Biotic Interactions in Lichen Community Development: A Review

Abstract

The extent to which biotic factors (competition, predation/disease, longevity) regulate lichen community development can be addressed by considering a number of general trends expected in higher plant successions and searching for supporting evidence from lichen studies. Four of the most frequently observed (or predicted) trends during succession are that: (1) superior competitors replace poor competitors; (2) ecologically specialized species replace generalists; (3) chemically well-defended species replace poorly-defended species; (4) long-lived species replace ephemeral species. Available evidence suggests that, for many lichen communities, competitive exclusion rarely occurs once thalli are established. This is especially true for communities that develop on the most stable habitats. An absence of competitive exclusion suggests that lichen successions are driven more by additions of colonists than by species replacements, and replacement trends observed in higher plant successions are therefore observed less frequently inlichen successions.