Modeling the effects of extreme marine heatwaves to identify areas of potential refugia for a marine foundation species

MSc Ana Giraldo Ospina1,2, Professor Gary  Kendrick1,2, Dr Thomas Wernberg1,2, Dr Renae Hovey1,2

1University Of Western Australia, Perth, Australia, 2Oceans Institute, Perth, Australia

Identifying areas of refugia for species vulnerable to climate change is a priority for conservation and management. Extreme climatic events, such as heatwaves, can drive major changes in species distributions in a short period of time compared to the pervasive effect of climate change. Yet, species distribution models have focused on long-term effects of climate change rather than extreme events, which are predicted to increase in magnitude and frequency in the future. In this study, we examined the use of predictor variables of extreme temperature to simulate the effects of different extreme marine heatwave scenarios in the distribution of a key habitat builder, the kelp species Ecklonia radiata. The efficacy of the predictor variables was tested by comparing the projected ensemble model to the known range contraction suffered by E. radiata after an extreme marine heatwave that occurred in the coast of Western Australia in 2011. The results of the heatwave scenarios were then compared to predicted distributions for three emission scenarios of ocean warming for 2100. Results indicate that extreme heatwaves may have similar effect on the distribution of E. radiata as the gradual effect of climate change, emphasizing the need to incorporate these events in climate change predictions of species distribution, since they have the potential to accelerate the ecosystem damage already predicted in climate change projections. The distribution patterns of E. radiata after the marine heatwave scenarios also identified deep reefs (> 40 m) as potential areas of refugia, where kelps can survive environmental extremes.


Anita, as she prefers to be called, is a benthic ecologist with a particular interest in biophysical interactions, spatial ecology, climate change impact prediction and conservation. She originally from Colombia but she completed a Bachelor in Marine Biology at James Cook University in Australia, a Master in Marine Ecology in Baja California in Mexico and is currently in the final stages of her Ph.D. in Perth, Western Australia. She has experience working in research and monitoring of tropical and temperate seagrass meadows, kelp forests and coral reefs. Her current projects include the prediction of the effects of extreme climate events on species distribution, the ecology of temperate mesophotic reefs and of artificial reef structures.

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