Wolves in Yellowstone Park - Mr. Lucelucemath.weebly.com/.../wolves_in_yellowstone_park.pdf ·...
Transcript of Wolves in Yellowstone Park - Mr. Lucelucemath.weebly.com/.../wolves_in_yellowstone_park.pdf ·...
Yellowstone: A National Park
In 1872, Yellowstone (in the state of Wyoming) was
declared the first national park in the United States.
Geologic Wonders
Yellowstone is famous for its beautiful geologic
features: hot springs, mountains, lakes, and forests.
The Beauty of Nature
But people also came to Yellowstone park to enjoy
the beautiful plants and peaceful animals, like elk.
Predators and Prey
Wolves eat elk. Some people were upset that the
beautiful elk were being eaten by the wolves.
Get Rid of the Wolves
The U.S. government gave permission to hunters to
kill the wolves. By 1926, all the wolves were gone.
Do We Need Wolves?
The park officials thought they were helping. They didn’t
understand that wolves are important to the ecosystem.
What do you think happened?
What do YOU think happened when the wolves were
gone? Write one prediction on your answer sheet.
Cause / Effect Flow Chart
Now, as you read the next section, fill in the
cause & effect chart to show what happened to
the Yellowstone ecosystem after the wolves
were gone.
Effects on Elk
With the wolves gone, the elk population grew too quickly. Thousands of elk starved because there was not enough food to feed them all.
Too Many Elk!
There were too many elk. Park rangers finally had to
shoot and kill the elk, to keep their population down.
Too Many Coyotes!
Wolves are natural predators of coyotes. When the wolves left, the coyote population also grew.
Effect on Smaller Predators
The coyotes ate too many small animals, which other
predators in Yellowstone (like foxes and badgers) eat.
Effects on Foxes and Badgers
The foxes and badgers populations decreased,
because the coyotes were taking all of their food.
Effeccts on Pronghorn Deer
Coyotes also eat baby Pronghorn deer. The
Pronghorn population declined and almost disappeared.
Effects on Trees
Plants were also affected. Elk love to eat saplings
(young trees) like aspen, cottonwood, and willow trees.
Effects on Birds
Too many elk ate the saplings, so there were fewer
trees. This means that were fewer homes for the
birds that lived in the trees.
No Homes for Birds!
The bird population of Yellowstone decreased,
because there was no place for them to live.
Effects on Beavers
Beavers eat trees. As the trees disappeared
(eaten by the elk), so did the beavers.
The Ponds Disappear
Beavers build dams that form ponds. Fewer beavers meant no ponds, and this meant no homes for the dragonflies and ducks that lived in the ponds.
Can the Problem Be Solved?
The park rangers finally realized they had a big problem.
They decided that maybe wolves needed to come back.
Cause / Effect Flow Chart
Now, as you read the next sections, fill in the cause &
effect chart to show what happened to the
Yellowstone ecosystem after the wolves came back.
Wolf Prey
The wolf packs quickly spread out and began
hunting for their favorite foods – elk and coyote.
Wolf Population Grows
With lots of elk and coyote to eat, the
wolf population grew quickly. There are
now about 150 wolves in the park.
Effect on Coyotes
Wolves hunted and killed about half of the coyotes.
Now, the coyotes stay away from the wolves.
Effect on Pronghorn Deer
With fewer coyotes, more Pronghorn fawns are able
to survive. The Pronghorn population is growing!
Effect on Smaller Predators
With fewer coyotes, smaller predators such as
foxes, owls, and badgers, now have food to eat.
Effect on Elk
The wolves are also helping to control the elk
population. Now, there are not as many starving elk.
Effect on Trees
Because there are less elk eating the trees,
the trees are starting to grow big and tall again.
Effect on Birds
With more trees, there are more homes for
birds. The birds are coming back to Yellowstone.
Effect on Ponds
The beavers are building dams again, creating
ponds that dragonflies and ducks can live in.
Why are wolves important?
But now we know that wolves NEED to hunt their
prey, or there will be too many prey animals.
Wolves affect the ecosystem.
When the wolves were gone, it affected many,
many other organisms – animals and plants both.
A Healthy Ecosystem Again!
Now that the wolves are back, the
Yellowstone ecosystem is getting back into
balance. It is becoming healthy again!
ALL organisms are important.
EVERY organism in an ecosystem is important.
EVERY organism affects the ecosystem community.