Patterns and processes of alien plant invasions across habitats

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Global trade and human migration have caused an unprecedented spread of organisms beyond their natural distribution range. While most introduced plant species fail to establish, some spread in large numbers and have detrimental effects on ecosystem functioning and services (invasive alien plants'). Theory predicts that the susceptibility of a plant community (invasibility') is a key factor for the success of alien plant invasions, but what drives invasibility across the diverse array of habitat types we encounter in the landscape is not well understood. Several hypotheses have been proposed, but empirical evidence has been mixed and difficult to interpret. The lack of scientific progress ultimately deprives practitioners of tools to prevent and manage invasive alien plans.******The goal of my research proposal is to improve our ability to predict and increase the resilience of habitats to alien invasive plants. Although the importance of habitat resilience has been stressed in the past, invasive species management has so far focused mostly on controlling already established plants through biological, chemical and mechanical means. My previous research has shown that this approach leads to high herbicide usage on public wildlands and can endanger ecological restoration by suppressing non-target native plants and beneficial mycorrhizae. By analyzing vegetation survey data, I have shown that habitats display contrasting levels of invasion, which raises the question whether invasibility is foremost driven by habitat properties, such as varying nutrient (resource') availability, diverging exposure to seed and plant material of alien plants (propagule pressure'), or a different capacity to tolerate human disturbance (human footprint'). ******In my envisioned Discovery Grant (DG) program, I will pursue research in three themes, each focusing on one of the following questions: (1) Does resource availability drive differences in the levels of invasion across habitats? (2) Do invasions across habitats follow similar trends in distant regions and globally? (3) How do human footprint and propagule pressure affect habitat invasibility?******Most of the envisioned program will be conducted in Alberta, where 16% of the flora outside of cultivation has been reported to be alien. It will be complemented by a study in Central Asia, an area where I have extensive research experience. The planned studies will use a broad array of methods, including vegetation surveys, modeling and experiments, and will involve 20 highly qualified personnel. By focusing on a wide variety of habitat types and including global data mining, I aim to detect underlying universal mechanisms that make habitats susceptible to alien plant invasions. In the long-term, I will build concepts for a habitat-based approach in the management of invasive alien plants.**