Fungal communities decline with urbanization—more in air than in soil

Abstract

Increasing evidence suggests that degradation of biodiversity in human populated areas is a threat for the ecosystem processes that are relevant for human well-being. Fungi are a megadiverse kingdom that plays a key role in ecosystem processes and affects human well-being. How urbanization influences fungi has remained poorly understood, partially due to the methodological difficulties in comprehensively surveying fungi. Here we show that both aerial and soil fungal communities are greatly poorer in urban than in natural areas. Strikingly, a fivefold reduction in fungal DNA abundance took place in both air and soil samples already at 1 km scale when crossing the edge from natural to urban habitats. Furthermore, in the air, fungal diversity decreased with urbanization even more than in the soil. This result is counterintuitive as fungal spores are known to disperse over large distances. A large proportion of the fungi detectable in the air are specialized to natural habitats, whereas soil fungal communities comprise a large proportion of habitat generalists. The sensitivity of the aerial fungal community to anthropogenic disturbance makes this method a reliable and efficient bioindicator of ecosystem health in urban areas.

Exposure to airborne bacteria depends upon vertical stratification and vegetation complexity

“…However, our findings suggest additional co-benefits from increasing urban tree coverage due to its potential to mediate aerobiome alpha diversity. Our results also corroborate other studies showing microbial alpha diversity increasing along densely-urban to semi-natural environmental gradients 50 , 51 .…”

Exposure to Airborne Bacteria Depends upon Vertical Stratification and Vegetation Complexity

“…However, our findings suggest additional co-benefits from increasing urban tree coverage due to its potential to mediate aerobiome alpha diversity. Our results also corroborate other studies showing microbial alpha diversity increasing along densely-urban to semi-natural environmental gradients ( 48, 49 ).…”

Assembly of the amphibian microbiome is influenced by the effects of land-use change on environmental reservoirs

“…In contrast to bacteria, the relative abundance of the common soil fungal phyla, Basidiomycota and Mortierellomycota, appeared sensitive to land-use change. These findings are consistent with other urban-focused studies that suggest that urbanization might drive homogenization of soil fungal communities towards increased abundances of Mortierellomycota and Ascomycota (Abrego et al, 2020;Becker & Lewis, 2012;Epp Schmidt et al, 2017;Jurburg et al, 2020;Karpati et al, 2011;van Geel et al, 2018). In turn, this could lead to decreases in functionally important taxa within Basidiomycota (Abrego et al, 2020;Epp Schmidt et al, 2017), which may be dispersal limited or are not as resilient to the impacts of land-use change.…”

“…These findings are consistent with other urban-focused studies that suggest that urbanization might drive homogenization of soil fungal communities towards increased abundances of Mortierellomycota and Ascomycota (Abrego et al, 2020;Becker & Lewis, 2012;Epp Schmidt et al, 2017;Jurburg et al, 2020;Karpati et al, 2011;van Geel et al, 2018). In turn, this could lead to decreases in functionally important taxa within Basidiomycota (Abrego et al, 2020;Epp Schmidt et al, 2017), which may be dispersal limited or are not as resilient to the impacts of land-use change. There remains the possibility that these communities have gone through an irreversible change in composition following historical land-use changes (Clemmensen et al, 2015;Cline et al, 2015;Dupouey et al, 2002).…”