Fungal communities colonising empty Cepaea hortensis shells differ according to litter type

Soil and litter fungi can colonise and decompose many natural materials, including highly resilient proteinaceous compounds of animal origin. The shells of terrestrial gastropods are formed from such a compound (conchiolin) combined with inorganic calcium carbonate. In this study, we investigated fungal communities colonising empty shells of the common terrestrial gastropod Cepaea hortensis. Shells were exposed on the surface of litter from four different forest types (alder alluvial, oak-hornbeam, peat-bog pine and scree forest) and the fungi were surveyed and identified in four 3-month periods. We found 27 fungal species, one fungus forming mycelial cords, seven types of sterile mycelium and streptomycetes colonising the shells. The most frequent fungal species identified were common soil fungi. Multivariate analysis revealed a significant effect of the litter type on the fungal community. Humidity and pH at the locality are likely to be more important for fungal communities than the proteinaceous material of the shell.