The Physiology of Lichens and Bryophytes in the Tropical Lowlands

In moist tropical lowlands, lichens and bryophytes reach only surprisingly low abundances, whereas in tropical montane forests, they are often so conspicuous that these forests are called “mossy forests.” The physiological basis behind this striking elevational pattern is not entirely understood, but differences in carbon-gain opportunities likely play a role. Our current understanding of the limitations of in situ carbon gain in lichens and bryophytes is in part based on pioneering physiological fieldwork conducted on Barro Colorado Island. We describe these earlier studies and current research efforts. Ongoing work primarily aims at predicting the effect of global climate change on these poikilohydric organisms, but baseline studies on their ecophysiology are still to be conducted.