Barrier Island Ecology of Cape Lookout National Seashore and Vicinity, North Carolina
NPS Scientific Monograph No. 9
EFFECTS OF MAN ON THE OUTER BANKS
Human beings probably paid visits to the Outer Banks
as long as the islands have existed. We know little about the activities
of Indians on the Outer Banks, although Indian burial grounds have been
found on Bogue Banks. It seems likely that the other islands were used
as bases for fishing and shellfishing at least at certain times of the
year. The Indians may have set fire to the grasslands at times, but
grassland ecosystems recover quickly from a light burn; in general, the
environmental impact of Indian use of the islands was probably rather
Technological man is another and sadder story. In
colonial times small settlements of fishermen and especially of
livestock raisers developed here and there along the Outer Banks. These
people cut wood for fuel and boat building. This, combined with natural
dune migration and sea-level rise, reduced the forest cover on several
islands. In at least one important respect, however, the early settlers
were more sensible than their modern counterparts; they built their
houses in sheltered sound-side locations rather than on the edge of the
ocean, and were safe from all but the most severe storms without the
help of artificial dunes and dikes (Fig. 96). See Dunbar (1958) and
Holland (1968) for comprehensive treatments of the human history of the
Fig. 96. Portsmouth Village was once the
largest settlement on the North Carolina Outer Banks. The few buildings
remaining were built a sensible distance back from the beach.
Livestock was the main industry; one could turn out
one's sheep, cattle, hogs, and horses on the broad acres of dune grass
and salt marsh without need of fences and know that they were safe from
land-based marauders. Overgrazing apparently became a problem on some of
the Outer Banks and is still troublesome on parts of Shackleford.
Portsmouth Island was considered severely overgrazed as early as 1810
(Dunbar 1958). Local people tell us that before the livestock was
removed from Core Banks in the 1950s, the island was nearly denuded and
the animals were starving. Whether such conditions were due to
overgrazing or to natural processes during that time is difficult to
determine. Nevertheless, grassland ecosystems of Core Banks are healthy
today, illustrating how quickly the islands can recover if allowed to do
so. Portsmouth Island, which has had the longest and most severe grazing
history, seems unfortunately to have been damaged beyond its natural
ability to repair itself. Most of the island is a low, bare flat, awash
with every high tide as were other islands on the Outer Banks (Ocracoke,
Bodie) before dune-building projects were begun in the 1930s; the
land-building processes of overwash and dune formation are not working
here. This is the only one of the undeveloped barrier islands which
might accurately be said to be "washing away." Extreme overgrazing
followed by some bad storms may have been responsible for the present
condition of Portsmouth. On Shackleford Banks there are still herds of
sheep, goats, cows (Fig. 97), and horses, and the damage they do is
evident, yet the conditions of Portsmouth have not developed here. In
the dunes the herds graze selectively on Andropogon scoparius and
also reduce the cover of Uniola paniculata (Fig. 98), but the
worst effects are blowouts and open sand due to trampling, which can
speed up dune movement (Fig. 99). In the maritime forest there is a
distinct browse line on the treesmostly due to the goatsand
tree reproduction is doubtless impaired (Fig. 100). But it is in the
salt marshes that grazing takes its worst toll (Fig. 101). The marshes
are the main feeding ground of the island's horses, and they bite the
Spartina down to within an inch of the mud, which must
significantly reduce estuarine productivity in this locality.
Fig. 97. Feral cattle on Shackleford
Banks, remnants of once large herds.
Fig. 98. Effects of grazing on the
Shackleford dunes; the square area represents an exclosure before the
fencing was stolen. During a year of relief from grazing, the cover
inside the fence increased significantly, particularly
Andropogon, which is selectively grazed.
Fig. 99. The network of paths and
openings among the Shackleford dunes is partly cattle and horse
Fig. 100. The parklike appearance of
Shackleford woods is due to browsing.
Fig. 101. Part of the Shackleford horse
herd and some of the salt marsh they have grazed down to the mud. After
2 years, the standing crop of Spartina alterniflora inside the
exclosure was 30 times that on the outside.
The overall effects of grazing animals on the Outer
Banks are difficult to assess. Some localized areas were undoubtedly
overgrazed and thus livestock were blamed for the "deteriorated"
condition of the entire Outer Banks. Yet, as Dunbar (1958) pointed out,
the peak of grazing pressure exceeded by at least a half century the
period during which the animals were blamed for this alleged
destruction. Indeed, Shackleford Banks, which had extensive moving dunes
at the turn of the century and was never stabilized by human activities,
yet all the while was grazed, now has extensive vegetation cover over
most of the island. Engels (1952) felt that the general nature of the
barrier islands was due primarily to natural forces, and our research
seems to support that view, although localized grazing pressure could
lead to more rapid sand movement than would normally be expected.
Livestock were not the only animals introduced. With
the settlers came the inevitable house mice and rats, as well as a
population of feral cats. The latter doubtless do a service in
controlling the rodents, but certainly prey upon the islands' many
species of ground-nesting birds as well.
Finally, certain game birds and animals, such as
pheasants and raccoons, have been brought to the islands for hunting,
but these seem to have fitted into the island ecosystems without
noticeable dislocation of the systems.
Plants have been introduced on the Outer Banks as
well as animals. The use of Ammophila (whose natural range is
north of Cape Hatteras) as a dune-building grass has already been
mentioned. Populus alba (silverleaf poplar) and
Gaillardia, a colorful composite, were brought in by the settlers
as ornamentals. The poplar survives in scattered locations, especially
in Portsmouth Village and villages on the Hatteras Banks, but the
Gaillardia has spread everywhere. There is no indication that it
has displaced any native species, however, and it performs a
sand-binding service. Loblolly pines and some exotic species of
Pinus were planted in the Cape Lookout area in recent years in a
well-meant attempt to control sand movement. How long they will survive
and how much good they will do are uncertain, but the tracks of the
truck used to plant them are still visible on the grassland and may
remain so for some time (Fig. 102).
Fig. 102. A 1971 photo of Core Banks
showing the tracks of the vehicle used to plant pine trees in 1969.
These tracks will be here for some time.
Modern development of the Outer Banks has usually
proceeded with unfortunate disregard for the dynamics of the environment
(Fig. 103). Houses, motels, roads, and recreational facilities not only
mean inevitable destruction of dunes, woodland, or salt marshes where
they are built (Fig. 104), but they require engineering work for
protection from the sea. The difficulties that arise from building
artificial dunes and from preventing overwash and island migration have
already been discussed. On privately owned sections of Bogue Banks and
elsewhere along the North Carolina coast, developers have leveled the
fore-dune in order to build as close to the sea as possible and have
removed maritime forests to create lots for homes (Fig. 105). The
inevitable result is rapidly moving sand and storm flooding on a part of
the island which grass and trees took years to stabilize. In addition,
exposed trees soon die from salt spray since they are no longer
protected by dunes or seaward vegetation.
Fig. 103. The effects of modern
development on Bogue Banks; contrast with the undeveloped beach in Fig.
Fig. 104. Bogue Banks at Atlantic Beach.
Marshes have been dredged and bays filled for housing developments and
trailer parks. All are vulnerable to a big hurricane.
Fig. 105. Dunes leveled by a developer
on Bogue Banks.
Last Updated: 21-Oct-2005