Organisations of land managers in landscape management face the challenge of combining the need to foster bonding social capital within their member groups with the need to develop bridging social capital with other stakeholders and linking social capital with public authorities. This paper compares the concepts of self-governing groups, boundary organisations and quangos, to analyse how agri-environmental collectives in the Netherlands navigate their identity in interactions with public authorities and manage potential trade-offs between different forms of social capital. It shows the paradoxical situation that these self-governing collectives have to adopt characteristics of public agencies, in order to meet the demands of the Dutch government and EU legislation, required to gain the trust of the authorities for more room for self-governance. The resulting ‘professionalization’ and enlargement of agri-environmental collectives is likely to reduce bonding social capital, which in turn is an important asset for effective landscape management. In order to prevent this counterproductive incentive of expecting self-governing groups to behave like public agencies, we recommend to nourish and protect the in-between identity of agri-environmental collectives, to acknowledge their variety, and to allow them to be self-governing groups as well as boundary organisations.