The framework developed in this chapter for analyzing interplay management in institutional complexes delineates four governance niches and helps to identify conditions for occupying them effectively - that is, in a way that supports overall problem solving. Applying the notion of institutional niches to four cases of Arctic environmental governance helps to identify distinctive features that can equip an institution particularly well for conducting the related tasks. I first link the notion of institutional niches to certain general tasks of governance: building knowledge, creating norms, enhancing capacity, and enforcing compliance. The four areas of Arctic governance in focus are transboundary air pollution, marine contamination, hazardous waste treatment, and fisheries management.