Can metabolic traits limit species invasions under climate change?

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Invasive species are currently considered second only to habitat loss as a cause of rapid and undesirable changes in the functioning of ecosystems worldwide. In the United Kingdom alone, the annual cost of invasive species is estimated to be ~£1.7 billion. In this context, major cause for concern is that human-mediated species translocations and global warming are both causing rapid shifts in species' ranges and phonologies at an escalating rate. For example, a Pacific diatom Neodenticula seminae was documented into the North Atlantic for the first time in 800,000 years due to climate-driven melting of the Arctic ice cap and changes in ocean circulation. Such abrupt introductions can result in novel interactions (e.g., predator-prey or resource competition), which then have the potential to result in disruptive invasions of non-native species into local communities. In this project, we will meet the challenge of developing a general framework for predicting invasion success by building the first-ever global database on the temperature dependence of metabolic (physiological) traits relevant to species invasions through interactions, use these data to develop and parameterize a novel theoretical framework, and test some key predictions of this theory using laboratory experiments with a globally important functional group, the Phytoplankton (photosynthetic unicellular marine and freshwater algae and bacteria). Phytoplankton form the base of form the base of most aquatic food webs and contribute over half of global primary production. We will address three core questions: (1) How will mismatches in how metabolic traits (e.g., respiration and photosynthesis rate) of natives and non-native species respond to temperature change affect invasions? This question is important because new species often arrive with the physiological "baggage" of the environment they originated in, and therefore may be poorly adapted to their new environment (at least initially).(2) Does the rate and magnitude of thermal acclimation (defined as phenotypic changes in thermal-response with change in environmental temperature) in a non-native species to its new environment influence its invasion success? This question is important because many species can overcome the initial disadvantage of a novel environment by rapidly adjusting the way their metabolism responds to temperature. (3) Are natural temperature cycles important determinants of invasion success? This question is important because species invasions, especially in temperate regions, take place in climates that change cyclically at daily (say-night cycles) and seasonal (e.g., winter-summer) scales. Therefore, a non-native species that arrives, say, in winter, may have a lesser chance of invading successfully than if it arrived in summer. Overall, this study will fill a major gap in our understanding of the importance of metabolic constraints on species interactions for species invasions. We expect our results to form a new and robust foundation for predicting species invasions in natural as well as human-dominated environments. Our global database on metabolic traits will be a valuable, long-term resource for mapping metabolic traits onto potentially invasive species, and also for parameterizing ongoing efforts to model the effects of climate change on ecosystem services, including the carbon cycle.