Early seral plant species’ interactions with an arbuscular mycorrhizal fungi community are highly variable

Arbuscular mycorrhizal fungi (AMF) are an important driver of plant community assembly, and as such may be critical for restoring plant communities. Previous work has shown that as plant communities develop, AMF density is a good predictor of what type of plant community is supported. However, interactions between plants, particularly facultative hosts, and AMF are often assumed from plant growth responses and lack concomitant AMF growth response data. We examined both plant and AMF responses in association using early- and mid-seral plant hosts and a homogenous AMF community. The goal was to determine how variable interactions are between facultative plant hosts and an AMF community. Plant responsiveness was measured using field soil with and without AMF. AMF density was measured by observing root colonization by AMF in a bioassay host plant grown in soils trained by the individual host plant species used in the plant responsiveness study. Plant species studied were highly variable in their interactions with AMF, and mutualisms, parasitisms, amensalisms and commensalisms were all prevalent. The presence of certain AMF facilitators may have a strong founder effect on plant communities and, where such feedbacks exist, identifying and utilizing these key interactions might facilitate the restoration of degraded ecosystems.

► Degraded soils may be missing key microbial components necessary for restoration.
► Early-seral plant species interact with AMF from degraded soils in a variety of ways.
► Plant species that respond poorly to AMF may be highly beneficial for the AMF.