Agri-environmental schemes (AES) have become the most important policy instrument of the Common Agricultural Policy (CAP) to foster the provision of environmental goods via agriculture. Farmers receive public payments when they carry out agri-environmental commitments. Besides the costs for payments to farmers, transaction costs as scheme organizational costs - emerge for both farmers and implementing administrations. This cumulative thesis addresses some unexplored aspects. It explains intra-scheme variances in magnitude and composition of public as well as private TCs with the help of a case study approach, taking the influence of the regulatory framework of the CAP explicitly into account. With the help of both quantitative and qualita...