Background
When
students think about a beach, one of the last habitats they would think of is a
desert because of all the "water, water everywhere". However, in many
ways, the dune and upper beach habitats are very similar to a desert. The
stresses of high temperatures on the sand, intense sunlight, wind, salt spray,
and dry soils demand special adaptations.
Plants on the dunes share some of the typical desert plant adaptations. Many of
the plants have reduced leaves, waxy coatings over the leaves, succulent stems
and leaves, or tiny hairs or spines covering the leaf surfaces. The plants also
have specialized root systems, often running deep and wide to collect water from
the porous sand. These adaptations are most noticeable among the primary dune
plants, such as sea rocket, Russian thistle, and sand bur. Even the shrubs of
the dunes, bayberry and wax myrtle, have waxy leaves. Occasionally, prickly pear
cactus and yucca plants growing in the dunes are obvious reminders of the desert
habitat.
Animals living among the dunes must also cope with the desert-like environment.
One of the best ways to get away from the intense sun and heat is to dig into
the sand. The ant lion digs in the sand without reinforcing the sides of its
hole, which becomes a funnel. Prey then slide down the sides of the funnel into
the waiting jaws of the ant lion. Other digging animals do reinforce their
holes: the ghosty crab with special secretions and the wolf spider with a
modified web. Blow gently across the surface of one of these holes to see the
web.
Some dune animals, like ghost crabs, have light body color which serves as
camouflage and reduces absorption of heat from sun. Some have hairs, which, in
addition to acting as sensory adaptations, help reflect the suns's rays. Many
dune animals are crepuscular (active at dawn and dusk) or nocturnal (active at
night), and thereby avoid the heat of the day.
Anyone who has walked across the hot sand barefoot during the summer realizes
the great effect the temperature might have on beach and dune inhabitants. By
measuring differences in temperature along the beach and dunes and by observing
plants and animals living there, students can gain a better appreciation for the
environmental stresses and the special adaptations which allow these organisms
to survive in their habitat.
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Photo
contributions courtesy of Gloria M. of http://members.tripod.com/~GloryM/index-3.html
Tell the class that this animal might like sand. Ask them why? Ask will it be found in the desert sand or the ocean beach sand habitat?
Ask them if they have ever seen or felt the fur of a tortoise.
This is a bunny. Is it a desert or an ocean sand dweller?
Ask them why or why not a rattlesnake likes sand?
Ask the pupils if this lizard lives in the desert sand or the ocean beach sand habitat.
These photos can be found at http://www.desertgold.com/park/parklife.html
This is a picture of a cactus plant known as the "Old Man." Ask pupils why it might have such a name.
This is a picture of a cactus plant known as the "Hedgehog Cactus." Ask pupils why it might have such a name.
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