Patterns in spatial distribution and root trait syndromes for ecto and arbuscular mycorrhizal temperate trees in a mixed broadleaf forest
Functional differences between trees with arbuscular (AM) or ectomycorrhizal (ECM) partnerships influence important ecological processes including nutrient cycling, community assembly, and biomass allocation patterns. Although most broadleaf temperate forests show both mycorrhizal types, relatively few studies have addressed functional difference among coexisting mycorrhizal tree species. The maintenance of ECM associations usually requires higher C investment than AM, leading to (A) lower root biomass and (B) more conservative root trait syndromes in ECM tree species compared to AM species. Here we quantified the representation and trait syndromes of 14 canopy tree species associated with either AM or ECM fungi in a natural forest community. Our results showed that, whereas species root abundance was proportional to basal area, some ECM tree roots were largely under-represented (up to ~ 33%). Most of the under-representation was due to lower than expected root abundance of Quercus rubra and Fagus grandifolia. Functional root traits in tree species were similar, with the exception of higher tissue density in ECM species. Moreover, closely related AM and ECM exhibited similar traits, suggesting inherited trait syndrome from a common ancestor. Thus, we found little evidence of divergent functional root trait syndromes between mycorrhizal types. Cores dominated by ECM species influenced trait distribution at the community level, but not total biomass, suggesting that mycorrhizal affiliation may have a stronger effect on the spatial distribution of traits but not on biomass stocks. Our results present an important step toward relating belowground carbon dynamics to species traits, including mycorrhizal type, in broadleaf temperate forests.
KeywordsMycorrhizal fungi Plant traits Root biomass SRL Root diameter Symbioses
The authors would like to thank Eugene Ryee and Chris Dejelo for their assistance in the field and processing samples. This study was supported by grants from the US National Science Foundation (DEB-0918240, DEB-0918878) and Department of Energy (DE-SC000433), startup funds provided Kent State University, an Art and Margaret Herrick Research Grant, and a David and Susan Jarzen Scholarship.
Author contribution statement
The group of authors have a common focus on the study of plant functional traits and ecological processes in temperate areas. OV-B, KS, LF, MK and CB conceived the study and contributed to data collection; OV-B and CB conducted the statistical analysis and OV-B, KS, and CB contributed to the writing of the manuscript.
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