Salvador Zarco Perello
Thesis: Persistence and Impact of Tropical Herbivorous Fish on Temperate Western Australia
As the ocean temperatures rise due to climate change, tropical species are migrating towards higher latitudes. The immigration of tropical herbivorous species to temperate ecosystems is of special concern, since they can modify the habitat and community structure by consuming and reducing the abundance of the habitat-forming vegetation. Some parts of the world have experienced transformations of productive macroalgae ecosystems into barren seascapes. Evidence that Australia is experiencing this process is emerging. The tropical herbivorous fish, Siganus fuscescens, has expanded its distribution to south-western Australia (SWA) following a marine heatwave in 2011 and this species is now the most important kelp consumer in some temperate reefs in the Perth region. However, further assessments considering the spatio-temporal variability of their impact is needed. My research is aimed to assess several of these aspects: (i) their current distribution and abundance in SWA, (ii) their movement behavior among temperate habitats, (iii) their reproduction and recruitment success, (iv) their feeding preferences and how these aspects change in space and time (different habitats and seasons of the year).
Why my research is important
At a regional level, the project will help determine the vulnerability of temperate ecosystems of Western Australia to tropicalization. If S. fuscescens continues its successful colonization, it can increase the likelihood in the ecosystems of the region of suffering phase-shifts to turf dominated ecosystem states. At a global scale, the project will be of great interest to the national and international scientific and resource management communities, since the tropicalization of temperate ecosystems is an international phenomenon with important socio-economic implications.