The impacts of hydrological disturbance, tree encroachment, and mowing management on arbuscular mycorrhizal fungal communities in fen peatlands.

Arbuscular mycorrhiza (AM) is one of the most widespread types of symbiosis on Earth and plays a key role in the functioning of many ecosystems, including potentially fen peatlands. Due to the scarcity of research on AM in peatlands, we do not know how the current anthropogenic hydrological disturbances of these ecosystems, as well as the associated overgrowth of shrubs and trees and the prevention of this process through mowing, may affect the communities of fungi participating in AM (AMF). In order to detect the potential impact of these factors on AMF, peat samples were collected from open and wooded areas within 24 peatlands with varying degree of hydrological disturbance in northern Poland. DNA was isolated from the peat and the SSU rDNA fragment was amplified and sequenced. In addition, the correlation between the composition of AMF communities and habitat variables such as climatic and chemical factors and plant community composition was examined. The composition of AMF communities differed significantly between hydrologically disturbed and undisturbed peatlands, with a higher number of OTUs and AMF reads detected in hydrologically disturbed peatlands, while no significant effect of overgrowth or conservation-related mowing on AMF communities was detected. The studied AMF communities were characterised by high beta diversity, and the potential impact of all studied habitat factors, including disturbances, accounted for a relatively small percentage of variance in the composition of these communities. The results suggest that although AMF communities are relatively resistant to habitat changes in fen peatlands, hydrological disturbance may affect them to some extent. Future studies could help determine whether further drainage will result in significant changes in the composition of AMF communities.