Investigating plant-soil feedbacks in tropical montane forest trees

Abstract Plant-soil microbial interactions play a central role in maintaining biodiversity and coexistence in terrestrial ecosystems. However, to what extent plant-soil feedbacks (PSFs) operate in tropical Afromontane forests remains unclear. In this study, we conducted a PSF shade house experiment using six tree species exhibiting diverse life-history strategies and abundances in a sub-tropical montane forest in Nigeria. Seedlings were grown under controlled conditions in sterilised soil with or without soil inoculum collected under mature trees of each of the six species. We assessed whether conspecific tree seedlings’ performance was altered in comparison to heterospecific seedlings when grown in the soil of their adult trees. Seedling growth did not significantly differ between inocula from conspecific and heterospecific adults in five of the six species tested, indicating no evidence of PSFs. In Garcinia smeathmannii, we found a significant increase in seedling growth when grown in conspecific soil inocula. Given that no PSFs were observed in five out of six species, our study suggests that PSFs may play a limited role in the performance of some species in this Afromontane ecosystem. Nonetheless, the facilitative interaction noted in Garcinia smeathmannii indicates a nuanced ecological dynamic worth further exploration.