This paper introduces a new ecological accounting model, the perimeter of which is not centered on businesses nor on States, but on ecosystems and their inter-organizational management on the landscape. The goal of this paper is to present this model as well as the key principles and the conceptual background on which it is founded. The model consists of three levels of accounts. It combines (1) the evaluation and monitoring of ecological issues in a given context, that provides a representation of the ecological values collectively created; (2) the evaluation and monitoring of stakeholders’ commitments, and of their contributions to the collective value creation processes; (3) the evaluation of the effects of these commitments on each stakeholder’s own value creation. Depending on the level of maturity of the collective ecosystem management situation, the model can be used as an exploratory device, a negotiation template or a full-fledged accounting tool. The paper provides a first illustration on how this approach can be applied based on a local ecosystem management case study (the Cam-Ely-Ouse catchment, UK). It finally shows how this accounting approach can be key in developing and implementing new biodiversity and natural capital policies using the current debates on environmental and agricultural policies in the UK as an example.