Does a diversity of species protect ecological communities from invasion? Recent work by SFI External Professor Andreas Wagner (University of Zurich) takes up this long-standing question for complexity science, at a microscopic scale. In his paper in Molecular Ecology, Wagner reports that microbial communities do indeed “become more species-rich, show higher biomass, and become more invasion resistant,” as they develop in reaction to invading outsider species that compete for nutrients.

Because of the challenges involved in observing species at the microscopic scale, invasion amongst microbes has been relatively under-studied as compared to macroscopic ecological communities. To get around these challenges, Wagner used a computer modeling framework based on genome sequence data and extensive biochemical information for hundreds of microbial strains to explore, in-silico, how real-world microbes would react and grow. In addition to finding that microbial communities become more diverse in response to invasion, he also found that certain combinations of species occurred more often than chance would predict. This could mean that certain “attractor” communities do better than others at fending off invasions.

Read the study: “Competition for nutrients increases invasion resistance during assembly of microbial communities” at