1995 lichen studies in Apostle Islands National Lakeshore: Final report

Abstract

This study of the lichens of the Apostle Islands was in two separate parts. Part one was to survey the lichens on Long Island in all vegetational types noting the species sensitive to sulfur dioxide and the substrates on which the lichens grew. Part two was to make collections for elemental analysis on Long Island and at the three localities sampled in 1987 and compare the results of elemental analysis in 1987 with those from 1995. The lichen flora of Long Island is quite diverse with 88 species found including 14 new species records for the park. There were four species very sensitive to sulfur dioxide. All of the lichens found were in good health and with normal fertility. The new species records are mainly due to the abundance of jack pines and red oaks. The lichens studied by elemental analysis show normal ranges of all elements in 1995 with no correlation between elements and localities. In comparison of the 1995 data with the 1987 data there are several noticable changes. Some elements have increased and some have decreased. The increase of Cr and Ni should be studied further as possible indicators of anthropogenic pollution. Recommendations are made for protection of Long Island, for moving the elemental monitoring site on Raspberry Island and for periodic (5 years) restudy of the lichens by elemental analysis.