Eco-engineered shorelines for biodiversity enhancement: A discrete choice experiment on citizens’ preferences

Abstract

Spurred by a widened awareness of the loss of natural coastal habitats and the low biodiversity associated with traditional concrete sea defense structures, ecologically engineered shorelines (i.e., eco-shorelines) as an alternative are gaining traction amongst policymakers and environmental practitioners. However, it remains underinvestigated how society evaluates the intended outcome of transforming manmade seawalls into eco-shorelines, which may hinder their development and implementation. Using Hong Kong as a case study, this paper explores social preferences for various eco-shoreline design alternatives focusing on three key aspects: morphological changes, biodiversity enhancement, and the provision of recreational facilities, via the application of a discrete choice experiment. An online survey was conducted during October to November 2021, from which a total of 308 valid responses were received. The analytical results, based on the mixed logit models and the Equality Constrained Latent Class model, reveal that mangrove eco-shoreline is the most preferred, followed by rocky eco-shoreline and vertical eco-shoreline, while biodiversity enhancement and provision of recreational facilities are less preferred. About 54.9 % of the respondents pay little attention to the amount of donation associated with eco-shoreline implementation, corroborating a relatively strong social preference for transforming existing seawalls into eco-shorelines, irrespective of the amount of donation they might have to make. This study not only sheds additional light into the societal preference and valuation for eco-shoreline implementation, but also generates scientific evidence to inform plans and policies for concurrent coastal protection and biodiversity conservation.