Climate
The park lies at 45° North, halfway between the always-frozen pole and the always-warm equator. Although Lake Michigan moderates temperatures somewhat, summers are hot sometimes over 90°F by day and winters are cold sometimes below 0°F. The vast water reservoir to the west means the heat is humid and the cold is snowy. Sunscreen and footwear to protect you from hot sand is essential in the summer. Spring comes fairly late, the chill of autumn can come early, and weather coming off the big lake can change conditions quickly, so dressing in layers is a good idea.
Flora and fauna
The sand dunes provide a distinctive environment for vegetation. Dune grasses' long roots seek out water and help to hold the dunes together, along with thistles, bearberries, and other hardy plants. Juniper and jack pine take hold in the sand. Oak and white pine trees are found slightly inland from the beach. Further inland where the soil is richer it's a prime example of a beech/maple hardwood forest with some hemlock, basswood, and black cherry.
Birds can be found throughout the park, especially waterfowl such as Canada geese, loons, ducks, mergansers, and gulls. Shorebirds such as the sandpiper are common; the endangered piping plover nests on the North Manitou shoreline, parts of which are off-limits during mating season for this reason. Bald eagles nest on the islands, but hawks and owls are the main predatory birds. Sandhill cranes can be found in some wetlands. Thrushes and warblers inhabit the woodlands; the threatened prairie warbler nests in the mainland dunes along Lake Michigan.
Despite the park's name, black bears are rare in the area. Chipmunks, fox squirrels, and gray squirrels including the uncommon black variety are commonplace. The northern flying squirrel which really just glides short distances lives here but isn't often seen. Several species of bats which fly quite well are out between dusk and dawn. Raccoons like to hang out around campsites to scavenge. Beavers, otters, and minks can be found around inland lakes and streams. Bobcats a feline slightly larger than a housecat are present but avoid human contact. White-tailed deer have become increasingly common since forests were cleared in the area they are hunted, in season -- and are known to host deer ticks, which also attack humans. Coyotes and opossums are other recent arrivals to the area. Cougars have been sighted see "Stay safe", though they are generally elusive and avoid contact.
The islands have a limited variety of mammals, due to their distance from the mainland and their small size. Beavers, mice, chipmunks, squirrels, snowshoe hares, bats, and coyotes can be found. North Manitou also has raccoons and white-tailed deer. The deer were introduced, and because they had no predators overwhelmed the island, eradicating some plant species and halting the growth of new maple, cedar, and pine trees. They are now hunted to keep their numbers down and much of the vegetation is recovering. On the other hand, South Manitou's plant life is fairly representative of what the mainland was like before farming and deer grazing. The trees are mostly beech and maple, with a stand of huge white cedars one fallen specimen was over 500 years old and yew growing in the underbrush. Trillium which are protected grow on both islands, along with many other spring wildflowers and orchids.
History
According to a Chippewa legend, a bear and her two cubs swam across Lake Michigan to escape a fire on the other side. The mother reached exhausted safety on the shore, but was unable to save her cubs, who drowned within sight of shore. The Great Spirit Manitou transformed the mother into a huge sand dune looking out toward the lake, and the cubs into islands.
The area became important to Great Lakes shipping in the 19th century, as one of the few large safe harbors on the way around the Lower Peninsula to Chicago. Farming, both for subsistence and to supply passing ships was an important local industry.
The National Lakeshore was assembled in the 1960s and 1970s, largely from private land and not without some controversy, eventually including not only the recreational immediate area of Sleeping Bear Dune, but the geologically – and scenically – significant shoreline to the south and northeast, and the two Manitou Islands.
Landscape
The National Lakeshore consists primarily of a 35-mile 60km stretch of Lake Michigan shoreline, featuring immense sand dunes rising as high as 460 feet above the lake, sculpted entirely by the winds and waters. The park includes or borders several small inland lakes and the mouth of the Platte River at its south end. The mainland portion of the park is broken into three sections by the villages of Empire and Glen Arbor.
The park also includes North and South Manitou Islands, each about 6-7 miles from shore. These were high points of ridges left as the glaciers receded, covered by wind-blown sand, and partially forested. North Manitou 7.75 by 4.25 miles includes low-lying sandy regions in the southeast, rising to hills and 400-foot sand dunes in the northwest. South Manitou about 3 by 4 miles features perched dunes on the west, descending to a wide, concave harbor in the east.