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By Victoria Parsons

Devastation caused by hurricanes is a familiar sight in Florida.

With high winds, torrential rains and storm surges that can sweep miles inland from low-lying coasts, the threat of a hurricane strikes fear into the heart of almost everyone who lives in Florida. In fact, two- thirds of the worst catastrophes in the nation's history - measured by insured property losses - have been caused by hurricanes.

From an environmental perspective, hurricanes cause shorelines to erode, stress seagrass meadows, and cause ancient trees to topple, destroying bird nests and transforming shady cool habitats into hot sunny spots.

The well-documented damages, however, may be partially counter-balanced with beneficial impacts that scientists are beginning to detail. Just as natural systems evolved to accept - and even expect - forest fires, Florida's coastline has been shaped by hurricanes over the millennia.

"There's a reason we call Hurricane Pass Hurricane Pass," says Abby Sallenger, an oceanographer with the U.S. Geological Survey who has spent most of his career studying hurricanes and other extreme storms. "Virtually every inlet from Fire Island, New York down the coast and out to Texas was created in a hurricane."

The barrier islands that attract millions of tourists every year - and protect mainland habitats from the worst of a hurricane - also owe their existence to extreme storms, Sallenger said. "High winds push water over the land and carry sand from the front of the island to the back like a conveyor belt. That moves the islands landward and widens them."

In a natural system, that movement is expected and causes minimal damage. "But everything changes when you put fixed structures on a barrier island because the island still wants to move and the structure doesn't," he adds.

Coastal Lagoons May Benefit

At Dauphin Island Sea Lab, located on a 17-mile-long barrier island south of Mobile, Ala., a National Science Foundation grant is helping researchers determine whether coastal lagoons actually benefit from hurricanes.

"We had been studying three coastal lagoons for the past five years so we had collected an enormous amount of data before Hurricane Ivan," notes Just Cebrian, lead researcher. "We're still taking measurements but everything looks good - seagrass meadows are healthy and there appear to be more organisms living in them."

Unlike estuaries, which receive fresh water from rivers and streams, coastal lagoons are generally located behind embayments or barrier islands and lack significant freshwater input. And while fresh water in estuaries like Tampa Bay often carries high levels of nutrients that damage seagrasses and other natural systems, coastal lagoons may benefit from increased nutrients delivered during extreme storms, Cebrian said.

"Growth in coastal lagoons is limited by nutrients, so as long as the wind is not too harmful, putting additional nutrients into the system is not always bad," Cebrian said. "It appears that Ivan was good for the vegetation and all the other organisms that live in and near plants in the lagoons we're studying."

Vegetation Protects People

Healthy vegetation, in coastal lagoons or mangrove forests found further south, can play a key role in protecting inland habitats for both people and wildlife, adds Steve Bortone, a scientist at the Sanibel Captiva Conservation Foundation. "Our lab is very old and we expected it to be demolished when Charley came ashore but it was surrounded by mangroves and they did a great job protecting the structure - we just ended up losing a few shingles."

Further north in Charlotte Harbor, Jim Beever, of the Florida Fish and Wildlife Conservation Commission, notes that damage could have been much more severe without natural vegetation. "Because of the preserved land surrounding Charlotte Harbor, there are fewer people living on the harbor and it's very likely that many many lives were saved. The mangroves did an excellent job - they took the brunt of the damage."

The damaged forests appear to be rejuvenating themselves, with the black and white mangroves rebounding more quickly than the reds, he added. Exotic plants, particularly the Brazilian peppers and Australian pines "fell over like tenpins - one of the major windfalls of this event."

The largest trees took the hardest hits, while low-lying vegetation fared much better. "There was very little damage to xeric scrub oak habitat but we lost a lot of large mangroves and oaks with heavy canopies and shallow roots."

Seagrasses sustained minimal damage in last summer's hurricanes, in spite of increased nutrient levels from large amounts of stormwater, Beever and Bortone said. However, the Peace River was completely devoid of oxygen for a short time after the storm. "There has been a lot of discussion about the cause, and it was certainly partially a result of the vegetative matter, but I also think there were some human causes," Beever noted.

Along with contaminants that washed away during the storm, residents were told they should burn damaged household items. "That was very bad advice - we had toxic bonfires up and down the river when people started burning plastics, upholstery and carpeting."

Unscrupulous landowners also exacerbated damage to eagle nests by knocking down trees and claiming the storm had done it, he said. "Except for one case, everything has been resolved now and most of the eagles are back in their nests, although not necessarily in the same situation."

But the most significant impacts of Hurricane Charley may not be evident for years, he adds. "We're in the midst of a big economic boom that's only partially from people rebuilding - it's mostly outside people who came over here to help with hurricane recovery and then realized that waterfront land here is so much cheaper than places like Tampa Bay or Miami-Dade.

"The new people are really amazed at how much natural land is still available, but they'll take it and destroy it. I think we'll look back at Hurricane Charley as an important mark in this history of this area - before Charley we had natural beauty, now we have all these condos."

Photo courtesy of Clearwater Marine Aquarium

Hurricane Survives Storm A juvenile Atlantic spotted dolphin found near Anclote Key on Sept. 28 nearly joined the list of Hurricane Ivan victims. Instead, the friendly young male - nicknamed Hurricane - is now at home in a pool at the Clearwater Marine Aquarium. "He's doing very well, he's eating and very responsive," said Terrie Weeks, public information coordinator. Still, he was orphaned so young he does not know to catch fish to survive and is not releasable, she adds. "Due to his lack of maturity, he won't be released and we don't have a final determination from the National Marine Fisheries Service on where he will end up." In the meantime, the dolphin endeared himself to staff and volunteers who spent weeks supporting him in the water and tube feeding him. The stranding resulted in second-degree burns over 40% of his body, followed by stomach ulcers and a severe case of gastritis. He's eating whole fish again, and gaining weight, but shows no interest in live fish, Weeks said.

Staff and volunteers help support Hurricane, a two-year-old Atlantic spotted dolphin, found stranded after Hurricane Ivan. Antibiotics are helping to heal the second-degree burns that covered 40% of his body.

© 2005 Bay Soundings
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