Greening of grey infrastructure: Stakeholder and public perceptions from Britain’s Ocean City of PlymouthOcean Sprawl

Jessica Allen¹, Anaëlle Lemasson¹, Mick Hanley¹, Antony Knights², Abigail McQuatters-Gollop¹, Louise Firth²

¹University of Plymouth, UK - ²University College Cork, Ireland

The artificial hardening of the global coastline is driving habitat fragmentation, biodiversity loss, and disrupting ecosystem functioning and service provision. Greening of grey infrastructure (GGI), a type of ecological engineering, modifies artificial structures such as seawalls to mimic natural reef features and enhance biodiversity. Whilst the ecological effects are well documented, socio-economic considerations, crucial for successful implementation, remain underexplored. This study investigated public and stakeholder perceptions of GGI, assessing willingness to pay, and potential origins of differing views. The questionnaire used the greening of a public seawall with a Living Seawall as an example of GGI. Overall, respondents had positive perceptions and showed high levels of support of GGI. Almost all respondents were in favour of greening existing seawalls and believed that all new seawalls should be constructed with green engineering principles. Ecological benefits were considered the most important potential benefits of GGI installations. When ranked against other proposed environmental and social projects, the greening of a seawall was prioritised highly, and seawalls with marine life were ranked as more aesthetically appealing than bare seawalls. Almost all respondents were also willing to pay for GGI in some capacity, although the amounts did not reach true installation costs. Despite cost challenges, our findings indicate strong public and stakeholder support for GGI. This suggests that, with appropriate funding mechanisms and local buy in, GGI could be a key tool for bringing marine life back to artificialized coastlines.