Human-induced alterations of the mycobiota in an alpine show cave (Italy, SW-Alps).

Anthropogenic alterations in show caves are well documented in scienti c literature. One of the main sources of perturbation derives from visitors, acting as carriers of propagules and or- ganic matter in the cave ecosystems. Such perturbation gener- ally results in a signi cant alteration of the natural subterranean microbiota. In this study, we characterize the mycobiota of the super cial alluvial sediment (0–5 cm) of the Bossea show cave (Nw-Italy) over two sampling seasons, aiming to investigate whether anthropogenic rather than natural factors contribute to the colonization and proliferation of alien mycobiota in the cave environment. we placed eighteen sampling plots at di er- ent distances from the touristic pathway that crosses the cave. e distance from the touristic pathway was used as proxy to sort the sampling plots in three groups according the degree of anthropogenic disturbance (high: 0–2 m; intermediate 2–40 m; low: >100 m). Moreover, in order to elucidate the potential ef- fect of other factors, we introduced in our analysis the distance from the subterranean river and the distance from the cave en- trance. In each plot, we collected two samples of alluvial sedi- ment, in winter and summer. Fungi were isolated from each sample and identi ed by means of an integrated morphological approach. we observed a rich and diversi ed fungal commu- nity – 63 taxa of Zygomycota and Ascomycota plus several un- identi ed yeasts – consisting of both native and alien species. Regression analysis points out a decrease of the abundance and the diversity of viable propagules at increasing distances from the touristic pathway rather than the cave entrance or the subterranean river. Accordingly, the exogenous organic materi- als passively conveyed by tourists, possibly explains the higher proliferation of alien species in the proximity of the touristic pathway. ere was also a seasonal variation in the diversity and abundance of propagules, which we interpreted in light of the peculiar microclimate of the cave. In a second step, we used Indicator Species Analysis to identify the most representative species of the di erent levels of anthropogenic disturbance. In particular, Aspergillus spelunceus was found to be indicator of low disturbance, whereas mucor corticola and A. asperescens were found to be indicators of intermediate and high distur- bance, respectively.