Barrier Island Ecology of Cape Lookout National Seashore and Vicinity, North Carolina
NPS Scientific Monograph No. 9
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The use of vehicles on the Outer Banks has other environmental consequences. One is positive: the tracks on the beach often catch wind blown seeds and start long double lines of Uniola paniculata and Spartina patens, some of which may become. dunes (Fig. 119). The seeds of Uniola, in particular, require burial before they can germinate (Wagner 1964) and when blown into the tracks are soon covered over by drifting sand. Another effect is not so desirable. Sand roads cut deeply into the grassland, and if they lead from the beach straight back to the sound, they serve as channels for excessive overwash (Fig. 120). High water which would otherwise have spread out harmlessly over the grassland becomes a torrent in the channel and sometimes badly erodes the island surface (Figs. 121 and 122). Uncontrolled vehicular use in dune areas can lead to destruction of vegetation and increase the rate at which the dunes migrate. Running vehicles on the beach can play havoc with shorebirds and other organisms that depend on the beach system for their livelihood. Heavily used beaches have few nesting shorebirds since the birds require a certain degree of solitude to raise young. Where vehicles constantly churn up the sand, there may also be significant changes in the functioning of the beach ecosystem, which includes innumerable, minute interstitial organisms as described earlier. We note that ghost crabs are commonly seen foraging in the daytime on the relatively wild beaches of Cape Lookout National Seashore, while doing so only at night on Bogue Banks and Cape Hatteras. Such behavioral differences may be the result of human interference.

Fig. 119. Young Uniola plants from seeds trapped in car tracks.

Fig. 120. This road running at right angles to the Core Banks beach became an overwash channel during Hurricane Doria in 1971.

Fig. 121. The same road, with downcutting by the channelized overwash.

Fig. 122. The other end of the road. The water broke through a dune line and pushed sand into Barden Inlet.

Solid waste is a problem on all the islands. The attitude of many visitors toward pop bottles and beer cans is "the sea will take care of it," and heaps of nonbiodegradable containers are left wherever they are emptied. Even if visitors would properly dispose of their rubbish, every drift line on the islands contains quantities of trash washed up with the dead eelgrass and Spartina. Some of this has been thrown overboard from boats, which are hard to police. More comes from dumps on the mainland. Salt marshes are a favorite site for rubbish disposal, and a high tide floats the trash out into the sounds and distributes it along the Outer Banks. If the Cape Lookout islands are to be kept safe and presentable, the National Park Service will have to employ crews to pick up trash for the foreseeable future.

Various permanent installations on the islands have been sources of solid waste. The more remote outposts simply dumped trash among the sand dunes, whence it was scattered about by every overwash. Noticeable pollution has also resulted from careless disposal of waste lubricating oil. In addition, oil pollution from ships at sea is becoming a problem of increasing concern. On numerous occasions we have found oiled sea birds dying on the beach and nearly every walk along the beaches turns up globs of solidified oil. If offshore oil production in this region becomes a reality, the hazards of pollution on the Outer Banks will be greatly increased.

Dredging to improve navigation in the sounds generally serves a useful purpose, although if a new channel is dug parallel to the back side of the islands and close to the marsh edge, new marsh growth into the sound is stopped and marsh erosion is encouraged. Another apparent difficulty with channel dredging is illustrated in Barden Inlet, which opened in 1933 and has been dredged ever since. The navigation channel is aimed directly at the back side of Core Banks, following the natural deep-water channel which is migrating into Core Banks, and thence out to the mouth of the inlet. Due to the natural tendency of flowing water to meander, outgoing tides are tearing away the island behind the lighthouse and the dredging probably exacerbates this problem (Fig. 123). Cape Lookout Lighthouse (Fig. 124) is perhaps in more danger of falling into the water from the sound side than from the ocean side, as the channel keeps moving toward the lighthouse at a rate of about 20 ft (6 m) per year, clearly an untenable situation (Fig. 125).

Fig. 123. Barden Inlet, October 1965, with a dredged channel aimed at the lighthouse. Superimposed is the 1942 shoreline.

Fig. 124. The resultant eroding shore of Barden Inlet.

Fig. 125. (A) The land end of the dock in the preceding figure, 1970. (B) The same in 1971, with considerable further erosion.

Any type of dredging increases the turbidity of the water, cutting down photosynthesis and giving filter-feeding invertebrates more silt load with which to cope (Fig. 126). In the past, dredge spoil has often been dumped on the nearest salt marsh, obviously a bad practice ecologically, but recently more constructive uses for it have been found. Spoil that was made into small islands, which now have low dunes and vegetation, is being used as rookeries by gulls, terns, skimmers, and herons in the Barden Inlet area (Fig. 127). Many similar spoil islands are becoming important rookeries as former beach habitat on the Outer Banks is disturbed, modified, or destroyed by human activities. If spoil is spread out at the correct intertidal elevation, it may be planted with Spartina alterniflora and will speedily become healthy salt marsh. This has been done successfully in The Straits behind Harker's Island (Fig. 128).

Fig. 126. A dredging operation in Carteret County, filling part of the estuary and making the rest turbid.

Fig. 127. The Harker's Island-to-Cape Lookout channel. The spoil islands flanking it are important bird rookeries.

Fig. 128. (A) In 1970, the island being created in Fig. 126 was experimentally planted with Spartina alterniflora by scientists from North Carolina State University and the National Park Service. (B) The same in 1971, showing the successful growth of the grass.

One positive aspect of man's presence on the islands has been the new habitat created by jetties and docks. The rocks and pilings are a solid substrate for numerous interesting marine creatures which require it and which would otherwise be very rare in North Carolina waters (Figs. 129-132). The fishing is good in these places, and educational field trips and scientific researchers make continuous use of them. The organisms on jetties and pilings need only to be protected from overly predatory SCUBA divers.

Fig. 129. Cape Lookout in 1965. The Cape owes its present shape largely to the jetty built in 1915; the former outline is shown by the large dunes visible in the photograph.

Fig. 130. Charts from 1888 and 1965 show the changes in the shape and orientation of Cape Lookout. Compare with Fig. 129.

Fig. 131. Like other jetties in the area, this one on the sound side of Shackleford Banks harbors plant and animal communities which delight marine biologists.

Fig. 132. A sessile community on a piling near Cape Lookout is dominated by barnacles (Balanus amphitrite) and tunicates (Styela plicata).

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Last Updated: 21-Oct-2005