Different control strategies of the invasive plant Arundo donax L. have taxon-specific effects on above- and belowground biodiversity

We assessed the short-term effects of different management strategies to control the invasive plant Arundo donax on biotic communities along a channelled stream in central Italy. We applied four treatments ordered by increasing management intensity: no management (C), one-cut per year (OC), three cuts per year (TC), and plastic mulching (M). Treatments started in June 2021 and ended in May 2022. Presence and abundance of vascular plants and soil bacteria and fungi were recorded from 24 plots immediately after the end of the treatments (May 2022) and five months later (October 2022). We tested the responses of A. donax and of the biotic communities to management intensity using generalized linear modeling and permutational analysis of variance. In May, M completely suppressed A. donax and plant communities, also reducing bacterial richness compared to C. However, plant communities under M recovered in richness by October, while A. donax under M and bacterial richness did not recover in such a timespan. Fungal richness was unaffected by treatments in both sampling seasons and decreased in October under all treatments. Management intensity had negative impacts on plant and bacterial functional diversity in both sampling seasons but did not affect fungal functional diversity. We highlighted that effective control of invasive species may imply short-term negative impacts on biotic communities. However, such impacts did not consistently affect different taxonomic groups. Plastic mulching should be used only in areas where rapid suppression of the invasive species is a priority, due to the short-term negative impacts on biodiversity of such practice.