This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.
This award will support a twenty-four-month research fellowship by Dr. Elizabeth M. P. Madin to work with Dr. David Booth at the University of Technology, Sydney and Dr. Philip Munday at James Cook University in Australia.
It has long been noted that trophic cascades, where removal of top predators alternately drives increases and decreases in abundances of lower trophic levels, are more commonly observed in temperate than tropical marine systems. Many factors have been hypothesized to affect the occurrence and magnitude of cascades, but only a subset likely vary over latitudinal gradients. This project quantitatively explores this issue by addressing the question: What factors are responsible for the apparent disparity in trophic cascade occurrence and magnitude in temperate versus tropical ocean ecosystems? As part of this project the first standardized, comparable data is being collected for these mediating factors over a large-scale gradient of different ecosystem types at seven locations along the east coast of Australia to determine which, if any, may be responsible for the latitudinal patterns observed globally. From this information, a predictive model of factors mediating marine trophic cascades is being developed that should provide valuable guidance towards preventing human-induced cascades. Australia?s east coast offers an unparalleled opportunity to explore latitudinal gradients in ecosystem function. The local project collaborators and their laboratories have critical expertise in the ecology of tropical and temperate marine systems, respectively. Dr. David Booth?s lab focuses largely on the temperate systems of southeastern Australia and he has a highly interactive lab group working on similarly large-scale ecological questions. Dr. Philip Munday?s research focuses heavily on fish-habitat associations, the key ecological interaction in marine trophic cascades, and climate change effects on these associations. Importantly, unlike most marine ecologists, both Drs. Booth and Munday have experience in the role of prey behavior in mediating interspecific interactions, a key component of this study.
This research will greatly increase our understanding of the system characteristics mediating top-down effects in marine ecosystems. This knowledge is critical because in order to understand how marine ecosystems are likely to change in the future we must first understand the factors that regulate them. The projected continued increase in the global demand for seafood means that fisheries stocks will likely exhibit increasingly unstable population dynamics leading to increased likelihood of trophic cascades.
