Distinguish between native, nonnative, indicator and keystone species. Give an example of each. Explain why amphibians are good indicator species. Lists reasons for their decline and at least one example where this is happening today.

Answer:Native specie are species that naturally lives in an ecosystem. They are usually assisted by new species.

Non native specie; These are species that exist outside their natural range. They usually exist where they have not naturally occured and they don't hinder the presence of other specie in the ecosystem.

Indicators are organisms whose existence is largely dependent on the condition of the ecosystem.

Key stone specie; These species have significant impact on their eco system. Non existence of these species can cause significant regress In an ecosystem.

Causes of decline of the listed species.

1) Pathogens and pest.

2) Human causes.

3) Loss of habitat.

4) Loss of pollinators and other plant partners.

Owl as an indicator specie has declined.