By Clint Calhoun
In nature, one way we differentiate fauna is by their specific feeding choices. Carnivores are meat-eaters, herbivores are plant-eaters, and omnivores eat both plants and animals. We rarely think about how plants feed and we certainly don’t think about them eating other things, at least not in a conventional way, unless we imagine something like Audrey II in The Little Shop of Horrors, but there are carnivorous plants found in many parts of the world. North and South Carolina are home to a multitude of carnivorous plants, including the famous venus flytrap, which is native only to North Carolina. These carnivorous plants are more specifically insectivores, meaning that their primary diet consists of arthropods and microscopic critters.
Carnivorous plants typically grow in bogs and seepage areas in what are basically sterile soils, lacking key nutrients, specifically nitrogen. As a result of this environment these plants have adapted unique feeding mechanisms to capture living nitrogen sources. The majority of our native insectivorous plants are found in the coastal plain in swamps, pocosins, and pine savannas, but because North Carolina (and South Carolina) have such diversity in ecological communities, the western parts of our respective states also can claim there own share of insectivorous plants.
One insectivorous plant that has always been of interest to me is the roundleaf sundew (Drosera rotundifolia). Sundews are somewhat similar to venus flytraps in that they trap their prey using a modified leaf. Sundews have multiple hairs on their spoon-like leaves that contain a drop of mucilaginous substance that serves as both an attractant and sticky deathtrap. The unsuspecting insect is drawn to the plant by the sugary sweetness of the mucilage. Upon contacting the substance, the insect becomes trapped and the leaf slowly engulfs the insect, digesting it in the process. Roundleaf sundew is found in Hickory Nut Gorge, in one known location in Chimney Rock State Park. It may be found in other places, but no one has reported it at this point. I have tried for years to get an opportunity to photograph this plant but lack of preparation prevented it. I have finally reached a point in my life where I am less willing to take unnecessary chances so I decided that I should try to find an easier place to photograph this particular Southern Appalachian endemic.
I was drawn to a place in upstate South Carolina, near the North Carolina/South Carolina state line called the Eva Russell Chandler Natural Heritage Preserve where an interesting cataract bog is located. A cataract bog is associated with streams that flow over granitic outcroppings. These outcroppings are typically dry environments but often have wet seepage areas, and where streams flow over the rock, organic matter will collect, providing a growth medium for specific types of plants, among those are certain types of carnivorous plants. Not only does this preserve have roundleaf sundew but mountain sweet pitcher plants (Sarracenia jonesii) and horned bladderwort (Utricularia cornuta) are also present. Mountain sweet pitcher plant is a federally endangered insectivorous plant that is only found in ten locations in North and South Carolina along the Blue Ridge Escarpment. Pitcher plants, like sundews, have a modified leaf that is basically the shape of a cylinder with a covering over the top. Liquid in the bottom of the “pitcher” contains digestive enzymes and has a sweet scent that draws insects into the pitcher. Once inside, the sides of the pitcher are waxy and slick, preventing the insect from escaping. Once it falls into the sticky soup, it drowns and is digested. Horned bladderworts are also insectivorous, making use of bladders found along their roots that have small trigger hairs. When the hairs are triggered by an aquatic insect, the bladders suck in water along with the insect that triggered the hairs.
I certainly got more than I imagined when I visited the Eva Chandler Preserve. As I mentioned before, my intention was to photograph one specific carnivorous plant, but I was very pleased that I got three for the price of one. I had never seen mountain sweet pitcher plants before, so it was a special privilege to see such a unique plant in what was also a very unique environment.
Southern Appalachian bogs and fens are such unique environments. We don’t often imagine “swamps” in the mountains and bogs and fens don’t necessarily qualify as a swamp. They are wetlands in the true sense of the word but are often found in environments that are the opposite of where we might expect to find a wetland. Fens are not true bogs which are most often found in floodplains or in areas with poor drainage. Fens are the result of groundwater seepage and in the Southern Appalachians are often associated with thin soils and granite domes. Depressions in the domes allow for the collection of sphagnum (peat moss) which holds significant amounts of water, creating bog conditions. The plants found in Southern Appalachian bogs and fens are so unique that bogs themselves have come under federal protection.
Our Southern Appalachians are home to some of the most unusual plants and animals in the world. How often do we just drive or hike through our southern mountains without taking time to pontificate on the things that make our area special. If you would like to learn more about my adventure to Eva Russell Chandler Natural Heritage Preserve, visit my blog at http://clintcalhounadventures.blogspot.com for a detailed account. Until next time!
Clint Calhoun is a naturalist and biologist and has worked in Hickory Nut Gorge for over 20 years. He is currently the Environmental Management Officer for the Town of Lake Lure.