Pine-ectomycorrhizal co-invasions alter ecosystem properties of native Eucalyptus stands
J. A. SIGGERS, J. NASH, E. Y. LAI, I. R. MOUNTS, B. BOCK, A. J. HALL, C. R. VIETORISZ, E. LEANDER, L. CAMUY-VÉLEZ, J. JAROS, I. BACY, J. S. BREWER, A. CARNEGIE, C. D’ANTONIO, N. A. HYNSON, R. VILGALYS, J. D. HOEKSEMA.
Department of Biology, Colorado State University, 251 W Pitkin St, Fort Collins, CO 80523, USA

In New South Wales, Australia, the establishment of >10,000 ha of Pinus radiata plantations has led to unintended and largely understudied ecological consequences for adjacent native ecosystems where pines are wilding (i.e., expanding in range). Key components to understanding non-native pine expansion are their ectomycorrhizal fungal symbionts, which may serve to promote establishment. We explored the effects of non-native P. radiata wilding on native Eucalyptus ecosystem properties, hypothesizing that microbial communities, plant litter characteristics, and soil properties will differ beneath wilding pines and eucalypts. Soil, roots, and plant litter were collected from beneath P. radiata and Eucalyptus spp. individuals to assess differences in soil physiochemical properties, bacterial and fungal community composition, substrate utilization, and litter composition. Initial results suggest that our focal species harbor unique bacterial communities (p = 0.001), with eucalypt soils containing more bacterial diversity than pine soils. Pine-associated arbuscular mycorrhizal communities were dominated by the genus Paraglomus, while Glomus were enriched in Eucalyptus-associated communities. Soil properties, such as soil moisture (p = 0.008), also differed between plant species dependent upon the size of the individual. Thus, the wilding of introduced pines could change microbial community and overall ecosystem characteristics within native Eucalyptus forests, causing unforeseen long-term outcomes.