the danger of re-introduction of invasive plants: A novel experimental test with two species from their introduced and native range

• Applicant: Professorin Dr. Katja Tielbörger
• Subject Area: Ecology and Biodiversity of Plants and Ecosystems
• Term: from 2008 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 103550304

Invasive plants exert significant impacts on native communities. Theories explaining the invasion paradox are based on rapid microevolutionary change in response to biotic interactions. The Evolution of Increased Competitive Ability (EICA) hypothesis predicts that plants evolved into superior competitors in their new range due to release from herbivores. Here, we formulate an innovative prediction based on the EICA: when reintroducing invasive ecotypes back into their native range they should exhibit an invasive behaviour. By testing this prediction, we address several previously neglected aspects of the EICA hypothesis in an integrative manner. We propose an innovative combination of experiments testing whether ecotypes in the new range are less affected by herbivores and have a larger competitive effect than their native progenitors. If so, they pose a threat when reintroduced into their native range, as done in recent crosscontinental studies. We address this question with experiments for two plant species of contrasting invasion pattern: Lythrum salicaria (native: Europe; invasive: US), and Impatiens glandulifera (native: India; invasive: Europe). Our study will help predicting invasibility and significantly further our understanding of fundamental processes structuring natural plant communities, and it adds an important innovation to theory and practice of conservation ecology.

• DFG Programme: Research Grants