Genetic components to belowground carbon fluxes in a riparian forest ecosystem: a common garden approach
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- •Soil carbon dioxide (CO2) efflux is a major component of terrestrial carbon (C) cycles; yet, the demonstration of covariation between overstory tree genetic-based traits and soil C flux remains a major frontier in understanding biological controls over soil C.
- •Here, we used a common garden with two native tree species, Populus fremontii and P. angustifolia, and their naturally occurring hybrids to test the predictability of belowground C fluxes on the basis of taxonomic identity and genetic marker composition of replicated clones of individual genotypes.
- •Three patterns emerged: soil CO2 efflux and ratios of belowground flux to aboveground productivity differ by as much as 50–150% as a result of differences in clone identity and cross type; on the basis of Mantel tests of molecular marker matrices, we found that c. 30% of this variation was genetically based, in which genetically similar trees support more similar soil CO2 efflux under their canopies than do genetically dissimilar trees; and the patterns detected in an experimental garden match observations in the wild, and seem to be unrelated to measured abiotic factors.
- •Our findings suggest that the genetic makeup of the plants growing on soil has a significant influence on the release of C from soils to the atmosphere.