Simplify the following text for a Grade 9 native English-speaking person.
Original: Within the North Cascades there is also a divere faunal population including mammals , birds , reptiles and amphibians . Examples of amphibian species occurring in the North Cascades include Bufo boreas and the Rough-skinned newt , Taricha granulosa , whose population in the North Cascades has the unusual feature that approximately ninety percent of adults are perennibranchiate .
Simplified: North Cascades National Park is located at the northernmost end of the North Cascades .