We examine the adaptability of collaborative governance regimes associated with publicly managed ecosystems as they move from direction-setting to implementation phases. This is an under-researched topic and is particularly relevant given the growth of collaborative environmental governance efforts around the globe. Through an in-depth analysis of a case study spanning 10 years of the Front Range Roundtable in Colorado, USA, we examine the effect of forces internal and external to the Roundtable on three attributes associated with the adaptive capacity of environmental governance: social capital, learning, and flexibility in implementing innovative actions. We find that the Roundtable has been highly sensitive to internal and external changes, and that the absence of mechanisms through which social networks and learning can be durably linked to implementation decisions of bureaucracies with management authority compromises the Roundtable's continued adaptability. From this case study, we develop three empirically testable propositions related to social capital and learning, national policy change, and boundary objects as collaborative regimes transition to implementation, along with an analytical framework to examine collaborative governance change and adaptability over time.