Functional diversity of leaf nitrogen concentrations drives grassland carbon fluxes

Abstract

Little is known about the role of plant functional diversity for ecosystem-level carbon (C) fluxes. To fill this knowledge gap, we translocated monoliths hosting communities with four and 16 sown species from a long-term grassland biodiversity experiment ('The Jena Experiment') into a controlled environment facility for ecosystem research (Ecotron). This allowed quantifying the effects of plant diversity on ecosystem C fluxes as well as three parameters of C uptake efficiency (water and nitrogen use efficiencies and apparent quantum yield). By combining data on ecosystem C fluxes with vegetation structure and functional trait-based predictors, we found that increasing plant species and functional diversity led to higher gross and net ecosystem C uptake rates. Path analyses and light response curves unravelled the diversity of leaf nitrogen concentration in the canopy as a key functional predictor of C fluxes, either directly or indirectly via LAI and aboveground biomass.

Plant functional diversity enhances associations of soil fungal diversity with vegetation and soil in the restoration of semiarid sandy grassland

“…2006; Milcu et al. 2014). The encroachment of dominant plants with more conservative resource use and greater nutrient retention can favor soil fungal dominance through the N‐poor litter recycling (Zeller et al.…”

Plant diversity increases soil microbial activity and soil carbon storage

“…Twelve monoliths (2.0 m in depth and 1.6 m in diameter) were excavated from the field site of The Jena Experiment and installed in the macrocosms in the Ecotron in spring 2012. These 12 monoliths reflected the diversity gradient of The Jena Experiment on a smaller scale 51 . Monoliths with high (16 plant species) and low plant diversity (4 plant species) were labelled with 13 CO 2 for 4 weeks.…”

A coordinated set of ecosystem research platforms open to international research in ecotoxicology, AnaEE-France

“…4). The largest units are in the Bterrestrial Macrocosms^platform of Montpellier designed to host intact or reconstituted samples of continental terrestrial ecosystems from 2 to 15 t each, for several month-to a few year-long experiments (Milcu et al 2014). This platform has 12-day lit units of 40 m 3 each and can accommodate soil cores from 2 to 5 m 2 with a depth from 0.5 to 2 m. Weather (temperature, humidity) and atmospheric conditions (CO 2 , 13 C-CO 2 ) above the soil core can be controlled in each macrocosm independently.…”

“…First, Ecotrons could allow testing the effects of toxicants under realistic physical, chemical, and biological conditions, including both aquatic and terrestrial ecosystems with a significant number of species representative of complex biological communities (e.g., Milcu et al 2014). In particular, Ecotrons can reproduce the climatic conditions of almost all European regions with their daily and seasonal patterns, and intact ecosystem samples can be introduced into most of the platforms.…”

“…They host longterm manipulations spanning several decades where it is possible to take into account ecosystem inertia and feedback loops than cannot be detected on the short term in Ecotrons or seminatural platforms. If needed, these sites can also provide intact ecosystem samples, differentiated by long-term manipulations, for specific experiments (Milcu et al 2014). …”