ibclogo XVI International Botanical Congess


Abstract Number: 5850
Poster No. = 185


LICHENS ON LEAVES IN TROPICAL RAINFORESTS: STRATEGIES FOR SURVIVAL IN AN EPHEMEROUS ENVIRONMENT


Robert Lücking (Lehrstuhl für Pflanzensystematik, Universität Bayreuth, D-95447 Bay-reuth, Germany).


The consideration of lichens as long-lived organisms does not apply to those inhabiting leaves in tropical rainforests, since these represent an ephemerous substrate. Foliicolous lichens are not fast-growing, but reproduction takes place soon after establishment. The tiny organisms are abundant in the forest understorey which requires low photosynthetic compensation, acchieved by reduced thallus morphology. Damage to the leaf prejudices successful reproduction by increasing the probability of parasite attack and leaf shedding, so foliicolous lichens adhere by mucilage and are easily detached by mechanical forces. In spite of these shortcomings, they develop high diversity on the small scale: up to 300 of the 600 species known world-wide are found at a single site, and 50-80 species on single leaves! Foliicolous lichens are therefore appropriate for studying the mechanisms that maintain diversity in tropical rainforests. They are also excellent indicators of microclimate-dependent microsites and anthropogenic disturbances.


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