that use the Great Lakes shipping port. Erie became an international port after the opening of the Saint Lawrence Seaway in 1959. Owing to the park's location relative to Erie, its climate is similar to that of the city. Erie and the peninsula are located in a snow belt that stretches from Cleveland to Syracuse and Watertown; accordingly, its winters are typically cold, with heavy lake-effect snow, but also with occasional stretches of mild weather that cause accumulated snow to melt. The Erie region lies in the humid continental zone (Köppen Dfa). Presque Isle's lakeside location helps to temper summer heat, with an average of only 3.8 days of + highs annually, and the highest temperature ever recorded was on June 25, 1988; there is an average of 2.5 days with lows of or colder annually, and the lowest temperature ever recorded was on January 19, 1994 and February 16, 2015. Ice dunes typically form along the beaches in the winter from snowfall and frozen spray, and normally reach a height over . The dunes protect the beaches from erosion during winter storms, and continue growing until the surface of Lake Erie freezes in the winter. Flora, fauna, and habitat Ecological zones and succession According to the DCNR, because it has so "many unique habitats, Presque Isle contains a greater number of the state's endangered, threatened and rare species than any other area of comparable size in Pennsylvania". The DCNR recognizes seven different ecological zones within Presque Isle State Park, each with a different plant and animal community. These zones are: Lake Erie; the beaches and shoreline; sandy plain and ponds; sand dunes and ridges; marshes and old ponds; heath and sub-climax forest; and the climax forest. Lake Erie, which surrounds the park, is the first zone and is home to 80 species of fish and at least six species of crustaceans. The remaining ecological zones, with their progression from shoreline to climax forest, are a classic illustration of the concept of ecological succession. Much of this progression is due to the changing nature of Presque Isle and its shifting shoreline and dunes. The shoreline, the second zone, is formed by wave action and is in equilibrium between erosion and deposition, with the initial plants stabilizing the sand of the new shoreline. The newly formed sandy plain and the ponds formed in it are the third zone. The ponds start