role, and attempts to regulate their use, appears in 
the section ‘“‘Protection of Coastal Wetlands.” 
Islands 
Within the United States are an estimated 26,325 
islands greater than 10 acres in size.’ Alaska con- 
tains much of the acreage in the Nation’s island 
estate—with over 6,000 islands accounting for 21 
million acres of the 28.6-million-acre total. The 
other 20,000 islands contain 7.5 million acres. 
Islands are extremely susceptible to damage, par- 
ticularly on the Atlantic and the Gulf Coasts where 
barrier islands protect the mainland from storms and 
waves. These islands are noted for their broad 
beaches and natural beauty, which attract recrea- 
tionists and developers. The instability of the islands, 
which tend to gain and lose area through natural 
processes, makes them vulnerable to storm damage. 
Barrier islands are invaluable because they, rather 
than the mainland shores, absorb the shock of off- 
shore storms. 
Attempts to stabilize barrier islands have proven 
futile, as demonstrated by the National Park Serv- 
ice’s (NPS) efforts on the Outer Banks of North 
Carolina. For years, NPS attempted to stabilize the 
narrow, sand islands that separate the ocean from 
large bays. It recently announced its discontinuance 
of efforts to stabilize the islands and acknowledged 
that it is inevitable that the barrier islands will 
change shape because of winds, waves, and storms. 
The Army Corps of Engineers has also become more 
reluctant to embark on large projects for shoreline 
stabilization. 
The value of the Nation’s barrier islands was 
highlighted in President Carter’s environmental mes- 
sage on May 23, 1977, in which he noted that 68 
barrier islands remain in relatively unspoiled condi- 
tion.* However, many of the islands are privately 
owned and subject only to the normal controls im- 
posed by the States and the Federal Government, 
such as wetland regulations or dune controls. In 
many instances, private ownership and _ privately 
controlled developments serve to preserve the island 
habitat by restricting general public access. 
Dunes 
Similar to barrier islands offshore, dunes serve to 
protect inshore areas from storm waters. Deposits 
of beach sand form a berm: that stabilizes the en- 
croachment of grasses and xeric plants. The dune 
system on a barrier island consists of two parallel 
lines of dunes. The oceanside dune is the first line 
of storm defense and is most susceptible to change 
from natural processes. The secondary landward 
5 U.S. Department of the Interior, Islands of America. Wash- 
ington, D.C., 1970, p. 6. 
6 US. Office of the President. President’s Environmental Mes- 
sage, May 23, 1977. . 
dune line grades into forested areas inland. 
Because these windrows of stabilized sand are 
important to the protection of the inland area, the 
alteration of dunes by construction or as the result 
of the gradual destruction of the stabilizing plants 
can lead to serious consequences. Wholesale destruc- 
tion of dune vegetation has resulted from excessive 
use of vehicles and trampling by animals and 
humans. In addition, because of their location on 
high ground overlooking the beach, dunes are prime 
areas for residential and commercial development. 
Estuaries ; 
Estuaries are the mixing zones between the salt- 
water of the ocean and the freshwater carried by 
inland tributaries. It is a zone of enrichment and is 
highly interactive chemically and biologically. Estu- 
aries are distinguished from bays and embayments 
by the degree of enclosure and the characteristics 
of the physical processes occurring within. Clark has 
suggested that estuaries, to be classified as such, 
must have a shoreline length in excess of three times 
the width of its outlet to the sea.” 
The distinguishing feature of estuaries, however, 
is their role as a mixing area for fresh- and salt- 
water. Fresh inland water carries nutrients, sedi- 
ments, minerals, organic matter, and contaminants. 
The interface of fresh- and saltwaters is highly pro- 
ductive, and, coupled with the influence of the adja- 
cent wetlands, creates a rich and diverse eco- 
system. Estuarine waters are often shallow and thus 
permit penetration of sunlight through a rich photo- 
synthetic layer. Such conditions produce large 
amounts of plankton and benthic organisms that 
serve a vital role in maintaining the food chains of 
finfish and shellfish. It is estimated that within their 
life cycles three quarters of the domestic commercial 
fish at some time live in the Atlantic and Gulf 
estuaries. 
Estuaries are nursery areas for a number of fish 
species. Among these are pink shrimp of the Gulf 
of Mexico, channel bass, striped bass, bluefish, 
croakers, mackerel, and menhaden. Destruction of 
the wetlands, reductions in inflow of freshwater, ex- 
cessive sedimentation, or pollution of the estuarine 
system by toxic substances impair the productivity of 
the ecosystem, thereby affecting fish populations 
and commercial and recreational harvest. Thus, the 
estuarine environment may be damaged by events 
that occur at great distances inland or at the head of 
tributaries. Estuarine systems generally are resilient 
to environmental damage, yet thresholds can be 
exceeded with disastrous effects. The greatest threat 
may be the chronic degradation of the estuarine en- 
vironment through the cumulative impacts of pollu- 
tion and gradual alteration of the adjacent wetlands. 
7John Clark. Coastal Ecosystems. Washington, D.C., Con- 
servation Foundation, 1974, p. 2. 
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