Are belowground clonal traits good predictors of ecosystem functioning in temperate grasslands?

Abstract

In herbaceous communities which host many perennial species, belowground clonal organs and traits remain largely overlooked in ecosystem functioning studies. However, the belowground compartment is expected to play a key role as the greatest proportion of biomass is allocated belowground. Our main goal was to test whether including underexplored clonal traits (in tandem with widely used aboveground traits) improves the ability to predict biomass production and soil carbon in temperate grasslands. We examined the relationships between five plant functional traits (canopy height, specific leaf area [SLA], lateral spread, multiplication rate, persistence of rhizome) and biomass allocation (aboveground, roots, rhizomes) and soil organic carbon (SOC). We studied 52 grassland plots clustered in two Central European regions differing by management intensity. We assessed biomass allocated aboveground and belowground (into roots and rhizomes separately). SOC was measured from averaging five soil cores at each plot. Trait community means were calculated for each trait from species compositions using databases. The most important traits in predicting biomass allocation were canopy height and persistence of rhizome. Results, however, differed for the two regions implying context dependency of the relationships. Persistence of rhizome and canopy height emerged as traits largely affecting ecosystem functioning at the less intensively managed grasslands—likely because of their links to biomass production and plant economics spectrum. At the more intensively managed grasslands, canopy height and SLA were negatively correlated with root biomass, with persistence of rhizome playing a (lesser) role. We found no significant predictors for SOC. Synthesis. This study is the first attempt to integrate belowground clonal and aboveground traits to predict biomass allocation and soil carbon. Findings indicate that the ability of plant functional traits in predicting ecosystem functioning is highly context dependent, varying greatly even within the same community type. Only SLA and, to a lesser extent, persistence of rhizome consistently predicted root biomass in the two regions. We call for a broader implementation of the whole‐plant multifunctional approach applied here, ideally extending to other open ecosystems. A free Plain Language Summary can be found within the Supporting Information of this article.

Strong impact of management regimes on rhizome biomass across Central European temperate grasslands

“…Data are available in the Dryad Digital Repository (Klimešová et al 2021 b ): https://doi.org/10.5061/dryad.1ns1rn8sq…”

“…This is because excavating and assessing belowground biomass for plants in their natural communities is challenging due to rooting depth, and belowground plant organs of different species are often tightly intermingled (Westoby and Wright 2006, Klimešová et al 2018). While we know from pot studies that herbs can invest approximately half of their biomass in belowground organs (Poorter et al 2015), in natural and seminatural grasslands the allocation into belowground biomass can be up to 80% of the entire community biomass (Titlyanova et al 1999, Mokany et al 2006, Klimešová et al 2021 a ). Does this mean that herbaceous communities found in nature invest considerably more to belowground resource acquisition than pot‐grown plants?…”

Sticking around: plant persistence strategies on edaphic islands

“…How these functions play out under specific circumstances can be assessed through trait-based approaches (Klimešová et al, 2019;Ottaviani et al, 2020a;Pérez-Harguindeguy et al, 2013;Weiher et al, 1999). A good example is offered by seasonal and disturbance-prone temperate grasslands hosting many perennial herbaceous species with different persistence strategies (Klimešová et al, 2016a(Klimešová et al, , 2021Ottaviani et al, 2020b). A major group comprises long-lived clonal species, capable of both sexual and vegetative reproduction and investing considerable resources belowground into bud-bearing and carbohydrate storage organs (Janovský & Herben, 2020;Klimešová et al, 2016a).…”

“…All of these plants can cope effectively with seasonally cold climates and recurrent disturbances (e.g. mowing, grazing, fire; Klimešová et al, 2018Klimešová et al, , 2021Ottaviani et al, 2020b). Some of them are also able to deal with increasingly drier seasons, nutrient deposition or altered management regimes (Fischer et al, 2020;Qian et al, 2021).…”

The species richness–productivity relationship varies among regions and productivity estimates, but not with spatial resolution

“…Indirect characteristics like nutrients in soil or biomass (Vermeer and Berendse 1983, Tilman and Pacala 1993, Klaus et al 2011, Grace et al 2016), environmental characteristics such as temperature, precipitation, evapotranspiration, tree stem density and various remote sensing indices (Šímová and Štorch 2017) are also used for estimating productivity. Another parameter, belowground biomass, is very rarely evaluated (Ravenek et al 2014, Ottaviani et al 2020) although this dimension can be even more important for ecosystem functioning than the aboveground counterpart in grassland communities (Klimešová et al 2021, Ottaviani et al 2021). Nevertheless, the consistent use of the same productivity estimates across studies is rare (but see Vermeer and Berendse 1983, Grace et al 2016).…”