Exotic plant invasion under increased environmental variability

• Applicant: Madalin Parepa, Ph.D.
• Subject Area: Ecology and Biodiversity of Plants and Ecosystems
• Term: from 2015 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 278590503

Plant invasions are amongst the most important drivers of global change, and cause substantial economic and ecological damage. Recent studies indicate that novel climatic conditions, such as changes in mean temperature and precipitation, can promote the spread of invasive plants. One dimension of climate change, however, which remains understudied, is changes in environmental variability. In a pilot experiment I showed that increased variability of nutrient supply, a common consequence of climatic variability, can strongly promote the invasion success of invasive knotweed, one of the worlds most noxious invasive species. It is now important to test how general this phenomenon is, how relevant it is under field conditions, and what its underlying mechanisms are. Here I propose a project that will thoroughly explore the relationships between changes in environmental variability, in the form of nutrient fluctuations, and plant invasion. My project has four aims: (1) to determine which types of variability promote plant invasion most by comparing the effects of nutrient fluctuations of different magnitudes and frequencies, (2) to test whether positive effects of increased variability on competitive dominance are a general phenomenon across (a) different invasive knotweed taxa, (b) other highly invasive plant species, or (c) also native species that are considered to be good resource competitors, (3) to examine, through stable isotope analyses, whether the success of invaders at high environmental variability is linked to their superior ability to take up and invest resources, and (4) to test the impact of nutrient fluctuations on plant invasion under field conditions. My project will increase our general understanding of the mechanisms underlying plant invasion, and of the interactions between invasion and other drivers of environmental change. Moreover, it will help to predict which habitats will be particularly threatened and thus, ultimately, to prevent and manage plant invasions.

• DFG Programme: Research Grants