This paper uses Q methodology to analyse multiple environmentalities underlying professionals' legitimacy discourses on implementation of contested peatlands regulation under the European Habitats Directive. This approach advances the literature on multiple environmentalities by providing a lens on the enactment of power-knowledge relations between stakeholders in collaborative environmental governance. The empirical results illustrate the significance of power-knowledge in the dominant discourse coalition emphasising a sovereign-neoliberal environmentality in a one-size-fits-all approach to compensation. This paper also provides insights into the strategic alliance reinforcing technocratic rationalities and agricultural priorities at a key stage in the policy process. An emergent, albeit marginalised, 'truth environmentality' underlying a pragmatic, site-specific approach to implementation is also evident. Policy outcomes illustrate the abandonment of sovereign environmentality over highly contested areas, and the reconstruction of scientific legitimacy and norms under Article 6 of the Habitat Directive, to converge with broader neoliberal socio-economic priorities and cost-effectiveness. The analysis reveals how power-knowledge interactions within and between socio-economic and environmental-ecological sectors contribute to policy discourses and to conflict on implementation. The research also reveals the power of the State to steer collaborative governance towards contradictory outcomes, relative to the environmentalities expressed by professional actors, a position which potentially undermines the cultivation of pro-environmental values at local level.