Ever­glades threat­ened by flood­ing, errat­ic weath­er and intruders

By Pur­bi­ta Saha

The marl ridge of Cape Sable was once a sweet spot for farm­ers. Its rich, damp soils made it a hub of agri­cul­tur­al activ­i­ty, while its promi­nent coastal loca­tion made it ide­al for fish­ing. Yet since the ear­ly 1900s high tides have washed over the ridge, nutri­ents have been washed away, man­grove forests have replaced marsh­es and the ridge has become barren.

Cli­mate change may soon make sim­i­lar alter­ations to oth­er parts of South Flori­da. With­in a cen­tu­ry the low­er half of the penin­su­la could resem­ble a Sea World exhib­it. Sci­en­tists say that some of the changes, such as flood­ing and the arrival of inva­sive species, are some­what pre­dictable. But oth­ers, such as cold­er tem­per­a­tures and less rain­fall, are more surprising.

“Change in many ways is unstop­pable. But what degree of change are we com­fort­able with?” asked Lar­ry Perez, a sci­ence com­mu­ni­ca­tions inter­preter at Ever­glades Nation­al Park.

Harold Wan­less, a geol­o­gy pro­fes­sor at the Uni­ver­si­ty of Mia­mi, has used cur­rent stud­ies and past sce­nar­ios to con­clude that the Ever­glades is well on its way to turn­ing into a marine cesspool. Wan­less expects there to be a three-foot increase in sea lev­els with­in the next cen­tu­ry. Such a dras­tic change, he said, will over­take coast­lines, bar­ri­er islands, reefs, bays, estu­ar­ies and wet­lands. “What’s gonna hap­pen in South Flori­da is we’re gonna keep the water lev­els high, and then we’re gonna have flood­ing. Then we’re gonna have a fight,” said Wanless.

The man­grove forests that bor­der Ever­glades Nation­al Park are impor­tant habi­tats for aquat­ic organ­isms like man­a­tees, shrimp, bar­racu­d­as, snap­pers and roseate spoon­bills. At the same time, they serve as chan­nels for marine water to min­gle with fresh water reserves. With these open avenues, ocean water can drift through the swamp and up to Lake Okee­chobee, con­vert­ing it into an estu­ary sys­tem. Brent Bachelder, a plant biol­o­gist from the Flori­da Fish and Wildlife Con­ser­va­tion Com­mis­sion, said that most of the dom­i­nant veg­e­ta­tion in the lake will not be able to sur­vive the intrud­ing salt water.

Wan­less agrees. “The south­ern Ever­glades is going to turn into a big mud­dy, decay­ing mess,” he said. The sit­u­a­tion will be rem­i­nis­cent of 1935, when a hur­ri­cane on Labor Day caused 8 inch­es of water to drown out the swamp. At the time, many of the man­groves were either knocked down by the storm or destroyed by the saline eruption.

Man­grove restora­tion should be one of the Nation­al Park Ser­vice’s top pri­or­i­ties, said Wan­less. The forests pro­vide a nat­ur­al bar­ri­cade for the park. Plus, they act as a sink by pulling car­bon diox­ide out of the atmos­phere and cur­tail­ing the effects of glob­al warming.

Anoth­er one of Wan­less’s sug­ges­tions is to use cat­tails to build up the wet­land sub­strate. This may not be a pop­u­lar notion, con­sid­er­ing that cat­tails are out­grow­ing the Ever­glades’ sig­na­ture saw­grass. But Wan­less said that the inva­sive plant, which thrives in phos­pho­rus-rich soils, can max­i­mize the organ­ic mat­ter of the swamp and cause peat to form. Unlike the 18,000 feet of porous lime­stone that make up the Flori­da penin­su­la, peat is able to retain fresh water and expel encroach­ing tides. After the sub­strate has been sta­bi­lized, Wan­less said that the cat­tails would be removed so that the land could be returned to the sawgrass.

Cli­mate change can caus­es heat waves and droughts, but it can also result in cold-weath­er events. While sci­en­tists are reluc­tant to pin spe­cif­ic weath­er episodes on cli­mate change, at the begin­ning of 2011, Okee­chobee expe­ri­enced a record win­ter with 19 nights below freez­ing. Bachelder said that as a result of the frost and snow, the pop­u­la­tion of pond apple trees was wiped out. Since then, the species has not been able to rebound, despite rel­a­tive­ly mild tem­per­a­tures. Pond apple is now con­sid­ered to be local­ly extinct in some parts of the Everglades.

Oth­er species, such as live oak and bald­cy­press, were not affect­ed by last year’s extreme­ly low tem­per­a­tures. Bachelder said that this may be because they are not lim­it­ed in dis­tri­b­u­tion like the pond apple is.

Pre­cip­i­ta­tion is also a big fac­tor in the cli­mate change equa­tion for South Flori­da. Eleanor Hodak, a ranger at Big Cypress Nation­al Pre­serve, said that while the entire region depends on water, it is espe­cial­ly crit­i­cal in the south­west where Big Cypress is locat­ed. The cycli­cal process begins as stand­ing water from the swamp evap­o­rates, con­dens­es into clouds, blows west­ward and dis­charges as rain on the terrain.

But sci­en­tists at the Uni­ver­si­ty of Mia­mi have found evi­dence that as the oceans get warmer, low­er-lev­el clouds are start­ing to van­ish. The leader of the research team, Amy Clement, said in a Time Mag­a­zine inter­view that reced­ing clouds are a good reflec­tion of cli­mate change. In the case of South Flori­da, they may also be a good reflec­tion of the decreased wet sea­sons and increased dry spells that will soon tam­per with Big Cypress’s lush environment.

Warmer weath­er also makes ecosys­tems more hos­pitable to intro­duced organ­isms. Bachelder said that in recent years, Okee­chobee has seen a boom in inva­sive pop­u­la­tions. “Accord­ing to the Nation­al Weath­er Ser­vice, East-Cen­tral Flori­da just emerged from the sev­enth warmest win­ter on record,” he said. This has caused a spike in float­ing inva­sives, such as water let­tuce and water hyacinths. By dense­ly cov­er­ing the lake’s sur­face, the let­tuce and the hyacinth are able to over­whelm the aquat­ic habi­tat and destroy res­i­dent plant, fish and inver­te­brate populations.

Cur­rent­ly, the U.S. Army Corps of Engi­neers has teamed up with wildlife agen­cies to con­duct exten­sive plant con­trol activ­i­ties that tar­get these species. But rein­ing in the let­tuce and the hyacinth is not easy, Bachelder said. Such efforts require lots of man­pow­er and money.

Soon, the human pop­u­la­tion of South Flori­da will also feel the effects of cli­mate change.

“Mia­mi is perched between a nation­al trea­sure and an ocean that is ris­ing,” said Perez. Thus, the peo­ple of Mia­mi-Dade Coun­ty end up being the medi­um between cli­mate change and the Ever­glades. Pro­tect­ing both the urban core and the South Flori­da envi­ron­ment will not be easy.

“We can’t play New Orleans,” said Wan­less, “at some point we’re gonna wake up and say, ‘we have to get a hold of this green­house gas­es thing.’ ”