We compare conservation outcomes between a protected area (PA) and four indigenous common-property regimes (CPRs) under differing degrees of market integration in the Ecuadorian Amazon. We first assess how market forces and common-pool resource institutions governing processes of forest conversion affect biodiversity and forest cover, and whether institutions mitigate the effect of market forces. We then analyze how biodiversity and forest cover differ between a PA, and communities with different market access. Finally, we link biodiversity and forest cover changes within communities to differences in land-use practices. While we show similar levels of forest cover and biodiversity between the PA and large CPRs with little access to local markets, institutions appear not to attenuate market effects on conservation outcomes in our case studies. We discuss results within a common-property theory context and highlight the importance of disentangling how market integration, common-pool resource institutions, and resource health interact over time.