Studies on Colombian Cryptogams XX. A transect analysis of the bryophyte vegetation along an altitudinal gradient on the Sierra Nevada de Santa Marta, Colombia

Along an altitudinal transect on the northern slope of the Sierra Nevada de Santa Marta, Colombia, 500-4100 m, five altitudinal bryophyte zones are distinguished – four forest zones and one paramo zone – based on ecosystem releve analysis concerning species presence, substrate preference and percentage cover of bryophytes, Releves were compared by using Sorensen’s Index of Similarity and a simplified dendrogram technique, and zonation diagrams were constructed. Bryophyte zonation seems primarily correlated with climatic factors (precipitation, air temperature) as preliminary data suggest. Species presence and cover percentage appear to be of almost equal significance in distinguishing the different bryophyte zones of the tropical forests and are highest in the so-called “condensation zones”. Work continues on other altitudinal transects in the Colombian Andes, in the framework of the ECOANDES project.