Pictured Rocks National Lakeshore (NL) is located on the southern shore of Lake Superior. Although it is known primarily for the colorful sandstone cliffs and the perched Grand Sable Dunes, it contains a myriad of interesting natural communities. It also is the only national park that contains an inland buffer area to protect the watershed surrounding the park. Sustainable timber harvest is allowed within this buffer, which is owned by the state of Michigan, corporations, and private citizens. NatureServe, U.S. Geological Survey Upper Midwest Environmental Sciences Center, Great Lakes National Park Service (NPS) Network, Michigan Natural Features Inventory, and NPS Vegetation Mapping Program have partnered to describe and map the natural communities of Pictured Rocks NL using the US National Vegetation Classification (USNVC). The USNVC was adopted by the Federal Geographic Data Committee in 1997 to ensure consistent classification of vegetation communities across the United States. The use of a standardized national vegetation classification system allows compatibility and widespread use of the information throughout Federal and state agencies. To develop this standardized classification for Pictured Rocks NL, 158 vegetation plots were collected throughout the park and managed buffer. For each plot, the vegetation was visually divided into layers (strata) and the average height, percent cover, and dominant species of each stratum was recorded. Nonmetric multidimensional scaling and flexible beta clustering analyses were used to evaluate vegetation patterns and classify plots to communities. Areas of the park not captured with plot data were classified by analyzing aerial photos.
Results/Conclusions Over 60 community types were identified within Pictured Rocks NL. Most of the park is dominated by sugar maple (Acer saccharum) and yellow birch (Betula allegheniensis) northern hardwoods. The remaining communities are quite variable. Boreal Jack pine (Pinus banksiana) woodlands and barrens are found both along Grand Sable Dunes and sandplains throughout the park. The perched dune area of Grand Sable contains many interesting and unique communities not originally documented for this area of the Great Lakes. Some of these communities are similar to those found on the Atlantic Coast and other perched dunes in the southern Great Lakes. In the buffer, current and historical management have changed the character of the communities although many of the species diagnostic to those natural communities remain. Pictured Rocks NL is a unique national park along Lake Superior with a variety of communities that are influenced by the lake and also by management within the buffer.
