Wikipedia Says that species that have dwindling numbers are divided into 3 categories
Critically Endangered (CR)-Extremely high Risk of Becoming Extinct (example. Florida panther, only occupies 5% of original range and only has 70 animals left capable of breeding)
- Endangered (EN)-A Species that is in danger of becoming extinct due to a range of reasons being: over hunting (from other animals and humans), changing environment, loss of environment, or just way to few numbers. (example. Nene which is suffering low numbers and loss of environment)
Vulnerable (VU)-A species who's runs a risk of becoming extinct but has not been qualified as an endangered species because numbers may still be high despite other factors like loss of habitat. (example. Polar Bear which still has decent numbers but is loosing habitat to global warming)
Invasive Species- a species that has been introduced to a non-native environment and has become harmful to the native environment and/or human health. (example. Coqui Frog which spreads fast due to high reproduction rate, and is hard to get rid of)
