Seascape Context and Marine Reserves in Seagrass Ecosystems: Managing Harvested Fish Communities

Abstract

Marine ecosystems are undergoing rapid change from a suite of human-induced stressors including overexploitation of resources, habitat fragmentation and loss, reduced habitat quality and changes to ecosystem functioning. Reserves are implemented and designed to reduce these influences, by preserving biodiversity, conserving marine habitats, increasing resilience of biota to disturbances, enhancing productivity, and facilitating the recovery of exploited fishery species. Although marine reserves can alter the structure and functioning of ecosystems, other factors such as seascape context and temporal variability can influence fish communities, ultimately determining the effectiveness of marine reserves. Ecosystem processes, abundances of harvested species and the spatial use of marine reserves can be largely influenced by the spatial properties that make up an ecosystem and other environmental factors such as climate. Although there is growing recognition of these processes, many of the key ecological characteristics that occur in protected seagrass ecosystems remain hitherto unstudied. I, therefore, aim to assess the influence of seascape context and temporal variability relative to the effectiveness of marine reserves for the protection of harvested seagrass fish species and the functions they provide. Ultimately, this thesis aims to determine the most suitable form of management of fish communities within seagrass ecosystems.