When the Application Programming Interface (API) of a framework or library changes, its clients must be adapted. This change propagation - known as a ripple effect - is a problem that has garnered interest: several approaches have been proposed in the literature to react to these changes. Although studies of ripple effects exist at the single system level, no study has been performed on the actual extent and impact of these API changes in practice, on an entire software ecosystem associated with a community of developers. This paper reports on an empirical study of API deprecations that led to ripple effects across an entire ecosystem. Our case study subject is the development community gravitating around the Squeak and Pharo software ecosystems: seven years of evolution, more than 3,000 contributors, and more than 2,600 distinct systems. We analyzed 577 methods and 186 classes that were deprecated, and answer research questions regarding the frequency, magnitude, duration, adaptation, and consistency of the ripple effects triggered by API changes. © 2012 ACM.