Incorporating rock pools in coastal guards, an eco-engineered approach to enhance biodiversity

Abstract

Driven by growing human populations and climate change concerns, artificial coastal structures have become crucial for meeting population needs. However, these structures often differ from natural counterparts and undermine biodiversity. Integrating eco-engineering methods during their construction is, therefore, essential to counteract the negative impact on marine biodiversity. In this study, we incorporated rock pools of two different sizes to three distinct intertidal levels within a concrete block breakwater in Bandar Abbas, Iran, and conducted an in-situ assessment of their biota. A total of 17 taxa were identified, with the barnacle Amphibalanus amphitrite being the most prevalent species. The findings revealed a fivefold increase in cumulative species number and a 30% rise in abundance due to the presence of rock pools. The results of PERMANOVA indicated that both rock pool size and intertidal levels, along with their interaction, significantly influenced species richness. Notably, small rock pools within the low intertidal level exhibited the highest species richness and abundance, whereas larger rock pools situated in high intertidal levels displayed lower richness and abundance. Our investigation underscores the effectiveness of integrating rock pools as an ecological engineering approach to enrich biodiversity on human-made structures within intertidal zones. The selection of rock pool dimensions and tidal positioning should be thoughtfully determined, considering the prevailing environmental conditions and the project's objectives.