PRESENTATION OUTLINE
American alligator
Alligators use their tails to make burrows to stay warm and when they move on, these burrows fill with water which is used by other species. Alligators are also predators, keeping the numbers of other species in check.
Prairie dogs
By eating grass, prairie dogs keep water in the soil instead of the water evaporating from the leaves of plants. By tunneling, they help channel rainwater into the water table. By burrowing, they mix different layers of soil, combine it with their droppings, and aerate the soil.
Sea otters
Sea otters are a keystone species in the kelp forests. They eat many invertebrates, but especially sea urchins. If there are too many sea urchins, they will eat too much of the kelp and destroy it.
Tiger sharks
These sharks will eat practically anything. This helps control populations of sea turtles and dugongs who may cause overgrazing of the sea grass in Western Australia. Since sea grass is where fish lay their eggs, overgrazing would lead to fewer fish.
Wolves
Being a top predator, wolves are important in many habitats. Wolves keep deer populations in check and too many deer will eat small trees, which leads to fewer trees. In turn, there would be fewer birds and beavers and the whole ecosystem would change.
