All organisms serve a purpose within their ecosystems. The Venus flytrap (Dionaea muscipula) is native to the coastal Carolinas, where it is a pioneer species following wildfires. All plants need nitrogen to grow. Fire releases an ecosystem’s nitrogen into the atmosphere. Nitrogen is the most abundant gas, but plants can’t access inert atmospheric nitrogen. Soil bacteria “fix” nitrogen into water-soluble compounds absorbed by roots. Venus flytrap captures nitrogen from insects as well as bacteria, so flytraps quickly return to recovering ecosystems.
The flytrap's life cycle and ecosystem maturity (succession stage) influences the amount of nitrogen that flytraps capture from insects. After a fire, insects provide 75 percent of nitrogen for flytraps of any age or size. For seedling flytraps to thrive, they must capture enough nitrogen to rapidly grow six leaves, which doubles their trap area and allows them to capture larger insects. As other plants return, they overtop and shade flytraps and slow their growth. A mature flytrap in a recovered ecosystem captures only 46 percent of its nitrogen from insects. When the ecosystem is completely mature, flytraps may be few or absent.
The Venus flytrap's natural habitat is bog-adjacent to savanna developed on the Cape Fear Arch, a continental shelf formation of sand and limestone that was uplifted during the Cretaceous period, 35 to 45 million years ago. Cape Fear Arch follows the coastline 250 miles from Cape Lookout National Seashore, North Carolina to Cape Romain National Wildlife Refuge, South Carolina. At its northernmost range, Venus flytraps may be found as far as 90 miles inland, near Fayetteville, North Carolina.
The Cape Fear Arch savanna includes areas of pocosin (shrub bog) habitats. Flytraps prefer sites where forest and grassland burns intrude into bogs. Prior to human habitation, the bogs were exposed to brief, relatively cool burns every five to 30 years during droughts.
Venus flytraps especially thrive on the moist soils of specific microhabitats: hollow depressions without sphagnum moss, small hummocks of soil around the base of shrubs without sphagnum moss, and mats of sphagnum molle or sphagnum tenerum. Seedlings are more numerous in hollows and mature adults are more numerous on mosses. About 75 percent of flytrap sites have some Sphagnum, which frequently dies back due to drought and heat during Carolina summers. Clear-cut logging sites, man-made firebreaks and environments damaged by roads and vehicles are also pioneered by Venus flytrap. Suppression of wildfire is reducing flytrap habitat.
Summer temperatures in coastal South Carolina can exceed 100 F and winters have only a brief season when short frosts are possible. Early settlers’ descriptions of the historic longleaf pine forests suggest that native Carolinians routinely burned the understory to create forage for deer and convenient hunting grounds. Longleaf pine and associated bunch grasses in Carolina have fire-dependent life cycles. Venus flytrap evolved fire dependent characters: Flytrap thrives in bright sunlight in open spaces, is fire resistant, can re-grow from rhizomes and becomes hardier after fire.