Marine Ecosystems Battling Oil ImpactsApril 18, 2014
Join Us at the Mitigation Banking ConferenceMay 3, 2014
by Colleen Tuite
Strike out west from Miami on Route 41, historically known as the Tamiami Trail. Pass through the jungle of overpasses and freeways, which then smoothes into a sea of urban sprawl – strip malls and Best Buys. Keep moving. The sprawl ends, suddenly, and gives way to something even more ominous: a forest.
These are Melaleuca and Australian Pine trees, planted extensively in the 20th century as a method to drain what was considered to be the unsightly and murky swamp we now call Everglades National Park.
Introduced from Australia in 1902 by the USDA, Melaleuca quinquenervia was considered a godsend: for the hand-wringing public officials of the 19th and early 20th century, convinced wetlands brought nothing but disease; for the U.S. military, charged with eradicating the indigenous Seminole people from their home; and for developers, looking to fabricate buildable and arable land. Deep roots pump up thousands of gallons of the so-called “miasmatic and malaria-filled” water which fuels the Everglades wetland system, effectively sucking it dry. By the 50s, it was understood that the rapid growth and ecosystem changes wrought by the Melaleuca may not bode well, but planting continued through the 70s, creating over 500,000 acres of water draining monoculture.
Continue your drive west, and eventually the forest opens to a grassland, punctuated by the skeletons of hundreds of dead Melaleuca trees. Now considered an invasive, Melaleuca is being controlled by quarantining, herbicides, and biological agents such as weevils. In the past 20 years the acreage covered by Melaleuca has been cut in half, with the intention of restoring native plants and habitat.
Press on and the landscape widens into a vast grassland. Notice that you are now driving alongside a canal – and slowly realize that the road you are traveling on is bisecting the flow of surface water through the Taylor Slough drainage system and into the Glades, effectively choking the system of much needed freshwater recharge. Instead of replenishing freshwater in the wetlands to the south, this captured water is diverted to be used for irrigation. Between the 1950s and 60s, over 1400 miles of canals were constructed for both flood control and to capture water for use in cities and agriculture.
The canalization of the Glades has created the Everglades Agricultural Area – an artificial oasis of farms, nurseries and roadside markets just above the protected boundary of the National Park. The willful mismanagement of this area began in the 1920s, with the dumping of manganese sulfate into the then-wetland to encourage agriculture. The tradition continues today: while the Glades remain starved for freshwater, here one can observe fields being irrigated by trucks cheerfully spraying thousands of gallons of water into the air – a demonstration of what has to be the least efficient method of watering possible.
Agriculture is a major culprit for diminished water quality in the Glades. Not only does decreased freshwater increase salinity, but runoff water from the farms that does make it into the wetland is often loaded with fertilizers and petrochemicals. Legislation in the early 90s has helped control levels of phosphorous, but mercury levels remain a concern, especially as it bioaccumulates in larger (often already endangered) animals, such as panthers.
For the past 20 years, a program called the Central and South Florida Project Restudy has been operating to create a comprehensive recovery plan for the Everglades. However, it’s difficult to undo almost two centuries of mismanagement/ willful destruction, especially now that industries in the region depend on the denial of resources to the Glades. However, over 36,000 acres of artificial wetlands have been created to capture stormwater, filter phosphorous from runoff, and recharge the Everglades, including a 16,000-acre site which takes home the title as the largest constructed wetland in the world. More recently, some canals have been rebuilt in order to allow water to flow back where it belongs.
Looking ahead at the future of the Everglades, it’s clear that after centuries of mismanagement and neglect, this unique ecosystem will never return to its pre-1800s condition. But that’s ok – South Florida is now a rich mosaic of nature and culture that will remain linked. Opportunities exist to restore ecological functionality to the Everglades, while still allowing for human needs within the landscape, such as farming and recreation. Constructed wetlands are the first step in creating a shared ecosystem between agriculture and nature. The removal and reconstruction of canals and levees to restore water flow into the Glades need not be the end of fishing – these popular spots can be mitigated by introducing fishing into the constructed wetlands, and by creating artificial lakes which double as freshwater storage during seasonal flooding. By understanding and designing to meet these layered needs, an ecologically and culturally complex and resilient landscape is possible.
Carter-Finn, Katherine, Alan W. Hodges, Donna J. Lee, and Michael T. Olexa. The History and Economics of Melaleuca Management in South Florida. EDIS New Publications RSS. University of Florida IFAS Extension.