Patches to Seascapes: Advancing Seascape Understanding of Fish Communities in Seagrass Ecosystems and its Applications to Conservation and Restoration

Abstract

Seagrass ecosystems in temperate estuaries are declining globally due to anthropogenic pressures such as climate change, coastal sprawl, and habitat degradation. These declines are concerning given that seagrass meadows support ecologically, economically, and culturally important fish communities, making active habitat restoration increasingly critical for ecosystem recovery and restoration of associated fish assemblages. However, restoration success remains limited partly due to inadequate consideration of the surrounding seascape and associated ecological processes, with less than 13% of projects incorporating seascape context and multi-scale spatial relationships into site selection and restoration design. To design restoration strategies that effectively support fish communities, we must first understand how the seascape influences these assemblages. Yet despite recognition of the role of seascape in shaping fish assemblages from a theoretical perspective, limited understanding exists of the seascape ecology of fish communities in seagrass meadows in temperate estuarine systems.This thesis addresses the critical knowledge gap in understanding how seascape and focal patch characteristics influence fish communities in temperate estuarine seagrass systems and develops a framework for applying this understanding to improve restoration outcomes. This research addressed four key questions via a logical progression from methodological foundations, through seascape ecological understanding, to practical application: (i) optimising sampling protocols for seascape-scale fish surveys, (ii) understanding how connectivity to artificial structures influences key fish assemblage metrics in seagrass meadows in urbanised estuaries, (iii) examining relationships between focal patch and seascape characteristics and seagrass-associated fish communities, and (iv) developing a decision-support framework for applying seascape ecological understanding to strategic restoration planning.