Soil carbon sequestration accelerated by restoration of grassland biodiversity

Abstract

Agriculturally degraded and abandoned lands can remove atmospheric CO2 and sequester it as soil organic matter during natural succession. However, this process may be slow, requiring a century or longer to re-attain pre-agricultural soil carbon levels. Here, we find that restoration of late-successional grassland plant diversity leads to accelerating annual carbon storage rates that, by the second period (years 13–22), are 200% greater in our highest diversity treatment than during succession at this site, and 70% greater than in monocultures. The higher soil carbon storage rates of the second period (years 13–22) are associated with the greater aboveground production and root biomass of this period, and with the presence of multiple species, especially C4 grasses and legumes. Our results suggest that restoration of high plant diversity may greatly increase carbon capture and storage rates on degraded and abandoned agricultural lands.

Step back from the forest and step up to the Bonn Challenge: how a broad ecological perspective can promote successful landscape restoration

“…The Society for Ecological Restoration (SER) defines ecological restoration as: “the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed.” What is often termed true restoration aims for high ecosystem structure and biodiversity, as well as high ecosystem functioning, in contrast to rehabilitation of a degraded ecosystem that mainly focuses on reinstating ground cover and some level of ecosystem functioning or service. Reclamation, on the other hand, involves replacing and stabilizing the degraded ecosystem by biologically productive, often intensive systems (croplands, improved pasture) that may provide one particularly desired ecosystem service but lack biodiversity and all its manifold effects on functioning and services (Bradshaw ; Yang et al ). However, when striving for true restoration in times of global change, there is a need to assess shifting baselines for ecological restoration, including what our target communities are, as reaching historical reference ecosystems may no longer be possible.…”

“…We argue that wherever possible we should aim for ecological restoration (see Fig. ) since it usually promotes the greatest biodiversity and ecosystem functioning (Benayas et al ; Isbell et al ; Yang et al ). Nonetheless, in light of climate change and eutrophication of many regions of the world, the call for flexible targets for ecological restoration is more important than ever (Harris et al ; Choi ; Suding ; Aronson et al ; Higgs et al ).…”

“…higher plant species richness and functional diversity lead to more root biomass, but only after an initial time lag of 4 years (Ravenek et al ). The time lag suggests that belowground interactions and reaction speeds are more buffered here than for the aboveground, which could have an effect on potential speed of belowground C sequestration during grassland restoration (but see Yang et al for the impressive potential for this). The positive biodiversity effect in grasslands sets in aboveground in the first year and becomes magnified over time as nutrients are removed from the system with mowing (Marquard et al ; Meyer et al ), thus fostering facilitative interactions in relation to nitrogen (Roscher et al ).…”

Edible Microorganisms—An Overlooked Technology Option to Counteract Agricultural Expansion

“…Even if the final approximation would underestimate the land area requirements for CO 2 capture, conversion and bacterial cultivation by an order of magnitude, this would still correspond to <1% of the surface area required to produce the equivalent amount of feed protein through conventional soybean cultivation. This in turn would enable large-scale restoration of agricultural lands to their original habitats-either forests or grasslands, which would not only benefit biodiversity preservation but could also be used for carbon sequestration (Silver et al, 2000;Nave et al, 2018;Yang et al, 2019). However, such an approach would need to be carefully evaluated to determine whether any net negative emissions gained from large-scale land sparing risk being offset by the embedded carbon footprint of the necessary industrial infrastructure in addition to any emissions associated with its energy consumption.…”

Incorporating Biodiversity into Biogeochemistry Models to Improve Prediction of Ecosystem Services in Temperate Grasslands: Review and Roadmap

“…High species richness reduces root decomposition by increasing root C:N ratios, except for legumes [47], with grassland species having widely varying turnover rates [48]. However, high biodiversity (in mixtures that were compared to monocultures) does tend to stimulate soil microbial biomass and soil respiration [49], and it strongly increases carbon sequestration [50,51].…”