Native pollinators without alternative resources go extinct, while the ones that reassign their visits to alternative plants decrease their density due to foraging on less profitable resources. Illustration: John Megahan

Just how successful are alien invaders and how do they impact natives? No, this isn’t about a classic video game or a threat from outer space.

Mutualistic networks of plants and their pollinators are key promoters of terrestrial biodiversity and crucial for our society’s food security. Unfortunately, the introduction of alien species into native ecosystems, together with climate change, widespread application of pesticides, habitat loss, and degradation, severely threatens the integrity of these systems and their critical ecosystem services.

“Despite the importance of plant-pollinator networks, we still lack predictive understanding of the factors and mechanisms determining their risk for being invaded by invasive species and the subsequent effects on native species,” said Fernanda Valdovinos, the study’s lead author and a professor of ecology and evolutionary biology and for the Center for the Study of Complex Systems at the University of Michigan.

Fortunately, such understanding of invasions in complex food webs has recently increased. In the Nature Communications paper, published online May 31, 2018, the researchers build on those efforts by further developing consumer-resource theory to elucidate the determinants of invasion success and the impacts of alien pollinators in complex plant-pollinator networks. The work develops predictive understanding of the factors and mechanisms determining the invasion success of non-native pollinators into these networks and their subsequent effects on native species. “We find that traits of non-native pollinators predict their invasion success and the network of interactions predicts their impacts on natives.”

Valdovinos’ coauthors are from Vibrant Data, San Francisco, Calif.; Center for Mathematical Modeling, University of Chile; GEMA Center for Genomics, Ecology and Environment, University Mayor; Argentine Institute of Arid Zone Research; and the Department of Ecology and Evolutionary Biology, The University of Arizona.

Native pollinators without alternative resources go extinct, while the ones that reassign their visits to alternative plants decrease their density due to foraging on less profitable resources. Illustration: John Megahan