Intermediate coupling between aboveground and belowground biomass maximises the persistence of grasslands

PLoS One. 2013 Apr 29;8(4):e61149. doi: 10.1371/journal.pone.0061149. Print 2013.


Aboveground and belowground biomass compartments of vegetation fulfil different functions and they are coupled by complex interactions. These compartments exchange water, carbon and nutrients and the belowground biomass compartment has the capacity to buffer vegetation dynamics when aboveground biomass is removed by disturbances such as herbivory or fire. However, despite their importance, root-shoot interactions are often ignored in more heuristic vegetation models. Here, we present a simple two-compartment grassland model that couples aboveground and belowground biomass. In this model, the growth of belowground biomass is influenced by aboveground biomass and the growth of aboveground biomass is influenced by belowground biomass. We used the model to explore how the dynamics of a grassland ecosystem are influenced by fire and grazing. We show that the grassland system is most persistent at intermediate levels of aboveground-belowground coupling. In this situation, the system can sustain more extreme fire or grazing regimes than in the case of strong coupling. In contrast, the productivity of the system is maximised at high levels of coupling. Our analysis suggests that the yield of a grassland ecosystem is maximised when coupling is strong, however, the intensity of disturbance that can be sustained increases dramatically when coupling is intermediate. Hence, the model predicts that intermediate coupling should be selected for as it maximises the chances of persistence in disturbance driven ecosystems.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomass*
  • Fires
  • Herbivory
  • Models, Theoretical*
  • Poaceae / growth & development*

Grants and funding

Financial support was provided by the Deutsche Forschungsgemeinschaft (DFG) and by the Robert Bosch Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.