Symbioses: Plant, Animal, and Microbe Interactions
Oberle, Brad , Zanne, Amy .
Seeing the forest for the fungi: plant traits and decomposition rates under changing climate.
A large fraction of terrestrial carbon (C) is locked up in woody stems, both living and coarse woody debris. The rate of carbon release from these pools depends on two factors: plant senescence and wood decomposition. These factors, in turn, are modulated by wood traits. Vascular anatomy and chemical composition may influence mortality during drought. They also may affect saprotroph community structure and function. These wood traits vary among species, with important consequences for the carbon balance of forests under climate change. As part of a larger project that integrates experiments and field observations with plant traits and fungal metagenomics, we established long-term experimental decomposition plots in the Ozark Highlands Ecoregion. Plots were situated at upland and lowland sites indifferent watersheds. Each included stem sections from 16 locally occurring species with contrasting traits. After the first year of decomposition, we analyzed variation in mass loss across sites and species. Overall, stems lost 12-50% of their mass. Mass loss varied between sites, with moister lowland sites decaying more quickly than drier upland sites. Mass loss also varied strongly among species. Species differences alone explained 56% of the variation in initial decay rates. These species differed in a suite of functional traits, including leaf size, specific leaf area, leaf area to sapwood area ratio, wood density, C and N content, and C:N ratio. Although each trait independently explained relatively little variation in decay rates, together they explained almost as much variation in decay rates as species identity. In addition to these measured trait differences, unmeasured differences between angiosperms and conifers (i.e. clade membership) contributed to variation in decay rates. On the whole, these results reinforce the well-known effect of environment on decomposition. Furthermore, they strongly suggest that plant species' functional traits and evolutionary histories play an extremely important role in wood decomposition. Exactly how species' differences influence saprophyte community structure and function will be the subject of future studies.
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1 - University of Missouri-St. Louis, Biology, One University Boulevard, St. Louis, MO, 63121, USA
2 - University Of Missouri - St. Louis, R223 Research Building, One University Blvd., St. Louis, MO, 63121, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Portland Room/Chase Park Plaza
Date: Tuesday, July 12th, 2011
Time: 4:00 PM