Effects of recreational rock climbing and environmental variation on a sandstone cliff-face lichen community

Abstract

Lichen community composition was evaluated for both lichen cover and richness on a cliff face commonly used for recreational rock climbing. The sandstone outcrop is located on the Sibley Peninsula, which extends from the north shore of Lake Superior. One-hundred and twenty plots were examined. Each plot was 1 m2 in size, with 60 plots located on unclimbed cliff sections and 60 more located where recreational rock climbing regularly occurs. Lichen richness and cover were significantly lower on the rock climbing sections compared with unclimbed sections. Linear regression models indicated significant relationships with cover and richness to environmental response variables and climbing treatment. Detrended correspondence analysis indicated a separation of lichen community groups on this cliff, and major separations occurred between plots in each climbing treatment. Canonical correspondence analysis indicated a significant amount of community group variation between climbed and unclimbed locations related to climbing treatment and aspect of the plots. Climbing is found to have an impact on this sandstone cliff-face lichen community.