Chapter 23 - Lichens as an Indicator of Climate and Global Change

Abstract

This chapter discusses the predicted, observed, and uncertain effects related to lichen and climate change together with the habitats of vulnerable lichens, with special attention to mountain tops in the tropics—the most likely place for possible extinction of lichens as a result of global warming. Lichens have been observed to respond rapidly to climate change. So far, the changes are as expected with a rather rapid increase of (sub)tropical species in temperate areas, and a gradual decrease of some boreo-alpine elements. No lichens have, so far, been reported to be seriously threatened by climate change. Marked shifts in occurrence and distribution have been predicted based on known habitat preferences and projected climate change. Lichens, like most cryptogams, tend to be widespread, much more so than phanerogams or land animals. Also, many of the species seem to be capable of rather rapid dispersal, as shown by the recent arrival of some (sub)tropical species in a temperate area. Lichens are unequivocally responding to global change. The effects are, so far, apparent only in the last two decades and in the temperate region only. Lichens have indirectly suffered from global change effects in arctic regions. The most severe effects of climate change, leading to probable extinctions, are expected on high mountains in tropical regions.