Roadside disturbance promotes plant communities with arbuscular mycorrhizal associations in mountain regions worldwide

Aim: We aimed to assess the impact of road disturbances on the dominant
mycorrhizal types in ecosystems at the global level and how this mechanism
can potentially lead to lasting plant community changes. Location:
Globally distributed mountain regions Time Period: 2007-2018 Taxa studied:
Plants (linked to their associated mycorrhizal fungi) Methods: We used a
database of coordinated plant community surveys following mountain roads
from 894 plots in 11 mountain regions across the globe in combination with
an existing database of mycorrhizal-plant associations in order to
approximate the relative abundance of mycorrhizal types in natural and
disturbed environments. Results: Our findings show that roadside
disturbance promotes the cover of plants associated with arbuscular
mycorrhizal (AM) fungi. This effect is especially strong in colder
mountain environments and in mountain regions where plant communities are
dominated by ectomycorrhizal (EcM) or ericoid-mycorrhizal (ErM)
associations. Furthermore, non-native plant species, which we confirmed to
be mostly AM plants, are more successful in environments dominated by AM
associations. Main Conclusions: These biogeographical patterns suggest
that changes in mycorrhizal types could be a crucial factor in the
worldwide impact of anthropogenic disturbances on mountain ecosystems.
Indeed, roadsides foster AM-dominated systems, where AM-fungi might aid
AM-associated plant species while potentially reducing the biotic
resistance against invasive non-native species, often also associated with
AM networks. Restoration efforts in mountain ecosystems will have to
contend with changes in the fundamental make-up of EcM- and ErM plant
communities induced by roadside disturbance.