The role of bryophytes and lichens in terrestrial ecosystems

Abstract The importance of bryophytes and lichens in primary succession has long been recognized. Otherwise these plants have generally been regarded as troublesome to identify when compiling releves but of little significance in the functioning of mature communities. This attitude has recently changed with the use of mosses and lichens as pollution monitors, and it has also been realized that they play a significant role in the functioning of undisturbed communities (Longton 1984; Seaward 1988; Slack 1988). Nowhere is the importance of mosses and lichens greater than in polar tundra and in northern forests and mires, which have so far been less modified by human activity than other, more complex ecosystems. Such communities are ideally suited to the study of fundamental ecosystem processes, and their cryptogamic component was intensively investigated during the International Biological Programme (Longton 1988a). Global warming is likely to be most intense at high latitudes, and the role of bryophytes and lichens in boreal and polar communities is therefore emphasized in this account.