SOIL FUNGAL COMMUNITIES IN A YOUNG AND AN OLD ALNUS-VIRIDIS COENOSIS

Soil microfungal communities of two adjacent, but differently aged Aln us viridis coenoses were studied using the soil dilution plate method. A total of 84 taxa were isolated: 59 from the young community, 51 fro m the old and 26 taxa shared. Mortierella parvispora and Pythium sp. h ad the highest density values in the young and the old alder community , respectively. Species compositions were compared between plots of th e two communities using a metric multidimensional scaling and a corres pondence analysis. Both analyses grouped plots from the young and the old community separately, suggesting a correlation between the changes in the fungal species composition and the age of the alder communitie s. The correspondence analysis produced two species groups more relate d to one set of plots or the other, together with another group formed of Mortierella, Micromucor, Geomyces and Trichoderma species, whose d istributions were more closely related to the general abiotic conditio ns than the age of the alder communities. It is proposed that the sign ificant differences in the composition of the two fungal communities m irror the existence of a seral fungal succession paralleling the aging of the alder communities.