Page - 30 - in options, Volume summer 2015

young scientists 30 options + summer 2015 www.iiasa.ac.at people at iiasa A quiet scourge is creeping through the muddy coastal shallows in the reservoirs of southeast Nebraska. The Chinese Mystery Snail, an invasive species first brought to the USA in the late 19th century, gorges itself on periphyton and algae, and can upset food chains, outcompete native species, and transmit parasites that can infect humans. The species can even become so abundant that piles of snails clog up pipes bringing fresh drinking water to people in nearby communities. Unsuspecting boaters and fishers brought the snails into Nebraska and continue to carry the snails from lake to lake. Where will the snails go next? Danielle Haak, a participant in the 2014 Young Scientists Summer Program (YSSP), and her supervisor Brian Fath came up with a new model that combined human movements with ecological networks to provide a more systemic view of how species spread. The researchers drew from both social and ecological network analysis and public health models of disease transmission. “We adapted the framework of infectious disease network modeling to simulate what would happen within the first 25 years after a hypothetical snail introduction,” says Haak. The study identified some of the most at-risk lakes, as well as the most risky infected lakes, giving managers key information as to where to focus their containment efforts. For her outstanding research project, Haak received the annual Peccei Award, which will allow her to return to IIASA for six months to continue her work. More information about Haak and the other three 2014 award winners is available at www.iiasa.ac.at/news/yssp-awards-14. KL www.iiasa.ac.at/yssp Large-scale fishing could lead fish populations to evolve into separate varieties, according to a new study led by Pietro Landi. He started the work, which was published this January, during the 2012/13 Southern African Young Scientists Summer Program (SA-YSSP). Previous IIASA research, led by Evolution and Ecology Program Director Ulf Dieckmann and research scholar Mikko Heino, showed that fisheries can influence evolution: when fishers selectively harvest the largest individuals, fish populations evolve to mature and reproduce earlier in their lifecycles. Landi’s study shows that such human-influenced selection could also broaden the diversity of fish populations, and even push them into evolving two varieties with distinct characteristics, a  process known as evolutionary branching. “Especially when fishers only harvest larger or mature individuals and preserve the smaller or juvenile fish, we found that such dynamics are possible,” says  Landi. While the study is theoretical at this point, it  shows an important potential human impact on the environment and exploited natural resources. The next step, he adds, would be to collect data to see whether there is empirical evidence for such dynamics. Landi is now continuing his SA-YSSP research as a postdoctoral fellow at Stellenbosch University, South Africa, and at IIASA. He plans to extend his work on evolutionary modeling with applications to the flora and fauna of South  Africa, including aquatic and terrestrial ecosystems. Landi says, “The SA-YSSP was really mind-broadening. It was a great opportunity to learn from people of many different cultures, fields, and backgrounds, and to set my research within the broader context of systems analysis and policymaking.” KL Further info Landi P, Hui C, Dieckmann U (2015). Fisheries-induced disruptive selection. Journal of Theoretical Biology 365:204–216 [doi:10.1016/j.jtbi.2014.10.017]. www.iiasa.ac.at/sa-yssp Fisheries may promote diversification A SA-YSSP participant publishes new research applying  mathematical models to the evolution of fish Invasion of the habitat  snatchers A YSSP award winner designs an innovative  model to understand how invasive species spread Pietro Landi Danielle Haak