Ecosystem services are deteriorating. It is essential to develop economic instruments that promote the production of ecosystem services. Conservation agencies use, among other things, payment systems for ecosystem services that remunerate private landowners to adopt pro-environmental practices on their spatially contiguous lands. Iterative or sealed bidding procedures are well suited to provide efficient incentive systems. Experiments have shown the superiority of iterative auctions. In order to better understand the processes implemented, we propose here to analyze the strategies of the landowners in the case of sealed bids auction format.