e a s h o r e l i f e o f f e r s e n d l e s s o p p o r t u n i t y f o r
d i s c o v e r y , e s p e c i a l l y t o t h o s e c u r i o u s e n o u g h
t o o b s e r v e t h e h a p p e n i n g s o n a n d a r o u n d a
b a r r i e r i s l a n d b e a c h t h a t p r o v i d e s w o n d r o u s p l a c e s f o r
d i s c o v e r y , w h e t h e r i t ’ s a w r a c k l i n e w h e r e t h e s t r o n g e s t
w a v e s d e p o s i t s h e l l s , s e a w e e d a n d d r i f t w o o d h i g h u p
t h e b e a c h , o r t h e s h a l l o w p o o l s t h a t f o r m i n t h e s a n d
b e t w e e n h i g h a n d l o w t i d e l i n e s .
This is the place of dunes and swales, where sea breezes sweep beach sand into
neatly mounded rows that run the length of the island.
The dunes are grown-over with tall sea oats, a grass adapted to the rigors of life in
heat and sunshine made more difficult by salty spray carried off the ocean, sometimes
by fierce winds. Sea oats grow through constantly shifting sand, from tough under-ground
rhizomes held in place by dense mats of fibrous roots reaching deep into the
sand in search of moisture. Sea oat leaves and flower stalks trap wind-blown sand
grains, causing the dunes to grow ever taller.
Between the dunes are low areas called swales. Swale habitats are relatively sheltered
places that support a greater variety of plant life, including the yucca and cactus,
along with salt-sculpted yaupon and cedar, all woven together by dense tangles of
thorny greenbrier vines. These vegetated patches are edged by a collection of wild-flowers
including Indian blanket, also called gaillardia, along with silverleaf croton,
which really has silvery-green leaves, and in autumn clumps of tall goldenrod plants
with bright yellow flowers that are a favorite source of nectar for butterflies and other
insects.
Once through the dunes and swales, the sound of wind and waves guide the
beachgoer to the most dynamic habitat on the coast, the open beach, but not before
crossing the high tide wrack line where the strongest waves deposit whatever the sea
brings to shore, including marine algae, driftwood and seashells. Poking about in this
material will often reveal little crescent-shaped animals the size of rice grains called
amphipods. These relatives of shrimp hide under seaweed and other sheltering objects
and hop about when disturbed, earning them the common name sand hopper or
beach flea. They are harmless and difficult to catch.
Flies and other insects may also hide in the wrack line. Some are food for the tiger
beetle seen running and flying up and down the beach. The tiger beetle is so-named
because it is a fierce predator of other insects. Tiger beetles chase down and eat biting
flies that bother beachgoers, especially when winds blow from the west.
Wrack lines are fun to explore, but to complete your barrier island journey you’ll
need to visit the surf zone where ocean waves break into foamy tumults that stir up
sand, push shells around and send countless little animals into frenzied motion. In this
narrow zone where ocean water sweeps up and down with each passing wave, you’ll
see small fish darting to and fro, staying with the water as it recedes back to the sea.
Some may be young fish that, once large enough, will move offshore to live as much
larger adults; pompano, permit and flounder are among the commonest in this group.
Another group of fish that spends an entire lifetime in and around nearshore
waters is the striped killifish, especially adapted to the turmoil of swirling ocean beach
waves. Killifish are tough little animals. Not only does this fish need to keep track of
where the waves are taking it up the beach, it must be prepared to flee from surf-zone
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WBM september 2012