COS 6-5 - Inclusion of plant-soil feedbacks in assessing Great Lakes tree expansion in response to global warming

Monday, August 8, 2011: 2:50 PM
6B, Austin Convention Center
Sarah M. Neumann, Forestry, Michigan State University, East Lansing, MI and Ines Ibanez, School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI

Many plant species are expected to shift their distributional ranges in response to global warming. Many other factors besides climate will shape the future composition of plant communities. In particular, plant-soil feedbacks (PSF) will likely have a large impact on colonization success of migrant plant species as they may be released from their natural soil pathogens and/or deprived of key symbiotic organisms in their new range. The overarching goal of this study was to evaluate the role that soil-plant feedbacks may play on the migratory potential of dominant temperate tree species at the northern limit of their distributional range in the Great Lakes region.

To test for the presence and strength of PSF, we assessed seedling survival over 10 weeks in a greenhouse experiment with eight tree species (Acer rubrum, Acer saccharum, Carya glabra, Liriodendron tulipifera, Prunus serotina, Quercus rubra, Quercus velutina and Robinia pseudoacacia) to soils that had been cultured in situ by each of the eight species in their current southern distributional range. We compared these results to the response of these same species to soils cultured in situ from a northern site that was beyond the current distribution for half of our study species (C. glabra, L. tulipifera, Q. velutina and R. pseudoacacia). By sterilizing field soil, we tested whether soil microbes were the mechanism creating these plant-soil feedbacks.


All four local species and two migrant species experienced negative PSF (conspecific cultured soil detrimental relative to heterospecific(s) cultured soils) and an additional migrant species experienced a positive PSF in southern soils. However, northern soils were beneficial to all local species and two migrant species relative to conspecific cultured soils from the southern range. Soil pathogens in conspecific cultured soil were the mechanism for the negative PSFs in A. rubrum, A. saccharum, L. tulipifera, P. serotina and Q. rubra whereas soil pathogens in heterospecific cultured soils was the mechanisms for the positive PSF in Q. velutina. The negative PSF occurring for R. pseudoacacia seedlings were chemically mediated occurring regardless of sterilization. Soil biota in northern soils had less of an effect on survival regardless of whether a species was local or migrant. Our results suggest that soil pathogens appear to be more virulent in the southern range and thus southern populations of both local and migrant tree species may experience a release from soil pathogen mediated plant-soil feedbacks during their migration northwards. 

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