This will be my last entry for Congaree Journal, A Diary of Life in the Swamp. I’ve enjoyed sharing my observations and experiences with you over these past two years about one of the most distinctive and biologically diverse parks within the national park system. And I appreciate John Grego and Friends of Congaree Swamp for providing an outlet for this diary.
I thought it appropriate that I close with an essay about changes in the park I’ve experienced over the past nearly fifty years.
On the surface at least, the Congaree of 2020 appears pretty much like the Congaree of 1974 when Jim Elder, Dick Watkins, and I first started knocking around the place on a regular basis. But just beneath that surface there have been lots of changes, some more noticeable than others. This is to be expected however, since we know that the one constant in nature is change itself. Indeed, even the most remote outpost on the planet is not immune from natural, and increasingly, artificial, change as a result of mankind’s dominion over earth.
One of the most obvious (and saddest for me) changes at Congaree took place shortly after the park was established. The drive into the park then on what is now the Sims Trail was lined with the most magnificent stand of giant loblolly pines anywhere in the world. It was breathtaking to walk along a half-mile stretch of a pine forest cathedral that soared 130-150 feet over your head. This magnificent avenue gave rise to an early name for the Congaree – “Redwoods East.” It didn’t seem possible that a tiny insect no bigger than a grain of rice could damage, much less destroy, those great trees but that’s exactly what happened when a pine beetle epidemic swept through and killed many of them.
The pine bark beetle outbreak was followed a few years later by Hurricane Hugo in 1989. This monster storm hit Congaree, and the Midlands of South Carolina, with sustained wind gusts of 90 miles per hour or greater, a figure never before recorded this far inland. I’ve noted in an early essay (Secrets of the Sweetgums) the impacts this once-in-a century storm (maybe even a two-century storm) had, and continues to have, on Congaree. Suffice it to say, however, this storm was a game changer for the park in many ways, particularly as it relates to the old-growth forest’s structure and composition.
The Congaree forest of fifty years ago fit well the classic description of “virgin” or “original” eastern forest noted by the early naturalists and explorers: tall, cathedral-like stands of large trees with a dense canopy that blotted out the sun. Walking at the obstruction-free ground level was ridiculously easy, and spotting a deer or turkey 300 feet away was routine.
This description began changing after Hurricane Hugo. Downed trees, limbs (many the size of small trees), tip-up mounds, vine tangles, thickets, and dead falls became commonplace, and the pattern seems to have only increased in the intervening years. I suspect that in some cases a delayed effect from hurricane damage to the canopy has taken place as gradual rot and insect damage from wind-inflicted wounds has resulted in fallen limbs and canopy loss years after the storm. Now, in many areas of the park, walking is not “ridiculously easy,” and moving in a straight line is out of the question with so many obstacles to negotiate.
Congaree’s “East End” was hit particularly hard by Hugo. The switch cane that was three-and-a-half feet high before Hugo has not only spread, but gotten taller, presumably from increased sunlight. The cane in some areas is now five- to six-feet high or more, and in company with numerous vines, shrubs, downed limbs and trees, has resulted in a nearly impenetrable jungle worthy of a Tarzan movie. Such tangles and thickets are now commonplace throughout the park.
Neal Polhemus and I were recently kayaking beautiful, black Upper Cedar Creek and stopped off at Big Hurricane Island for a break. This aptly-named piece of high ground, surrounded by muck swamp, was also heavily damaged by Hugo, with many of the big four- and five-feet diameter loblolly pines being felled or snapped off. Years later Hurricane Matthew knocked over a good number of large hardwoods. Now the island looks more like a logged-over forest than an old-growth one and “Big Thicket” Island might be a better name for it.
One of the biggest challenges facing any park manager is the spread of exotic, non-native plants, and Congaree has not been exempt from this threat. Chinese privet, Ligustrum sinense, is one of the worst invaders of floodplains, and it’s not hard to find bottomland forests that have been completely taken over by this aggressive species. Initially I wasn’t too worried about privet at Congaree, but after Hurricane Hugo opened up the canopy, perhaps coupled with extensive areas of soil disturbance created by pig rootings, I have noticed more and more privet seedlings rearing their ugly heads throughout the park. Some other worrisome plants that have showed up at Congaree include chinaberry (Melia azedarach), Japanese climbing fern (Lygodium japonicum), Japanese honeysuckle (Lonicera japonica), non-native bamboo, and Japanese stilt grass (Microstegium vimineum). The latter has been a particularly bothersome ground cover that in only a few short years has made its aggressive presence known throughout the park. It is perhaps significant that I encountered none of these species, except for small patches of Japanese honeysuckle growing along the floodplain edges, fifty years ago.
Changes in the park’s fauna have kept pace with changes in its flora. In the 1970s it was almost unheard of to see a wild pig in the park and there were no beavers, coyotes, or armadillos. The proliferation of feral swine began in the mid-1980s when some of the surrounding hunt clubs began stocking their lands with semi-domestic pigs. Within a few years the pigs, one of the most fecund animals in the Western Hemisphere, were everywhere in the park. I wonder sometimes if the fact that I see so few snakes at Congaree than I remember from years ago is due to a lot of hungry swine. Perhaps one good thing about the newly-arrived coyote population will be as predators of young pigs.
Beavers don’t fit the exotic introduction pattern since they were native to Congaree, and much of the Southeast, 150 years ago before they were all trapped out. I first began noticing beaver sign in the park in the early 1990s. Although the big rodents damage and sometimes kill sweetgums and other swamp hardwoods, their benefits far outweigh any negatives since the dams and ponds they create hold water during dry periods and benefit a host of fishes, reptiles, amphibians, birds, and other wildlife.
What of the future? What is in store for the park if the current warming trend continues? One immediate example that comes to mind, and presumably related to global warming, is the spread of the golden-silk orb spider (Nephila clavipes). In the 1970s this magnificent arachnid was only found in South Carolina on the barrier islands and in a narrow strip of coastal forest. It has been spreading inland ever since, and I first saw evidence of it at Congaree in the mid-1990s. Like many newcomers, plant and animal, it is now one of the most common spiders found in the park.
Climate change, by affecting rainfall patterns, could alter the park’s flooding cycle and hydrology. Rising temperatures can affect tree growth and even eliminate certain species. National Park Service scientists, working in collaboration with other institutions, have predicted that, based on rising temperatures, many higher-elevation coniferous forests of western parks will eventually be replaced by deciduous forests, with profound consequences for animal species that depend on them.
I believe the largest threat to the park, like for so many of the world’s ecosystems and natural areas, is the invasion of exotics, whether plant or animal. My biggest fear for Congaree is that some sort of introduced blight or exotic insect pest will wipe out an entire tree species. It happened less than a hundred years ago with a blight that wiped out the most abundant and magnificent tree of the Appalachian forest, the American chestnut. More recently, an exotic insect pest is on its way to eliminating the eastern hemlock. Introduced ambrosia beetles are currently decimating redbays along the Southeastern coast, and Dutch elm disease has destroyed millions of beautiful elm shade trees of the Northeast and Midwest (so far the elms of Congaree appear healthy and secure).
As I write this in late 2020, I learn that the dreaded emerald ash borer has been found in the neighboring states of Georgia and North Carolina. This small exotic beetle, a native of Asia, somehow found its way to North America, where it was first discovered in Michigan in 2002. Since then it has killed more than seven million ash trees in that state alone. It is depressing to think that in a few years we may be looking at a Congaree skeleton forest of dead ash trees, a species that currently represents about fifteen percent of the bottomland hardwood forest. I tremble when I think of other exotic pathogens wiping out entire stands of giant Congaree sweetgums, or some bug or blight killing what remains of the park’s virgin bald cypress, some perhaps more than a thousand years old.
Change, even in nature’s most pristine and remote places, is inevitable and unavoidable. But the unprecedented scope of foreign, accidental introductions as a result of our increasingly interconnected world, coupled with rapid climate change, threaten to overwhelm native forests and ecosystems on an unprecedented scale. We must move beyond the academic stage to confront this crisis and recognize that it will take widespread public support and funding to combat it.