The Everglades National Park of Florida: its geological history and spectacular environments Arun Kumar

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The Everglades National Park of Florida: its geological history and spectacular environments Arun Kumar The United States Congress in 1934 authorized the creation of the Everglades National Park to

1 The Everglades National Park of Florida: its geological history and spectacular environments Arun Kumar The United States Congress in 1934 authorized the creation of the Everglades National Park to preserve this subtropical wetland ecosystem and its biota.. The present day Everglades originated around 3,200 years ago when the rate of sea level rise slowed significantly from 23 centimeters to just 4 centimeters per century. The Everglades National Park comprises a vast, interconnected assortment of diverse and discreet ecosystems. These habitats are constantly changing due to the influences of local geology, water quality, fire and weather conditions. In early February, 2013, on my return trip from the eastern Caribbean islands of Trinidad, Tobago and Barbados I decided to stop for another nine days at the home of my sister-in-law Vandana Shankar and her familyin the Fort Lauderdale area of southern Florida. During these days we visited the Everglades Holiday Park (Figure 1) which is a part of the much larger Everglades National Park (Figure 2). During my graduate student days I had read quite a bit about this unique and vast fresh to brackish water wetlandand its wilderness and had heard a lot about its remarkable flora and fauna, the most famous being Cypress swamps and its alligators. In this article I present a short account of this national park, its geological history, mosaic of its various habitats, flora and fauna. The United States Congress in 1934 authorized the creation of the Everglades National Park to preserve this subtropical wetland ecosystem and its biota and for the first time federal land was set aside for this purpose.but the park came into existence in It is one of the largest national parks in the USA that covers an area of over 1.5 million acres. According tothe documents on the impact of climate change on the Everglades (websites 1 and 2) this park protectsthe largest stand of sawgrass prairie in North America, the largest protected mangrove forest in the northern hemisphere, the vast estuary of Florida Bay, and cultural resources chronicling approximately 10,000 years of human experience in southern Florida. This park is a vast subtropical grassy wetland which is an important habitat for rare and endangered species like the manatee, American crocodile, and the Florida panther. The history of this park is provided by the National Park Service of the U.S. department of Interior as follows (website 1). Water in south Florida once flowed freely from the Kissimmee River to Lake Okeechobee and southward over low-lying lands to the estuaries of Biscayne Bay, the Ten Thousand Islands, and Florida Bay. This shallow, slow-moving sheet of water covered almost 11,000 square miles, creating a mosaic of ponds, sloughs, sawgrass marshes, hardwood hammock, and forested uplands. For thousands of years this intricate system evolved into a finely balanced ecosystem that formed the biological infrastructure for the southern half of the state. However, to early colonial settlers and developers the Everglades were potential farm land and communities. By the early 1900s, the drainage process to transform wetland to land ready to be developed was underway. The results would be severely damaging to the ecosystem and the species it supported. 1

2 Figure 1: Reception Center of the Everglades Holiday Park (Photo: The author, February, 2013). Figure 2: The Everglades National Park in South Florida, USA (website 2). 2

With the support of many early conservationists, scientists, and other advocates, Everglades National Park was established in 1947 to conserve the natural landscape and prevent further degradation of

3 With the support of many early conservationists, scientists, and other advocates, Everglades National Park was established in 1947 to conserve the natural landscape and prevent further degradation of its land, plants, and animals. Although the captivation of the Everglades has mostly stemmed from its unique ecosystem, an alluring human story of the Everglades is deeply interwoven with its endless marshes, dense mangroves, towering palms, alligator holes, and tropical fauna. Various groups and people navigated through and wrestled with the watery landscape to make it home, and even to exploit its natural wonder at times. The Everglades are primarily sawgrass marshes, mangrove forests, and tropical hardwood hammocks inhabiting fresh or brackish water wetlands (Figures 3, 4, 5, 6 and 7). A portion of it is also submerged under the shallow estuarine waters of Florida Bay. The airboats are used to ferry tourists on guided excursions of the park (Figure 8). Geological History South Florida s landscape has resulted due to a series of interconnected geologic events of the Plio-Pleistocene epochs. The geologic record of the region is well preserved in the Everglades National Park despite various anthropogenic undertakings of the immediate past. The shallow marine Tamiami Formation (Pliocene) beneath the Cypress Swamp occurs at or near the land surface in southern Florida arethe oldest rocks in this region. It is a poorly defined lithostratigraphic unit containing a wide range of mixed carbonate and siliciclasticlithologiesand associatedmarine faunas (Missimer, 1992). Its fossil contents include barnacles, mollusks, corals, echinoids, foraminifers and calcareous nannoplankton (website 1). Figure 3: The airboats that carry tourists on guided excursions of the Everglades; Vandana Shankar in foreground (Photo: The author, February, 2013). 3

4 Figure 4: The wetlands of the Everglades; the author in foreground (Photo: Vandana Shankar, February, 2013). Figure 5: Hardwoodhammocksof the Everglades (Photo: The author, February, 2013). 4

5 Figure 6: Sawgrass marshes of the Everglades (Photo: The author, February, 2013). Figure 7: The marshes of the Everglades (Photo: The author, February, 2013). 5

6 Figure 8: An airboat with tourists on a guided excursion of the Everglades (Photo: The author, February, 2013). Throughout the earth s history climate has always changed between warm and cold episodes of various intensities and durations. During the Plio-Pleistocene epoch several glacial cycles have fluctuated altering the landscape and impacting the sea levels all over the world. The rocks beneath the Everglades were formed during the Great Ice Age. Due to extensive glaciation during this Ice age sea levels in South Florida had gone down as much as 300 feet below the present levels. However duringthe interglacial warming periodthe sea level in South Florida rose. During the interglacial stage that occurred about 100,000 years ago the sea level in South Florida rose 100 feet above the present levels. This led to the deposition ofmiami OoliteFormationand Miami Bryozoan Limestone that cover most of the area east of the Everglades National Park and most of the Florida Bay (website 1). According to Lodge (2005) Florida s land mass developed during times of high sea level, when oceanic waters covered the peninsula and deposited both clastic and non-clastic sediments over existing limestone. Intermittently, this growing land mass emerged from the ocean floor and submerged again in response to the cycles of glacial and interglacial periods. Around 17,000 years ago, during an interglacial period, the climate began to warm once againand south Florida gradually became humid and subtropical (Lodge 2005). Regular summer rains fedthe recently formed Lake Okeechobee and during times of heavy rainfall, the shallow lake would overflow into a rising ocean (Lodge 2005). The present day Everglades originated around 3,200 years ago when the rate of sea level riseslowed significantly from 23 centimeters to just 4 centimeters per century (Davis 1994). This led to the deposition of mud and sand at Florida s southern coast forming a ridge that acted as a low dam and kept the ocean water from crossing over it. This natural dam also 6

7 retained rainfall and prevented overflow of water from Lake Okeechobee inundating vast areas forming the extensive wet land region now calledthe Everglades (Davis 1994). Environment and various ecosystems of the park The following information has been summarized from the website of the National Park Service (website 1). The Everglades National Park comprises a vast, interconnected assortment of diverse and discreet ecosystems. These habitats are constantly changing due to the influences of local geology, water quality, fireand weather conditions. Anthropogenic activities like introduction of non-native species, disruptive water management actions and the disturbance of natural processes have all worked to undermine the integrity of this historic ecosystem. Oncethe Everglades National Park came into existence in 1947 a large tract of wilderness was permanently protected not merely for its scenic value, but also for the benefit of the unique diversity of the life it sustained. The following eight distinct habitats have been identified. The GORP website (website 2) provides detailed information about the flora, fauna and the environment of the Everglades national Park. 1. Mangrove Occurs in the coastal channels and winding rivers around the tip of South Florida. Theyare species of salt-tolerant trees that inhabit the harsh growing conditions of the coast. The red mangroves (Rhizophora mangle), the black mangroves (Avicenniagerminans) and the white mangroves (Lagunculariaracemosa) flourish in tidal waters, where freshwater from the Everglades mixes with saltwater from the sea. 2. Hardwood Hammock These are dense stands of broad-leafed trees that grow on a natural rise of only a few inches in elevation and are found among other Everglades ecosystems. Many tropical species such as mahogany (Swieteniamahogoni), gumbo limbo (Burserasimaruba), and cocoplum (Chrysobalanusicaco) grow alongside the more familiar temperate species of live oak (Quercusvirginiana), red maple (Acer rubum)and hackberry (Celtislaevigata). This diversity of plant life supports a diverse array of wildlifeas well. 3. Pineland Pine forests take root in the exposed limestone substrate of south Florida and are predominantly slash pine (Pinuselliottii var. densa). Natural fire is a requirement for survival of the pine forest thus many plants that grow here are adapted to a life of frequent fires. 4. Coastal Lowlands The regions between the tidal mud flats of Florida Bay and dry land, the coastal lowlands are a well-drained area of shrubby, salt-tolerant vegetation. Periodic flooding by tropical storms keeps these areas devoid of mangroves.salinity levels in the region vary significantly thus resulting in a variety of salt-tolerant communities that inhabit the region. These communities are characterized by succulent and other low-growing, desert-like plants. 7

8 5. Freshwater Slough These are low-lying marshy areas that channel water through the Everglades. They are relatively deeper and remain flooded year-round. 6. Freshwater Marl Prairie Vast areas of freshwater marl prairie border the deeper sloughs of the Everglades that are characterized by a diverse assemblage of low-growing vegetation. Algae, bacteria, microbesand detritus that areattached to submerged surfaces, serveas an important food source for invertebrates, tadpolesand some fish. 7. Marine and Estuarine Florida Bay is the largest body of water within the Everglades National Park that covers more than 2,072 square kilometers of marine environment. It is mostly covered by submerged vegetation where seagrass and algae provide shelter and sustenance to numerous marine organisms. Corals and sponges inhabit the hard bottom areas of the bay. A wide variety of fish, crustaceansand mollusks thrives within the estuarine environment. 8. Cypress The cypress tree (Taxodium spp.) is a deciduous conifer that can survive in standing water. In the Florida Everglades these trees are often found growing on the limestone substrate. Clusters of cypress trees are known to grow in the shape of a dome, with larger trees in the middle and smaller trees all around. In areas of less-favorable growing conditions, stunted cypress trees, called dwarf cypress, grow thinly distributed in poor soil on drier land. Plants The geographical location of the Everglades National Park is at the confluence of temperate North America and the tropical Caribbean; thus plant communities here are a blend of tropical and temperate species adapted to the wetlands of the Everglades.Additionally, the assortment of habitats of the Everglades Ecosystem supports several species of plants and animals that occur only here (Figures 9, 10, 11 and 12).The regionsupports a lush growth of plant life sustaining a diverse flora and several endemic species that grow here are protected by law.the main reason to establish the Everglades National Park was to preserve the region's rare and beautiful plants and associated environments. This national park contains around 1,000 different kinds of seed-bearing plants and various ferns, mossesand lichens. The following are major trees in the park (website 2): Cypress tree (Taxodium spp.) Red Mangrove (Rhizophora mangle) Bald Cypress (Taxodiumdistichum) Slash Pine (Pinuselliotti var. densa) Gumbo Limbo Tree (Burserasimaruba) Sabal Palm (Sabal palmetto) 8

Everglades (Photo: The author, February, 2013).

9 Lysiloma (Lysilomalatisiliqua) Strangler Fig (Ficusaurea) Royal Palm (Roystoneaelata) Figure 9: Various plant communities of the Everglades (Photo: The author, February, 2013). Figure 10: Various plant communities of the Everglades (Photo: The author, February, 2013). 9

10 Figure 11: Various plant communities of the Everglades (Photo: The author, February, 2013). Figure 12: Various plant communities of the Everglades (Photo: The author, February, 2013). 10

11 Animals Theluxuriant and sprawling wetland of the Everglades supports a wide range of animals ranging from the tiny grass frog to the largest crocodile. Like the plant communities, animals from the tropical Caribbean coexistwith animal species from temperate North America.Reptiles like American Crocodile(Crocodylusacutus), American Alligator(Alligator mississippiensis; Figure 13), and Caiman (Caiman crocodilus), various species of turtles, tortoise, lizards and snakes are among the animals that exist here. Among amphibians a large variety of frogs and toads occur here. Florida panthers are an uncommon large cat species of this national park.a large variety of fish (Figure 14) and birds (Figures 15, 16, 17, 18 and 19) also inhabit this park. Impact of climate change During the past 3,200 years the sea level rise in south Florida was relatively slowerbut this rate accelerated over the past century (Wanlessand Vlaswinkel,2005).Due to the rising sea level in Cape Sable the interior freshwater marsh has disappeared, and nearby lakes are now filled with marine sediments. Along the coastal regions, high tides and storm surges have washed away sediments due to the erosion along Cape Sable (Wanlessand Vlaswinkel,2005). Over the past 50 years the influence of sea level rise has reached far inland, e.g., due to increased salinization of groundwater and the soil various plant species are forced to migrate (Stabenauet al. 2011). During the same period, the red mangroves have expanded inland, at places over 1 km and have displaced several freshwater species (Ross et al. 2000). Climate change is causing an increase inthe frequency and intensity of oceanic storms all over the world. Thus rising sea levels along with storm surges and resultant over-washsalt depositsinto the soil ismaking freshwater species extend farther inland. As a resultincreasing saline coastal environments helps saline species in their growth, but reduces the area of freshwater marshy lands (Ross et al. 2000). Understanding sucha change is very important because we know the consequences of a sea level rise may indicate what these coastal habitats will be like in the future. It is clear that climate change challenges the environment of this park. Thereby the National Park Service has created a Climate Change Response Strategy with the objectives to address climate change utilizing science, mitigation, adaptationand communication to guide various activities within this park.constant monitoring of environmental indicators like coral health, nesting of wading birds, vegetation communities, fish abundance and diversity, hydrology and water quality, threatened and endangered species help to understand the impacts of climate change in the park. Impact of growing population and increasing economic activities According to the Third Biennial Report-2010 of the National Research Council of the National Academies in the Unites States at present over seven million people inhabit South Florida and at least seven times more visit this region every year. Urban and agricultural developments have condensed the Everglades to less than half of its original extent. The remaining parts of the Everglades are managed through the Central and South Florida 11

project s network of canals, levees and pumping stations to serve competing demands for development of land, water supply, flood control, recreationand environmental conservation (Figure 20).

In 1999 a long term Comprehensive Everglades restoration Plan (CERP) was jointly initiated by the Federal and Florida governments to protect and restore the remaining Everglades while meeting the

12 project s network of canals, levees and pumping stations to serve competing demands for development of land, water supply, flood control, recreationand environmental conservation (Figure 20). Constant environmental degradation and endangerment of wildlife has led to a series of efforts to protect and restore the Everglades. In 1999 a long term Comprehensive Everglades restoration Plan (CERP) was jointly initiated by the Federal and Florida governments to protect and restore the remaining Everglades while meeting the growing demand for water supply and flood control. The 2010 report of the National Research Council (NRC) presents a consensus report on the restoration accomplishments and emerging challenges covering the past ten years of their work. Figure 13: An alligator in the Everglades (Photo: The author, February, 2013). Figure 14: A fish caught by the guide of our airboat tour (Photo: The author, February, 2013). 12

13 Figure 15: Birds of the Everglades(Photo: The author, February, 2013). Figure 16: Birds of the Everglades (Photo: The author, February, 2013). 13

14 Figure 17: Birds of the Everglades (Photo: The author, February, 2013). Figure 18: Birds of the Everglades (Photo: The author, February, 2013). 14

15 Figure 19: Birds of the Everglades (Photo: The author, February, 2013). Figure 20: Management of the Everglades by the government agencies (Photo: The author, February, 2013). 15

The Gator Boys are professionals who perform various acts with the crocodiles and alligators which are kept in safety from poachers.

16 Tourism The website of the Everglades Holiday Park provides tourist information (website 3). The airboat adventure ride takes tourists on a guided tour several times daily. It is both informative and entertaining. The Gator Boys are professionals who perform various acts with the crocodiles and alligators which are kept in safety from poachers. These shows are quite popular with the visitors of the park (Figures 21 and 22). Figure 21: The Gator Boys Alligator Rescue Center of the Everglades Holiday Park (Photo: The author, February, 2013). Figure 22: The Gator Boys Alligator Rescue Center of the Everglades Holiday Park (Photo: The author, February, 2013). 16

17 Suggested Readings: Davis, Steven M Sea level control on stability of Everglades wetlands. In Everglades The Ecosystem and Its Restoration, edited by Steven M. Davis and John C. Ogden, St. Lucie Press. Lodge, Thomas E The Everglades Handbook Understanding the Ecosystem. CRC Press LLC. Missimer, T.M., 1992, Stratigraphic relationships of sediment facies within the Tamiami Formation of southwestern Florida: Proposed intraformational correlations; in Scott, T.M., and Allmon, W.D., (eds.), The Plio-Pleistocene stratigraphy and paleontology of southern Florida; Florida Geological Survey Special Publication 36, p Ross, M., J. Meeder, J. Sah, P. Ruiz, and G. Telesnicki The Southeast Saline Everglades revisited: 50 years of coastal vegetation change. Journal of Vegetation Science 11: Stabenau, Erik, Vic Engel, Jimi Sadle, and Leonard Pearlstine Sea-level rise: Observations, impacts, and proactive measures in Everglades National Park. Park Science 28: Wanless, Harold R. and B. M. Vlaswinkel Coastal landscape and channel evolution affecting critical habitats at Cape Sable, Everglades National Park, Florida. Report to Everglades National Park. Progress Toward Restoring The Everglades, The Third Biennial Review National Research Council of the National Academies. The National Academies Press, Washington, D. C. 311 p. Web references Website 1: Website 2: Website 3: About the author Dr. Arun Kumar is an Adjunct Professor, Department of Earth Science, Carleton University 1125 Colonel By drive, Ottawa, ON K1S 5B6, Canada. 17

An NPS Wetland of International Significance!

An NPS Wetland of International Significance! A World Class Tourism Destination Linda Friar Chief of Public Affairs 305-242-7714 Linda_Friar@nps.gov The Everglades - International Recognition as a special