Chassahowitzka Swamp Pits and Monsters

Six or eight of us were planning to explore some of the Chassahowitzka Swamp yesterday Sunday, but instead a whopping thirteen people showed up! Our quarries were sinkholes that extend like a string of pearls along an on-again, off-again clear water karst stream called Blind Creek. One group wanted to snorkel the sinks, another wanted to photograph the nature of the place and a third group preferred to explore for outliers. I guess I should also mention that Bruce felt responsible for the entire assemblage, so we let him get mad once when he finally realized that this collection of cats, including a couple of us ferals, simply could not be herded.

The first stop was at Buford Spring and Buford Siphon. These two sinkholes are connected via a short segment of Blind Creek, the water resurging at the spring and disappearing into the ground at the siphon (naturally). Although the water looks dark in the photo, and it is partly tannin-stained, it was clear enough underwater for snorkelers to see the sink’s bottom and spring cave entrance. Later, we encountered two cave divers from Maryland that dove the spring using rebreathers. I never dove this site when I was a cave diver even though I share its uncommon name. The photo shows Manuel (red-and-black) and Alan tripoding up for some photography, plus a wood duck nest box with raccoon excluder.


From there, James and I walked NNE about 0.13 miles to Brown’s Sink, named for James by Tom Morris but possibly known by other cave divers under another name. Its water also appears relatively clear from above, but none of the Sunday group swam there so I don’t know whether Brown’s Sink has a cave dive. James said that yet another sinkhole was a little further northward in the swamp, so off I strode to try to find it. I walked a third-mile loop to the NE without finding the sink, so circled back to Brown’s Sink but James was gone. I then walked back to Buford Spring and everyone was gone. Hmmm, alone in the woods… How to find them? I figured that the snorkelers were probably cold and ready to head back, so I started walking back to the parked cars, and then decided to try and use the cell phone to call Alan even though I felt certain that we were out of range of the cell phone towers. Nope, I reached Alan’s voice mail and left a message, and he called back a few minutes later to tell me they were at Warm Spring. So I turned around and took a compass direction based on the GPS and struck off, and danged if I didn’t serendipitously encounter James waiting patiently for me at Buford Siphon. The need for better communication became evident.

Warm Spring is the resurgence of Blind Creek downstream from Buford Siphon. It was the largest sink we encountered that day, and again the water was far clearer than the photo might indicate. In case you are wondering, no one saw any alligators Sunday in any of the sinks even though the habitat looked right for monsters. After swimming there, the students of geology and archaeology had had enough and walked back to the vehicles to leave. Bill and John accompanied them back, leaving only six of us to continue the day’s explorations.


We followed the clear-water spring run NW from Warm Spring to a sink I call Warm Siphon (formerly Pool 7 to those who were there on Sunday). Most of the water appears to sink into the siphon, but a small portion of it overflows and continues in a NW direction. Here it separates into a defined channel and a broad region of shallow braids, all of which goes through a slightly deeper section of the Chaz Swamp. The small stream finally goes to earth in a linear sink containing one or more small swallets, which we named Mitis Swallets. Some of the guys still had not seen Brown’s Sink, so we made a beeline there for more photography and then walked back to the cars.

Walking through the Chassahowitzka Swamp is not easy. First, the swamp is permanently wet, so we wore neoprene socks (two pair for me), boots and polypro thermal underwear bottoms. Most of us were wet up to mid-thigh for the day even though we were seldom in water deeper than 6 inches. The quaking earth is soft or very soft everywhere, being composed of silt and organic detritus. If too many people in your party walk a path ahead of you, you will often suddenly break through the root mat and plunge down into the mud another unexpected foot or so. Tie those bootlaces tightly! Cypress knees and sweetbay root loops rise up out of the mud, blending cryptically into the background leaf litter and tripping the unwary gawker, or in my case banging the crap out of my knee and crippling me during the late evening. Ouch! I walked only 5.5 miles through the swamp on Sunday, but the mud and the cold water and the roots wore me out. Oh, but it could have been worse! There could have been lianas to trip over, pesky mosquitoes to swat incessantly or pickup-stick logs to maneuver over and around, but there weren’t. There could have been a whiner, because after all there were thirteen of us, but other than Bruce’s exasperation there was not.


We saw some neat flora and fungi, of course. Nodding nixie (Aptera aphylla) was occasional. I have seen it blooming around here from summer to mid-winter. Alan spotted several individuals of Florida adder’s-mouth orchid (Malaxis spicata) scattered around singly, not in bloom but seeding. Fragrant ladies’-tresses orchid (Spiranthes odorata) was commonly sighted, again thanks to Alan’s attentiveness, and I got a pic of one of them, below. Also blooming were swamp aster (Aster carolinensis), an unid blue-eyed grass (Sisyrhinchum sp.) and Spanis needles (Bidens mitis). Mitis swallets was named after the Spanish needles that were blooming there. There were many species of ferns in evidence, including macho sword fern (Nephrolepis biserrata), plume polypody (Pecluma plumula), shoestring fern (Vittaria lineata), giant leather fern (Acrostichum danaefolium) and several very common species (cinnamon, royal, ovate shield, resurrection, lady and netted chain fern). There was a single patch of the invasive exotic Boston fern. Oh, and I flushed a pair of woodcocks! Apologies to the birds.



And saving the best for last, Alan (there’s that name again) spotted a sphingid moth carcass that had been parasitized by an other-worldly fungus known as Cordyceps sphingus. This organism invades the living body of a moth in the family Sphingidae. You can barely recognize the moth in the pics below, with its head-body and wing remains covered over completely by the fungus’ yellow hyphae. The long spine-like things are actually the fungus’ ascophores, or fruiting branches, that bear the spores of the species. A sister species, Cordyceps militaris (http://www.nifg.org.uk/cordyceps.htm), parasitizes only pupae, and looks totally different from C. sphingus. Cordyceps is related to an ant-parasitizing fungus, which causes the ant to climb to the top of a shrub or tree, impale a twig with its mandibles and then die. The fungus then consumes the ant’s soft tissues and sprouts an ascophore from the ant’s head, from which spores rain down onto the bodies of ants scurrying below.


Now if you will excuse me, I have this strange urge to climb a tree and gnaw on a twig.

Sanchez South Creek

It started out looking like bad weather this weekend for getting out into the woods, but Sunday turned warm and was essentially rainless. Brack and I took advantage of the weather window and headed to San Felasco Hammock State Park to continue exploring the SW part of the hiking-only section. We parked at the trailhead on Millhopper Road and headed mostly northward through the low and mesic hammocks mentioned last weekend, intending to explore a 10-acre karst depression to the immediate north. I was expecting the depression to have comparably interesting karst geology and flora as the lowlands did last weekend, but if not then the plan was to head off to the NE to a short valley that runs almost due north to discharge into Sanchez Prairie. And the latter is exactly what we did, taking the easy way back (hiking trails) back to cover a total of almost 9 miles.

As mentioned in my last post, this tract is part of the transition zone between the impermeable highlands and karstic lower elevations. Sinkholes here are constantly opening up and plugging shut. Take the “Dumbbell Sinks” example from last weekend where a stream and groundwater seepage originally drained into a pair of sinkholes. The west sink then became plugged with clayey sediments, causing the sink’s water level to rise and overflow into the east sink. A small sudden-collapse sink adjacent to the west sink more recently opened up and now takes surface flow from the west sink, and is eroding a channel that is small now but will surely grow wider over time.


A little further to the north is a medium-sized sinkhole with a very fresh mini-collapse-sink at its south end. Clods of dirt are still falling into the new little pit.


We encountered another, small sinkhole about 10ft deep with sides almost vertical, way too slick and steep to climb in and out of without aid, and too dark under a closed laurel oak canopy to be photographed. This sink looks like it collapsed opened within the last several years.

A very interesting part of the trip for me was seeing the above-mentioned short valley that enters Sanchez Prairie from the south. This valley is totally absent on the USGS topo and derivatives, including my Garmin GPS topo, but is depicted clearly on the Alachua County Fernandez Grant 2-ft topography. I call it Sanchez South Creek. We encountered it about midway along its mapped length and walked along it and a little ways out into Sanchez Prairie, following its incredibly sinuous stream.


The photo does not do service to two things about the creek. First, it gives only a hint of one section after another of parallel, 30ft long sections of stream oriented perpendicular to the direction of valley flow. I guess that the ratio of perpendicular flow to parallel (to valley flow) is almost 2:1. The second thing the photo does not show is the damage by feral pigs. They have torn up literally every square inch of this streambed such that not a single plant can be found in the bed. How many species of plants are now rare here, or no longer occur here at all because of pigs? And what about the small animals that lived here, like crayfish and salamanders? Mostly eaten, by pigs.

It is truly disheartening to see nearly every square foot of San Felasco’s streams, sinkhole bottoms, wetland edges, currently-dry wetland floors and mesic karst valley bottoms thoroughly plowed up by pigs. Pigs are bad enough in so many wild places in Florida, but the situation may be worse in Florida state parks because pig hunting is not allowed and FDEP does not have an effective feral pig control program of its own. You and I, and the state’s biodiversity, suffer as a result. “I sho’ got to git me a remedy” (Marjorie Kinnan Rawlings).

In another place on the day’s trail, we both were struck by this life-laden log:


It supports turkey tail fungus, green-fly orchid, resurrection fern, moss and myriad invertebrates that woodpeckers dine on. And you know why it is covered with plants and fungi? Because feral pigs can’t reach it!!!

Geology isn’t the only thing changing in San Felasco. Check out this huge live oak. It is a former Florida Champion Tree, more than 9ft in diameter, but its end might be near. You can see two limbs have died and fallen off it, including one that may have supported a quarter or a third of the tree’s leaves. Bob S showed it to me in the late 1970s or early 80s, and that big limb was alive then.


During these San Felasco explorations, I am obtaining waypoint locations for all the sinkholes encountered, and am up to almost 80 in number. I hope to eventually get enough of these sinks mapped that the patterns of lineaments and karst features begin to form a bigger picture of San Felasco’s hidden hydrology.

San Felasco State Park SW Dayhike

Last Sunday, I explored the woods in the SW part of San Felasco Preserve State Park, parking at the Millhopper Road entrance and hiking a total of about 9 miles. I had been in that region of the park before and had marveled at its wetland sinkholes, but I didn't really know exactly where they were. Available topo maps are based on the USGS Topo Quad, which does not depict several of the streams or the actual extent of wetlands there, and in one location there is a sinkhole pond rather than the mapped hillside. It did not help that I previously did not have a GPS unit with me, either. Google Earth aerials of the park are of little help because their photosignatures show only whether an area is dominated by deciduous trees or evergreens. As a result, mesic slope forests and wetland planer elm forests appear nearly identical.

This time I had the GPS, but what’s a fellow to do about maps? I compromised and packed an aerial, a topo, a park trail map, and then got an idea for a fourth map. I focused on the area of interest using Google Earth aerial photos, over which I overlaid a two-thirds transparent topo from GPS Visualizer dot com. Unfortunately, the topo overlay adds green color to the aerial, but not too badly. If you have not yet tried working with GPS Visualizer topographic overlays onto Google Earth imagery, I urge you to do so.

San Felasco is transitional between the Northern (impermeable) Highlands and the Williston (karst) Plain. On the highlands, streams flow into rivers that flow into the sea. The karst plain has essentially no streams; its drainage is internal to the limestone directly underneath, which eventually vents as artesian springs that flow to the sea. The transition zone is where streams can discharge into either sinkholes or rivers, where springs may be artesian or surface seeps, and where spring runs can flow into either sinkholes or sea-bound streams. In short, drainage is unpredictable, and thus most interesting! Many of my caving buddies pretty much eschew San Felasco because of its poor caving potential, but that doesn’t mean it’s a boring karst landscape. It means that until you have seen it all, you don’t know what karst features you might have missed. Obviously, thorough field “work” is in order!

Sunday’s walk started in laurel oak scrub, but the trail quickly pops out of that onto the main loop trail. I went counter-clockwise from there to a forest dominated by loblolly pine with a hardwood understory. Probably, this will one day be a hardwood forest:


Soon I was lured SE off the trail by a small sinkhole, and then followed its now-dry feeder stream a short distance to the upper edge of a slope where several seepage springs issue at the contact between the impermeable Hawthorne sediments and the porous sandy soil. These seeps had healthy discharges into a couple of small drains that combined to form this tiny stream:


Which quickly enlarged to this:


And then sank at this point (you can barely see surface water in the stream in the middle of the picture), completing the transition from seepage spring to surface stream to sinking stream in a sinkhole:


Continuing north past the sinkhole that swallowed the creek, over a sill that appears to be breached during high water flow when the sinkhole can’t take all the stream discharge, you come out onto what I call Planera Pond A, named after the dominant plant, the planer elm (Planera aquatic):


How about those bromeliads? They are mostly Bartram’s airplant (Tillandsia bartramii). Oddly, Spanish moss (T. usneoides), our commonest Tillandsia, is absent!

The NE corner of Planera Pond A has a tiny, then-dry tributary drain that I followed upstream to a small sinkhole wallowed out by feral pigs, then continued along yet another drain connecting the latter sink to still a third, dry sink. From there I walked north to an interesting karst feature. It is a polje with two sinkholes connected by an inundated slough that becomes a stream as it approaches and discharges into the east sink, and having a second stream entering the polje from the NE that discharges into the east sinkhole pond also. Obviously, the east sink is where all the water goes, right? Nope. At the SW edge of the west sink is a fresh-looking, 5ft wide by 4ft deep sinkhole that was receiving overflow from the west sink. So this system has an older (east) point of discharge that may be being replaced by a newer (west) swallet. This is what the east sink pond looks like:


I followed the east sink’s second stream as it headed almost due east, becoming a well-defined ravine like the first stream mentioned. Curiously, the north side of the ravine exhibited essentially no seepage whereas the south slope was a seepage slope from end to end, yet the topo and my eyes both said the two slopes had equal elevation. Some of the seeps have sufficient flow to form picturesque, steep, fern-lined channels in the Hawthorne clay:


After that, I took the loop trail to look for more transitional karst and found a few more items, but nothing of note. One part of the trail that I particularly liked was this mature longleaf pine forest, which is obviously burned regularly to keep the hardwoods at bay:

San Felasco Sweetgum Seed Rain

A couple of cavers came down from Tennessee last weekend to relax in Florida’s warmer weather, so Bruce, JJ and I took them out to San Felasco Hammock State Park for some biking and hiking on Saturday. We took the Cellon Creek Loop (south) bike trail to the Tung Nut Loop bike trail through an overgrown field to Sanchez Prairie. At that point, the Tennesseans had to turn back due to one of them just not quite being over his recent head cold. Bruce, JJ and I abandoned the bikes at the edge of the prairie and continued on foot from there. We hiked first along the toe of the prairie’s western slope to the third tributary, then wandered westward along the edge of that little karst valley to its head, from which we hiked back to the bikes along the “highland rim” of the prairie and then biked back to the vehicles. My GPS recorded 7.5 miles of biking and another 3.0 miles of hiking – an easy day, for once! Well, it‘s easy if you’re not sick.

The layout of the karst valleys is interesting to me. Imagine three lines of sinkholes developing in impermeable sediments atop soft limestone, trending in fairly straight lines (lineaments) oriented roughly east to west. Give those lineaments a little geological time and a couple of things happen. First, the sinks expand until they coalesce, and second, new sinks form westward of the last ones. By this process, the valleys undergo headward erosion and extend into the uplands. Unfortunately, very little rock is exposed and no caves are apparent.

Seepage springs occur at the head of each valley and occasionally along the lower slopes of the valleys. These lateral seeps are heavily damaged by feral pigs, which root up anything edible to a pig and then wallow in the clayey spring run bottoms. Whatever ferneries might once have existed in these places are now reduced to a few sprigs here and there. I saw a group of feral pigs a few weeks ago in the third valley, and we saw a group there again on Saturday. Based on the number of pigs, their sizes and coloration, I suspect this is the same (family?) group I saw before. A predictable nuisance is a manageable nuisance. Is anyone from park management reading this?

We did not see any feral pigs in the prairie bottom, but then I didn’t see any feral pigs in that part of the bottom last time, either. Perhaps that area is part of the territory of the pigs in the third valley.

Upon returning to the bikes, Bruce and JJ noticed they were being “rained” upon by tiny objects. From my more sheltered location it sounded like they were being pelted by aphid honeydew, but when I went over to them it became immediately obvious what it was. Back in 1971, I was walking across the University of Florida campus at, well, probably exactly this same time of the year through a monocultural stand of small but mature sweetgum trees. As I stopped to look at something I have since forgotten, the faint sound of a light rain could be heard, but instead of tiny droplets on my sleeve there were tiny seeds from the sweetgums. Evidently, sweetgum seeds dehisce simultaneously and then fall in one or more episodes over a short period of time. That is what Bruce and JJ had noticed – a sweetgum seed rain! When looking at darker backdrops like a downed tree trunk we could readily see the seeds falling abundantly. What a pity that our cameras were unable to video the event. It was only the second time in my life that I have experienced a sweetgum seed rain, and was a first for Bruce and JJ.

Incidentally, sweetgum seeds contain shikimic acid, the starting ingredient for making antiviral drugs to combat bird flu.