Lichens of Voyageurs National Park, Minnesota

Abstract

Over 8000 lichens representing 405 taxa were collected at 128 dif- ferent localities during 11 weeks collecting in the park in 1978 and 1979. Several areas of special interest to the lichen flora are noted. Eighty-eight new state records were found within these collections and all but eight of the species collected by Bruce Fink in 1901 were recollected. Three new records for North America were identified: Arthonia fuliginosa (Turn. & Borr.) Flot., Chaenothecopsis savonica (Riis.) Tibell, Lecidea epixanthoidiza Nyl. Lichens for winter food for caribou would probably not be a limiting factor in the success of any reintroduction of woodland caribou to the park. The scarcity of Xanthoria elegans was studied and is probably due to lack of wave splash. The lichen flora is rich in fruticose lichens, which suggests that no air pollution is present. The lichens of Minnesota have not been studied much since Bruce Fink's work near the turn of the century (Wetmore 1978). A few lichenologists have visited the state recently but little new information on the lichens has been published since Fink's Lichens of Minnesota (Fink 1910). For the past ten years I have collected in many areas not visited by Fink, and have revised the lichens in the University of Minnesota herbarium as part of several lichen projects within the state. As a result, numerous new records have turned up and about 85% of the names in Fink's 1910 paper have been changed. One of the most extensive studies done was this lichen flora of Voyageurs National Park. Voyageurs National Park lies along the northern border of Minnesota adjacent to Can- ada and extends for 32 miles along the boundary just east of International Falls. The park was officially established in 1975 and development of the park is still underway. The vegetation of the park is typical southern boreal forest. Most of the park has been logged and burned at least once beginning about 1910 but a few small areas remain that were never cut. A large part of the park has regrown to quaking aspen (Populus tremuloides Michx.) and white birch (Betula papyrifera Marsh.), especially in places with deeper more moist soil. Dry rock outcrops occur frequently and are surrounded by jack pine. (Pinus banksiana Lamb) (Fig. 1-2). Jack pines are also common on ridgetops and areas with thin, dry soil and in a few of these areas stunted red oak (Quercus rubra L.) is found in open stands. A mixture of red pine (Pinus resinosa Ait.) and white pine (Pinus strobus L.) grow in some localities but large old trees are found only in buffer zones along a few of the large lakes and in a few places not logged during the most recent timber operations. Moist hillsides may have black spruce (Picea mariana (P. Mill.) B.S.P.) with or without balsam fir (Abies balsamea (L.) P. Mill.), but, due to logging, fires and insect damage, there are no large stands of balsam fir. There are many islands and bays and the lowland bay heads and valleys have stands of eastern white cedar (Thuja occidentalis L.) or black ash (Frax- inus nigra Marsh.) but most of these have also been logged. Black spruce bogs and beaver ponds are frequent in depressions but tamarack (Larix laricina (DuRoi) K. Koch.) is rare.