Nutrient availability and invader density regulate the diversity–invasibility relationship mediated by soil microbes

<b>Abstract</b><br/><p>This dataset accompanies a study examining how native plant diversity, nutrient availability, and invader density interact to influence the growth of the invasive plant <em>Phytolacca americana</em> via soil microbial mechanisms in a temperate forest ecosystem. The dataset includes (1) aboveground biomass data of <em>P. americana</em> grown in soils conditioned by varying native plant diversity levels (1, 3, or 6 species), under different nutrient conditions (fertilized vs. non-fertilized) and invader planting densities (1, 2, or 4 individuals); and (2) soil fungal community data derived from high-throughput sequencing, including taxonomic profiles (from phylum to genus) and functional classifications assigned using FUNGuild (e.g., saprotrophs, pathogens, symbionts). These data support analyses of how plant–soil feedbacks and soil microbial composition mediate invasion success, and are valuable for researchers in the fields of invasion ecology, soil microbiology, and plant–microbe interactions.</p>