What impact did the reintroduction of wolves to Yellowstone National Park have on the ecosystem?

Answer 1

They hope and expect the herds of big grazers will decrease in size and be more healthy as the wolves will prey on the weaker animals first. The same will happen with American schoolchildren going on outings to the park. Only the healthy and strong will survive, making America's youth stronger than ever before.

Answer 2

With few natural predators, deer had taken over Yellowstone National Park, cropping its grassland and shrubbery down to nothing. When wolves were reintroduced to the park in 1995 the following things happened.

• The wolves killed some of the deer, but they also changed their behaviour.
• The deer moved away from the flat river areas into higher more difficult terrain.
• Immediately the vegetation regenerated. Some of the trees grew to five times their size in just six years.
• The bare sides of the valleys quickly became forests of aspen, willow and cottonwood.
• Birds and beavers returned and started to grow in number.
• The beavers with their dams created niches for other species, which also returned, otters, muskrats, reptiles, amphibians and fish.
• The wolves killed coyotes, so numbers of rabbits and mice increased.
• This attracted more hawks, weasels, foxes and badgers.
• Ravens and bald eagles came to eat the carrion left by the wolves.
• Bears fed on it too, and their population increased, partly because there were more berries on the trees.
• The wolves also changed the rivers.
• The regenerating forests stabilised the river banks, so they didn't collapse so often, and the rivers became more fixed in their course.
• The trees and shrubs stabilised the sides of the valleys, too, so there was less soil erosion.

So the wolves not only changed the whole ecosystem of the park. They also changed it physically!

Answer 3

The usual hypothesis of the most obvious effect of adding wolves back to Yellowstone National Park was that wolves would curb the populations of deer and elk.

However, when scientists reintroduced a small wolf population there, they found that this:

• reduced deer and elk populations leading to
  
• growth of new foliage and trees
  
• a return of small game like rabbits, which ate foliage, prompting new growth
  
• The foliage and trees lead to less erosion especially near the river along with the return of migrating birds resulting in
  
• that the river became less stagnant along with the spreading of plant and tree seeds on the banks
  
• Scientists learned that wolves can even change a river!
  

Answer 4

The reintroduction of wolves decreased the population of elk, bison, and deer to drop slightly.

Answer 5

increased maple population