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Soil disturbance changes arbuscular mycorrhizal fungi richness and composition in a fescue grassland in Alberta Canada

Stover, Holly J., Naeth, M. Anne, Boldt-Burisch, Katja
Applied soil ecology 2018 v.131 pp. 29-37
DNA, Festuca, canopy, carbon, disturbed soils, ecological invasion, electrical conductivity, embryophytes, genes, grasslands, gravel, hills, indigenous species, introduced plants, landfills, mycorrhizal fungi, nitrogen content, nutrient availability, pH, phosphorus, ribosomal RNA, sequence analysis, species richness, Alberta
Native grasslands are endangered by non-native plant invasion worldwide, including foothills fescue grasslands in North America. Large populations of non-native plant species have established in these disturbed fescue grasslands, forming dense monocultures and spreading into undisturbed areas. Soil disturbance and plant invasion can alter the arbuscular mycorrhizal fungi (AMF) community, an important symbiotic partner of most land plants, which could negatively affect native plant reestablishment. The objective of this study was to assess whether AMF communities on a fescue grassland shifted in response to disturbances by landfill storage and gravel quarrying and with invasion of non-native plant species relative to undisturbed grassland.Soil and root-AMF samples were procured from disturbed and undisturbed areas at three sites. Plant canopy cover and species richness were assessed. Soils were analyzed for pH; electrical conductivity; total nitrogen, carbon and phosphorus; and available nutrients. For relative AMF taxa abundance assessment, NS31 and AMF specific primer AML2 were used to amplify a central fragment of the V3 and V4 region of the 18S rRNA gene. AMF were characterized using 454 pyrosequencing and multiplexed barcoded samples amplified from genomic DNA isolated from roots.There were 92 AMF, including 15 potentially novel taxa detected. AMF communities in disturbed and undisturbed sampling locations were distinct except for one site, and indicator AMF virtual taxa (VT) for undisturbed grassland and disturbed sites were identified. AMF richness was higher in undisturbed (72 VT) than disturbed (64 VT) sites and AMF richness was positively correlated with plant species richness, diversity and native plant cover, and negatively correlated with non-native plant cover. There were 43 AMF VT on undisturbed and disturbed sites, 62% with higher relative abundance on disturbed sites. Site disturbance shifted AMF communities relative to undisturbed native fescue grassland; thus restoration success with native plants might be highly dependent on reintroducing native AMF.