Great egret, anhinga and chicken turtle in pool along Red Trail. Photo by D. Sillman
(Click on the following link to listen to an audio version of this blog … Florida 3 Woods and swamps Part 1
The Ron Sapp Egans Creek Greenway is a 300 acre park that stretches out along Egans Creek on the northeast side of Amelia Island, Florida. The park opened in 2000 and is named after Ron Sapp who as city commissioner was instrumental in securing funding and generating public support for the Greenway project. The park is maintained in as natural a state as possible and has over four miles of graveled, packed dirt, and grass-covered walking and biking trails that wind through freshwater swamp forests in its southern and central sections and saltmarsh and maritime forest in its northern sections.
We parked at the southern tip of the Greenway and walked off past a broad pond and then over a pedestrian bridge to begin our hike on the Red Trail of the Greenway. Basking on the shore of the pond were numerous turtles, two American alligators and a resting flock of brown pelicans.
Winer woods along Red Trail. Photo by W. Hamilton
Since it was mid-February, very few of the deciduous trees along the trail had any leaves. This made them very difficult to identify! The swamp forest that surrounded the hiking trail was a dense, tangled mass of layered vegetation (there was a heavy ground cover, a thick shrub layer and an emergent tree canopy layer). These vegetative layers were filled with mostly bare trunks and branches and browned hints of past vegetation. All of this woody material was tightly interwoven around the edges of the stagnant water pools.
Male anhinga next to pond. Photo by D. Sillman
I remember being told by my forestry professor when I took dendrology at Ohio State that taking a similar course in the south was considerably more work! The diversity and species richness of the warm, wet, southern forests are staggering! For example, Florida forests have 262 native species of trees while Ohio forests only have 99! Looking into these mostly leafless thickets bordering the trai, all I could imagine were all of the tree species I had never seen before, and that most of them didn’t have any leaves! Help!
Some of these “ standing sticks” were definitely cypress trees. These were very recognizable in spite of their lack of defining needles (cypress is a deciduous conifer) because of their distinctive “knees” that poked up through the surface of the dark water of the pools. These knees enable the underwater roots of the cypress trees to get oxygen even as they grow through the very anerobic muds of swampy pools. These knees are a vital adaptation that enable cypresses to live in their water-dominate swamp habitats. Bald cypress (Taxodium distichum) and its very similar (but slightly smaller) con-generic, pond cypress (T. ascendens) were probably both well represented along the edges of the swampy pools.
Photo by W. Hamilton
Another feature of cypresses which helps in their identification even in these leafless, winter months is the presence of the epiphyte called Spanish moss (Tillandsia usneoides). Long streamers of Spanish moss drape over the branches of cypress trees. Spanish moss is a non-parasitic plant (it does not harm the tree on which it is growing) and tends to be primarily and possibly exclusively found on cypress trees (especially bald cypress) and also on live oaks (Quercus virginiana)). There were no live oaks in these very wet, swampy woods (live oaks prefer slightly drier soils). Also, live oaks retain their leaves in the winter (hence their descriptive name “live!”) and would have stood out very clearly against the gray-brown dominance of the leafless swamp woods.
The dense patches of Spanish moss scattered along the barely flowing swamp-river, to me, indicated localized abundances of cypress trees!
Spanish moss. Photo by PxFuel
Spanish moss is a very interesting plant although it is very oddly named. It is not from Spain (early Spanish explorers in the American Tropics, apparently had some colorful encounters with the plant and, so, their country’s name was appended to it!), and it is not a moss! It is rootless vascular plant that is in the same plant family (Bromeliaceae) as the pineapple! It has a high degree of specificity upon which trees it grows. As I mentioned above, cypress trees (especially bald cypress) and live oaks are by far the most common “host trees” for this epiphyte (although, the black tupelo (also called the “black gum”)(Nyssa sylvatica) is sometimes listed as possible Spanish moss host)! Two possible reasons for this tree preference of Spanish moss have been offered: 1. The barks of both the bald cypress and the live oak are heavily fissured and, thus, give the Spanish moss strands something realtively solid to hang onto, and 2. The leaves of the bald cypress and the live oak leach high quantities of inorganic nutrients (like calcium, magnesium, potassium and phosphate) and these nutrients are needed for the growth of the moss epiphyte!
Great blue heron and his turtle army! Photo by D. Sillman
It is very amazing to me that the expert consensus of the impact of dense coverings of Spanish moss on the branches of the “host” trees have no negative impacts on the growth or survivability of the tree! In fact, these moss masses hold so much water (a clump of Spanish moss can retain up to 10x it weight in water) that they may act to cool the tree during very hot, summer days. The Spanish moss, then may actually be a mutualistic symbiont for these southern trees!
The Spanish moss masses are well used by animals. Birds make nests out it, numerous insects, spiders, bats and snakes live in the clumps or, at least, find refuge there. If you ever happen to tug on a bunch of Spanish moss (it is relatively lightly attached to the tree, so the clumps pull free fairly easily) be careful because often the clumps have snakes in them. There is even a species of jumping spider (Pelegrina trillandstae) that is ONLY found in Spanish moss!
Spanish moss is very sensitive to air pollution. It is declining considerably in forests near urban or industrial areas.
Beard lichen. Photo by Geograph
There is a group of lichens that very closely resemble Spanish moss. These lichens (and remember lichens are composite organisms of algae and fungi) are called “beard mosses” or “beard lichens.” These lichens may also be called “old man’s beard,” although that name can confuse these lichens with a vascular plant (a clematis) of the same name. These Spanish moss-like lichens are species in the genus Usnea, and, emphasizing the similarity of the appearance of these lichens to Spanish moss, Usnea is the root of the scientific species name of Spanish moss (“usenoides”).
The Usnea lichens are, like most lichens, quite rich in chemicals. Some of the Usnea chemicals have been used in traditional medicine to treat bacterial infections, sore throats and even lung infections. One of the more abundant chemicals in these Usnea lichens is usnic acid. Usnic acid can have negative effects on other plants and also upon animals that eat the lichens.
We took a day during our Amelia Island visit to drive down to Osteen, Florida where we visited some old friends (Don and Andrea) from Pennsylvania. While we were there Andrea mentioned that she had been using Spanish moss as a mulch on her outdoor, potted plants, but that someone had pointed out to her that she was, in fact, using something that resembled Spanish moss, and it was very likely to kill her plants! She had put strands of beard lichens around her plants, and the usnic acid was making the soil in the pots intolerably acidic.
(Next week: more on the woods and swamps of Amerlia Island!)