Tree Species Identity Drives Fungal, but Not Bacterial, Soil Community Shifts in Tropical Monoculture Plantations

Tree plantations can help reverse the negative impacts of deforestation and land degradation worldwide, and soil microbial communities play key roles in tree growth and productivity. We studied microbial communities in the bulk soil of five native species monoculture plantations in the Republic of Panamá to assess how bacteria and fungi were affected by soil chemistry and plant identity after seven years of tree growth. Relative to the other species, Terminalia amazonia accumulated over three times the aboveground biomass and had lower mortality. Soil nutrients, especially phosphorus, were low, and we found no differences in soil chemistry across the five plantation types. Similarly, there was no difference in alpha diversity of the soil microbial communities across plantation types, and the bacterial communities showed no compositional variation or enrichment of any individual taxa. However, soil fungal communities differed in T. amazonia plantations as compared to the others, exhibiting enrichment or absence of specific taxa of arbuscular mycorrhizal fungi and putative phytopathogens. Our results suggest that T. amazonia may associate with certain microbial taxa that help it overcome low nutrient availability in these habitats. Consideration of plant–soil–microbe interactions in restoration efforts may facilitate tree growth and help to promote climate resilient forested areas.