Temperature variation and compensatory density feedback drive life stage-specific establishment of tropical fish in temperate seas
Dr Cristián Monaco1, Dr Ivan Nagelkerken1, Dr David Booth2, Dr Corey Bradshaw3, Dr Bronwyn Gillanders1, Dr David Schoeman4
1University Of Adelaide, Adelaide, Australia, 2University of Technology Sydney, Sydney, Australia, 3Flinders University, Bedford Park, Australia, 4University of the Sunshine Coast, Sunshine Coast, Australia
Climate change is driving shifts in the distribution of many species globally as they track isotherms along latitudinal and elevation gradients. A species’ ability to keep pace with the spatial velocity of shifting climate depends on stochastic expression of population growth rates, as well as the influence of compensatory density feedbacks on these. Abundance time series estimated at the leading edge of a species’ distribution provide opportunities to quantify the relative contribution of these drivers, and build models to predict future establishment and abundance trajectories. Using the tropical Indo-Pacific sergeant fish (Abudefduf vaigiensis) as a model organism, we applied phenomenological population dynamical models to quantify the relative importance of endogenous and exogenous drivers of population growth rates. This species is increasingly found settling along temperate latitudes of southeast Australia, aided by an intensifying East Australian Current and rising sea surface temperatures. Using variants of the Gompertz-logistic model, we show that (1) density feedback contributes to the dynamics of these transient populations; however, while (2) rates of settlement are indirectly influenced by temperatures experienced by parents at the tropical source population, (3) subsequent survival of transient offspring is mostly explained by the temperatures experienced at the temperate sink. While previous research has drawn attention to the association between temperature and fish species redistribution, our quantitative analyses highlight the need to consider species’ responses throughout ontogenetic development. Only by incorporating such complexities will we be able to improve our predictions of species distributional shifts resulting from climate change.
Biography:
Earned a PhD in Biology at the University of South Carolina, under Brian Helmuth, looking at the thermal ecology and physiology of a key predator-prey system from the rocky shores of California.
Then conducted postdoctoral research at Rhodes University (South Africa), working with Christopher McQuaid. This work also involved understanding mechanisms that determine which species may be winners or losers under climate change scenarios, but using intertidal mussels as study models.
Currently doing a second postdoc, now at the University of Adelaide (Australia), under Ivan Nagelkerken. The project he is part of aims at scaling-up those individual-level responses that have been his focus thus far, to get a bigger picture of relevant processes taking place at the population and community-levels. This time, the system of study includes tropical marine fishes which are currently shifting distributions southwards along the east coast of Australia.