Download KEYSTONE SPECIES KEEP ECOSYSTEMS TOGETHER

KEYSTONE SPECIES KEEP ECOSYSTEMS TOGETHER
Sometimes, one species affects a whole ecosystem—because
of its place in the food web, its behavior, or for some other reason.
These keystone species affect many of the plants and animals living
in an ecosystem. If they disappear, other species may disappear, too,
or their populations may change drastically.
A KEYSTONE SPECIES MAY BE…
VERY LARGE...
An African elephant bulldozes pathways
through forests, changes water holes, and
strips and uproots trees. Tender young shrubs
and grasses grow to replace the trees. They
become fresh, tender food for other species of
animals.
OR VERY SMALL.
A kangaroo rat spends hot desert days in
burrows and comes out at night to eat
mostly grass seeds. When kangaroo rats are
kept out and cannot eat the seeds of big
grasses, some desert shrublands can change
to grasslands.
IT MAY BE A PREDATOR…
IT MAY BE A PREDATOR…
An American alligator digs wide holes that
hold water during dry periods. Fish,
amphibians, and other water life survive in
these holes until rains return. Birds and
mammals gather near them in order to feed
and drink.
OR EVEN A TREE.
The Douglas fir feeds and shelters many
living things. In a fir tree, algae, lichens, and
plants grow on branches; insects burrow in
bark; rodents eat needles or seeds; and birds
nest and feed. After death, the decaying tree
becomes home to still other organisms.