Action versus Result-Oriented Schemes in grassland agroecosystem : A dynamic modelling approach

摘要

Effects of agri-environment schmes (AES) on biodiversity remain controversal. While most AES action-oriented, result-oriented and habitat-oriented schemes have recetly been proposed as a solution to improve AES efficiency. the objective of this study was to compare action-oriented and result-oriented schemes in terms of ecological and productive performance as well as in terms of management flexibility. We developed a dynamic modelling approach based on the viable control framework to carry out a long assessment of the three schemes in grassland agroecosystem. The model explicity links grazed grassland dynamics to bird population dynamics. It is applied to lapwing conservation in wet grassland in France. We ran the model to assess the three AES scenarios. The model revealed the grazing strategies respecting ecological and productive contraints specific to each scheme. Grazing strategies wereassessed by both their ecological and productive performance. The viable control approach maid it possible to obtain the whole set of viable grazing strategies and therefor to qualify the managment flexibility of the grassland agroecosystem. Our results showed that habitat and result-oriented scenarios led to much higher ecological performance than the action-oriented one. Differences in both ecological and productive performance between the habitat and result-oriented scenarios were limited. Flexibility of the grassland agroecosystem in the result-oriented scenario was much higher than in that of habitat-oriented scenario. Our model confirms the higher flexibility as well as the better ecological and productive performance of result-oriented schemes. A larger use of result-oreinted schemes in conservation may also allow farlers to adapt their managment to local conditions and to climatic variations.