The ecosystem services (ES) concept has emerged as a major theme in environmental research and governance in recent decades (Chaudhary et al., 2015; Costanza et al., 2017). Proponents of the concept highlight its potential to alert policy makers, businesses, and citizens to our dependence on the natural world. Yet since its inception the concept has been plagued with criticisms of putting market prices on, and ultimately commodifying, nature. This thesis aims to explore debates and tensions within the ES concept through a series of conceptual discussions and empirical investigations. What is revealed is that ES is neither a silver bullet, nor a grave threat. It is a deeply ambiguous concept that takes multiple forms in the different contexts in which it is applied. Through a case study in Scottish inshore governance I show how the concept is shaped by existing institutions, norms, and policy priorities. Rather than dismissing the concept then, what is important is guiding its deployment to ensure it reflects the complex ways in which humans live in, with, and from the non-human world. To this end, I identify guiding principles for the ES concept including inter-and transdisciplinary working and of the consideration of pluralistic environmental values. With these principles in mind, the rest of the thesis is given over to methodological considerations. I first make the case for a post-normal science framing in ES research. This post-normal approach is then demonstrated through the application of a Deliberative Democratic Monetary Valuation in the context of marine planning. This thesis is therefore both descriptive and prescriptive, and ultimately intends to help guide the operationalisation of the ES concept.