Co-invasion hypothesis explains microbial community structure changes in upland streams affected by riparian invader

Abstract

AbstractNonnative riparian plants can affect stream microbial dynamics by altering the quality, quantity, and timing of allochthonous inputs, but little consideration has been given to the potential influence of co-invading mutualists associated with nonnative riparian invaders. We used a high-resolution ecogenomic approach to examine the effects of riparian invasion by nonnative willows on microbial composition in associated small temperate streams. Willow infestation led to significant differences in fungal and bacterial communities between willow-infested and reference reaches. Fungal taxon richness was lower and phototrophic bacteria were less common in willow-infested reaches. Aquatic hyphomycetes contributed less to community composition of fungal communities in willow-infested reaches. Nonnative ectomycorrhizal fungi Inocybe spp. and Tormentella spp., known willow mutualists in their home ranges, were primary drivers of microbial community differences among infested and reference reaches. Nonnative...