Topography-based Enhancement of Multifunctionality on Coastal Infrastructure

Abstract

The surface topography and configuration of coastal environments is pivotal in shaping ecological patterns and processes through its influence on microclimatic conditions and trophic niches. Coastal urbanization, and the associated simplification of natural shoreline complexity, can therefore have far-reaching effects on the composition and functioning of coastal ecosystems. The aim of this thesis was to understand how marine eco-engineering can restore and enhance the multifunctionality of artificial shorelines. I begin by reviewing how topography creates microhabitats through the modulation of environmental and ecological factors (Chapter 1), before empirically investigating several of these mechanisms. I found that habitat complexity and spatial scale are crucial drivers of thermal microhabitat formation on different topographic surfaces (Chapter 2), with topography-driven canopy establishment further broadening microclimatic niche conditions beyond initial topographic effects (Chapter 3). I furthermore studied relationships between substratum structure and biogenic habitat structure in natural, artificial and eco-engineered systems. Scale-dependent rugosity emerged as a key topographic factor underpinning the spatial occupancy of habitat-forming seaweeds and habitat-modifying grazers (Chapter 4), while, conversely, in rockpool-dominated habitats, configurational and topographic effects on biogenic habitat morphology were overshadowed by water retention effects (Chapter 5). Investigation of community formation in an eco-engineered system showed that multi-metric complexity increases biodiversity and supports near-natural habitat characteristics across multiple biodiversity metrics and scales (Chapter 6). Lastly, I linked structural and biogenic complexity to ecosystem services and climate change mitigation, showing that both topography and seaweeds can alter wave overtopping (Chapter 7), while seaweed growth on complex topographies can also substantially enhance the blue carbon storage potential of eco-engineered seawalls (Chapter 8). In summary, this thesis explores some of the fundamental mechanisms through which topographic, spatial and biogenic complexity shape intertidal ecosystems across multiple metrics and multiple scales, and provides novel methods for future coastal infrastructure design.

Date of Award	2026
Original language	English
Awarding Institution	University of Plymouth
Sponsors	Natural Environment Research Council (NERC) and ARIES Doctoral Training Partnership (DTP), grant ref: NE/S007334/1 & Arup Group
Supervisor	Mick Hanley (Director of Studies (First Supervisor)), Antony Knights (Other Supervisor), Andy Foggo (Other Supervisor) & Louise Firth (Other Supervisor)