Soil Microbial Community Effects on Quercus Rubra Seedling Survival at Harvard Forest 2016-2017

Feedbacks between plants and their soil microbial communities often drive negative density dependence in tropical forests, but their importance for tree demographics in temperate forests remains unclear. Additionally, the relative contribution of intraspecific seedling competition and soil pathogens to density-dependent patterns has rarely been assessed. We assessed how the soil microbial community influenced Quercus rubra seedling survival by growing seedlings in a greenhouse inoculated with soil collected from beneath conspecific and heterospecific mature trees. We found that seedlings grown with soil from beneath conspecific adults had a higher mortality rate than seedlings grown with soil from beneath heterospecific adults; therefore adult plant-soil feedbacks decrease seedling survival in Q. rubra.

植物与其土壤微生物群落之间的植物-土壤反馈（plant-soil feedbacks）常驱动热带森林中的负密度制约现象，但该作用对温带森林树木种群动态的重要性仍不明确。此外，种内幼苗竞争与土壤病原菌对密度制约模式的相对贡献鲜有研究得到评估。本研究以北美红栎（Quercus rubra）为研究对象，通过将其幼苗栽培于接种了取自同种（conspecific）与异种（heterospecific）成年树木下方土壤的温室环境中，探究了土壤微生物群落对幼苗存活的影响。研究结果显示，与接种异种成年树木下方土壤的幼苗相比，接种同种成年树木下方土壤的幼苗死亡率更高；因此，成年植物-土壤反馈作用会降低北美红栎的幼苗存活率。