Rising ocean temperatures through climate change is producing shifts in the distribution of tropical species to temperate regions in existing ecosystems worldwide. This shifts, known as tropicalisation, lead to the poleward expansion of tropical herbivores into cool temperate waters, where they become abundant, increase their grazing pressure on macroalgal biomass and modify the faunal assemblages. This research focuses on tropical herbivorous fish species that are expanding their ranges southwards into temperate seagrass communities. It aims to understand the impacts that the increasing abundance of tropical consumers have in temperate seagrasses in Western Australia.
Tropical herbivores have already impacted kelp forests in several places globally. However, far less is known about their effects on seagrass meadows. The western coast of Australia, with its extensive seagrass meadows, provides an ideal environment to begin examining the effects of tropicalisation on seagrass systems. In Western Australia, tropical fauna is already present in the temperate waters. Thus, a poleward shift in the distribution of the tropical herbivorous Siganus fuscescens has already been documented. The current research attempts to test the prediction that such expansion of tropical herbivorous species will result in profound alteration of temperate seagrass ecosystems in the region. It will allow quantifying current levels of grazing on seagrass in different climatic regions, and predict the grazing rates and impacts on seagrass function based on future fish assemblages in temperate seagrass meadows.
Edith Cowan University
Holsworth Wildlife Research Endowment Equity Trustees Limited
2016 – 2019
Mrs Maria Samsonova, PhD candidate
Professor Glenn Hyndes
Professor Kenneth L. Heck Jr. (University of South Alabama)
Dr Adriana Verges (University of New South Wales)