Effect of collembolan grazing on interspecific competition between microfungi, decomposition of organic matter and bio-available nitrogen.

Summary

The effect of selective grazing by a collembolan (Folsomia fimetaria) on the reproduction and ability to degrade organic matter of 3 species of microfungi was measured. It was expected that the interspecific competition between the fungi might change as a result of the selective grazing.
The results showed that the reproduction of the fungus (Alternaria infectoria) F. fimetaria preferred the most was negatively affected in competition with a less preferred fungus (Penicillium hordei), whereas reproduction was not altered by the presence of another less preferred fungus (Mucor hiemalis). A. infectoria did not seem affected in terms of the ability to decompose the substrate when grown with either of the 2 other fungi. Whenever A. infectoria was present in the microcosms the pattern of both respiration and content of bio-available nitrogen was dominated by this fungus. M. hiemalis was largely unaffected by competition and grazing in terms of reproduction. P. hordei was more affected by competition and grazing in terms of reproduction than was expected from the food preferences of F. fimetaria.
Grazing by F. fimetaria generally stimulated decomposition, measured as fungal respiration.