Cayman Brac’s unique ecological treasures
by J. Wallace Platts
OF 13 CLAIMS TO ECOLOGICAL FAME, WE SCORED “YES — UNIQUE TO CAYMAN BRAC” on 8 of them which is 60 %. We realize Grand Cayman could make a list of its own, and so could Little Cayman. Both would beat us all hollow on the subject of ponds and wetlands – we are almost devoid of these, thanks in part to creation and in much greater part to mankind (our thoughtless destruction of wetland – every “cut” or blockage we made has been N/S whereas our ancient wetlands lay E/W virtually along the whole island, on both sides).
HERE ARE SOME ECOLOGICAL NICHES UNIQUE TO CAYMAN BRAC among the three Cayman Islands
Most but not all the following are phenomena directly related to our height of land. The Brac is much higher than the other two islands. We rise to 140 feet above sea level but only 120 feet at the lighthouse which some may think is our highest point. These heights of vertical rise are low for serious climbers. One nearby island nation has 10,000 foot cliffs plunging into the sea. Our small cliffs offer a challenge for “free climbing” but are really just for entertainment – tourists can rent helmets and gear, enjoy the passing thrill of looking down into sea water, and tell their friends back home they went climbing.
LARGE CAVES IN THE TALL CLIFF FACE
There are books that name all these caves but human interference can chase away the natural inhabitants such as bats and owls, and can break stalactites. “No helmets” is the rule I enforced, as a volunteer guide. The most stunning cave is Neptune’s Cave or Window Cave, which probes the island in a horizontal run (approximately E/W) of many hundreds of feet, and has branches too. “Drinking straw” formations occur deep inside, hanging vertically except as blown by the inner wind which always promises a further “run” if one could squeeze so small. There are other caves almost as large but in this article we will emphasize their natural value rather than their human entertainment value, since the two are incompatible.
The Brac probably has many more caves than we know of. This is as it should be. Nani Cave is so full of stalactites you could not fit a tennis ball on the actual “roof”. Another cave (I’ll tell you where if you bribe me) angles down for 70 feet, at which point total silence reigns except for the circulation of your blood. When you reach an end point, blocked by a natural grid to stop you crawling further, there is a breeze in your face. Cayman Brac is riddled with caves and mystery.
SMALL CAVES IN THE TALL CLIFF FACE
The ones on the NE high cliff provide safe nesting for most of our White-tailed Tropicbirds, while a complicated, vertical slit cave there is the site of a bat emergence every evening – bats called Molossus molossus (Velvety free-tailed bats). Hundreds emerge in a continuous, chatty line that swoops down to gain flying speed before dashing off into the void, to catch flying bugs of all kinds. The classic description from a lady who once lived there was that the phenomenon looked “Like oil pouring from a kettle in a high wind”. In the past, someone set fire to the large mound of guano at the base and the burn mark is still visible, above a profusion of a wild plant called “Basket Wiss” (from the word withes): Trichostigma octandrum.
Experts have counted at least five varieties of bats making their home on the Brac.
Back to the White-tailed Tropicbird. They back into high “cavelets” so their beaks can protect their nests and nestlings against predators such as rats. They can emit quite a squawk if one accidentally approaches too closely.
The construction of bat houses on the other two islands is laudable. We don’t need them on Cayman Brac because our tall cliffs are riddled with perfect nest sites.
PLANT, ANIMAL AND FUNGAL LIFE in and on our tall cliffs
Only Cayman Brac has tall cliffs and they happen to be vertical. In addition to bats living on this vertical habitat we have the Brac’s only endemic plant that lives exclusively in this habitat – Verbesina caymanensis by name. The base of the cave face that it calls home extends about a mile, and lies in the area that gets the least amount of sun – it is in the shade of our tall cliff for most of the year. This is due to the Brac’s orientation (NE/SW) and the fact that we are quite north (19 degrees latitude) which is close to the Tropic of Cancer (23.4 degrees N approximately). It may be better to say “This plant’s competitors are averse to shade” rather than “This plant prefers shade”. Either way, it is exclusive to this small part of the earth’s surface. By the way, its growth does creep down onto the flat land at the base of the cliff face but only for a few feet, in a few places.
Look at the title above – “Plant, Animal and Fungal Life in and on our tall cliffs”. Are there specialties there we don’t know? In my opinion this is quite likely. This is where the climbing community could assist the scientific community. I have free-climbed the tall face in two locations but I didn’t pay attention to life forms while doing it, except for a large “Soldier Crab” that was nearing the top when I was.
SIXTY FOOT SINKHOLES
I measured two of them which are located very close together. In fact there are three, closely spaced. I was there with other members of the old-time National Trust, when all of us were a bit younger. Walking the narrow “bridge” between two of them was like walking the plank on a pirate ship. I re-visited on another occasion and sent down a thermometer on a length of fishing line, thinking the temperature might be cooler and more pleasant down there. When I yanked it to the surface again the reading was hotter! By the way, with another Trust member we walked for six hours in this location once, on a straight line. And with another hardy member we tried unsuccessfully to encircle the largest tree on Cayman Brac with our arms. It is well hidden in the dense, ancient forest, and you’ll not be able to guess the species. (Location: ask the author; Accessibility: easy for any fit person; Status: protected)
DEEP, FOSSIL WATER
Some is fresh, some is salt, and its extent has been measured at least in the eastern half of the Brac. In the west of the island the water table has been compromised by quarrying virtually to the water table. Other than that huge loss, one gets the impression that our limestone island is permeated with eons of fresh water, and under that, salt water following all the fissures and the porous limestone.
The time for water to percolate down after an inch of overnight rain has been measured inside the larger caves– the rate of drip and the accretion of limestone at the tip of each stalactite. A lovely sight is the “knuckle” in the middle of the larger stalactites, where each one meets its associated stalagmite. Some are thick as trees. Some are hollow. I used to play music on an “organ” of thin, hollow pipes – the scale was more like the oriental scale than the “well-tempered” scale given us by the composer JSB.
Please leave the fossil water in place. Perhaps some day it might be utilized by the Water Authority for drinking, to reduce the tremendous electricity bill required by Reverse Osmosis. At present the Authority uses partly saline water near their plant. We can have good water for drinking, washing and bathing, for our small population (only 2000 people, where it has stayed for over 30 years).
Subterranean tunnels were left by underground streams and rivers that once flowed from the base of sinkholes to the face of the closest cliff. Our fatal sale of quarry rock to Grand Cayman gives us one advantage – the vertical quarry cuts show some of these tunnels, mostly of a modest diameter in my limited experience. We are selling our island for a mess of pottage and charging the tiny royalty of 25 cents per cubic yard, last time I checked.
What forms of life swam or travelled in these subterranean tunnels? Will we ever know? Location: face of limestone quarrries; Accessibility: permission required; Protection: private ownership may provide some protection.
There may be another in the Cayman Islands but not that we know of. In Alberta Canada I checked a “living” one called Turbine Canyon, half-way down the slopes of Mt. Jellicoe, where a stream crashes down and splits itself on the rocks. Here, we have one in that precious but unprotected zone called high bluff edge forest. Each of our two is 25 feet deep. The bottom has been explored but not dug down to the horizontal tunnel which undoubtedly took all the water flow to the face of the nearby cliff. At the top, the natural inlet trench or cut is still clearly evident. (Location: ask the author; Accessibility: easy for any fit person; Status: unprotected)
SEVERE KARST LIMESTONE TERRAIN
This feature may perhaps be shared with the two other islands, but I doubt if either one has a greater percent coverage of the jagged, pointy, variably eroded rock which is virtually impenetrable. One small patch on Grand Cayman is called HELL and is a tourist attraction. Wherever we have kept our native forests, especially on our southern high bluff terrain, the “substrate” is severe karst limestone. It has been differentially eroded, i.e. the numerous “points” represent less soluble limestone (dolomitic limestone is our rock type), and the holes where you could lose a leg if they’re covered by leaves or tree “trash” were once comprised of somewhat more soluble limestone rock. The whole effect is impossible to traverse. Once, trying to follow a straight line (this will be explained) * a friend and I had to clamber down very rough sinkholes and up again, and many times we lost sight of each other while only 25 or 50 linear feet apart! By this mode we found an area we dubbed “Biodiversity Heaven” because every tree and plant was of a different species from its closest neighbor, and there were few repetitions of species.
*In a random natural area such as our severe karst forest, sticking to a straight line represents a random path. This has been pointed out by some top scientists – it solves the problem that we may accidentally drift onto animal paths etc., blindly taking a line of lesser resistance.
NB We and our pioneers on the Brac have disrespected this unique landscape – we wanted smooth areas for footpaths, agriculture, houses and even views. We used machetes and fires – burning these fires upwind (west to east) in order to heat the spiky rock more thoroughly so it can be knocked apart even with the back of one’s machete. Nowadays large yellow machines do the job and bring us closer to suburbia – that much-to-be-feared transformation of our wild island into house lots for sale to ourselves and to temporary residents who want a piece of our tax-free country. We need to beware of bland, suburban existence. On the Brac we don’t yet have strip malls and fast-food outlets crammed beside gambling dens, gas stations and the other kind of strip bars, but we’re heading that way. Unfortunately, a HUGE number of houses are built and used only part-time, or not at all. Someone once counted 15 in three miles.
If Haymon’s Pond is not the only very broad, shallow (filled in) sinkhole, it may at least be best. We know the origin because both the inlet and the outlet split still exist, and contain some water. (One geologist thought a meteor might have struck but that is clearly incorrect.) The large circle is no longer a “pond” but was once used as a cattle-watering station. Parts of old stanchions may still be visible – entry was from the north but nowadays we walk in from the south along a path shown to us by the late Alva “Billy” Bodden). To this author’s knowledge there is no better “open, large, shallow sinkhole” in the three islands. The pond is filled with the large fern called Acrostichum aureum, not listed as occurring on our island in any of the reference books. (We have 34 native plants not attributed to the Brac, but to one or both the other two islands, in the official reference texts.) (Location: rough trail from the south; Accessibility: easy for any fit person; Status: unprotected)
We know two places where shrimp come in to our ponds — small, lowland, flatland ponds or holes — using underground channels! One is called the Red Shrimp Hole and the other, the Black Cuban Shrimp Hole. Both are on south side and both are now ruined – the Red Shrimp Hole seems dead from leachate from The Brac’s ugly, ever-larger, never-sealed Public Dump (much bigger per capita than Grand Cayman’s famous Mount Trashmore). Until Hurricane Paloma a second Red Shrimp Hole existed, this one in Spot Bay, but is now apparently clogged with small beach rock jammed in by the hurricane. Being small in circumference it carried the ironic Brac name of Big Pond.
The Black Shrimp Hole (a Cuban species) is also dead, but the reason is gentrification. The natural hole has been fitted with a pump to make a fountain for wealthy guests, who would probably be horrified at this thoughtless and cruel exploitation of a rare and precious nature site*.
Location: – ask the author; Accessibility – easy; Protection – too late.
*We naturalists including a specialist were chased off this site by the somewhat wicked owner, while trying to identify the very large shrimp – as large as a chunky carrot that doesn’t taper at the end.
Another subject for study on the Brac is PRIMEVAL FOREST, NEVER TOUCHED BY MAN. As a scientist, wouldn’t you love to study terrain that established itself by hook or by crook, but was never modified by Man? According to a reference called Constant Battles (Steven A. LeBlanc, 2003) there are almost no such sites, even in the high Arctic and the “wild Amazon – everything has been crossed by Man. But our island is most inhospitable, with intimidating cliffs, no water, piercing rocks, very poor soil for growing, an island with scarcely any soil at all, no mammals, no natural inlets or harbors. A team of anthropologists excavated a cubic dimension at the entrance to Great Cave on our southeast corner, and found no sign of human visitation, let alone settlement. Miskito Indians came to our west end by canoe, but never settled here.
DRIED-UP WATERFALLS that once spouted from tunnels that emerged in the high cliff face and crashed down the rock to the flat land below.
These reflect back to the height of the bluff – any such features on the other two islands either did not exist or became flooded in rising seas over the millennia. One such ancient waterfall spilled over from a very broad river* that once traversed our high bluff edge, running almost parallel to that edge, and apparently running west to east. The spillway is still there for investigation but has never been investigated.
(Location: midway along south side; Accessibility: easy for any fit person; Status: unprotected)
*This river bed on top of the bluff is still very clear. It is U-shaped in cross-section – one has to clamber down one side, walk across the bottom and scramble up the other side. I tried but failed to throw a rock from one side to the other. This was a considerable river, and might pre-date the last inundation of our island, Cayman Brac.
(Location: ask the author; Accessibility: it took us 3 hard hours to reach this place; Protection: most of this area is unprotected – our island has the least percentage of protected terrain of all three islands, by a large margin.)
THE MOUNTAIN I’ll not spending much time on “the mountain” which I think is a collapsed Ceynote. My best evidence is the rounded surfaces of the large collapsed rocks comprising the mound and still visible … and the fact that they are of a different rock formation than the surrounding rocks. An interesting aspect of The Mountain is the sparse vegetation on the east or windward side of the mound itself, in contrast to the lush vegetation on the immediate west side of the circular mound. The likely explanation is our prevailing wind from the east – from SE in summer and from NE in winter. The steady wind sweeps the upwind side clean but deposits the soil, sand, Sahara Dust and other airborne particulate matter on the west side of the mound, like a snow fence does with snow up north. I saw one Opuntia dillennia there with leaves as large as dinner plates. (Location: ask the author; Accessibility: the old, rocky path is fine for a fit person with good balance; Protection: sadly, it is unprotected. Information on the laboratory dating of the aberrant rock can be found in Islands From the Sea by the late Dr. Murray Road, p.62.)
Did I ask the question WHAT ELSE MAY LIE OUT THERE? No, I did not. I’ve explored three caves big enough for a grown elephant – there may be more. This is trackless wilderness – difficult to find every nook and cranny. Sometimes I think that a rock thrown into the middle or eastern middle of our island might well find something totally unknown to us. One guy was sold a lot of land – one of dozens of lots in the raw forest – and when he went to check it out he asked to trade it “because it’s just a gigantic hole!” The seller gave him title to another one.
Underneath Cayman Brac there may be a lake capable of hiding a small armada!
These are just a few of the possibilities of tiny Cayman Brac, just 12 miles by one mile wide, approximately … my favorite piece of terra–not –very-firma. A jewel in the sea –not well studied, not well protected.
October 5, 2022; Cayman Brac, Cayman