Heterogeneity of patterns and processes along biological invasion successions

• Applicant: Professor Thorsten Reusch, Ph.D., since 1/2014
• Subject Area: Ecology and Biodiversity of Plants and Ecosystems ; Evolution, Anthropology ; Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: from 2013 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 243421602

Biological invasions have been shown to drive significant ecological impacts that in some cases lead to substantial economic losses. Characterizing intrinsic biological drivers of invasions is a crucial step to understand current, and predict future patterns of invasion. Invasion is a complex, multi-stage process including introduction, establishment and spread of the non-native species until it becomes harmful for native communities and therefore a pest in some cases. The traditional approach is to identify relevant biological traits that underpin a species ability to invade. However, recent studies suggest that traits beneficial at the start of an invasion (i.e. favouring the colonization of novel habitats) might be different from traits being favoured at later stages of invasion. Such variation in observed traits along the invasion succession should therefore be visible at both the phenotypic and genomic level. For example, at the front of invasion, individuals may have better predator recognition skills and/or a more efficient immune system to endure novel pathogens. Similarly, at the population level higher dispersal rates and/or higher reproductive rates may prove to be determinant during the early stage of invasion. Therefore it seems crucial for an individual to express a specific trait at key stages (e.g. establishment, spread) for a successful invasion to occur. However, currently we do not know whether there is a genetic underpinning to these traits variations or if they arise directly from phenotypic plasticity. In addition, the contribution of individual phenotypes to specific invasion stages remains to be shown. In this project, we propose to characterize these patterns of trait variations within an invasion succession and test for the significance of these variations (i.e. genetic and phenotypic) at different stages of the invasion. Using field surveys and large-scale semi-natural experiments, we aim to determine how the genetic and phenotypic heterogeneity of invasive populations along an age-gradient of invaded habitats is expressed. In order to generalize findings, we will use both terrestrial and freshwater model organisms that have clear ecological and socio-economic impact on a range of ecosystems services. These organisms have been extremely well studied and detailed characterization of invasion history across Europe already exist (i.e. time since invasion), with large spatial collection of specimens in support of our project. Based on these empirical evidences, we will establish a sampling strategy to collect additional information on several phenotypic traits (morphology physiology, behaviour) along with biotic and abiotic data for populations at different stages of the invasion. We will also estimate reproductive and dispersal rates, as well as genetic neutral and non-neutral diversity to understand the origin and consequences of variation with population age. Second, we will create populations of different composition (phenotypic traits, life history traits, and relatedness) in innovative and realistic large-scale experimental set-ups allowing measuring dispersal, colonization and impact on ecosystems. Outputs from the field survey and the experiments will be used to calibrate individual-based models aiming at generalizing our results, and at providing an effective tool for stakeholders. Such tool will be useful to managers for prioritizing and anticipating actions limiting the spread of non-native species.

• DFG Programme: Research Grants
• International Connection: France, Sweden
• Participating Persons: Professor Dr. Tomas Brodin; Professor Dr. Jean Clobert
• Ehemaliger Antragsteller: Dr. Christophe Eizaguirre, until 1/2014