Stories of the Swamp

Armchair Interpretive Walks

Friends of Fakahatchee: Dedicated to financial and volunteer support to preserve the unique ecology and cultural heritage of Fakahatchee Strand Preserve State Park and educate the public about its importance.

Fakahatchee’s Bay Trees fall Victim to Globalization

FOF March 14, 2017 Armchair Interpretive Walks

It happens over and over again.  A foreign shipment arrives in some U.S. sea or airport. Only a tiny portion of the cargo can be inspected. Unnoticed, hitch-hiking in the wooden packing material of something as innocuous as kitchen tiles, may be a non-native insect’s eggs or larvae. The tiles and infested wood quickly move through the distribution chain, and the insects freed from their native controls and with plentiful hosts, rapidly multiply. Another invasive species has arrived that will probably remain undetected until it’s too late and out of control.

In this horde of invaders are numerous species of bark beetles belonging to the weevil subfamily Scolytidae. Over 55 different exotic scolytids species have now established themselves in the USA. Among their ranks are some of the most damaging insects our North American forests. In western United States alone, aided by shifts in temperature and increased water stress from climate change, they are felling as many as 100,000 trees a day.

The rust colored leaves of a red bay killed by laurel wilt. Photo by Patrick Higgins

Here in the Fakahatchee you’ve probably noticed rust-colored dry leaves suddenly appearing in many of our hardwood hammocks. These are redbay trees (Persea borbonia) that have succumbed to laurel wilt. The disease is vectored by a tiny bark-boring beetle, the redbay ambrosia (Xyleborus glabratus) which arrived on wooden pallets from Asia in Georgia in 2002.Here in the Fakahatchee you’ve probably increasingly noticed sprays of rust-colored dry leaves poking through the canopies of many of our hardwood hammocks. These are red bay trees (Persea borbonia) that have succumbed to laurel wilt. The disease is vectored by the tiny bark-boring, redbay ambrosia beetle (Xyleborus glabratus), which arrived from Asia on wooden pallets in Georgia in 2002.

Most ambrosia beetle species only attack dead and dying trees and can actually be considered beneficial to forest ecosystems as they speed the recycling of nutrients. The redbay ambrosia beetle, however, attacks healthy trees. These are in the Laurel family and include avocado, sassafras, spicebush, swamp-bay and of course redbay.

The beetle has a symbiotic relationship with a pathogenic fungus (Raffaelea lauricola) whose spores it transports in special pockets in its mandibles. When it initially attacks, the redbay ambrosia beetle bores through the tree’s trunk without ingesting the wood tissue, leaving behind telltale frass in the form of a sawdust straw on the outer bark.

The characteristic sawdust toothpicks at the entry point of an ambrosia beetle. Photo Patrick Higgins

The beetle doesn’t create galleries directly below the bark like most bark borers, but heads straight for the sapwood where it injects its symbiont’s spores into the vascular system, effectively farming it. The growing fungus leaves a streaky black discoloration in the xylem. This is the ‘ambrosia’ upon which both the adults and larvae feed. Most of the life cycle takes place within the galleries, where beetles mate and lay eggs. It takes about 30 days to develop from egg to adult. As the next generation of female beetles matures, they collect fungal spores to carry to another hapless tree. It is thought females can fly 2-3 km in search of a host, whereas the males are flightless.

The fungus quickly spreads throughout the tree’s vascular system clogging it and depriving the tree of water. The tree wilts and dies within a few weeks of initial infection. It happens so fast the tree doesn’t even have time to form abscisic acid, the usual reaction to severe stress that causes leaf loss, hence the characteristic brown dried leaves that persist well after the tree is dead.

Because our bays evolved on the opposite side of the world from this disease, they haven’t had an opportunity to develop resistance. So far there’s nothing we can do to stop this plague other than monitoring it and avoiding transporting dead wood.

During a field trip to Naples Botanical Garden, however, my wife’s 4th grade class members were involved in transplanting and tagging bay tree seedling into specialized air-pots. (Photo of healthy redbay plants by Chad Washburn.) The Garden has been working with several local conservation organizations to collect bay tree seeds that they have been growing indoors. The idea is to preserve a pool of the tree’s genetic diversity. They currently have about 150 plants.

Chad Washburn, the Garden’s Deputy Director shared an interesting thought. Since juvenile bay trees don’t seem to be susceptible to the ambrosia beetle, Chad is considering experimentally coppicing healthy bay trees to protect them, i.e. cutting them right down to the ground so they will re-sprout. Hopefully this can buy time while a long term solution is sought, or at least allow the bell curve of the epidemic to peak. Other strategies involve chipping infected wood. The fungus dies within a couple of days of chipping but can persist in a standing tree for at least a year. Chipping also disrupts the beetle’s life cycle. Unfortunately this is not practical on an ecosystem scale.

Palamedes swallowtail butterfly, endangered by the loss of their host plants in the laurel family. Photo Patrick Higgins

However the damage doesn’t stop with the trees’ demise. Apart from losing a valuable shade tree in our hammocks, there is a knock-on effect in the food web. White-tailed deer forage on new bay leaves; black bear, and wild turkey and other birds feed on the redbay’s fruit. But most serious of all, our redbays are the major host plant for two of our swallowtail butterfly species; the palamedes (Papilio Palamedes) and the spicebush (Papilio troilus). If the redbays, go so may they.

If this was not enough, there’s an even more menacing invader looming over the horizon. It’s the emerald ash borer (Agrilus planipennis). Although not a scolytid, it’s also a native of Asia that probably arrived on wooden packing material. In common with many invasive species, in its native range it’s not a significant pest. But here in North America it is decimating our native ash trees, threatening the entire Fraxinus genus. It hasn’t reached Florida yet, but on November 8, 2016, the Emerald Ash Borer was confirmed in neighboring Alabama.

The State of Alabama has just issued a quarantine order “prohibiting the movement of firewood of all hardwood (non-coniferous) species, ash nursery stock, non-heat treated (green) ash lumber, and any other living, dead, cut, or fallen, material of the genus Fraxinus, including logs, stumps, roots, branches, and composted and uncomposted chips that have not been ground to a small enough size to destroy Emerald Ash Borer in any life stage, by any means of conveyance whatsoever.”

Alabama’s quarantine will slow, but probably not stop the emerald ash borer’s spread. Unfortunately, 85% of our iconic ghost orchids grow on pop ash trees (Fraxinus caroliniana). Globalization is a real threat to biodiversity.

 

Autumn in the Fakahatchee

Next Steps Collective November 8, 2016 Armchair Interpretive Walks

by Patrick Higgins

Autumn has come to the Fakahatchee; not with the spectacular color display of the northern woods but nevertheless it’s here. You just have to look a little closer for subtler signs, and I don’t mean the proliferation of out-of-state license plates. In early October it seemed like mother nature had suddenly turned off the tap and we went instantly to the brilliant blue cloudless skies of the dry season and the cooler nights of autumn.

Here though in southwest Florida, nearer the equator, the shortening days of autumn have a less dramatic effect on foliage than up north. Cooling doesn’t become significant until much later in the season, so it’s the dry-down that has biggest impact. We see one last fling from many plants and a super abundance of food. Holly, beautyberry, myrsine, sabal palm and wild coffee are laden with fruit, and our oaks are beginning to produce a welcome bounty of acorns. This comes at the very time when the nutritional value of our prairie grasses are ebbing to its lowest.

Even though they don’t hibernate, our Florida black bears – in response to primordial patterns – will be fattening up on this excess. The bears are preparing for ‘winter’ denning from late December through March, when they will reduce activity and the females will cub.

Already the water has left our marl prairies. Drying periphyton is leaving a khaki film that will add minutely to the very thin soil layer. Muhly grass is beginning to cast a purple haze over the grasslands, especially in areas that were burnt earlier in the year.

autumn-phragmitesAlong the lower sections of Jane’s Scenic Drive there’s a lushness of impending senescence and an explosion of flowering in a rush to set seed. Tall, tasseled phragmites are bending to autumn winds, and masses of broom sedge are spreading their fluffy seeds. Spikes of goldenrod are adding color amongst the delicate white umbels of water dropwort that remind me of Queen Anne’s lace back home in England. There’s a riot of creamy-white climbing hempvine covering almost everything, and the needles of lonely dwarf pond cypress are browning.

Image by Rita Bauer.

In the swamp, clamshell orchids are blooming under an already thinning canopy. Pop ash are casting off their leaves and the normally seasonally confused red maples seem to be getting their act together. Carolina willow just gives up: its leaves blacken, whither and quickly drop off. Dogwood foliage has a pretty scruffy end too, but the undersides of giant leather fern fronds now have a glow of golden brown spores.

Through a combination of evaporation and a fresh infusion of cypress branchlets, the water is darkening to the color of stewed tea. Our snakes are a little more visible in autumn as they climb more frequently out of cooler water onto old stumps or cypress knees to thermoregulate.

autumn-climbing-asterAlong our trams, poison ivy and Virginia creeper are reddening, and the saltbush have a dusting of white flowers. Fresh, green toothpetal orchid stalks are thrusting upwards out of the leaf litter. There’s a profusion of buckeye butterflies, their numbers augmented by northern migrants. I also notice quite a few ruddy dagger-wings visiting the purple-tinged climbing asters which are now at their peak.

Image by Patrick Higgins.There’s still plenty of water about elsewhere, so there aren’t yet huge congregations of wading birds in the Fakahatchee. However, at the very beginning of Jane’s Scenic Drive, just before the park entrance where the borrow ditch is most shallow, a mixed flock of ibis and egrets are feasting on newly concentrated prey and roosting in nearby trees in between.

As the season and dry-down progresses, so they will advance up the Drive until they reach the deepest sections of the borrow ditch. Their large numbers by then will produce enough phosphate-rich guano to sustain the out of place cattails for another season.

Our swallowtail kites are long gone, but I saw my first wheeling flight of white pelicans, newly arriving from the western lakes. The signs however are not just visual; there’s the rattling of dried leaves and seed pods in the wind, and I think I heard the faint turkey-like wattle of distant Sandhill cranes. So we do have seasonal change, it’s just a little bit slower and only apparent in the detail.

Patrick Higgins with an apple snail. Photo by Robert Fisher.

Patrick Higgins with an apple snail. Photo by Robert Fisher.

Patrick Higgins is a National Association of Interpretation Certified Interpreter, Vice-President of the Friends of Fakahatchee and Project Manager for the development of the Boardwalk Master Interpretive Plan.

Life in a high rise

FOF April 21, 2016 Armchair Interpretive Walks

by Patrick Higgins

Sloshing through the swamp, our view is primarily tree trunks and water. However for our recently arrived migrants from the Amazon, the swallow-tailed kite, it’s an entirely different view. As they swoop low over the swamp’s canopy to snatch an unsuspecting tree frog, they see an undulating carpet of almost endless green. Occasionally this verdant aerial landscape is punctuated by a splash of color. This will be the bloom of epiphytes.

Epiphytes in the canopy

Southern needle-leaf, cardinal airplants and Spanish-moss festooning an oak canopy. Photo by Patrick Higgins

Epiphytes are plants that grow harmlessly on other plants without drawing nourishment from them, using them merely for support. Ours fall into 5 main groups; bryophytes, lichens, ferns, bromeliads and orchids. The largest concentrations of epiphytes are found in tropical rainforests. Thinking about that environment, it’s easier to understand the evolutionary pressures to become an epiphyte.

Light and space on the forest floor are scarce. That same forest floor may become periodically flooded. So it’s natural that some species would migrate upwards towards brighter light, protection from flooding and from the foraging of animals. There also is greater air circulation for better seed and spore dispersal.

But as always in nature there is a trade-off. Perched in the canopy water is scarcer; removed from the ground, nutrients are harder to obtain. So these plants have had to evolve special adaptations to retain moisture and to capture nutrients. Some root systems have become diminished, functioning solely as anchors. In these plants nutrient absorption has been taken over by their leaves. While others, like our ghost orchid, have abandoned leaves altogether and evolved strap-like chlorophyllous roots in their place to both anchor them and produce food.

Other adaptations are micro seeds that are easily wafted by the slightest breeze or tufts of fine hairs to help transport seeds on the wind. However, the evolutionary arms race is two sided. Whilst Fakahatchee’s epiphytes seldom achieve enough mass to damage branches, many tropical trees like the gumbo limbo have evolved shedding bark to rid themselves of juvenile epiphytes and twining vines.

Our most obvious epiphytes are our bromeliads, those spiky growths in our trees that resemble the tops of their terrestrial cousin, the pineapple. They are almost exclusively tropical and a new world phenomenon. Of the 3,400 known species, just one has made it outside of our hemisphere. Here in the Fakahatchee near the northern limit of their range, our 16 native species qualify us as the U.S. bromeliad capital.

Bromeliad water and nutrient absorption have largely been taken over by their leaves and they can be categorized by how this absorption takes place. Spanish moss and ball moss are atmospherics or true ‘air plants’. Their leaves are typically silvery gray and coated with unique leaf scales called trichomes. Trichomes can absorb water – and the minerals dissolved in it – directly from the air when available, then clamp down to minimize moisture loss when it’s not. Their silvery surface also helps to reflect light, further reducing moisture loss.

The rest of our bromeliad gang are impounders. These have their leaves arranged in whorls to trap water in a central reservoir. This tank also collects litter falling from the forest canopy and drowned insects. The process of decay transforms the water into a broth from which the plant extracts valuable nutrients. These tanks also form miniature ecosystems in their own right where micro-organisms may live out their entire life cycles. In the tropics some may even become nurseries for tadpoles. It’s not uncommon to see birds drinking from them, who might then leave nutrient–rich droppings.

Most of our silvery-gray bromeliads have another important adaption to living in Florida’s periodic drought conditions. They employ CAM photosynthesis rather than the more common C3 pathway. In CAM the leaf stomata only open at night to take up CO2 which is then stored for use in the daytime. This avoids their pores having to open in sunlight when water loss would be higher.

Half of the Fakahatchee’s native orchid species are epiphytic. All have precise fungal associations necessary for nutrient uptake, many have pseudobulbs – swollen stem bases that serve as water storage organs – and three are leafless. They are also all of tropical origin, with most in common with Cuba. This connection is not surprising as the Park is less than 200 miles from Havana – the direction of our prevailing winds. But there’s more to it than that.

Our sloughs, especially the central slough, continuously radiate humidity even in the driest years from an accumulation of peat. The moisture is trapped by the forest canopy creating a microclimate. In the summer it’s always just a little bit cooler and in the winter just a little bit warmer. This means that many parts of the Strand never freeze in the even the coldest years, allowing those minute, windborne orchid seeds blown up from the tropics to flourish.

Less spectacular are our bryophytes (mosses and liverworts). They are often represented by a fuzzy green layer on logs and branches, which if you examine closely appear as tiny forests. They have a lifestyle halfway between that of aquatic algae and ferns. They require moisture, but can dry out, go completely dormant, then spring back to life when moisture returns. Their ability to readily store and release water is an important ecosystem function. They can also help create a secondary ‘terra firma’ high up on horizontal branches by stabilizing detritus. This improves the habitat for other epiphytes.

Another epiphytic group is our lichens. They form those beautiful blotches of pink, orange, white and blue-gray on almost every trunk and limb, varying in texture from crust-like to scaly or even filamentous like old man’s beard. Lichens can be so numerous it’s hard to discern a tree trunk’s true color.

They are composite organisms: a fungus and an algae or cyanobacteria living together symbiotically. The fungus provides shelter and water absorbing services to the algae, which would otherwise be unable to survive, and the algae in turn produce sugars through photosynthesis.

It was often thought that lichens were more abundant in northern latitudes, but in 2009 a group of lichenologists conducted a 5-day survey in the Fakahatchee and recorded 432 species, putting paid to that theory!

Our epiphytic community wouldn’t be complete without mention of our half a dozen or so species of epiphytic ferns. Many of them utilize the organic material in the boots of Sabal palms like rabbit foot, hand, and shoestring ferns.

The most remarkable of all is our resurrection fern which favors rough-barked trees. Its leaves curl and turn brown when desiccated, then resurrect themselves after a good rainfall, quickly becoming a lush green – a throw-back to a bryophyte ancestor.

The canopy and all its plant diversity combine to sequester carbon, produce oxygen and support a complex web of life, from pollinators and millions of other insects, to spiders, mites, snails, tree frogs, snakes, lizards, birds, bats and squirrels. We don’t often get a close-up look, but this may all change.

Epiphytes in the canopy

Architect’s renderings of future Canopy walk in Phase II of Big Cypress Bend Boardwalk Expansion Project. Rendering by David Corban pllc

In partnership with the state, FOF has a major boardwalk improvement project underway at Big Cypress Bend. Phase 1 this year is a new parking area, a bridge over the canal, and low-level marsh boardwalk. Yet to be funded is Phase 2, that includes plans for an 1100 ft. long elevated canopy walk through the Strand. In a few years we  may all be able to experience life in the high rise.

Patrick Higgins with an apple snail. Photo by Robert Fisher.

Patrick Higgins with an apple snail. Photo by Robert Fisher.

Patrick Higgins is a National Association of Interpretation Certified Interpreter, Vice-President of the Friends of Fakahatchee and Project Manager for the development of the Boardwalk Master Interpretive Plan.

Mosquito fish – Our Unsung Heroes

FOF April 6, 2016 Armchair Interpretive Walks

by Patrick Higgins

Mosquito Fish

A female Eastern Mosquito Fish (Gambusia holbrooki). Photo by Patrick Higgins.

I’m often privileged to take people into the Fakahatchee for their very first swamp walk. It’s nearly always a transformative experience for them. After marveling about the dappled light, oohing over the epiphytes, commenting on the clarity of the water, the fresh minty smell and how surprisingly firm the footing is, they often quizzically remark “but there are no bugs.” Well, that is if you take them to the right place at the right time of the year. And if the mosquito fish are dong their job.

By bugs of course they mean mosquitoes and so, on cue, I can launch into a talk about those little two-winged flies and their nemesis, the humble mosquito fish. As Floridians we can be very proud; we have over 80 species of mosquitoes. That’s more than any other state. These can be divided these into two broad groups; floodwater and standing water mosquitoes.

Floodwater mosquitoes, like our particularly vicious black salt marsh mosquito (Aedes taeniorhynchus), don’t lay their eggs in water. Instead they seek out moist ground. The eggs need to dry out before they hatch and lay dormant in mud cracks and crevices. When they are inundated by heavy rains, or in the upper reaches of our salt marshes, monthly by spring tides, they quickly develop. The density of mosquito eggs in a floodwater habitat can be staggering, as high as 1.3 million per acre.

All but 3 other species of our ‘swamp angels’ are standing water mosquitoes that lay their eggs in water. They cannot withstand drying out and usually hatch within 24 hours. Fortunately in both categories it’s only the females that need a blood meal as a protein source for egg development. The males typically feed on nectar. Think what it would be like otherwise.

In a perfect model mosquitoes should only be a problem at the beginning and end of the dry season when there are isolated pockets of water that our native mosquito fish cannot reach. But it’s not as simple as that, because sometimes the rains don’t follow our seasonal model. Last summer was a classic example. The rains started in a timely manner in June, but kind of stopped in July, then came back with a vengeance in September. I was reconnoitering a potential new swamp walk off South Main a few weeks after this occurred, and the mosquitoes were so bad I couldn’t escape soon enough.

We’d had repeated deluges that had flooded the dry swamp landscape, triggering floodwater eggs and creating habitat for standing water mosquitoes to breed. And breed they did at a much faster rate than their vertebrate predator, the mosquito fish. This created a lag, which if you plotted on graph paper would show a classic bell curve as the mosquito population surged, then a rapid decline as the mosquito fish population multiplied and spread across the newly created aquatic landscape. Eventually we reached a nice equilibrium for our swamp walk season.

Mosquito fish

An egret’s eye view of our native Mosquito Fish. Photo by Patrick Higgins.

So our unsung hero in all this is the Eastern Mosquito fish (Gambusia holbrooki). The females are about 2 ½ inches long, and the males are about an inch shorter. Gambusia are viviparous – they bear live young, which enhances their survival probability. In nature the quantity of offspring is usually inversely related to the chances of any individual reaching maturity and reproducing. So, for example, when a female cod spawns she lays hundreds of thousands of eggs. A mosquito fish typically only gives birth to 25 live young, but can do this up to nine times a season. These young reach sexual maturity in 4-6 weeks. They are technically planktivores, but are voracious predators of mosquito larvae when available. A large female can consume hundreds a day.

But here’s the rub, as demonstrated by a remark made to me on a recent tram tour –  “We should get some of those and take them up to Michigan.” That’s exactly what has been done all over the world. The problem is that they have co-evolved here in a highly competitive environment where they’ve had to eke out a specialized niche. When they are introduced to non-native waters they tend to prey heavily on the eggs and young of other fish species – perhaps the very ones that ate mosquito larvae there. So if you search the literature on mosquito fish, you’ll find most of it is about how to get rid of them where they have been introduced.

Incidentally a British biotech firm is in the late stages of FDA approval for a trial release of genetically modified male Aedes aegypti mosquitoes here in Florida. The idea is to help control the spread of Zika and dengue fever. They have been engineered to pass on a ‘kill-switch’ gene when they mate with our wild females. This prevents their offspring reaching maturity. Trials in other countries have reduced the target Aedes population by more than 90 per cent, but I’m not sure the locals in Key Haven, the chosen test site, will go for it so we’ll just have to rely on our Gambusia.

Patrick Higgins with an apple snail. Photo by Robert Fisher.

Patrick Higgins with an apple snail. Photo by Robert Fisher.

Patrick Higgins is a National Association of Interpretation Certified Interpreter, Vice-President of the Friends of Fakahatchee and Project Manager for the development of the Boardwalk Master Interpretive Plan.

Mollusking in the Fakahatchee – Part 1

FOF March 9, 2016 Armchair Interpretive Walks

By Patrick Higgins

As I was recently stalking through one of Fakahatchee’s sloughs, I found myself fantasizing that I was a great big wading bird. It seemed perfectly natural to move ponderously so as not to create a ripple in the golden water. I slid each foot forward in slow motion, conscious of everything around me: the Sun streaming through a leafless winter canopy, a single red maple leaf floating by, a movement in the cutgrass to my left, the rustle of an anhinga taking flight ahead, the plop of a frog into the water. I froze as my eye caught something shimmering on the dark bottom. And then, fortunately just before I plunged the imaginary spear-like bill on my face into the water, I shook myself out of my revelry.

A handful of Florida shiny spike (Elliptio buckleyi) freshwater mussels shells fished up from one of Fakahatchee’s sloughs. They can grow up to 100 mm (3.9”) The neatly chiselled holes look like the work of a limpkin. Photo by Patrick Higgins.

A handful of Florida shiny spike (Elliptio buckleyi) freshwater mussels shells fished up from one of Fakahatchee’s sloughs. They can grow up to 100 mm (3.9”) The neatly chiselled holes look like the work of a limpkin. Photo by Patrick Higgins.

Instead I fished down clumsily with my hands, wetting my sleeves in the process. I had to feel around a bit due to refraction, but finally my fingers closed around my target. It was the fragment of a bivalve’s shell and shone like burnished silver. When we think of swamp invertebrates our minds tend immediately to go to crayfish, insects, snails and such, but we seldom give much thought to the snail’s mollusk cousin: the freshwater mussel.

After a bit more probing I was able to come up with a whole shell, although it was empty. Its ebony exterior was striated by growth rings, some of which had eroded revealing the iridescent mother-of-pearl beneath. In the center was a neatly chiselled rectangular opening, probably the work of a limpkin’s bill.

This is the same mother-of-pearl that was used for over half century in button production until plastic came into being in the 1940’s. Today ground freshwater mussel shell is still favoured as a seed material for Japan’s cultured pearl industry.

However, freshwater mussels are not simply freshwater versions of the marine mussels we love to eat cooked with butter and garlic and washed down with a glass of white wine. True, they both are aquatic filter feeders, sort of resemble each other by having asymmetrical shells that are longer than wide, and are both bivalves, but freshwater mussels are members of an entirely different subclass (Palaeoheterodonta). In fact, marine mussels are more closely related to oysters and scallops than they are to their freshwater namesakes.

The biggest difference is in their life cycles. Marine mussels are sessile. They typically attach themselves in clumps with those stringy byssal threads we scrape off when preparing them for the pot. They reproduce by releasing sperms and eggs into the water in a rather hit or miss fertilization process. They then go through a floating planktonic stage before settling out of the water column to live in a fixed location.

On the other hand, freshwater male mussels release gametes into the water column. The gametes are then sucked into a female’s siphon, where her eggs are fertilized internally. The fertilized eggs develop in specialized brood chambers in her gills into tiny motile glochidia. This specialized larval form has an array of hooks, which allow them to attach to fish where they live as parasites for a period.

Many species are highly host specific. Some mussels even use mimicry to lure in host fish by packaging their glochidia to look like prey items such as fish eggs or insect larvae. Typically the glochidia attach to the fish’s gills, although some species also utilize the tail fins. This is an important adaptation to aid distribution. Otherwise, in freshwater streams and rivers distribution would be one in direction only, i.e. downstream. After a few weeks feeding on the host fish they complete their metamorphosis into juvenile mussels, then detach and fall to the bottom to begin their adult stage.

This is where a second huge difference comes in. Freshwater mussels have a powerful clam-like foot which enables them, through a series of muscular contractions and expansions to burrow, anchor themselves or move along the bottom. They seldom move more than a few hundred feet, but that could be critical to survival as water levels drop. Finally, they are known for their longevity. Some species live up to a hundred years.

The mussel I was holding in my hand appeared to be a Florida shiny spike (Elliptio buckleyi or to some taxonomists E. jayensis) – one of 365 North American, 62 Floridian and 14 lower-peninsula species. I say probably because many freshwater mussels are incredibly hard to identify without the aid of magnification.

The same species from different habitats often have variations in shell shape. There is so much speciation in freshwater mussels due to their intolerance to saltwater. This inhibits spreading from one river basin to another, isolating populations. It is therefore not surprising that 69% of Florida’s freshwater mussels are endemic, some to specific catchment areas.

To date, three host fish species have been identified for Florida shiny spike’s glochidia. These are Bluegill, Largemouth Bass and the Florida Gar, but in the incredible web of life about 40% of shiny spikes are in turn parasitized by several species of mites.

Freshwater mussels provide an important ecosystem function. As filter feeders they are constantly straining bacteria, algae and particulate matter from the water column, cleansing it in the process and reducing contaminant loads. They can filter as much as of 1-2 quarts per hour depending on the bivalve’s size. Their faecal matter and ejected particulates then provide food for invertebrate communities that in turn support fish populations.

They occur in almost every freshwater habit, except highly acid rivers which inhibit shell production. However, some 60 North American and 7 Florida freshwater mussel species are listed as threatened or endangered. This is due to habitat loss or alternation such as silting or pollution. So keep a look out for those telltale glittering fragments of mussel shells next time you’re in the swamp.

Oh, one final difference between marine and freshwater mussels: they are a prized food source of raccoons, otters, crayfish, and many wading birds. Also, they were consumed by Native Americans after much boiling, but apparently taste like old boot – something I haven’t put to the test yet!

Patrick Higgins with an apple snail. Photo by Robert Fisher.

Patrick Higgins with an apple snail. Photo by Robert Fisher.

Patrick Higgins is a National Association of Interpretation Certified Interpreter, Vice-President of the Friends of Fakahatchee and Project Manager for the development of the Boardwalk Master Interpretive Plan.

Hammocks and Cypress Domes

FOF March 9, 2016 Armchair Interpretive Walks

by Tony Marx

cypressdome-tonymarx
Visitors to Southwest Florida are often intrigued by the undulating tree-covered backdrop which seems to comprise small hills. Most obvious as you drive along I-75 Alligator Alley, this is also evident in the Fakahatchee Strand State Park as you begin driving along the dirt-surfaced Janes Scenic Drive after leaving the paved road. Look to your right at the distant tree line and it is not level as you would expect, when viewed across the open marl prairie. Rather than a rise and fall in elevation, the dome shaped mounds of trees actually indicate a water-filled depression or solution hole under the dome. At its deepest point, the bald cypress trees grow tallest, gaining height and strength from the peat that accumulates at its deepest point. Where the trees grow around the edges of the dome, they grow shorter although they are actually the same age.

These Cypress Heads, or Domes as they are called, remain wet all year round, when the sawgrass prairie and open areas dry up and become parched during the winter and early spring Dry Season. Here alligators and wading birds collect to feed on the surviving aquatic life, and the turkey vultures gather in great numbers to feast on the left-overs. In winter, the cypress trees are bare as they annually shed their needles. These decay and, besides adding to the peat, produce acid which continues to dissolve the limestone base. Thus, the depression very slowly expands over the years.

The sub-tropical South Florida landscape, although seemingly flat, is sensitive to the slight rise and fall of elevation, when a matter of inches can promote a sharp change in scenery. The Fakahatchee Strand Preserve State Park offers an ever changing skyline. Just about all tree and plant communities found in the larger adjoining Big Cypress National Preserve and Everglades  National  Park  are found here. Where the land remains mostly unflooded, pine and palm trees replace the cypress or dense tracts of hardwoods. The ‘tree islands’ seemingly sprouting out of the open stretches of marl prairie as you drive along Tamiami Trail are also found here and one can be seen next to the road on your left about a mile along Janes Scenic Drive.

The opposite to a Cypress Dome, which sometimes looks like a tree island set in a wide expanse of sawgrass prairie, is a Cypress Head, or Hardwood Hammock. It may be a small clump of hardwoods and palms growing on a limestone ridge above the surrounding marshland. Or it may be a wider stretch of jungle vegetation dominated by Gumbo Limbo, Cabbage Palms, Oak, Mahogany, Red Maple, and others which need to remain several feet above the surrounding swamp land. As may be expected, it is home to a variety of animals, birds, and reptiles.At the center it often contains a ‘gator hole’ where alligators gather when the surrounding marsh land dries up in winter. In times of heavy rain – when the surrounding area can flood to a depth of several feet – deer, bear, and Florida panther may also take temporary refuge there.

Seen from the air or on maps, these hammocks have a distinct tear drop shape usually running north to south. They rarely flood and are often surrounded by a moat of water which keeps fires at bay. A profusion of ferns, orchids, and bromeliad adds to the jungle atmosphere. Knowing and recognizing the different tree and plant cover as you drive along Janes Scenic Drive will make your trip all the more rewarding. Deer may be seen on the open prairie, wading birds in shallow water, an owl perched silently watching for an unsuspecting rodent, a raccoon climbing a tree, and always an alligator floating lazily by or resting close to the trail. If you are really lucky, and it’s early morning or close to dusk, you may encounter a black bear or panther crossing the road or appearing ahead on the trail.

Take your time, drive slowly, and stop where safe and clear. Look down at the water, then through and up into the trees, and you will often get a pleasant surprise and a photo opportunity. Whether you see them or not, the Fakahatchee animal, reptile, and bird population is always nearby. Find a spot to park and watch quietly; one of them may appear and venture across the road or be noticed only a few feet away. Of course, a short hike along one of the marked trails is better still. Walk quietly and stop now and again to look and listen. A rustle, call, or movement will direct you to where one of our wildlife friends is going quietly about their business.

Tony Marx is a Florida Master Naturalist and former FOF Board Member. He is also a volunteer interpreter for the Fakahatchee guided tram tours and frequently contributes articles to The Ghost Writer.

Walking on Gators

FOF November 10, 2015 Armchair Interpretive Walks

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by Patrick Higgins

Anyone who sails in the skinny waters of the Ten Thousand Islands, as l regularly do on my catamaran Tropicbird, will occasionally bump the bottom. And so I suppose it’s inevitable that if you stomp around the swamp often enough, you will eventually step on an alligator. I did so for the first time a few weeks ago.

Far from scary it was quite Pythonesque (of the Monty variety). Mike Owen and I were alone deep in the Fak, about 1,000 yards west of East Main surveying some ghost orchids. It was just before the September deluge and water was scarce.

We found ourselves in a broad, shallow depression where there was still 6-8” of water and were focusing on pop-ash trunks about 6 feet above the ground. Mike was ahead as I was determined to make my own discovery, which I didn’t, of course – at least, not of a ghost.

As I put my foot down, a gator whipped around in a lightning splash and grasped onto it. Now, you have to look at this from the poor gator’s perspective. It had nowhere to go as there wasn’t water elsewhere; so it probably had elevated down as I approached, pressing itself hard against the bottom to gain a few inches of cover. It can’t be pleasant to have 240 pounds step on your back. Its reaction was purely defensive.

Luckily I was already raising my foot as its teeth fastened onto my boot, so it had a grip on the sides on my sole rather than the top of my foot where I would have felt the bite force. Also, it was only a five-footer.

So there we were; the gator’s teeth stuck momentarily in the rubber sides of my boot’s sole and me hopping backwards on one leg dragging the creature with me whilst trying to keep my balance with my stick – all the while trying to shake the darn thing off and shouting, “Mike, I got a five foot gator on my foot!” This impasse lasted only a few seconds. I think the gator was as keen to let go as I was for him to do so and maybe even had his teeth stuck.

Mike almost stepped on a cottonmouth coiled on a dry patch during the distraction but was most solicitous, insisting if there was any skin broken I go to the hospital because of the risk of infection. But the only injuries were my pride and a few small perforations in my boot sole. I did get some kudos, though, because scientist to the end, even in my excitement, I hadn’t exaggerated the gator’s length. When we approached him afterwards sure enough he was five feet, and with nowhere to hide, he rotated around to face us and scowled.

I suppose seeing the humor of the moment even as it happened comes from a long, albeit sporadic, association with reptiles. Growing up my father wouldn’t allow us to keep any pets that could harbor fleas, and so by eleven years old I had a caiman living in my bath tub and a collection of snakes and lizards.

I should mention for the benefit of those whom I lead on swamp walks, that it was entirely my own fault and that when I lead the public groups I always pre-reconnoiter the route so I can concentrate on their safety and enjoyment. In any case, our swamp walks are during the cooler months when gators are less active or inactive. As I often tell my parties: they normally avoid humans, don’t feed when the water temperature is below 70°, and like all predators are very cautious about injury so won’t tackle prey bigger than themselves. And even if you’re not six foot one like me, when you’re in a group you seem like a big organism.

I’ve never actually encountered an alligator on a public swamp walk in the water. If we see one it’s usually on the tram and by that, in case I’m alarming any potential tram tour participants, I mean on the old logging trails which in the Fakahatchee we have come to call trams, not on the tour vehicle! But just knowing they are out there, along with black bears and panthers, adds to the enjoyment of being in one of Florida’s last remaining wilderness areas.

Patrick Higgins is a National Association of Interpretation Certified Interpreter, Vice-President of the Friends of Fakahatchee and Project Manager for the development of the Boardwalk Master Interpretive Plan.

One man’s fruit; another man’s poison

FOF September 3, 2015 Armchair Interpretive Walks

by Patrick Higgins

After spending July in England I was ready for a Fakahatchee fix. So still jet-lagged I headed to the swamp, stopping first at Big Cypress Bend Boardwalk to see how our new signs were faring. Donning my Fakahatchee cap and in a matching shirt, I was an obvious target as I stepped out of my SUV and was quickly waylaid by a charming French couple and their ten year old daughter. They asked if the Indian Village was worth visiting. Hmm – a common misconception that our new entrance will address.

They had pulled over to picnic and complained they had just been on an airboat tour and not seen a single gator. They quoted their guide, “with so little water gators are hard to find.” This was August. When I left the rainy season was in full swing. What was up?

I ended up giving our French guests an extended tour, but sure enough there wasn’t any water until the gator hole, except for the small pond in the root hollow created by a toppled tree. Nevertheless they were delighted. I was able to point out a well camouflaged 6 ft female alligator with half a dozen hatchlings in the borrow ditch. The hatchlings were the smallest I’d ever seen and couldn’t have been more than a day old. After that a barred owl obligingly flew in and roosted not 10 ft from us and a six lined skink let us get close–up and personal. Their day was made. The new signs were holding up well by the way.

My next stop was to check out Six-pipe slough on Janes Scenic Drive. Instead of water gushing through the culvert, there was barely as much water as we had for our winter swamp walks. If rain didn’t come to the Fakahatchee soon, and lots of it, the season ahead looked tough. It was then that I spied the marbled-green fruit of a pond, aka custard apple.

Pond apples, (Annona glabra) with their cherry-like bark, big glossy leaves and buttressed trunks are one of my favorite trees. They bear the largest fruit of any of our natives and its light wood was used by Calusa and later Native Americans to make fishing floats. The pond apple also happens to be the larval food of the giant sphinx moth; the pollinator of the ghost orchid. Although the vast majority of our ghosts are found on pop ash trees, about 15% utilise pond apples.

Ripe pond apple

Ripe pond apple fruit has poisonous seeds, mild yellow flesh, and is an important wildlife food. Although sometimes called alligator apple, it’s more commonly consumed by turtles, birds, raccoons and squirrels.

. The creamy yellow flower of the pond apple with petals and sepals in 3s

The creamy yellow flower of the pond apple with petals and sepals in 3s.

I collected a fallen fruit and sliced a wedge out with my knife, being careful to avoid the poisonous seeds and took a bite. Not quite ripe – the flesh hadn’t yet turned yellow. Perhaps a passing vehicle had detached this one prematurely. Its taste was not unpleasant, although a bit insipid with just a hint of passion fruit. But it’s an important wildlife food, hence one of its other aliases alligator apple, although more commonly it’s consumed by turtles, birds, raccoons and squirrels.

Pond apple trees were once much more common in Florida. Patrick D. Smith, in his A Land Remembered, paints a portrait of a vast bygone pond apple forest that grew along the southern shores of Lake Okeechobee, swarming with moon vine, airplants and Carolina parakeets that has since been destroyed by drainage dikes to make way for sugarcane and other agriculture.

Like most of our tropicals, the pond apple is at the northernmost limit of its range. They naturally occur on both sides of the Atlantic aided by their buoyant fruit and range from South Florida through the West Indies, to South American and West Africa.

Due to its hardiness and tolerance of brackish conditions A. glabra has been used as a rootstock to graft some of its more desirable cousins, such as soursop (A. muricata) and sugar apple (A. squamosa). What’s one man fruit is another man’s poison. In Australia escapees from this process have become highly invasive, especially in the wet tropics of northern Queensland where ironically, or maybe in a case of poetic justice, the invasive pond apple threatens their melaleuca wetlands, as well as some native mangrove communities.

The Friends of Fakahatchee’s Captain Franklins Adams remembers a large pond apple swamp along Janes Scenic Drive in the late 1950’s and early 60’s when the Fakahatchee was still a State of Florida Wildlife Management Area run by the old Game & Freshwater Fish Commission.
Franklin says, “My family and friends would camp and sometimes hunt the area for turkeys or buck deer. Janes Scenic Drive had not been designated and the old main logging road was then referred to locally as the Copeland Grade.”

“The pond apple swamp location as I recall was near the west end of the Copeland Grade primarily on the south side of the tram. In the evening wood ducks would fly into the pond apple swamp to roost for the night. We sometimes camped in the wide spot on the south side of the grade where today there are some sour orange trees, the Fakahatchee sign and a water gauge location. On the opposite side are the old rock borrow pits.”

“1961 was a drought year and may have been the year that fire was able to enter the pond apple swamp and burn the muck down to the limestone foundation. Nothing remained of this beautiful area and subsequent wet seasons filled the limestone cavities with detritus.”

Franklin has been back a number of times to try and find the pond apple swamp’s remains but there’s no trace of it. For now we’ll have to be content with a scattering of trees along our trams and Janes Scenic Drive and the population deep in the swamp.

The Fakahatchee Wetlands

FOF April 8, 2015 Armchair Interpretive Walks

by Anthony (Tony) Marx

Photo taken by the author off Janes Scenic Drive.

Photo taken by the author off Janes Scenic Drive.

The Fakahatchee Ecosystem is unique. Although part of the United States mainland, it contains plants that exist only within its borders (or very close by); others are found in the Caribbean, Central and South America. Many elements contribute to this delicate and fragile wilderness, each dependent on the other. Its preservation has enabled us to experience what much of South Florida looked like prior to the twentieth century.

South Florida has a sub-tropical climate, but the Fakahatchee Strand Preserve State Park itself actually enjoys a tropical climate within its depths. Thus, a mild temperature exists year round, slightly warmer in winter and slightly cooler in summer, perfect for the rare ferns, bromeliads and orchids that exist year round. Some are visible from the Boardwalk and on the hiking trails, while others only reward those who venture into the interior swamps off the trail, usually by joining a ranger-led swamp walk.

Much of the Fakahatchee is natural wetland, meaning it existed  before  man  began altering its topography, but it includes uplands and aquatic systems, too. Seen from the air it presents a mosaic of contrasting colors. It includes sweeps of dun-colored upland prairie studded with contrasting green hammocks of tropical hardwood and clumps of pineland rooted on higher ground. The interior is a dark green forested swamp studded with stands of tall Royal Palms poking above the canopy. These are matched only by the occasional Bald Cypress which escaped the loggers attention sixty to a hundred years ago.

The ground slopes gently south, 2” to 4” per mile, quickly becoming wetter, with a central linear strand slough (wide, straight, shallow moving river) fed from two directions. Water enters the park from the north and flows south to disperse in the marshes south of US-41, and finally into the coastal mangroves. The depth ranges up to 6’ in summer, leaving a series of ponds that remain during the dry winter months. Theses provide the humidity needed for vegetation and a water source for the park’s wildlife. South of US-41, the wetlands consist of mostly open, saw grass prairie, with patches of marsh and swamp and shallow water courses navigable by kayak. Finally, mangroves herald the transition from brackish to saline, signaling proximity to the Gulf and home to the endangered American crocodile.

Although the Fakahatchee recovered from its period of logging from 1913 and reaching maximum output in the 1940s and 1950s, it is also partly an ‘Altered Ecosystem’. It is somewhat impacted by run-off from agricultural and ranchland to the north, its crucial water supply sources being the Okaloacoochee State Forest near Immokalee and the Caloosahatchee basin to the north-west. In both cases, before reaching the Park, the water flow competes with the needs of agricultural businesses and now the expanding development of Ave Maria and the  huge planned city of Big Cypress stretching east from North Naples to Immokalee. Thankfully, during its progress through the Park, these pollutants are captured and absorbed by wetland plants, helping protect the crucially important spawning areas without which commercial and recreational fishing cannot survive.

The hiking trails and road access are all located in the northern half, starting at the Copeland ranger station, using the beds that were formerly logging rail tracks known as ‘trams’. The interior of the park is bisected by the dirt-surfaced Janes Scenic Drive, with hiking trails leading off it, elevated on what were originally the beds of trams hauling lumber out of the interior. These are the West and East Main, Mud Tram, and Uplands Trails. For those preferring a less strenuous introduction to the Park, the Boardwalk on US-41, located 7 miles west of the Everglades City Junction, offers enchanting views of the tropical forest and its wildlife, accompanied by newly-designed interpretive signs along its length.

The never-ending battle of conservationists versus developers will continue. The good news is that nearly 70% of Collier County is preserved under the jurisdiction of local, state, federal, and private management. More is being added on a regular basis, either by county and state government acquisition or private bequest. This is how the Fakahatchee State Park has expanded since 1974, when only a third of its present size at the outset.

At 85,000 acres it is the largest of Florida’s State Parks and is surrounded by protected and preserved land managed by other authorities. It is bounded on the north by the Florida Panther Preserve, and the Picayune State Forest adjoins its western side. The vast Big Cypress National Preserve is on its eastern side across State Road 29, and the Everglades National Park Ten Thousand Islands section is on its south-eastern corner.

Tony Marx is a Florida Master Naturalist and FOF Board Member. He is also a volunteer interpreter for the Fakahatchee guided tram tours and frequently contributes articles to The Ghost Writer.

Fire, a Natural Part of our Ecosystem

FOF February 26, 2015 Armchair Interpretive Walks

By Patrick Higgins

I just happened to be leading a combined tram tour and swamp walk on the 29th of January when the Park’s Burn Specialist, Steve Houseknecht, and his team were setting Lee-Cypress Prairie ablaze. It was of course a prescribed burn, in this case of some 400 acres from the road to the margins of the swamp beyond.

Trundling down Janes Scenic Drive on the Ghost-rider, our passengers had a front row view of the burn crew, decked out in their helmets and yellow Nomex jackets, igniting the dry grasses and shrubs with their drip-torches. We traversed a smouldering landscape with flames lapping at hammocks in the distance. Hawks moved from perch to perch just ahead of the fire head watching for fleeing prey or perhaps some fresh barbeque. Later, wading in Six Pipe Slough we had the novel experience of snow in the Fakahatchee, as white ash rained down upon us.

South Florida is the lightning capital of the USA with an average of 25 lightning strikes per square mile and more thunderstorm days than anywhere else in the country. This, coupled with seasonal drying, makes wildfire a natural component of our environment. As a consequence most of our ecosystems have evolved to be fire dependent.

The majority of lightning strikes are between June and September, coinciding with the peak of our wet season, so the resulting fires tend to be lighter in touch and more localized. However wildfires from thunderstorms in late spring, when there’s lots of accumulated dry fuel about, tend to be wider sweeping, more severe, and can even alter the soil structure. But with the creation of roads and  canals that act as firebreaks and fragmentation of the habitat, this cycle cannot take its natural course. So we have prescribed burns that attempt to mimic this otherwise natural phenomenon. The Fakahatchee has the largest prescribed burn program in Florida’s State Park system.

Fire maintains the habitat by preventing succession. Without fire, shrubs and trees would invade our marshes and wet prairies, eventually drying them out. Fire releases and recycles nutrients locked up in plant tissue, keeps non-fire adapted invasive plants in check, and alters the landscape spatially, creating clearings and opportunity for burnt areas to experience increases in native wildflowers, birds and other wildlife. In the case of prescribed burns, they also protect Park neighbors and facilities by reducing potential fuel for wildfires.

New growth abounds n Lee Cypress Prairie just two weeks after a prescribed burn. Photo by Patrick Higgins.

New growth abounds in Lee Cypress Prairie just two weeks after a prescribed burn. Photo by Patrick Higgins.

I tramped across the charred landscape 2 weeks later and was greeted by fresh sweet green shoots of grass already 6 inches high being grazed upon by white-tailed deer. More remarkable were the thistles in flower everywhere, poised to create seeds to colonize new terrain. The burn also revealed some of the prairie’s normally hidden structure like the recumbent trunks of saw palmettos, cap rock, or circles of cypress knees around old logged stumps, as well as a littering of white shells from the previous seasons’ apple snails.

Of particular interest to me was how the prairie hammocks had faired. Many of the smaller islands of cabbage palm and saw palmetto appeared incinerated, although I knew within a few weeks the palmetto’s blackened trunks would be sprouting new fronds. The hardwood hammocks however were largely untouched. Some are protected by shallow perimeter moats, but it’s the deep shade of their interiors that create microclimates with higher humidity that seems to keep them safe. In most cases it was just the volatile wax myrtle around their margins that had burned.

There’s no water in most of the borrow ditch paralleling lower Janes Scenic Drive right now, so the burnt prairie is easy to access. Try investigating it on foot before the grasses gets too high again and compare it with unburnt Copeland Prairie to the east. Personally I’m waiting for autumn when the muhly grass ought to be spectacular. It flowers best after a good burn.