Growth and regeneration of seagrass after disturbance from dugong grazing • back to student info Kathryn McMahon*, James Udy*, Michelle Waycott**, Marion Cambridge*** *Marine Botany, Centre for Marine Studies, The University of Queensland, Brisbane, Australia 4072 **James Cook University, Townsville *** University of Western Australia, Perth Completed 2005

Seagrasses are the major diet of dugongs. In Moreton Bay, Queensland, dugongs generally feed in large herds. They harvest the seagrass by plowing a trail through seagrass meadows, removing both the above-ground shoots and below-ground rhizomes. This feeding behaviour alters the species composition and age structure of the seagrass community, favouring faster growing, colonising species such as Halophila and Halodule. The aim of my PhD research is to use two case studies to investigate recruitment dynamics of sub-tropical seagrasses exposed to natural disturbances, both large scale, stochastic events and small scale, repeated events. The first case study focuses on the intertidal seagrass, Zostera capricorni and examines meadow development following extensive seagrass loss due to a flood and where the meadows were recruited from seed. The second case study focuses on smaller scale but repeated disturbance from dugong grazing on the seagrass Halophila ovalis. The role vegetative growth and sexual reproduction plays in maintaining these sub-tidal seagrass meadows is investigated.