Poster Sessions Concurrent Sessions Conference Proceedings Oak Symposium Home This paper was not included in the Symposium Proceedings.	Pre-Symposium Abstract of Paper Shifting connections: The succession of ecto- and arbuscular mycorrhizal networks on seedlings of three oak species A. E. Lindahl, M.F. Allen, L. M. Egerton-Warburton, C.S. Bledoe, D. Southworth, and D. Rizzo University of California, Riverside, University of California, Davis, and Southern Oregon University Common mycorrhizal networks (CMNs) connect plants, via their mycorrhizal fungi, transferring nutrients and water. Quercus agrifolia is capable of dually hosting both ecto- and arbuscular mycorrhizal (AM) fungi, and link into CMNs of varying function. Oak seedlings that colonize AM grassland ecosystems are frequently infected with AM fungi. As seedlings are planted at the edge and under the canopy of established, mature oaks, they form ectomycorrhizal (EM). This trend was observed in three oak species (Querus agrifolia, Q. garryana, and Q. douglasii) transplanted into a southern Californian oak ecosystem. Oak seedling mycorrhizal fungi in the grassland have low similarity values with the mature plants while seedlings under the canopy have indistinguishable communities from the mature tree. These results suggest that oak seedlings in a grassland ecosystem largely failed to link into the CMNs of mature oaks at the site and thereby likely fail to benefit from shared fungal connections. The importance of an AM network connection is unknown. Those establishing at the edge and under existing canopies appear to tap the existing EM mycelial matrix.
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