Details

Autor(en) / Beteiligte

• Chen, Weizhe
• Ciais, Philippe
• Zhu, Dan
• Ducharne, Agnès
• Viovy, Nicolas
• Qiu, Chunjing
• Huang, Chunju

Titel

Feedbacks of soil properties on vegetation during the Green Sahara period

Ist Teil von

• Quaternary science reviews, 2020-07, Vol.240, p.106389, Article 106389

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• During the early to middle Holocene, the Sahara received enhanced precipitation and was covered by steppe-like vegetation with a large-scale hydrographic network of lakes, wetlands and fans, which is known as the Green Sahara (GS). However, most coupled land-atmosphere models underestimate the precipitation and vegetation cover, suggesting that critical atmospheric or land surface processes are lacking in those models. Climate-induced vegetation cover change can modify soil texture and physical properties over the long term, which in turn have feedbacks on vegetation. In this study, we examine five plausible soil-vegetation processes in a land surface model, which are expected to increase soil moisture for plants and possibly sustain equilibrium vegetation for a lower rainfall level. The annual precipitation required during the GS epoch to match the modelled vegetation distribution with paleorecords is inferred. Results demonstrate that these soil-vegetation processes have strong positive impacts on vegetation and soil moisture, especially the increase of soil evaporative resistance. After including all soil feedbacks on vegetation, the model requires only a mean precipitation of ∼400 mm/yr to reproduce the pollen-inferred GS vegetation, instead of ∼600 mm/yr when no soil feedback is included. From the mid-Holocene to pre-industrial period, we infer that terrestrial carbon stocks decrease by ∼58 PgC due to the removal of carbon in vegetation, soil and litter pools of the GS. This work highlights the importance of soil-vegetation interactions for simulating dry-region vegetation coverage in models, and the impacts of natural land cover change on carbon budgets in the geological past. •A dynamic vegetation model is used to reproduce the Green Sahara vegetation.•Strong soil-vegetation interactions determine modelled vegetation distribution.•The relative importance of each soil feedback is separated by factorial simulations.•The carbon stocks in the mid-Holocene Sahara are ∼58 PgC higher than today.