Monday, February 04, 2013

The Southern Florida Ecosystems Before Human Infrastructure Development
Image soorce: NASA
Great Blue Heron
My wife and I spent a couple of weeks last month on a trip to southern Florida. We visited the Everglades and Biscayne National Parks, the Pennenkamp Coral Reef Florida State Park,  the Big Cypress National Researve, and the Rookery Bay Marine Estuary Reserve. We made a similar trip two years ago.

Gators Sunning Themselves
We are not expert bird watchers, but we have counted some 60 species of birds on these short trips. They included white pelicans, great blue herons, and roseate spoonbills -- some of the largest birds in the world. We saw large birds not only one by one, but in flocks. There are alligators and crocodiles even sharing the same waters. We did not see deer nor Florida panthers, but there remain viable populations of both. The coral reefs swarm with life.

We love driving for miles on narrow roads surrounded by a landscape that is fully comparable to that which existed in 1491. We love boating through one of the world's largest mangrove forests, again existing much as those forests existed in 1491. We love boating through the barrier islands and driving down the Florida Keys.

I quote from NASA's Earth Observatory:

Before humans constructed drainage canals, dams, dikes, and reservoirs, much of central and southern Florida was covered with one kind of wetland or another. From swampy forests dominated by giant cypress trees, to bogs and various types of marshes, to the tree-island-dotted Everglades, almost every ecosystem on North America’s southeastern tip was under the sway of water. 
Runoff from the north kept the Kissimmee River Floodplain in the central part of the peninsula almost perpetually under water. From there the water flowed south into Lake Okeechobee. The spillover from the lake glided slowly over the Everglades in a slow-moving, horizontal sheet. Today's flow is dramatically reduced, and the Everglades are only about half the size they once were.
The Everglades are unique in the world. The coral reefs too are a unique ecosystem due to their northern location.

Southern Florida As It Is Now 
Image source
Compare the two maps and you will see that the protected areas are only a small portion of the original aquatic ecosystems. We drove from Homestead to Lake Okeechobee which has been almost totally converted to agriculture with some urban development -- miles of commercial nurseries and miles of sugar cane. The east coast -- the so called Gold Coast -- is heavily populated and growing. The west coast too is urban with a growing population. The Florida Keys are populated and commercialized.

 The topographic map shows current sea level.
Land areas 5 meters (red) and 10 meters (yellow)
above sea level are at risk for flooding from storm
 surges and sea level rise.
While there has been a major effort to rectify the engineering works that were drying up the Everglades and Big Cypress Swamp, but there will be a competition for water in Florida for decades and possibly centuries to come. I question whether nature preservation will compete well with urban development and agriculture for water resources.

Global warming is going to lead to rising sea level, which is likely to do damage to the reefs, barrier islands, and mangrove forests. Indeed, changes in weather may threaten plant and animal systems. Coral reefs are threatened by whitening.

Invasive species such as the Burmese Python and Australian Pine are already damaging the ecosystems. The Florida panther is clearly threatened. Bird populations are a small fraction of what they were in 1819 when Florida became part of the United States.

We find ourselves wondering how long Americans will be able to enjoy the natural riches of southern Florida, and how long the United States will safeguard the world heritage represented by this region.

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