What happens to the mycorrhizal communities of native and exotic seedlings when Pseudotsuga menziesii invades Nothofagaceae forests inPatagonia, Argentina?.

SALGADO SALOMÓN, M.E.; BARROETAVEÑA, C; PILDAIN, M.B.; WILLIAMS, E; M. RAJCHENBERG

Valdivia

Workshop; International workshop of Mycorrhizal symbiosis in the southern cone of south America.; 2017

Universidad Austral de Chile

Presentación oralMycorrhizae associations are vital for Nothofagaceae forests and P. menziesiiplantations? establishment and development. In Patagonia, P. menziesii is beingplanted close or within native forests, showing an aggressive invasion behaviour.We studied the mycorrhizal status of seedlings along sixNothofagaceae+P.menziesii invasion matrices to investigate their role in thisprocess. Our results present evidence that P. menziesii invasion of Nothofagaceaeforests occurs with the co-invasion of their mycorrhizal partners. Also, soilenvironments located beyond invading conifers seedlings have shown to holdectomycorrhizal (EM) inoculum capable to associate with incoming new plants. Wehave evidence that P. menziesii invasion could produce maladaptation of native EMcommunities. Most of the EM species detected for all forests types correspond togenera reported as pioneers, commonly present in disturbed sites and previouslyreported in invaded matrices. Undoubtedly, these pioneer genera are a co-adjuvantfactor in P. menziesii seedling invasion. Hebeloma mesophaeum, a Wilcoxina sp.(early-stage and common P. menziesii?s EMs) and a Pyronemataceae sp. (widelyassociated with Nothofagaceae spp.) were found shared by P. menziesii andNothofagaceae spp. Interestingly, and contrary to our expectations, Hebelomahiemale and Wilcoxina sp., common mycorrhizal partners for P. menziesii inPatagonia although not registered from Nothofagus forest, were found associatedwith N. antarctica, this is the first report for both fungal species. Pseudotsugamenziesii seedling seems to have the ability to form different AM colonization types(Paris-, Arum- Both-, Intermediate-type) depending on sites conditions. Significanthigh presence of Intermediate-type was found in seedling grown in invaded soils,where the colonization was less abundance. The presence of different mutualassociation gives P. menziesii a strong ability for seedlings establishment. Thenursery mycorrhizal effect has been observed consistently in different environments,therefore, this fact should be considered in the design, site selection and invasionmanagement of fast growing exotic plantations in Patagonia