Abstract
The microbial community of the leaf is extremely complex just as the environment that they inhabit. When a perturbation is applied, the microbial community could be affected and change its composition and/or functionality or remained stable. In this context, I studied how the microbial community, fungi and bacteria, of the oak green leaves and leaf litter responds to external disturbance in the area of South Tyrol (Italy). The phyllosphere was subjected to nitrogen aerial fertilization in a short term experiment. Upon perturbation the bacterial community increased the alpha diversity but not the beta diversity while fungal community had a stable alpha diversity but beta diversity was affected by the treatment. For the leaf litter, the first experiment used three different plant species. All the plant species were decomposed in their environment and in the other two sites. For each litter microbial community structure, enzymatic activities, chemical composition and temperature were measured. Microbial community was influenced by time but not by the site of decomposition while enzymatic activity did not follow the same temporal variation. The results suggested a decoupling between microbial community structure and functionality. In the second experiment on litter decomposition, oak litter decomposers were studied more in details. Temporal succession of different taxa was found and also the influence of the site of decomposition especially for fungal genera. In all experiments, I have investigated how the microbial community of leaf responds to perturbation. Fungi were influenced more by the perturbation both in phyllosphere and in the leaf litter experiment while bacteria turned out to be less influenced by the modification.