Keystone Species Questions and Answers 1 Make a

Keystone Species Questions and Answers

1. Make a list of the organisms in the article dealing with wolves. • • • Wolves Grizzley Wolverines Bald Eagles Gold Eagles Ravens Mt. Lions Otter Mink Fish Willow -jays -magpies -martins -black bear -coyotes -foxes -hares -moose -wading birds -frogs -Aspen -deer -rodents -insects -fungi -bacteria -elk -beaver -ducks -songbirds -grass -cottonwood

2. Make a list of some species interactions. • Predator-Prey: wolves and elk, coyotes and mice • Interspecific comp: wolves and mt lions, moose and beaver • Intraspecific comp: mice with mice, wolves with wolves • Mutualism: beaver and willow • Commensalism: magpies and wolves

3. Food Web from list

4. What is a Trophic Cascade?

• A Trophic cascade is when a predator has an indirect effect (either increase or reduction) on a non-prey item at a lower trophic level. • Example: the predator (bird) has a positive effect on the basal species (plant) via reduction in the abundance of the herbivore (caterpillar).

5. How is the starfish a keystone species?

6. Are keystone species always predators?

• They help to maintain suitable habitats for many other species in savanna and forest ecosystems. • directly influence forest composition and density • In tropical forests, elephants create clearings and gaps in the canopy that encourage tree regeneration. • In the savannas, they can reduce bush cover to create an environment favorable to a mix of browsing and grazing animals. • Many plant species also have evolved seeds that are dependent on passing through an elephant's digestive tract before they can germinate; it is calculated that at least a third of tree species in west African forests rely on elephants in this way for distribution of their future generations.