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Magazine Articles

Killer Instincts

November/December 2013

Photographs by Christian Ziegler

Insects have nowhere to hide in the Green Swamp Preserve, home to one of the most diverse carnivorous plant populations in the world.

On January 24, 1760, Arthur Dobbs, the colonial governor of North Carolina and an amateur scientist, sent a letter to an esteemed botanist in London regarding "The Great Wonder of the Vegetable Kingdom."

Found in the swamps of southeastern North Carolina and northern South Carolina, the dwarf plant that Dobbs marveled at bore white, star-shaped flowers. But its most remarkable feature was the plant’s paired concave leaves, which folded shut like a set of jaws.

“Upon any thing touching the leaves or falling between them,” Dobbs wrote in the first known description of this species, “they instantly close like a spring trap, and confine any insect or any thing that falls between them.” Considering the diminutive size of the plant’s potential victims, Dobbs christened it a “flytrap.” The Venus’ flytrap would be the first carnivorous plant recognized in the world, upturning the food chain and astounding the scientific community.

This particular botanical rarity exists in the wild only within a 90-mile radius of Wilmington, North Carolina, where acidic, nitrogen-poor soils have created a niche for carnivorous plants that feast on insect protein. The flytrap shares the coastal low country with a slew of meat eaters, including slender pitcher plants, bladderworts, butterworts and alien-looking sundews.

Forest plantations and residential development have destroyed or fragmented much of this unique habitat, and poaching has further reduced Venus’ flytrap numbers. At least 70 percent of the populations monitored by the state disappeared between 1982 and 2002. To stave off encroachment, The Nature Conservancy established the Green Swamp Preserve, one of the largest contiguous protected habitats for carnivorous plants, about half an hour west of Wilmington. There are 14 species of carnivorous plants here. The preserve also provides a home to 18 species of orchids, such as the rosebud orchid and ladies’ tresses. In addition, the Conservancy owns a smaller preserve near the Marine Corps’ Camp LeJeune, and local staff help maintain other state-owned lands where carnivorous plants thrive.

Green Swamp Preserve is “one the last big holdouts for Venus’ flytraps,” says James Luken, a plant ecologist at Coastal Carolina University in Conway, South Carolina. “It is absolutely critical.”

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The sundew’s flexible tentacles secrete sweet, gooey droplets to attract, capture, coat and suffocate unlucky visitors within minutes, making it one of the Green Swamp’s quicker killer plants. Botanists have tallied more than 600 species of carnivorous plants around the world, most of which thrive in areas where soils are nutrient-poor. While carnivorous plants can often survive without consuming insects, predation provides a dietary supplement. The Green Swamp Preserve is remarkable for having 14 distinct species of carnivorous plants packed into a relatively small area. © Christian Ziegler

The first thing a visitor will notice about Green Swamp is that it’s not really a swamp in the mold of, say, Florida’s Everglades. The area’s pocosin wetlands have sandy, peaty soils. The 17,424-acre preserve, established in 1977, also contains some of the Southeast’s last remaining longleaf pine savannas. This ecosystem—which once covered 30 million acres from Florida to Texas—has been almost entirely cleared or replaced by plantations of faster-growing loblolly pine and commercial and agricultural development. The interface of the savanna and the pocosin is the magical place where the meat-eating plants thrive.

Scientists have long been fascinated by carnivorous plants’ unorthodox feeding strategy. By releasing a sweet odor, they entice insects, such as flies and beetles, to land on their deceptive leaves. In the case of pitcher plants, the bugs lose their footing on fine hairs inside the plant’s trumpet and slip down toward their demise. For flytraps, if an insect triggers hairs on the leaf’s surface, then the jaws snap shut in a 10th of a second—making it one of the fastest plant movements on the planet. The plants then secrete chemicals that help slowly digest the insect’s nutrients.

Despite their reputation, carnivorous plants are actually quite vulnerable. During a recent visit to the Green Swamp, conservation coordinator Sara Babin pointed out dozens of tiny holes in the soil where poachers had extracted the plants for illegal sale to nurseries. The Conservancy has worked with local law enforcement to stop poachers, with limited success. Even though they can be easily cultivated, carnivorous plants continue to be taken for quick, cheap sale.

Frank Galloway, a local landowner who dates his family’s arrival in North Carolina back to the era when Dobbs was governor, has been working with the Conservancy for years. “If it weren’t for that organization,” he says, “a lot of these plants would have disappeared.” With the preservation of Venus’ flytrap habitat, these rare and hungry plants that once confounded Victorian-era naturalists and later inspired a book by Charles Darwin can continue to capture human imaginations—as well as insect prey.

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Charles Darwin and other early researchers observed that the jaws of the flytrap do not shut completely when triggered; their interlocking teeth leave a gap large enough for small insects to escape. When Darwin examined the carcasses of insects trapped in the jaws, he realized that the plants were being selective about their prey by targeting larger bugs. © Christian Ziegler