This Month in Science: Biodiversity of the Cape Fear

The Cape Fear region is one of the most biodiverse areas along the Atlantic Coast, meaning it has a wide variety of biologically distinct plant and animal species. In 2016, the North American Coastal Plain, an area of land that stretches from northern Mexico to southern Maine, was designated a Global Biodiversity Hotspot. A Global Biodiversity Hotspot is defined as a region with at least 1,500 endemic species of plants and greater than 70% loss of primary native vegetation. There are only 36 hotspots recognized around the world, and the Cape Fear region is part of one. The high level of biodiversity in the Cape Fear is a by-product of the unique geology and variety of natural environments present in the region.

Biodiversity is a measure of the overall health of an ecosystem. An ecosystem, sometimes called a natural community, is an interconnected network of the living things in a specific area interacting with the surrounding physical environment. The presence of a wider variety of plant and animal species makes an ecosystem more resilient to changes in the environment. Natural disasters, such as forest fires, hurricanes, drought, flooding, or disease, can be catastrophic to a community lacking biodiversity. While some species may be severely depleted or wiped out by such an event, there is a higher likelihood that other species have adapted to survive and regrow in a biodiverse region.

The Cape Fear region consists of seven counties: New Hanover, Pender, Brunswick, Duplin, Onslow, Columbus, and Bladen. These seven counties contain a total of 298 different species, 19 of which are endangered or threatened, and 63 that are protected by the state. In addition, 22 plant and 19 animal species are endemic—meaning they exist in a specific geographic location and nowhere else on earth. The Venus flytrap is one of the most well-known endemic plants. The biodiversity of our region is thought to be caused, in part, by a unique geological feature that spans the Cape Fear Region known as the Cape Fear Arch. The Arch has a slightly higher elevation than its neighboring coastal areas to the north and south, but the name has more to do with the layers of rock that form the arch, than the physical shape of the formation itself. Although the surface appears flat, it is actually the layers of rock underneath that are arched. Millions of years ago, the land that is now the Arch experienced an uplift. Over time, weather eroded the elevated rock back to the relatively flat land we see today; however, this resulted in the rock layers on top of what was once a physical uplift being older and more compact than the neighboring rock beside it.

Because the Arch is slightly elevated, the region has been above sea level for a longer period of time relative to the surrounding landscape. In the distant past, the Arch was a peninsula when the rest of the coastal plain existed underwater. As a result of this unique feature, both wet and dry habitats emerged in the region over time. From wet, marshy Carolina bays, to dry, sandy scrubland, the Arch has many environmentally distinct areas.

Out of 126 natural communities found in North Carolina, 14 of them are found in the Cape Fear. A sampling of the diversity in community types found include the Wet Marl Forest, Coastal Fringe Sandhill, and Cypress Savanna. The Wet Marl Forest is a flat or gently sloping upland area with poor drainage and marl (rock made of soil and lime) or limestone near the surface. Worldwide, this type of forest is only known to exist in Rocky Point, NC, and is home to at least eight rare plant species. Coastal Fringe Sandhills are sandy areas generally a few miles inland from the coast that experience frequent low-intensity (low heat) fires. Cypress Savannas are characterized by clay-based Carolina bays, wet depressions, and an open canopy of cypress trees. This ecosystem is dependent upon flooding and fire and is home to at least 20 rare plant species. Carolina Beach State Park has both Coastal Fringe Sandhill and Cypress Savanna communities. In addition to the three natural communities described here, the Arch has many types of wetland, maritime forest, savanna, flatwood, and sandhill ecosystems.

Biodiversity hotspots are both biologically rich and severely threatened. Protecting, conserving, and, in some cases, restoring biodiversity in an ecosystem is essential to the global health of our planet. To get involved with local conservation efforts, reach out to the Cape Fear Arch Conservation Collaboration or NC Coastal Land Trust. If you’d like to learn more about some of the diverse ecosystems in North Carolina, you can read previous This Month in Science columns about Carolina Bays and Longleaf Pines, and explore Museum Park and the Discovery Gallery exhibit.

 

Previous Columns

December: Snowflakes
November: Carolina Bays
October: The Longleaf Pine
September: Jellyfish
August: What’s in Your Childhood Chemistry Set?
July: What Happened to the Dinosaurs?
June: Hurricane Season
April: Quantum Levitation
March: Venus Flytrap
February: A Shifting Magnetic Field
January 2019: Giant Ground Sloth
December: Snowflakes
November: Citizen Science
October: Parker Solar Probe Voyaging to the Sun
August: Sea Turtle Season
July: Plastic Free July
June 2018: All About Alligators


Biodiversity Hotspots in North America.
Source: The Nature Conservancy

The Cape Fear Arch.
Source: Longleaf Alliance

The Arch has unique geology. Green areas represent older rock layers than surrounding white areas.
Source: East Carolina University, Department of Geological Sciences

A Cypress Savanna in North Carolina.
Source: NCparks.gov

Carolina Beach State Park is an example of a Coastal Fringe Sandhill.
Image Credit: Gerry Dincher
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