Walrus remains have been reported on Andrews Island, west of Isle au Haut; Addison Point, northeast of the Schoodic Peninsula; and Gardiner, west-northwest of Isle au Haut. The mammoth bones were found at Scarborough, southwest of Isle au Haut. The ecological zones at Acadia National Park, from highest to lowest elevation, include: nearly barren mountain summits; northern boreal and eastern deciduous forests on the mountainsides; freshwater lakes and ponds, as well as wetlands like marshes and swamps in the valleys between mountains; and the Atlantic shoreline with rocky and sandy beaches, intertidal and subtidal zones. Tiny subalpine plants grow in the granite joints on mountaintops and on the downwind side of rocks. Stunted, gnarled trees also survive near the summits. Spruce-fir boreal forests cover much of the park. Stands of oak, maple, beech, and other hardwoods more typical of New England represent the eastern deciduous forest. Pitch pines and scrub oaks inhabit isolated forests at their northeastern range limit, while jack pines reach the southern limit of their range in Acadia. Fourteen great ponds and ten smaller ponds provide habitat for many fish and waterfowl species. More than 20% of the park is classified as wetland. Marshes and swamps form the transition between terrestrial and aquatic environments, maintaining biodiversity by providing a habitat for a wide range of species. Native wildlife frequent wetlands alongside species that are nesting, overwintering or migrating, such as birds along the Atlantic Flyway. Wetlands are composed of 37.5% marine (sea water), 31.6% palustrine (stagnant water), 20% estuarine (coastal, brackish water), 10.7% lacustrine (freshwater lakes and ponds), and 0.2% riverine (flowing streams). Approximately of perennial streams and of intermittent streams flow through the park, while about of shoreline surround 110 lakes and ponds encompassing . Intertidal flora and fauna inhabit more than of rocky coastline. The nutrient-rich marine waters cover the intertidal plants and animals twice a day. Pools of calm water form among the rocks around low tides, inhabited by starfish, dog whelks, blue mussels, sea cucumbers, and rockweed. Flora common to both deciduous and coniferous woodlands include lowbush blueberry, Canadian bunchberry, hobblebush, bluebead lily, Canada mayflower, wild sarsaparilla, shadbush, starflower, rosy twisted stalk, wintergreen, and white pine trees.