Abstract
This developmental paper examines entrepreneurial ecosystem functioning under seasonal disruption in riverine economies through a multisited comparative study on Marajó Island in Pará, Brazil. Entrepreneurial ecosystem research has improved understanding of how regional configurations of actors, institutions, intermediaries, and infrastructures shape entrepreneurial outcomes, but it remains strongly oriented toward relatively well-connected settings. The paper addresses this limitation by treating seasonal disruption and infrastructure unreliability as constitutive conditions of ecosystem functioning rather than background context. It develops a mechanism-based explanation centred on transaction frictions, liquidity and cash flow constraints, and coordination capacity, and examines how these mechanisms link environmental vulnerability, infrastructure conditions, and hybrid governance to outcomes such as entry, upgrading, value retention, inclusiveness, and resilience. Empirically, the study compares Soure, Breves, and Afuá using ecosystem reconstruction, transaction reconstruction interviews, structured observation, and contextual indicators. The developmental paper seeks feedback on mechanism specification, comparative operationalisation, and its contribution to entrepreneurial ecosystem theory in peripheral and climate-exposed regions.