Participatory mapping of ecosystem services to understand stakeholders' perceptions of the future of the Mactaquac Dam, Canada

Rebuilding or removing a dam at the end of its lifespan will change provision of and access to ecosystem services. Understanding such changes involves assessing their biophysical provision, economic value and social demand, of which the latter is often neglected. We used participatory mapping to understand the spatial distribution of social benefits from ecosystem services around the Mactaquac Dam, New Brunswick, Canada, and assessed whether perceptions of ecosystem services under future scenarios can be mapped. We asked 32 participants to map places that were important to them for several ecosystem services, and asked how those places and services would change if the dam were rebuilt or removed. Participants benefitted from services throughout the reservoir, downstream of the dam, and in unaffected tributaries. Those who preferred to rebuild the dam mapped places in and around the reservoir, while those who wanted to remove it preferred the tributaries and downstream reach. Most participants could not map service distribution if the dam were removed, but could describe non-place-specific changes. Participatory mapping is useful for understanding how and where stakeholders benefit from ecosystem services, and to prompt discussion of perceived future changes. It is less useful for producing maps of ecosystem services under various scenarios.