|Beck, A; Peršoh, D; Rambold, G: First evidence for seasonal fluctuations in lichen and bark colonizing fungal communities, Folia Microbiologica, 59(2), 155–157 (2014), doi:10.1007/s12223-013-0278-y|
Endophytic fungal communities in leaves of deciduous trees usually undergo pronounced seasonal changes. We hypothesized that such compositional shifts are predominantly caused by annuality of the leaves and therefore less pronounced in fungi colonizing the perennial substrates bark and corticolous lichens. To test this hypothesis, thalli of the foliose lichen-forming fungal species Xanthoria parietina and Physconia distorta, along with the adjacent bark, were sampled during spring and autumn at two sides of a single tree in southern Germany. Analysis of clone libraries by restriction fragment length polymorphism (RFLP) revealed 588 singleton and 221 nonsingleton RFLP types of non-lichenized fungi. The communities differed significantly between host lichen species. Season and exposure had only a significant impact when the two factors were combined in the analysis. Accordingly, bark- and/or the lichenassociated fungal communities change throughout the year's course, a finding that rejects the initial hypothesis. This survey revealed valuable information for future broad-based studies, by indicating that (i) an relatively high diversity of non-lichenized fungi is associated with corticolous lichen thalli and the adjacent bark. Furthermore, the structure of non-lichenized fungal assemblages associated with corticolous lichen communities obviously depends at least on the following factors: 'lichen species', 'exposure', and 'season'.