Long term development of a realistic and integrated socio-ecological system
We developed a discrete and qualitative model of integrated socio-ecosystems, with the help of formal Petri nets. We illustrated such Petri nets in the case study of temporary marshes in the Mediterranean part of France, the Camargue delta, by integrating biotic, abiotic and human-related components along with their processes into the same interaction network. The model demonstrated that when marshes are exposed to extensive grazing the presence of marsh heritage species is facilitated by opening up the vegetation through various trajectories. This supports the commonly used management practice of extensive grazing to conserve certain protected habitats. With this Possibilistic approach, we identified all potential ecosystem trajectories and provided their differential (non-systematic) impacts on heritage species richness (number). Hence, we rigorously demonstrate with this new type of model that grazing benefits marsh species which are faced with competition from common grassland species. The detailed analysis of the explicit state space and trajectories allows exploring simultaneously the identification of a range of recommendations for management strategies.