 Sand dunes and ridges are the fourth zone , formed when beach sand transported by wind and waves becomes trapped by vegetation . Dunes grow and are stabilized by grasses , followed by other types of vegetation . This provides habitat for amphibians , birds , mammals , and reptiles . Old dunes can become more permanent ridges , which shelter ponds . These dunes , ridges , and ponds are often remnants of previous shorelines ; at the Presque Isle State Park " Long Pond " just east of the marina , dunes and ridges mark the eastern shoreline from 1862 . The fifth ecological zone consists of old ponds and marshes . Ponds protected by dunes and ridges are more stable ; these old ponds support more plant and animal life , and as they fill with vegetation , they become marshes . Old ponds and marshes have high biodiversity . Nearly 400 species of terrestrial vertebrates live on Presque Isle , including 318 different birds , 48 kinds of mammals , 13 types of amphibians , and 19 reptile species . 
