Hunting Patterns of Wolves Change Yellowstone Ecology
The U.S. Fish
& Wildlife Service 1987 Northern Rocky Mountain Wolf Recovery Plan
proposed reintroduction of an "experimental population" of wolves into
Yellowstone. In a report to Congress, scientists from the University of Wyoming
predicted reductions of elk (15%-25%), bison (5%-15%), moose (10%-15%), and mule
deer (20%-30%) could result from wolf restoration in Yellowstone.
Minor effects were predicted for grizzly bears and mountain lions.
Coyotes probably would decline and red foxes probably would increase.
The reintroduction of
wolves to Yellowstone National Park 10 years ago has greatly changed the
park’s ecosystem. Over the last decade, the wolf population has grown from 31
gray wolves, to about 130 wolves that roam the park in 13 packs.
Wolves have reduced the
size of the elk population, as well as altered the movement of herds, forcing
the animals to continuously seek safer regions of the park to graze. With the
redistribution and lower population of elk, vegetation has begun to flourish in
certain areas, which in turn allows other wildlife populations to swell. Willow
and cottonwoods stabilize streams, increasing the amount of trout. Beavers that
feed on willow and aspen are thriving; there are now 10 beaver dams where there
was only one in 1996. Grizzlies, coyotes, magpies, and ravens feast on the elk
carcasses left by wolves.
The National Research
Council report, Ecological Dynamics on Yellowstone’s Northern Range,
examines how populations of ungulates -- elk, bison, deer, and other species --
affect the vegetation and landscape of Yellowstone's Northern Range, and how
natural regulation would influence those interactions. The report discusses,
among other factors, how wolves, recently re-introduced, might cause additional
ecological changes there.
MODELING
ESSAY ANSWERS
QUESTION:
Wolves
have been introduced to certain areas from which they had been eliminated
(extirpated) by humans. Explain how
such reintroduction might affect species richness and the ecosystem.
VARIOUS
STUDENT ANSWERS:
The
wolves will eat one type of animal.
The
wolf’s prey will be affected.
Whatever
the wolves feed on will decrease.
The
wolves may eat and kill off certain species in the area they are located to.
O.K.
ANSWER:
The
wolf, a carnivore that preys or animals such as elk and deer, has been
reintroduced to Yellowstone National Park.
This will lead to a decrease in these prey populations but an increase in
predator populations. A balance
will be reached in time with just so many wolves hunting just so many elk and
deer. The species richness will
increase by one species namely the wolf. The
ecosystem will have more biodiversity.
BETTER
ANSWER:
The
reintroduction of wolves to certain areas after they had been eliminated by
humans will decrease the number of certain species that wolves prey on such as
deer, elk, and moose. Wolf numbers
will increase and prey species will decrease until a balance is reached.
As these herbivore prey animals decrease plant growth should increase and
with it room and habitat for new animals to live.
Animals such as squirrels, chipmunks, various birds, mice, rabbits, and
other small animals should increase as well as animals that prey on them.
All this will both increase species richness, the number of species in an
ecosystem, as well as the total number of all animals in the ecosystem, species
diversity.
EVEN
BETTER ANSWER: