South Carolina struggles with “alien” invaders
|By Mary Elizabeth Williams-Villano|
Invasive plant and animal species are wreaking havoc on the state’s native plants.
It’s not a story from the new “Twilight Zone” series, but aliens are involved. “Alien” is the term some researchers use to describe invasive species, and according to a story in the Charleston Post and Courier, a variety of alien flora and fauna are wreaking havoc on the state’s ecology.
One such invader, a beetle, has reportedly stripped bare nearly every large red bay laurel tree, known to the state’s residents as the “evergreen of the coast.” Their decimation was accomplished in less than 20 years. The second most prevalent hardwood in the state, common sweet gum is at high risk if “a certain Asian beetle” crosses its borders.
Invasive species problem are a leading cause of the extinction of native plants and animals around the world and are becoming more of a threat to plants and wildlife in the Palmetto State.
A recent study of 953 extinct species by University College London in England found one-third of the species were lost partly to invasive species, and 126 of those entirely because of invasive species.
“The invasion of an alien species is often enough to cause native species to go extinct,” says bioscientist Tim Blackburn, the study’s lead researcher.
More than 150 “aliens” have been discovered in the states’ freshwater streams and lakes alone. Tropical lionfish are all over the sea bottom offshore, preying on sought-after grouper and snapper.
On land, invasive feral hogs root up forest plant communities. And out-compete other wildlife for food. They can deplete acorns and nuts faster than native deer and turkeys can get to them.
Red fire ants marched north into the state decades ago, after accidentally being imported into Alabama in the 1930s.
Phragmites, tall-growing reeds that choke out native food plants, can wreck a coastal wetlands ecosystem. That’s already happening in stretches of Winyah Bay near Georgetown and other waterways.
The story states that Jeff Jackson of the S.C. Native Plant Society and a Charleston landscaper has seen a Chinese wisteria plant in the Sullivan’s Island maritime forest kill a live oak tree that was two feet wide at the trunk. He’s seen river bottoms completely covered with invasive privet shrub, strangling out native bottom food sources.
Researchers at Clemson University say that 42 percent of the nation’s endangered and threatened species have declined as a result of encroaching exotic invasives. The economic impact of these invaders is estimated at $138 billion per year.
About 30 native plant and animal species found in the state are considered endangered. Another 18 are labeled threatened and hundreds more are considered to be “species of concern.” They include one-of-a-kind plants such as the Venus fly trap.
Life has been harder for native species due to the increase in global transport, climate change and loss of habitat, particularly for those that are less adaptable and require very specific habitats. As they weaken, they’re more prone to be overrun by invasives.
“It absolutely could get worse,” the story quotes David Jenkins, the S.C. Forestry Commission’s forest health coordinator, as saying.
Happily, there is some good news. The article says that South Carolina, with its many forests, riverlands and coastal wetlands is doing better than many places when it comes to holding onto its native species. And a number of efforts are underway to try to control the alien invaders.
Herbicides are being used to battle phragmites, and foresters will isolate an infested area by thinning trees and cutting breaks between sick and healthy red bays. Divers have been harvesting lionfish for the seafood market; it turns out that humans consider them good eating. And, the state has virtally declared an open hunting season on the feral hogs.