TROPHIC INTERACTIONS ON EQUATORIAL ARTIFICIAL COASTAL DEFENCES

Abstract

Coastal development, flood and erosion risks exacerbated by climate change, and the subsequent proliferation of artificial hard defensive structures, have transformed shorelines worldwide. Singapore, an equatorial island city characterized by intense urbanization, has successfully employed ecological engineering techniques to bolster marine biodiversity on seawalls. However, our ability to predict biodiversity responses in the face of future changes remains constrained by gaps in understanding of species interactions within these habitats. In this thesis, I investigated intertidal assemblages and their trophic interactions on seawalls in Singapore, with a specific focus on intertidal gastropods. Through field surveys, manipulative in-situ and ex-situ experiments, as well as stable isotope analysis, I quantified the effects of predation, herbivory, and competition in these urban marine communities and food webs. Overall, my results show how seawalls act as important habitats and feeding grounds in urban coastal ecosystems.