Inoculation with native grassland soils improves native plant species germination in highly disturbed soil

Abstract

Background Grasslands are globally imperiled, facing continued threats from anthropogenic disturbances. Seeding remains a common grassland restoration method, and yet, is typically met with limited success, partially because soils of degraded systems inhibit the germination of native species. Methods We assessed the germination success of 16 native grassland species sown in soils collected from a degraded grassland converted into a nonnative warm‐season perennial grass, Bothriochloa ischaemum, and areas previously subjected to the eradication of this nonnative species. Our objectives were as follows: (1) determine native seed germination in soils collected from B. ischaemum or eradication control sites, compared to germination in native grassland soil, and (2) assess if native soil inoculation improves germination, compared to germination in degraded soils without inoculation. Results Germination of native species was exceedingly low when seeded into soil dominated by B. ischaemum, or in soil previously treated with combinations of herbicide and prescribed fire, relative to native grassland control. However, amendments with native grassland soil resulted in germination equivalent to native grasslands, alleviating the negative influences of degraded soils. Conclusions Our results highlight the role of native soil in improving the germination of desirable plant species following intensive management and soil degradation. Our research may improve restoration outcomes for managers focused on the conservation and restoration of grasslands.

Effects of Commercial Arbuscular Mycorrhizal Inoculants on Plant Productivity and Intra-Radical Colonization in Native Grassland: Unintentional De-Coupling of a Symbiosis?

“…Establishing a regimented control over quality and product control of AM fungal bioinoculants is essential, as it has long been established that the reintroduction of AM fungi could be critical to the re-establishment of plant species in areas with a land use history, where the soil community is drastically altered by disturbances, such as the reclamation of mine spoils [65], abandoned agriculture [46], or recovery from invasive plant species [66]. Previous studies have shown that additions of whole soil from adjacent native ecosystems, including native AM fungal communities, are key to the establishment of native plant species [67][68][69][70][71][72]. However, acquiring soil from native ecosystems is not practical for large-scale restorations, as the collection and transfer of enough native topsoil are highly destructive to the very ecosystems we are trying to restore and protect, and these soils may not be available.…”