2005 THE MICHIGAN BOTANIST 13 THE ROLE OF FIRE IN GREAT LAKES ALVAR LANDSCAPES Judith Jones1 and Carol Reschke2 1Author for correspondence. Winter Spider Eco-Consulting, R.R. #1 Sheguiandah, Manitoulin Island, Ontario P0P 1W0 Canada E-mail:
[email protected] . 2The Natural Resources Research Institute University of Minnesota 5013 Miller Trunk Highway Duluth, Minnesota 55811 E-mail:
[email protected] ABSTRACT The role of fire in alvar landscapes in the Great Lakes region of the United States and Canada was examined through the notes of the original land surveyors, through field work which looked for burn evidence, and through a comparison of alvars on two sets of aerial photographs taken 40 to 45 years apart. The results show that alvars existed in all regions of the Great Lakes prior to settlement of the area by European immigrants. Also, fire can create alvars and has done so in the last 150 years. Some alvar community types correlate strongly with past burning while others correlate with no burning. Some community types show noticeable change in a 40 year period while others show lit- tle or none. Although the presence of burn evidence is common, fire is shown to be infrequent in alvar landscapes, with some communities experiencing fire return intervals of at least 200–500 years. In these communities, fire is not the primary factor maintaining the open condition. The history of Great Lakes alvars is shown to be diverse and complex. Controlled burning is not recommended for all sites or all alvar community types. INTRODUCTION “Alvar” is a Swedish word used for the grasslands on the island of Oland, in the Baltic Sea.