June 5, 2014. I deliver some maps this afternoon and decide to spend time on the boardwalk afterwards. It has been hot today, but a breeze has picked up and it feels comfortable in the swamp. I am dressed in tourist attire – shorts and a T-shirt, a uniform I don’t normally recommend for the swamp this time of year. The mosquito meter is still registering “3,” but the little pests are almost non-existent on the low boardwalk.
Lizard tail, Saururus cernuus has started blooming in the muck swamp and I see one swamp milkweed, Asclepias perennis, with its tiny, delicate white flowers. First described in the 1700s by the great South Carolina botanist Thomas Walter, this milkweed, unlike most of its kin, grows in deep shade and tolerates flooded conditions.
Off in the background I hear the scary squeal of a pig. The sounds these swine make when upset or in distress can be blood curdling.
Shortly I spot a mammal near the boardwalk, one you don’t often see in the swamp, a marsh rabbit, Sylvilagus palustris. It’s a smaller, and darker, version of the well-known cottontail of upland fields and hedgerows. Marsh rabbits have a fairly restricted distribution, being found only in Florida and the coastal plain of five other southeastern states. This little-known rabbit was first discovered and described for science in the 1830s by the intrepid Charleston naturalist, the Reverend John Bachman. Despite its name, this rabbit is also found in heavily-wooded swamps and river bottoms like the Congaree. And it should not be confused with its much larger cousin, the swamp rabbit, Sylvilagus aquaticus, the so-called “cane cutter” found primarily in the Savannah River drainage and parts west.
I check out some of the shallow pools in the muck swamp and see lots of activity on the bottom – dozens of crayfish about two-and-a-half inches long scurrying for deeper water at my approach. All the water and flooding we had this past winter and spring have been good for the “mud bugs” which in turn is good for the barred owls, otters, raccoons, herons, ibis, and just about every other critter in the swamp that feeds on them, directly or indirectly.
I head back to the parking lot via the Sims Trail, where mosquito and deer fly activity picks up noticeably. The sedge “meadows” within the swamp are now a lush, luminescent green, benefiting I assume from the frequent flooding of March and April. In parts of the swamp the sedge meadows cover extensive areas, providing a lawn-like appearance. This has been best captured by the artist Blue Sky on his magnificent mural of the swamp at the visitor’s center.
Unfortunately a recent grassy invader of the swamp has reared its ugly head and may eventually replace many of the native sedges. Microstegium vimineum, Japanese stilt grass or “Vietnam grass,” is a very invasive grass from the Orient which apparently was first reported in Tennessee in the early twentieth century and has now spread throughout most of the Eastern United States. Like the native sedges, Japanese stilt grass tolerates flooding and low light conditions. It thrives in bottomland forests, and especially in the Piedmont, has completely taken over the ground floor in many areas, to the point that native plants are shaded out, and tree seedlings cannot get established. As with many exotics, this bad grass gets a head start from soil disturbance which, in the case of the park, is amply provided for by acres and acres of pig rootings.
Along the high boardwalk section west of the Sims Trail I see, curled up against some exposed tree roots in the muck swamp, a copperhead. It blends in well with its surroundings and I suspect most of today’s visitors have walked by without noticing – it looks like it has been in this position for a long time. They are beautiful snakes with their tan and brown hour-glass pattern. I usually see a half dozen or so in the swamp, without looking for them, between April and October. It is telling that this is the first poisonous snake I have seen in the swamp this spring.