Modeling vegetation and carbon dynamics of managed grasslands at the global scale with LPJmL 3.6

Susanne Rolinski (1) , Christoph Müller (1) , Jens Heinke (1) , Isabelle Weindl (1, 2, 3) , Anne Biewald (1) , Benjamin Leon Bodirsky (1) , Alberte Bondeau (4) , Eltje R Boons-Prins (5) , Alexander F Bouwman (6) , Peter A Leffelaar (5) , Johnny A Te Roller (7) , Sibyll Schaphoff (1) , Kirsten Thonicke (1)

1 PIK - Potsdam Institute for Climate Impact Research
2 HU Berlin - Humboldt-Universität zu Berlin = Humboldt University of Berlin = Université Humboldt de Berlin
3 Leibniz Institute for Agricultural Engineering and Bioeconomy
4 IMBE - Institut méditerranéen de biodiversité et d'écologie marine et continentale
5 Wageningen University and Research, Plant Production Systems
6 Department of Earth Sciences – Geochemistry [Utrecht]
7 Alterra, Wageningen Environmental Research

Grassland management affects the carbon fluxes of one-third of the global land area and is thus an important factor for the global carbon budget. Nonetheless, this aspect has been largely neglected or underrepresented in global carbon cycle models. We investigate four harvesting schemes for the managed grassland implementation of the dynamic global vegetation model (DGVM) Lund–Potsdam– Jena managed Land (LPJmL) that facilitate a better representation of actual management systems globally. We describe the model implementation and analyze simulation results with respect to harvest, net primary productivity and soil carbon content and by evaluating them against reported grass yields in Europe. We demonstrate the importance of accounting for differences in grassland management by assessing potential livestock grazing densities as well as the impacts of grazing, grazing intensities and mowing systems on soil carbon stocks. Grazing leads to soil carbon losses in polar or arid regions even at moderate livestock densities (< 0.4 livestock units per hectare – LSU ha −1) but not in temperate regions even at much higher densities (0.4 to 1.2 LSU ha −1). Applying LPJmL with the new grassland management options enables assessments of the global grassland production and its impact on the terrestrial biogeochemical cycles but requires a global data set on current grassland management.

Domaines: Sciences de l'environnement

Susanne Rolinski, Christoph Müller, Jens Heinke, Isabelle Weindl, Anne Biewald, et al.. Modeling vegetation and carbon dynamics of managed grasslands at the global scale with LPJmL 3.6. Geoscientific Model Development, 2018, 11 (1), pp.429 - 451. ⟨10.5194/gmd-11-429-2018⟩. ⟨hal-01788178⟩