Format: POSTER

Ezequiel Antorn-Pilar*1, Jaime Madrigal-Gonzlez2, Joaqun Calatayud1

1 Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Madrid, Spain 2 EiFAB-iuFOR, Universidad de Valladolid, Soria, Spain

Understanding species coexistence is not only about exploring the classic paradigm of competitive exclusion but also considering the role of other ecological mechanisms. In plants, plant-soil feedback (PSF) has been identified as a relevant factor influencing plant performance and population dynamics, but its role in the coexistence of competing species is still poorly explored. This study explores how PSF mediated by microorganisms, may regulate or impact coexistence mechanisms of two competing species. Rather than relying exclusively on direct competition, we hypothesized that population dynamics and distribution of species could be driven by PSF. A common garden experiment were conducted involving two species, Cistus ladanifer and C. laurifolius. Performance measures, focusing on root and shoot biomass, were recorded under experimental conditions. We used soils dominated by each of the two species, conducted a cross-experimental approach that used sterilized soils and soil microorganism inoculum from both species. This separation aimed to discern the effects of soil physic-chemical properties and living microorganisms. We found that the interaction of soil properties and microorganisms drive early growth of both species. Both species grow better in richer soils where only one species prevails. Yet, this only occurs when plants are experiencing microorganisms from their own soil. Consequently, our findings suggests that PSF play a key role in regulating population dynamics of competing species, challenging the conventional understanding dominated by direct competition.