What is the scientific evidence on the linkages between citizen science engagement levels and protected areas’ governance outcomes? A systematic map and qualitative synthesis

•How do citizen science (CS) participation levels affect protected area governance?•A systematic search for empirical literature done in the Scopus and WoS search platforms.•Collaborative and co-created CS is mainly conducted outside Europe or North America.•Contributory CS has less diverse governance outcomes and affecting factors.•Protected area managers are encouraged to explore the potential of collaborative CS. Citizen science (CS) entails different citizen engagement levels in research. It is not well-known how these levels affect protected area (PA) governance. This review systematically maps and analyses how the empirical scientific literature has constructed the links between three CS engagement levels (contributory, collaborative, co-created CS) and their outcomes for protected areas’ governance. From our search results (5486 records), 63 articles dealt with the topic in-depth. The most common engagement level was contributory CS. Almost all collaborative and co-created CS projects were conducted outside Europe or North America. All CS levels support the strategy-formation phase of the governance cycle, whereas collaborative CS supports the monitoring and evaluation phase, and co-created CS the practical implementation. The collaborative/co-created CS supports legislative, cooperation-based, and information instruments, whereas economic instruments are not well-recognised by any CS level. Collaborative and co-created CS target a more diverse set of actors and governance levels, than contributory CS. Collaborative and co-created CS often mention project funding and collaboration as factors to achieve the outcomes, whereas contributory CS frequently mentions CS cost-effectiveness. In our total sample, CS is mainly conducted in national parks and Marine Protected Areas and targets simple monitoring objects. It shows a knowledge gap for other PA types and points to the need to diversify monitoring indicators. We suggest PA managers explore the potential of collaborative and co-created CS, especially in the European and North American context, as these CS levels support a more complex set of practice-oriented governance outcomes needed for strategic adaptive PA management.