Ol

Fh

Chaetopsina fulva

31.0%

16.0%

5.5%

Trichoderma koningii

15.5%

54.0%

81.8%

Mortierella rammanians

1.8%

11.0%

23.6%

Data from Tokumasu (1996).

Data from Tokumasu (1996).

new colonizer reject - inhibition

reject - inhibition

accept - mutual tolerance new challenge accept - mutual tolerance

acceptance and rejection new challenge

new colonizer established acceptance and rejection

new colonizer established

Fig. 5.8. Example of interactions between fungal colonies during succession.

Several authors have tried to describe fungal succession in primary decomposition, beyond simply naming species in sequence. One study in northern Germany followed the activity of fungi over 1 year in black alder forests (Rosenbrock et al., 1995). In this study, the function of active hyphae was described after washing off spores and other dispersal and inactive propagules. Two media were used in the laboratory: a cold water soil extract agar for slow growing species, and a malt extract agar for faster growing species. The role of fungal species was determined by enzymatic assay in vitro on various substrates. Although this assay determines whether species possess enzymes to digest a substrate, it does not determine whether that enzyme was being used when it was sampled. However, it provides an idea of the functional sequence of species succes-

sion on the leaf litter. The study was able to correlate species succession with changes in the enzymatic potential. The functional succession was similar to results obtained in other studies. What is clear from the results is that the patterns of species succession and enzymatic potential differ. Although particular species come and go and their periods of activity differ, successive species have overlapping digestive enzymes (Fig. 5.9). The authors note that even within genera, species vary in activity period through the year (but the enzymatic potential is probably similar).

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