a relatively flat landscape with more than 790,720 acres of connected wetlands. This system is mostly made up of cypress, pine, and hardwood forests. To help with drainage the prairie and sloughs are used to drain these Ten Thousand Islands and the rookery bay estuarine system. The Big Cypress sub region’s major ecological communities are the pinelands, hammocks, beach dunes, coastal strand, prairies, cypress swamps, mangroves, freshwater and saltwater marshes (Service, n.d.).

From Biscayne Bay down through the Florida Keys, this sub region began to form about 100,000 years ago. Over the course of the last hundred thousand years the marine and tropical habitats have a wealth of biological diversity. The geographic location of the keys is isolated and bring numerous endemic plants and animals. The natural community consists of hardwood hammocks, pine Rocklands, freshwater wetlands, mangrove wetlands, seagrasses and coral reefs. Each of these communities play their own important role in the protection and nourishing of the marine life. The hardwood hammocks and pink Rocklands are most known for containing tress, shrubs, and plants that contain more than 120 species. The mangrove wetlands help provide shelters for ocean life as well as the coral reefs such as The Florida Key’s coral reef tract. These communities also provide nursery areas for many fish (Service, n.d.).

South Florida has a subtropical climate and is a very humid state, the average rainfall is about 54 inches and usually falls 50 to 60 percent between June and September. The prediction of ecological change can be done with using different scenarios. One major scenario is with climate change, if we continue to ignore these vastly changing climates, we are not going to have any control in the future. We can already see here in South Florida that over the last couple of decades the sea level has risen, this is from the melting of the artic solar cap. There were studies done of climate change and level of sea water that shows in 2060, Modeling results depending on a particular scenario, can show significant changes to water budgets and will have concluded a water supply and ecosystem of the Greater Everglades. If we continue with these draining projects in the Everglades a lot of the fish will be forced to relocate, and the alligator will suffer significantly. There are some things that we cannot control like mother nature, hurricanes, fires, floods, but there are things that are happening that can help with the protection such as the Comprehensive Everglades Restoration Plan (CERP). With the amount of tourist, we see here in South Florida, means more pollution to our marine life. We need more beach clean ups and to not neglect the important coastal ecosystem that keeps the cycle going. We also need to find new ways to help with the sea level rising, because part of Dade County is already under water and it will only get worse over time.

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