Why pocosins are amazing

Pond pine cones, which require heat to open. (W.D. Brush - USDA-NRCS PLANTS Database)

This past week, I’ve been putting a lot of time into writing up material for Part One of my book on red wolves, a lot of the interviewing for this section is being done in the field while I shadow the biologists who work on red wolf recovery. When I was there the week before Halloween, it marked my fourth trip to the red wolf recovery area, and I’m starting to get a deeper feel for the beautiful and diverse landscape where this program takes place. One of the more interesting habitat types that occur in the recovery area is called a “pocosin.” In fact, one of the three National Wildlife Refuges that comprises the public land of the recovery area is called Pocosin Lakes National Wildlife Refuge.

Pocosins, it turns out, are pretty darn wild. They are southeastern shrub bogs. I don’t know why exactly — perhaps it is the sand-in-my-shoes Florida girl in me — but I’ve always had a certain fascination with swamps, wetlands and watery forests. Yes, they can be buggy and muddy, but these habitat are also so productive and full of interesting creatures. So I was so understandably excited to discover this habitat in my adopted state and to find out more about it.

The word “pocosin” comes from the Algonquian Native American language family and it means “swamp on a hill.” Think on that for a second. Most wetlands are found where the land forms shallow depressions and surface water drains to the point of lowest elevation. But the pocosins of eastern North Carolina are in areas of slightly higher elevation. They form when organic vegetative matter, like leaves, pine needles and sticks, become saturated with water and decay over time to form peat. Roughly speaking, it can take 100 years to form a single inch of peat. When these dark, black soils are water-logged, it forms a hypoxic environment devoid of oxygen. The peat acts like a gigantic sponge, soaking up rainfall and then slowly, slowly releasing the water to the lower-lying areas surrounding the shrubby bog. In this way, it regulates the sheet flow of water over vast areas.

In North Carolina, the pocosins in the far east of our state formerly delineated the southern extent of the Great Dismal Swamp, which is now known mostly in Virginia, with about a third of the swamp located in far northeastern North Carolina. But historically, the Great Dismal Swamp would have stretched much farther south and there would have been scattered pocosins as far south as the modern-day Croatan National Forest (at least, possibly even further I think). What I find so interesting about this is that in my research into descriptions of eastern North Carolina by early settlers, I found one anecdote describing wild dogs (possibly wolves) that swam across the Swamps and waterways and sometimes got eaten by alligators. John Lawson, in his book A New Voyage to North Carolina, (1709) wrote of camping in a “percoarson” landscape in what is now southern North Carolina when:

When we were all asleep, in the Beginning of the Night, we were awaken’d with the dismall’st and most hideous Noise that ever peirc’d my Ears: This sudden Surprizal incapacitated us of guessing what this threatening Noise might proceed from; but our Indian Pilot (who knew these parts well) acquainted us that it was customary to hear such Musick along that Swamp-Side, there being endless Numbers of Panthers, Tygers, Wolves, and other Beasts of Prey, which take this Swamp for their abode in the Day, coming in whole Droves to hunt the Deer in the Night, making their frightful Ditty ‘til Day appears, then all is still in other Places. (pg. 32-33) [Note: "Tygers" likely refers to bobcats, which are very common in this area.]

I know I’m blurring the line here between true pocosins and what may have been a flatwoods swamp in this anecdote, but it was so interesting I didn’t want to leave it out. Plus, there’s no reason to think the wolves didn’t use both habitat types. But let’s get back on track with true pocosins. There are two kinds of pocosins: low and high. A low pocosin is characterized by vegetation that grows in a somewhat dwarfed state, while a high pocosin is characterized by vegetation that grows much taller. Here’s the catch: the exact same kinds of plants and trees grow in both a high and a low pocosin. So what gives? Answer: nutrients. Low pocosins have deep layers of peat which can reach ten to fifteen feet in some parts of eastern N.C.; but peat itself doesn’t have many nutrients. So the plants growing here are comparatively limited in their access to nutrients, and they grow more slowly and don’t attain the same stature as their counterparts in the high pocosins. The peat in a high pocosin is generally two feet deep or less, and so the plants can grow their roots past this layer and tap into the nutrient-rich soils underlying the peat. This edge gives them greater growing power. Pretty nifty, eh?

Plants and trees growing in pocosins are usually broad-leved evergreens, like pond pines; red, sweet and loblolly bays; wax myrtle; and greenbriars. Black bear, white-tailed deer, bobcats, raccoons, painted turtles, mink, eastern glass lizards, skinks, southern chorus frogs, southern dusky salamanders, alligators, pygmy rattlesnakes, rainbow snakes, eastern king snakes, river otters, marsh rabbits and yes, even red wolves, use the pocosin habitat. Birds found here include red-cockaded woodpeckers and tons of migratory waterfowl. For a full list of species, check out this PDF of Pocosin wildlife.

Below is a community profile map, copied from a 1982 Fish and Wildlife Service report called The Ecology of Southeastern Shrub Bogs (Pocosins) And Carolina Bays: A Community Profile. The gray shaded areas have natural pocosin habitat, and the dark areas show pocosin that has been ditched and drained to create agricultural land. Much of these areas are still in agriculture, but Pocosin Lakes NWR and the nearby Alligator River NWR are actively trying to restore hydrologic function to the altered and natural pocosin habitat within their boundaries. This involves regulating the water outflowing from a highly developed series of ditches and canals in the pocosin area by holding the water back long enough to allow the soils to become saturated and water-logged once more.

The ditching and draining for agricultural uses has decimated the pocosins, leading the peat to dry out. Some pocosin plants need fire to regenerate — like the pond pine pinecones which only open when heated by fire — but the dried out peat areas burn differently than the water-logged unaltered areas. The dried peat burns deeply, the fire can smolder for weeks or months eight to ten feet below the surface, and catastrophic wildfires can ensue. In 2008-2009, the Evans Road Fire burned 40,704 acres over six months and the braided smoke plumes could be seen billowing into the Atlantic from space. Areas where the peat had oxidized lost substantial amounts of soil cover, leaving trees in a condition known as “stilted” where soil losses of two to four feet left their root wads exposed. In my mind, this is empirical evidence that speaks to the importance of restoring hydrologic function to these amazing pocosin landscapes.

Evans Road Fire, stilted trees. (credit: US Fish and Wildlife Service)

NOTES:
Special thanks to Wendy Stanton, Pocosin Lakes National Wildlife Refuge Biologist, for providing much additional information in an interview.

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