Abstract
This review summarizes a series of studies demonstrating the diversity and functions of fungal communities along geographical gradients and their relationships with environmental variation. The diversity and functions of leaf litter-decomposing fungi responded significantly to latitudinal and elevational gradients and to environmental changes due to forest cutting and succession. Fungal isolates were then examined in pure culture tests to verify the effects of individual environmental factors on the potential ability of these fungi to decompose leaf litter. The species richness of endophytic fungi of tree leaves decreased gradually, whereas the degree of specialization of the interaction network between endophytes and plant species increased, from subtropical to cool temperate and subboreal forests in Japan. Wood-rot fungi were compared among subtropical, cool temperate, and subalpine forests in Japan to demonstrate the dominance of white-rot basidiomycetes that simultaneously decompose lignin and cellulose during early stages of decomposition of coarse woody debris in these forests. In later stages of decomposition, on the other hand, xylariaceous ascomycetes, soft-rot ascomycetes, and brown-rot basidiomycetes function in the selective decomposition of cellulose in subtropical, cool temperate, and subalpine forests, respectively.
