Modelling the effect of fertiliser, mowing, disturbance and width on the biodiversity of plant communities of field boundaries

To evaluate the effects of nitrogen, disturbance, mowing and boundary width on the composition of plant communities of field boundaries a spatial plant competition model was developed that incorporates competition for nitrogen and light as well as mineralisation and population dynamical processes. The model was parameterised for four grassland species: Poa annua, Holcus lanatus, Anthoxanthum odoratum and Festuca ovina. To test the model, simulation results were compared with data from a pot and a field experiment. In addition, several long-term simulations were performed to analyse the effect of the various factors on field boundary composition. The results of the simulations were generally in agreement with experimental results. The simulation study indicated that perennial diversity was maximal when nutrient input and degree of disturbance were low, cuttings removed and the boundary wide. The simulations and experimental results indicated that to enhance diversity of the field boundary vegetation the following measures should be taken: (1) preventing nutrient input from the arable field; (2) mowing and removing of the mown material; (3) restricting annual disturbance to less than 20% of the area; (4) keeping the boundary as wide as possible but at least wider than the maximum fertiliser misplacement.