Manipulating plant microbiomes in the field: native mycorrhizae advance plant succession and improve native plant restoration

The plant microbiome is critical to plant health and is degraded with
anthropogenic disturbance. However, the value of re-establishing the
native microbiome is rarely considered in ecological restoration.
Arbuscular mycorrhizal (AM) fungi are particularly important microbiome
components, as they associate with most plants, and later successional
grassland plants are strongly responsive to native AM fungi. With five
separate sites across the United States, we inoculated mid- and late
successional plant seedlings with one of three types of native microbiome
amendments: 1) whole rhizosphere soil collected from local old-growth,
undisturbed grassland communities in Illinois, Kansas, or Oklahoma, 2)
laboratory cultured AM fungi from these same old-growth grassland sites or
3) no microbiome amendment. We also seeded each restoration with a diverse
native seed mixture. Plant establishment and growth was followed for three
growing seasons. The reintroduction of soil microbiome from native
ecosystems improved restoration establishment. • Including only native
arbuscular mycorrhizal fungal communities produced similar improvements in
plant establishment as what was found with whole soil microbiome
amendment. These findings were robust across plant functional groups.
Inoculated plants (amended with either AM fungi or whole soil) also grew
more leaves and were generally taller during the three growing seasons.
Our research shows that mycorrhizal fungi can accelerate plant succession
and that the reintroduction of both whole soil and laboratory cultivated
native mycorrhizal fungi can be used as tools to improve native plant
restoration following anthropogenic disturbance.