Thursday, December 15, 2011

The Changing Face of Florida’s Gulf Coast

Florida has often been referred to as a paradise, partly because its abundance of beautiful palm trees. In classical versions of paradise like Atlantis and the Garden of Eden, palms are often a key element. Likewise, most iconic scenes of Florida include palms—holding the ends of a hammock on a sunny beach, flapping violently in hurricane winds, or silhouetted against a pastel sky of a smoldering Gulf sunset. But, as anyone who’s paddled Florida’s Gulf Coast lately can attest, there is trouble in paradise. Our cabbage palms are dying.

Palm die-offs have become all-too-common in recent decades. The first was in the 1970, when a disease called lethal yellowing devastated a huge percentage of South Florida’s coconut palms. However, as much as we love coconut palms, they are exotic and their loss is ecologically less significant than losing a native species like cabbage palms. Not only are cabbage palms native, they are an important element of the Florida landscape.

Historically, cabbage palms were used for food, fiber,, and for shelter. The classic Seminole chickee consisted of a cypress log frame covered by palm fronds. Paddlers in the everglades know these structures well. European settlers found plenty of uses for cabbage palms, too. Forts made of fibrous palm logs were uniquely able to absorb the impact of cannonballs. One palm-walled fort on Sullivan Island, South Carolina, was credited with saving Charleston from a British attack during the American Revolution. To commemorate this event, the cabbage palm was designated South Carolina’s State tree in 1939. Florida followed suit by naming the cabbage palm (also known as the sabal palm) as our State Tree in 1952.

Commercial use of cabbage palms has been limited. One of the more ambitious enterprises was a brush manufacturing plant built in Cedar Key in 1910. This factory made rigid scrub brushes from the fibrous “wood” of palm trunks. It was a relatively short-lived industry, however, and the overall impact on the regions palms was minimal. Of more importance has been the widespread harvesting of the trees central growth bud to make swamp cabbage. It was from this regional delicacy that the tree got its name. Another common name for this edible bud is “heart-of-palm.” This “heart” bud is the vital life-force of the tree. Removing it kills the tree. Harvesting swamp cabbage has fallen into disfavor in recent decades and is illegal on public lands. You can still order heart-of-palm salad in some specialty restaurants—most of it obtained as a byproduct of land clearing operations.

Perhaps the cabbage palm’s greatest value is aesthetic. The graceful sway of their smooth, grey trunk and large, fan-leaves bunched attractively at the top, is like no other tree. It is their presence, more than any other tree, that gives Florida’s coastal rivers and some inland waterways, their uniquely Florida appearance. And yet, they are so common, we sometimes become complacent about them. When that happens, we should read people like John Muir. “I caught sight of the first palmetto in a grassy place, standing almost alone…this palm was indescribably impressive and told me grander things than I ever got from human priest…whether rocking and rustling in the wind or poised thoughtful and calm in the sunshine, it has a power of expression not excelled by any plant high or low that I have met my whole walk thus far.” (Thousand Mile Walk to the Gulf. P. 92).

Carl Linnaeus, the “father” of the modern classification system of classifying species, was equally enchanted by palms, calling them the “prince of trees.” He felt that humans evolved in the land of palms and that we are essentially “palmivorous.”
With nearly 3,000 species worldwide, the huge Palmae family is well entrenched in every tropical and subtropical corner of the globe. They have a wide range of adaptations which include the largest fruit, largest inflorescence and longest leaves in the plant kingdom. With such adaptability, it’s a mystery why there aren’t more palm species in central and northern Florida.

One answer is their toughness. Cabbage palms can tolerate colder temperatures than other palms, growing as far north as South Carolina. They’re also drought tolerant. While they prefer the damper conditions of coastal hammocks, pine flatwoods, and river forests, they can ride out an extended droughts with little problem. Their tough, leathery leaves are not prone to desiccation under Florida’s blazing sun and are unfazed by salt spray from the ocean. They can even tolerate growing in slightly brackish water—but not salt water. And therein lays the problem.

In the 1990’s, when coastal residents in the Nature Coast and Big Bend areas reported unusual numbers of palms dying, scientists first looked to the usual suspects. Lethal yellowing, while still killing many palms (coconuts and many other exotic species) every year, is not known to attack any native Florida species. Other diseases of cabbage palms such as the palm weevil, bud rot and Texas Phoenix palm decline (which primarily attacks Phoenix palms but also effects an occasional cabbage palm) were also ruled out.

As scientists worked on the problem, they made another, more troubling observation; hardwoods and other unrelated species were also dying. This implied the problem wasn’t a disease (which are usually specific to one species) but something environmental. Researchers, including George Agrios and Francis E. Putz of the University of South Florida's botany department and Ed Barnard of the Department of Forestry in Gainesville, eventually concluded that the culprit is something far more common than any disease—salt water.

For the past 16,000 years, as the earth has steadily warmed from the last Ice Age, water levels have been rising by about 0.6 millimeters per year. But, with additional atmospheric warming caused by the emissions of our modern, industrialized world, this rate has increased significantly. NASA scientists have determined the worlds sea levels are now rising about 3 millimeters per year.

In Florida, increased salinity of nearshore waters is being enhanced by a more local problem. With ever-increasing withdrawal of fresh water from the Floridan aquifer by wells throughout the state, less fresh water is reaching the coastal estuaries. Besides the fresh water that flows into these estuaries by way of surface runoff, the artesian (spring) water that previously entered from submarine springs is now diminished as well.

Perhaps the most alarming aspect of this pending natural disaster is the lack of public awareness. The areas most affected by this die-off are relatively remote. And, while many trees are dying in Tampa Bay and other populated areas, as well as some places along the Atlantic coast, the best places to see the full effect of this die-off are the quiet, uncivilized corners of the coast—the realm of the paddler.

So, as you paddle areas like the Nature Coast, Big Bend and the Florida Keys, be sure to take lots of pictures and spare no words when describing the environment in your journal. Hundreds of years from now, your words and images may be referenced by people describing a long lost paradise that, like Atlantis and Eden, was consumed by the sea. Sunbathers on Tallahassee Beach might gaze southward upon the wide expanse of the Gulf of Mexico and wonder if such a wonderful place could ever have existed at all.

Friday, August 26, 2011

Close Encounters of the Turd Kind

Hiking in Ichetucknee Forest this morning, I was reminded that nature observation requires a few basic skills. Spontaneity is high on the list. When you spot a pair of slugs slowly sliding over each other, you must be willing to forego all plans and stop to watch them. You may never again see two slugs interacting. Next, you must have the patience to sit quietly for hours watching your slimy subjects for any hint of interesting behavior. Being observant also helps. Make mental notes of distinguishing marks that will help you identify the species when you get home to your field guide (you know, the “field guide to slugs;” the one you’ve stayed up way-too-late reading way-too-many times). You must be content with meager results. This will ease the disappointment of realizing dusk is falling quickly and your slugs have barely moved for two hours. Be thorough. Before you leave, move close so you can see any smaller physical details. You might even want to prod them a little with a stick to see their undersides. Lastly, as in all things, you should have a sense of humor. It will get you through little setbacks, like when you discover that two slugs you’ve been observing for a couple of hours are actually a pair of squirrel turds.

While I’m usually unwavering in my appreciation of nature’s gifts, I could have spent far less time contemplating those two turds and been content. As I sulked down the trail toward home, I consoled myself with the notion that I probably wasn’t the only creature out there that could list turd-watching (do aficionados prefer to call it “turding?”) as one of the most significant achievements of my day. In fact, some species live for the stuff.

In the hardwoods and swamps of the Ichetucknee Forest, and in virtually every other habitat in Florida, scarab beetles hailing from nearly 250 known species spend their days cleaning up waste produced by larger species (in Florida, these feces specialists are commonly know as "turd tumblers"). High in nutrients (a lot of plant material passes through the digestive tracts of herbivores undigested) and easily obtained, dung is a precious commodity for which scarabs compete savagely. Ideally, they will avoid conflict by being first to arrive at a new heap where they’ll quickly sculpt a ball several times their own size and roll it to a waiting underground chamber. The beetle then lays eggs inside the dung ball which will serve as food for the larvae when they hatch.

In most cases, being first on the scene is largely a matter of luck; being at the right place when a passing animal unloads. But, a few species have learned to buck the odds. Every morning in the forests of Panama, certain species of scarab fly into the tree canopy in search of howler monkeys. Positioning themselves strategically on the animals butt, the scarab waits for the monkey to defecate. It then jumps aboard the first train out of the station and clings for dear life as it plummets 100 feet to the ground. Similar, though less extreme dramas are played out on the back-side of other animals such as kangaroos, wallabees and sloths.

But turd-tumbling scarabs are not the only connoisseurs of feces. If you’ve ever had a pet rabbit, you know about their not-so-adorable habit of eating their own poop. Coprophagy is common to a wide assortment of animal species; mostly herbivores, whose digestive systems are relatively inefficient. Giving the food a second pass through the digestive tract allows the animal to digest more of the nutrients from it. Pigs, rabbits and most rodents are habitual coprophags.

For some animals, including our beloved manatees, coprophagy aids digestion in another way. Because plant material is difficult to digest, these animal’s digestive systems are full of bacteria that break it down. However, these bacteria are often absent in newborn calves. To get bacteria in their own gut, the babies must eat some bacteria-rich feces of an adult.

For those species whose survival doesn’t depend on feces, attitudes toward the stuff are decidedly less enthusiastic. Most birds avoid the stuff altogether; a fact that was capitalized upon by the Big Girl (mother nature) when she designed the amazingly turd-like caterpillars of swallowtail butterflies. A similar strategy keeps the white egg masses of Dobson flies safe from small birds as they glean the leaves of trees overhanging rivers, where these eggs are deposited.

While we can't know what goes on in a bird's brain, it's often hard not to anthropomorphize. For instance, when we see terns deliberately (and very accurately) dropping turd bombs on animals approaching their nests in sand dunes, they clearly seem to know it is disgusting. For turkey vultures, being disgusting comes naturally. Besides being famously hard-to-watch when eating, they are equally gross when they poop on their own legs and feet to keep them cool.
The only animals that consider wearing poop to be a good thing are some humans. In some cultures, it is good luck when a bird poops on your head. I prefer to take my chances.

(NOTE: I’m often asked what inspires these “reveries” (thanks Lola). Today’s came on the wings of a Carolina wren. As I sat on my patio, staring at a blank, imposing computer screen and hoping for a sign, a tiny wren landed on top of the monitor. It seemed as startled by its choice of landing spot as I was and immediately flew away. But, not before depositing a little gift on my screen. Not quite the sign I was looking for, but who am I to question the Muse.)

Listening to Water

Of all Leonardao Da Vinci’s great ideas, one of my favorites is also one of his simplest. No diagrams, no assembly required, just a simple re-purposing of an everyday item—the canoe paddle. He suggested if we put its blade into water and then pressed our ear against its shaft, we could hear the sounds of aquatic life. Once again, Leonardo was way ahead of it’s time. Not only did this idea pre-date sonar, it predated the belief that the sea was worth listening to.

In a study published in 2009, a group of biologists in Australia described a rich “vocal repertoire” of vocalizations among long-necked freshwater turtles, Chelodina oblonga. The list of sounds included “clacks, clicks, squawks,hoots, short chirps, high short chirps, medium chirps, long chirps, high calls, cries or wails, hooos, grunts, growls, blow bursts, staccatos, a wild howl, and drum rolling.” Of course, to assume that other turtles—including any of the 15 species in our beloved Santa Fe—have similar “vocabulary” is to enter dangerous and highly unscientific territory. But, non-scientifically speaking, it seems unlikely that one species of turtle is chatting away in a language of 17 unique sounds and that others are mute. I’d love to think that that our own turtles occasionally kick back their heads and let out a “wild howl,” in decibels we can’t hear--their own version of the alligator bellow—or that on nights when the moon is just so, and the owls assure them there are no humans in earshot, they crowd onto logs and launch into fevered bouts of “drum rolling.”.

Unlike turtle talk, there’s nothing subtle about alligator bellows. When William Bartram first described alligators arching their back and “making the earth tremble with their thunder,” few people believed him. It would be decades before this phenomenon was confirmed by others. Both male and female gators bellow without regard to the hour of day or night or if they’re on land or in water. The only quiet time is winter. It’s assumed to be a general announcement of the gator’s presence, but this too is only speculation. The most spectacular bellowing is the “water dance,” done only by the males. In this display, the male rears his head, lifts his tail and then powerfully contracts his body, causing it to vibrate. If the gator is in water, the contraction causes water between the scales of its back to spray up in a misty fountain. Diane Ackerman described it beautifully, in “A Natural History of the Senses,” as “frying diamonds.”

To be clear, it’s not that marine animals make sounds that’s new, it’s the notion that they use these sounds for communication. In the days of wooden ships, sailors could hear the eerie sounds of whale’s songs emanating up from the ships hull. Some people speculate that this was the origin of the myth of Sirens, the legendary beauties who sang enchanting songs from the rocky shore and caused ships to come close and crash.

To date, researchers have identified over 1,000 fish that make sounds.


Minyard Connor savors his weightlessness. He’s oblivious to the gentle whitecaps churning thirty feet above him. He’s been down for over a minute without an air tank, listening and watching. In his years as a free diver, Minyard has learned that seas are noisy places. He recognizes the calls and chirps of the fish he’s hired to find by men like the one whose fishing line is now attached to his spear; the one who is likely swilling his fifth Bud Light in the boat overhead. Minyard knows the sounds, but he doesn’t know their meanings. He’s okay with that. Down here, at least, he’s not expected to understand.


Researchers have sorted out some of the details. For instance, it’s mostly male fish that make sounds. In those cases where a purpose has been determined, it’s usually for mating and courtship. Butterfly fish whisper, Seahorses make a click by tossing back their heads, streaked gurnards and rockfish growl. As we paddle the waters of Chassahowitzka and Suncoast Keys this weekend, we’ll listen for the “bubble and thud” of eels, the “cronk” of sea robins, the “grunting” of toadfish and the “umph” of bass.

The list of aquatic species that make the water hum with their chatter is diverse. The one thing most of them have in common is the absence of external ears. Instead they have an assortment of pressure-detecting organs. Fish have lateral lines on their sides, blind cave fish have neuromasts on their heads, manatees have a depression on their cheek, and so on, but none of them have ears. And, therein lays the key to our own deafness in water. No matter how hard Minyard listens, he’ll never hear more than a fraction of the conversation going on all around him, any more than we can hear the radio waves in our own terrestrial world of light air. We go about our days clueless that the air is full of Lady Gaga and Garrison Keillor until we turn on our high-tech sensory device—our radio. All the happy melodies and fascinating discussions that take place constantly in the rivers and seas, will only ever be heard by researchers with their gadgets. And even then, it will be an opera—beautiful music and babel.

As for using our paddles as listening devices, it appears that in this instance, Da Vinci had an idea better suited to poets than engineers. But, I’m okay with that. I find comfort in knowing that besides holding up my hat, my ears allow me to hear such beautiful sounds as bird song, the wind in palms, fireside stories of people like my friend Minyard, and the finest of all river sounds, the blip, swish, plink of a canoe paddle doing the task it was designed for.