Catchment scale patterns of aquatic hyphomycetes. The role of physicochemical variables and substrate composition in structuring conidial communities

Abstract

Spatial dynamics of aquatic hyphomycete species were studied in four streams of a catchment in Hungary. Conidial pools at 11 sites were sampled by membrane filtration of stream water. Spatial relationships of the studied stream sites based on conidial communities were demonstrated by minimum spanning tree analyses. Metric multidimensional scaling was used to represent the similarity structure of the sites based on different sets of data. The evaluation of the results by procrustes analyses suggested that the effect of abiotic variables and the substrate composition on the structure of hyphomycete communities were both important, but not to the same degree. Ordination based on abiotic habitat variables showed somewhat higher similarity to ordination based on the hyphomycetes data than to ordination based on leaf litter data. The relationships between environmental variables and aquatic hyphomycete species were analysed by canonical correspondence analysis. The results suggested that altitude, water hardness and conductivity were the major factors correlated with the distribution of individual species. An alternative sampling technique for analysis of leaf litter composition in streams is discussed.