Klimešová, Jitka; Mudrák, Ondrej; Martínková, Jana; Lisner, Ales; Leps, Jan; Filartiga, Arinawa; Ottaviani, Gianluigi

Soil core sample

Plant characteristics (traits) measured on aboveground plant parts and organs are usually used not only for predicting aboveground ecosystem functions (e.g. productivity) but also for belowground ones (e.g. soil carbon stock). This is because aboveground traits are more accessible and better studied than those of belowground organs. In this study, we found that belowground traits characterizing clonal growth of plants may be as good predictors as aboveground traits and bring a new perspective on ecosystem functioning.

We assessed community-level biomass allocated to aboveground plant parts, and belowground to rhizomes and roots, together with analyzing soil organic carbon for 52 temperate grasslands in two Central European regions. As predictors, we used aboveground traits associated with functions linked to leaves and plant stature (such as photosynthetic efficiency), and traits describing belowground functions linked to rhizomes, namely ability to occupy a new area and persist there, and speed of clonal reproduction. The regions differed in management regime (i.e. mowing frequency), soil properties, species composition and productivity.

Above- and belowground traits contributed to prediction of biomass allocation strategies, but we found no significant relationships between traits and soil organic carbon. Belowground traits measured on rhizomes were as good as aboveground traits at predicting biomass allocation in less intensively managed grasslands (i.e. mown once a year). The lack of predictive ability of traits in more intensively managed grasslands (i.e. mowing twice a year) likely resulted from a significant decrease of aboveground and belowground biomass (especially a marked reduction in rhizome biomass). We discovered that rhizome-related traits (important for population dynamics, i.e. clonal growth) provide complementary information on biomass production at community level to that offered by aboveground traits linked to e.g. photosynthetic efficiency of leaves.

Despite a conspicuous context dependency of predictive power of plant traits between the two study regions, we have shown that clonal traits can significantly help in unravelling ecosystem functioning in temperate grasslands where most biomass is allocated belowground.

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