This week for Flora and Fauna Friday it’s a wily freshwater shorebird that many believe is make-believe, the Wilson’s Snipe (Gallinago delicata).
I’m sure many of you have tales of taking part in a “snipe hunt”, some incomprehensible campground ritual you practiced in good faith which quickly turned out to be a carefully crafted fool’s errand, all for entertainment at your expense. A made-up method for locating a made-up creature. Well, I’m here to tell you that Snipe really do exist! They’re just a lot easier to find then you may have been lead to believe.
The Wilson’s Snipe is our only species of Snipe found in South Carolina. It’s a medium-sized shorebird at about the size of a Quail. In appearance they look like an amalgamation of a Woodcock and a Dowitcher, with a long bill, large eyes, yellow legs, round body, streaked flanks, and cryptically colored plumage of browns, orange, white and black. Snipe are difficult birds to sneak up on but otherwise not that hard to find. They are common here in winter along wet fields, marshes, impoundments, and pond edges. They prefer freshwater habitat but will also pop up on brackish fringes. Snipe use their long bill to probe wet soil for insects and invertebrates, which they pluck out and eat. As alluded, Snipe are very stealthy and difficult to see due to their camouflage, general motionlessness, and crepuscular behavior. Normally, one doesn’t find them until they explode upward from the edge of a dike or drainage ditch, darting back and forth midflight before spiraling into the air on their powerful wings. However, if your eyes are keen and your motion slow, you can sometimes catch a glimpse of them between the reeds or corn stubble. Snipe are actually a game bird in South Carolina too, so one can go on a true Snipe Hunt, without the practical jokes, if they are so inclined.
This week for Flora and Fauna Friday we’re talking about something a little off topic, an ecological phenomenon rather than a specific organism; this week we’re in awe of the Rainbow Swamp.
Cruising down a causeway a kaleidoscopic glimmer grabs your gaze. A truly Technicolor tapestry torn between the tree trunks. You’re beholding the rainbow swamp. Every winter our swamps and bottomlands are blessed by this truly beautiful chromatic aberration of a reflected refraction. This phenomenon arises from a complex interplay of geology, hydrology, meteorology, astronomy, ecology, and biochemistry that all together lead to our Lowcountry swamps being bathed in a blazing spectral display.
Let’s start with the geology and work our way up. Our swamps and bottomlands are found in low elevation areas called floodplains. Their low elevation means that they naturally have a high water table and that rainfall from surrounding areas flow into these floodplains. Floodplains have overtime accumulated a clay substrate which is not particularly pervious to water. Our bottomlands are the lowest areas of the floodplain which are either inundated year-round or fill seasonally. Species of trees and shrubs that can tolerate this long term flooding colonize these areas and transform it into a swamp, a type of forested wetland. As the trees grow and photosynthesize, they pull water from the swamp and transpire it up into the atmosphere to cool themselves down. Thus in the spring and summer, the water level is lowest in a swamp due to evaporation from our hot summers and the transpiration of the overarching trees. Some swamps will go totally dry. However, tropical rains will often fill them back up during late summer and fall. In late fall these wetland trees go dormant and shed their leaves into the water below. As winter rains roll through our state, they fill the swamps to their brim as the trees are no longer taking up water and the cold temperatures slow evaporation considerably. Beneath the water’s surface, anaerobic microbes digest the leaves and various detritus that collect on the bottom of the swamp. During this decomposition process, assorted natural oils found in the plant detritus are released and float up to the surface of the water. Due to the cold temperatures, these oils are able to collect on the water’s surface without being broken down by aerobic microbes in the water column. In slow moving swamps and ephemeral pools, these oils are able to accumulate into a surface film. Our climate in the Lowcountry is also warm enough that the water’s surface rarely freezes either, which would either trap the oils beneath the surface of the ice. Another key piece of the puzzle is that in the winter the sun is lower in the sky due to the tilt of the Earth’s axis. This shallow angle of the sun means the light reflected off the water’s surface is also at a shallow angle and so we can easily see it at a standing height from a distance. As mentioned before, the trees have lost their leaves as well. So the light of the sun is able to hit the surface of swamp in winter where it would be in permanent shadow during summer. As the winter sun hits the surface of the swamp, it encounters the thin sheen of natural oils that have accumulated. These oils function like a natural refractive prism, reflecting each wavelength of light at a slightly different angle which results in the full color spectrum reflecting off the water’s surface. This prismatic effect is not perfect and some unrefracted light reflects too, which is what give the rainbow swamp its characteristic pastel palette. All these different requirements have to be met in order for the Rainbow Swamp to be visible, which is what makes it a uniquely beautiful part of the Lowcountry.
The best time to see the rainbow swamp is usually nine to eleven in the morning in mid-January through February. Yet it’s intensity, appearance, and location depends greatly on the weather throughout the winter leading up to it. It can appear on practically any still body of water with a clear surface beneath a forested wetland. However, given that the sun is in the southern sky, it’s only visible in its full glory when you’re facing southward.
This week for Flora and Fauna Friday we’re taking a gander at our most miniscule member of the amphibians, the Little Grass Frog (Pseudacris ocularis).
A resident of the coastal plain of South Carolina, the Little Grass Frog is a widespread but hard to see member of the Chorus Frogs. They can be found in grassy ephemeral wetlands, especially those bordering forests, all throughout the Lowcountry. However what makes them hard to see is not their rarity, it’s their size. The Little Grass Frog is the smallest terrestrial vertebrate in the United States. A full grown frog is about the size of your fingernail! They’re also cryptically colored to boot, which makes them even harder to spot. The frogs are usually a bronze-brown or copper-orange color with a dark ebony-brown stripe running through and beyond the eye and occasionally some dark stripes down their back. This blends them in well with the grassy environments they prefer. The only good way to locate these frogs is by the male’s song. Male Little Grass Frogs will sing to court a mate. Like most frogs, they possess an expandable throat pouch which increases the volume and resonance of the call. For the Little Grass Frog, that call is a high pitched, glassy chirp which sounds much like the calls of many of our katydids and crickets. Little Grass Frogs will sing and breed throughout the year but I find them easiest to locate in mid to late winter after a good warm rain. They are one of our earliest frogs to stir each year, right alongside our Spring Peepers. Like many of our amphibian species, Little Grass Frogs depend on ephemeral wetlands to survive. Due to their itty bitty size, they’re a target for almost every species of fish and their eggs and tadpoles have little chance to survive in a fish-filled wetland. So they utilize ephemeral wetlands, which dry out every year, as their breeding pools. These wetlands typically fill up in winter while the vegetation is dormant and dry out in summer once the growing season is in full swing. Their shallow, predator-free waters make the perfect nursery for many frog species, including the Little Grass Frog.
This week for Flora and Fauna Friday we have a much maligned and often misidentified member of the mighty oaks, Darlington Oak (Quercus hemisphaerica).
Darlington Oak, also called Sand Laurel Oak, is a medium-sized oak with a mostly straight growth form, relatively smooth gray bark with shallow vertical fissures, and small, simple, emerald-green evergreen leaves. It loves sandy soils, tolerates drought well, and grows best along our hot, dry uplands. It can grow tall and straight in a forest or broad and round when on its lonesome. Its acorns are small, round, and greenish-brown. Darlington Oak is found in the coastal plain of the Southeast. It is likely our most common member of the red oaks on Edisto Island and the second most common Oak behind the omnipresent Live Oak. However, most people I meet have never heard of it before, yet are nonetheless oh so familiar with it.
Darlington Oak is often confused with, or generically referred to as, Water Oak in our area. Water Oak (Q. nigra) is actually a different but closely related species that prefers moist clay soils and has larger spatula-shaped deciduous leaves. In fact, there are two other oak species, Laurel Oak (Q. laurifolia) and Willow Oak (Q. phellos) that are also closely related and look very similar to Darlington Oak. It doesn’t help either that they can all interbreed and hybridize. But I digress. Darlington Oak and Water Oak are of note because they are derided by property owners across the Island. These two species have a propensity to drop limbs, collapse, uproot, or spontaneously die that is unmatched by our other common tree species. They do make good firewood at least.
Water Oak earned this reputation from its less than rot-resistant heartwood and preference for wet, humid woodlands. Their preference for moist clay soils also means they don’t develop all that deep or robust of a root system. So they topple easily. Darlington Oak, however, lives on our driest, sandiest soils where it grows a deep and expansive root system and rot is not as big of a concern on these well drained soils. This makes Darlington Oak a bit sturdier and longer lived than Water Oak but it is prone to shedding limbs nonetheless. What rots Darlington oak is instead drought. Drought stresses the trees which, if severe, can kill the tree outright but more often makes them more susceptible to disease. Disease creates chronic stress and allows saprophytic soil fungi to invade the trunk. Over the years these fungi will worm their way throughout the tree, weakening it structurally, until one day the whole tree collapses. This fungal invasion is also what causes the tree’s interesting habit of sheering clean off at the soil line with nary a root showing. The heartwood becomes weakest near the soil where the fungal attacks are most concentrated and the physical stress on the trunk is most concentrated at this point as well. So when a hurricane blows through, trees can snap clean off at the bottom. Oaks of all types can also rot from the top down. If rainwater is able to collect in a trunk fork for too long, it will eventually lead to the bark beneath dying and the wood below slowly rotting ever deeper. This can lead to a tree top suddenly splitting apart or shearing clean off as the core of the trunk is hollow.
This week for Flora and Fauna Friday it’s a one of our winter waterfowl, the Bufflehead (Bucephala albeola).
Buoying between the breakwaters and burying itself beneath the brine is how the Bufflehead enjoys its vacations Edisto Island. One of our most common winter waterfowl, the Bufflehead can often be spotted cruising down our creeks or sailing through the surf and sea throughout the winter months. They are common in winter throughout the coastal United States and breed in Canada come warmer times. Buffleheads are our smallest diving duck and about the size of a Teal. The birds have a short bill, large round head, and a mainly monochromatic plumage. Females have a circular head that’s charcoal-black with a white elongated spot below and behind the eye. Their above is that same charcoal black and the below a sooty gray and white. Males are a bit more over-stated with an ink-black back, ice-white belly, and a tall pointed head wrapped in an iridescent sheen of green that blends into purple and topped with a snow-white edge pointing down to the eye and drawing your attention beyond to the aluminum-gray bill. Buffleheads are diving ducks and thus they stick to deeper waters. You’ll most often spot them on lakes, deepwater creeks, inlets, and just off the beach cruising alone or in small flocks. To dive, they throw themselves forward, head outstretched, and slip beneath the drink. Underwater they search for crustaceans, mollusks, and snails to eat and generally stay under for about ten to fifteen seconds.
This week for Flora and Fauna Friday it’s a blossoming beach winter wildflower, Beach Evening-Primrose (Oenothera drummondii).
Winter weather leaves us wishing to welcome warm winds and waking wildflowers. Well I’m pretty good at publishing the hot air part of that equation but I can’t do much to make the flowers stir. However, I can at least highlight one of our few cold weather flowering plants. Beach Evening-Primrose is a not an uncommon member of our beach dune ecosystems. It does not grow on the beach itself but is found just behind the dunes. However, its cousin, Seabeach Evening-Primrose (O. humifusa), does grow on the beach. (Just to make things confusing.) Beach Evening-Primrose has a weakly upright posture and usually grows as a low shrub. Its leaves are simple and lance-shaped with a bluish-gray cast to their color. Beach Evening-Primrose is quite similar in appearance to some of our other Evening-Primrose species but what makes it special, apart from its adaptation to the harsh beach dune ecosystem, is its second bloom period. Its primary bloom period is April. Yet, here on Edisto, and the surrounding barrier Islands, you’ll often see this species in full bloom in the middle of January. Four glowing golden-yellow heart-shaped petals folding out into a nearly three inch flower, fluttering in the chilling ocean breeze. It’s an odd but reinvigorating sight in the midst of winter.
An interesting tidbit about this species is that there is evidence to suggest that it can “hear” certain sounds and react to pollinators. A recent study [Viets et al. 2019] found that Beach Evening-Primrose flower petals would vibrate to the hum of insect wingbeats and signal the plant to sweeten that flower’s nectar within just a few minutes. Such a reaction could increase pollination rates by getting preferred pollinators to stick around longer and come back more often while letting the plant avoid wasting nectar on non-pollinating insects or surface bacteria. Whether this acoustic response has any practical benefit to the plant in a natural setting has yet to be studied but the general auditory capacity of plants is a fascinating thing to think about.
This week for Flora and Fauna Friday we have a clade of clingy calcareous crustaceans, Acorn Barnacles (Subclass Cirripedia, clade Sessilia).
You read me right, Barnacles are crustaceans and not mollusks. They belong to the same clade as crabs, shrimp, and crayfish. Life as a listless lump requires some lifestyle changes from the typical crustacean we know. Barnacles are sessile organisms, meaning they can’t relocate once they attach to a surface. Thus they are generally filter feeders and get their meals by straining seawater through a pair of feathery appendages. There are many species of barnacle of a myriad of shapes with a wide array of lifestyles but most fall within two major groups. Acorn Barnacles are the conical-shaped hard-shelled creatures we’re used to seeing here in the Lowcountry. However there are also Stalked Barnacles who grow off of a surface by means of a muscular stalk, but you’ll likely only ever see them washed ashore on driftwood in South Carolina. Acorn Barnacles are surrounded by a phalanx of interlocking plates of calcium carbonate. As they grow, these plates grow with them. At the top of this pyramidal shell is an angled pair of interlocking plates. These plates are hinged lengthwise to allow the barnacle to close up on command and protect their soft barnacle bits within. Below it all is a base plate that grows directly onto their selected substrate, firmly anchoring them in place. Acorn Barnacles can attach and grow on just about anything from rocks to wood to crabs to oysters to whales to boats to ropes and even to each other.
Here around Edisto you’re most likely to see Acorn Barnacles from a select few species. These species are adapted to life in the intertidal zone and thus are the easiest for us to observe since they appear above water twice a day. The three species I’ve seen most often glued to piers and pylons in our tidal creeks are the Ivory Barnacle (Amphibalanus eburneus), the Striped Barnacle (Balanus amphitrite), and the Fragile Barnacle (Chthamalus fragilis). The Ivory and Striped Barnacle are a similar conical shape and the same size at about half to three-quarters of an inch around. The Ivory Barnacle is a pure ivory-white and prefers to grow just below the low tide line but can often be seen on exceptionally low tides. The Striped Barnacle has many vertical mauve stripes and tolerates being out of the water better than the Ivory Barnacle, so you’ll often see it growing several feet above the low tide line. The Striped Barnacle is a native of the Indian Ocean and has been established in South Carolina for over a hundred years. It’s the one that’s probably the easiest to find. The Fragile Barnacle is much smaller in size than the other two, usually less than a quarter inch across. It’s flatter and can sometimes have an irregularly shaped border to its base. They tolerate exposure to air the best and will often be the barnacle growing the farthest up a structure. Fragile Barnacles will even grow on the stalks and leaves of Smooth Cordgrass. There is a fourth hard to miss species of Acorn Barnacle that is a recent introduction to South Carolina, the Titan Acorn Barnacle (Megabalanus coccopoma). The Titan Acorn Barnacle is a huge barnacle, growing about two inches high, and is a shade of muted-fuchsia across much of its shell. It was first discovered in SC in 2006 and can now be found growing along the jetties and groins of several Barrier Islands, including Edisto Beach.
This week for Flora and Fauna Friday it’s a curious coastal shrub that’s as good at inflicting pain as it is at killing pain, Southern Prickly-Ash (Zanthoxylum clava-herculis).
Southern Prickly-Ash is a small tree in the citrus family found scattered across the coast of the Southeast United States. Here in South Carolina, it’s limited to the Lowcountry and primarily to barrier islands and Sea Islands, like Edisto. It’s a common sight on beaches and in sandy forest edges further inland. Southern Prickly-Ash has a gnarled growth, pale-gray bark, leathery emerald-green compound leaves, and is covered in corky protrusions and prickles. It generally grows about ten to twenty feet tall with multiple stems. Southern Prickly-Ash goes by many names including, Toothache Bush and Hercules’ Club, and each alludes to a different characteristic. The name Hercules’ Club references the trunk of the plant. The club of the Greek hero Hercules is often depicted as being covered nodules or conical points and indeed our plant is covered in pointy conical nodules all along its stem. Southern Prickly-Ash tells us the plant is found in the south, it’s prickly, and it resembles an Ash tree. Conveniently, it is all three. Both the stems and the trunk of Southern Prickly-Ash are all covered in vicious woody prickles and the prickles on the trunk eventually transition with age into corky pyramids. (Prickles is the technical term here, as these pointy bits are grown out of the plants’ bark. Thorns grow out of the wood of the stem and spines are modified leaves.) Also, its leaves do in fact look a bit like an Ash, with a pinnately compound leaf usually holding seven to nine leaflets. However, the most intriguing name is Toothache Bush. The leaves of Southern Prickly-Ash are glossy with a burgundy rachis down the center studded by prickles between the leaflets. They are also thick and leathery. As these plants often grow in stressful habitats with poor soils and these leaves take a good deal of work to grow, they strongly prefer if critters don’t make their lives any harder by eating their leaves. To this end, they have covered themselves in prickles and have also invested in chemical warfare. The flesh of Southern Prickly-Ash contains chemicals designed to repel and incapacitate insect pests. One of those chemicals is spilanthol, which kills insects but can work as a local anesthetic in humans. Traditionally, Native Americans often used it to treat toothaches, as chewing on the twigs or leaves of Southern Prickly-Ash will numb the mouth and tongue with a tingling sensation that allows you to ignore mouth pain. However, this chemical warfare isn’t perfect and I know of one species of insect that has learned to tolerate it, the Giant Swallowtail. The Giant Swallowtail is our largest species of butterfly in the South Carolina and its native host plant is Southern Prickly-Ash. Southern Prickly-Ash is also important to other wildlife. It blooms in mid-spring with cluster of tiny green flowers utilized by pollinators and produces small black berries eaten birds.
This week for Flora and Fauna Friday is a big alabaster bird we’re all familiar with, the Great Egret (Ardea alba).
The Great Egret is found in temperate coastal areas and tropical wetlands all across the globe. Here in South Carolina, it is most common in the tidelands of the Lowcountry but can crop up along wetlands throughout the state. The Great Egret is a large wading bird, standing about three feet in height, with slender features and an S-curved neck. They’re plumed from chin to tail with feathers of icy-white and lacking any discernable markings. They have long black legs, pastel-yellow eyes, and a golden-yellow, dagger-shaped bill at the end of an even longer neck. Great Egrets stick out like a full moon at midnight as they stand offshore in their preferred pluff-mud floored salt marsh habitats. However, believe it or not, this unpigmented plumage is their camouflage. It’s just that they’re hiding from fish and not from you. Great Egrets are ambush hunters and their prey are fish and crustaceans. By donning a blinding white coat of feathers, they can stand in the middle of the water in front of the sunlit sky and go unnoticed from those below the rippled surface. Their feathers act like a mirror for the light reflected off the water and their featureless plumage blends in with the infinite expanse of sky. Just another cloud. In the turbulent shallows they hunt in, that’s all it takes to disappear in plain sight. It also doesn’t hurt that their black legs blend in with the dark sediment, their front profile is very narrow, and they use forward speed to ambush their prey. Great Egrets, like other Herons and Egrets, use their sharp, pointed bill to grab, or occasionally impale, their prey. They do this by folding their neck into an “S” and then launching their bill straight forward with blinding speed. This direct, forward strike minimizes lateral movement and inhibits their prey’s ability to see the attack coming.
Great Egrets are solitary hunters but they tend to sleep in groups for protection. They also nest in groups in areas called rookeries. Rookeries tend to be in trees hanging over or growing in standing water or marshes and are often filled with nests of many different species of wading bird. Wading Birds do this to limit predation from Raccoons, Opossums, and Owls by concentrating in one small area and using the water, and any alligators swimming in it, as a deterrent. Leading up to the nesting season, mature Great Egrets will grow plumes from their back and the skin around their eyes will turn a brilliant chartreuse. Their elegant plumes are thin, covered in wispy barbs, and trail almost to the ground. Around the turn of the 20th century, these plumes were highly prized for use in women’s fashion and the Great Egret, along with other American wading birds, were nearly extirpated from the United States. Thankfully plume hunting was banned shortly into the 20th century and Great Egrets have made a splendid recovery.
This week for Flora and Fauna Friday we have a showy shrub of the Southeast, Hearts-a-Bustin’ (Euonymus americanus), AKA American Strawberry Bush.
Hearts-a-Bustin’ is a small to medium-sized deciduous shrub found throughout the Southeastern United States. It’s a fairly common sight in moist forest understories, as it is tolerant of deep shade, but it does best on forest fringes with partial shade. Heart’s-a-Bustin’ is an easy plant to identify but also one that can be easy to overlook at certain times of the year. It has thin, spindly, solid green stems and a somewhat unkempt growth-form, usually with multiple stems. Its leaves are small, simple, and ovular with a pointed tip and can be quite thick, almost leathery, when the shrub is small. Leaves are arranged opposite each other on the stems and are the same shade of green as those stems. This monochromatic character is a rather unique combination and is often enough to identify it with just a glance. Heart’s-a-Bustin’ is a favorite food of White-tailed Deer and, leading up to winter, they often get browsed down until they’re nothing but a collection of green stems. If the deer don’t strip them bare by fall, their leaves turn a shade of crimson-red before falling to the forest floor. Heart’s-a-Bustin’ blooms twice each year, once at the end of April and again at the end of September. Small five-petalled, green-white flowers with a tinge of pink and a lime-green center emerge from the ends of long, thin pedicels that anchor back below the base of a leaf. Each flower has a twin on the other side of the stem. These flowers will mature into a unique looking fruit that gives this plant its many names.
The fruit of Heart’s-a-Bustin’ is a capsule that’s dyed an eye-catching shade of magenta and textured with many small conical points. At a glance it resembles a Strawberry but up close there’s no comparison and the best analogue for its shape is a Sea Urchin. As this capsule ripens, it dries and eventually splits apart at the bottom to reveal up to five bright-red fleshy seeds that dangle downward from the tip of each arm of the capsule. These fleshy seeds are known as arils, the same type of seed produced by Magnolias. Arils are biologically different from a drupe in that the flesh that grows around the seeds originates from the seed itself and not the fruit of the parent plant. They’re also poisonous, so don’t eat them. These capsule-aril combos are quite a striking sight and make identification of the shrubs a breeze when they’re fruiting. In case you’re wondering, the name Hearts-a-Bustin’ doesn’t have any deeper cultural meaning to it that I can find. It’s simply a poetic, romantic name for a reddish-purple fruit that bursts apart.
