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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #332729

Research Project: Adaptive Rangeland Management of Livestock Grazing, Disturbance, and Climatic Variation

Location: Livestock and Range Research Laboratory

Title: Plant-soil feedbacks and mycorrhizal type influence temperate forest population dynamics

item BENNETT, JONATHAN - University Of British Columbia
item MAHERALI, HAFIZ - University Of Guelph
item Reinhart, Kurt
item LEKBERG, YLVA - University Of Montana
item HART, MIRANDA - University Of British Columbia
item KLIRONOMOS, JOHN - University Of British Columbia

Submitted to: Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2016
Publication Date: 1/13/2017
Citation: Bennett, J.A., Maherali, H., Reinhart, K.O., Lekberg, Y., Hart, M.M., Klironomos, J. 2017. Plant-soil feedbacks and mycorrhizal type influence temperate forest population dynamics. Science. 355:181-184.

Interpretive Summary: • Problem- Spontaneously generated plant communities, like temperate forests, exhibit high levels of variation in species composition, dominance, and diversity. For example, some forests are highly diverse while others are near monocultures of a single species. These patterns are thought to depend in part on whether adult trees facilitate or inhibit establishment of like (i.e. conspecific) species. These recruitment syndromes may be driven by many factors including complex plant-soil biota interactions (e.g. pathogenic effects and pathogen protection). • Accomplishment- Experiments on 55 tree species indicated that seedling performance was often lower in soil from conspecifics than other species, especially for tree species with roots that associated with only arbuscular mycorrhizas. In contrast, tree species with roots that associated with ectomycorrhizas often grew equally well in soil from like versus other tree species. Ectomycorrhizas seemingly provided seedlings with a high level of soil-borne enemy (e.g. pathogen) protection. Variation in plant-soil biota interactions, meditated by mycorrhizal associations, corresponded with local and regional variation in conspecific inhibition and facilitation. • Management implications- Our findings highlight the importance of ectomycorrhizas, but not arbuscular mycorrhizas, in seemingly protecting trees from soil-borne antagonists that proliferate around conspecific trees and impact forest composition.

Technical Abstract: Feedback with soil biota is a major driver of diversity within terrestrial plant communities. However, little is known about the factors regulating plant-soil feedback, which can vary from positive to negative among plant species. In a large-scale observational and experimental study involving 55 species and 550 populations of trees in North America, we found that the type of symbiotic mycorrhizal association explained significant variation in plant-soil feedbacks. In soil collected beneath conspecifics, trees forming arbuscular mycorrhizas experienced negative feedback, whereas trees forming ectomycorrhizas displayed positive feedback. Additionally, arbuscular mycorrhizal trees exhibited strong conspecific inhibition at multiple spatial scales, whereas ectomycorrhizal trees exhibited conspecific facilitation locally and less severe conspecific inhibition regionally. These results suggest that mycorrhiza types, through effects on plant-soil feedbacks, could be a major driver of population regulation in temperate forest trees, with potentially large impacts on forest community structure and diversity.