A guide for planners and managers - IUCN

238 MARINE AND COASTAL
PROTECTED AREAS
Photo by John Clark.
4.5 Barrier Islands
The seacoast of some countries is
edged, in part, by elongated sandy
islands or peninsulas. These “barrier
islands” and “barrier spits” are
mobile, not fixed, geological features.
They grow or shrink in response to
storms and to fluctuations in sea
level, currents, and sediment supply
(Figure II-48). They also may move
inland, seaward, or laterally,
according to changing conditions.
Beach protection often requires control of visitors.
The changes are the net result of
erosion and deposition. The multiple
rows of parallel ridges (inactive dunes) that form the stable structure of barrier
islands are often visible in the patterns of vegetation. While classified as islands they
are functionally the edge of the continental coastline and the beach frontier where
great battles between natural forces often take place. (Clark, 1991)
FIGURE II-48.
The barrier beach at Rio Lagartos in Yucatan, Mexico, was severed by
Hurricane Gilbert in 1988, leaving some houses stranded.
FIGURE II-47.
4.6 Design and Management Guidelines Summary
The natural properties of
barrier islands and their
beaches provide a strikingly
unique combination of values.
A typical barrier island—with its
ocean beach, sometimes junglelike
interior, and broad expanse
of marsh—has scenic qualities
unequalled in the coastal zone.
Barrier islands enclose and
protect lagoon and estuary
resources and provide habitat
and food for hundreds of
species of coastal birds, fish,
shellfish, reptiles and mammals.
The major design and management considerations for beach MPAs may involve the
following: 1) species protection, 2) habitat protection, 3) erosion protection, 4) visitor
control and safety, 5) visitor facilities and interpretation (Figure II-49), and 6) MPA
boundaries. A summary of guidelines for these considerations is presented below.
Photo by John Clark.