Diversity of microfungal communities inside saxicolous lichens from Nahal Oren, Mount Carmel, Israel.

Abstract

In this study, we examined the endolichenic fungal communities of saxicolous lichens covering the rocks in the Nahal Oren valley, northern Israel. A total of 60 fungal species belonging to 35 genera were isolated from six lichen species collected in the summer and winter on the south-facing slope (SFS) and north-facing slope (NFS) of the valley. We verified that rocks serve as a possible source for the formation of endolichenic communities because communities colonising lichen thalli and the rock surface shared 39% of species and clustered together on the SFS. On the NFS, with a compara-tively favourable microclimate, lichen thalli abundantly harboured typical soil fungi such as Clonostachys rosea and Fusarium spp. in winter and summer, respectively. At the same time, more severe environmental conditions on the SFS facilitated the prevalence of melanised fungi with thick-walled and multicellular spores irrespective of season. The lowest species richness and isolate densities of endolichenic communities were registered in the thalli of Collema cristatum . This decrease, especially expressed in the summer, was probably associated with the antifungal effect of substances produced by its cyanobiont, as well as with the heavy dehydration of thalli during the dry season.