as trapped pockets of lake water and can erode away or be filled by wind-blown sand or drifting dunes. The new ponds provide habitat for plants and animals: for example, the state park is home to 89 species of Odonata (dragonflies and damselflies) and Lepidoptera, including 35 different butterflies, as well as 84 different sorts of spiders. 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. The sixth and seventh ecological zones are characterized by their shrubs and trees, and Presque Isle State Park is home to 633 plant species (195 monocotyledons, 410 dicotyledons, 5 gymnosperms, 5 horsetails, 13 ferns, and 5 mosses). The sixth zone, thicket and sub-climax forest, forms when shrubs grow on dying marshes, followed by small trees. The trees shade and thin out the thickets of shrubs, leading to a sub-climax forest. The seventh and final stage is climax forest, where many large trees form a canopy. If left undisturbed, this ecological succession is believed to take between 500 and 600 years, although visitors to parts of Presque Isle State Park can walk through all of these zones in . The Pennsylvania Audubon Society has listed the park as Pennsylvania Important Bird Area (IBA) #1, and it considered one of the best birdwatching sites in Pennsylvania. The diversity of habitats on the peninsula makes it an ideal home for over 320 species of birds. (For comparison, the United States has about 925 bird species.) Forty-five of the bird species found in the park are listed as "endangered" or "threatened",