Background information

An extensive body of research suggests that invasive plant populations often undergo phenotypic and ecological divergence from their native sources. These changes can result due to selective pressures in the new range or through demographic stochasticity during introduction. Given the life-history traits of trees that gives them long lifespans and generation times, it is not surprising that the evolutionary dynamics of invasive trees are still comparatively poorly understood and that their invasion potential has been often underestimated. Invasive trees have significant impacts worldwide and these are increasing rapidly in many parts of the world.

Several cases are known where invasive tree populations show differences in morphological or physiological traits or altered ecological interactions (e.g. mutualistic relationships) compared to their native sources. Despite such evidence, the understanding of the drivers and the extent of these changes remains sketchy compared to other plant forms, such as annual herbs.

The first aim of this workshop is to synthesize our current knowledge on the key processes underlying tree invasions worldwide by investigating the role of different potential drivers, including pre-adaptation, artificial selection/selective breeding, polyploidy, hybridization, reduced enemy pressure, new mutualistic interactions, and novel selection pressures, in facilitating evolutionary change. A second aim is to elucidate the dimensions of these processes to better understand across which temporal, spatial and taxonomic scales such changes can occur. This includes, for example, findings on how certain drivers are represented across different taxa, how rapidly divergence from native sources can develop and/or if a species’ invasion success across wide geographical ranges can be the result of different drivers. Further, we aim to explore how such processes may bias management and control approaches and how research could reduce such biases, thereby increasing our general knowledge of, and ability to manage, tree invasions.

We are inviting leading experts in tree invasions to participate in this workshop. The workshop will be a perfect platform for a diverse group of scientist to present their work, to have valuable discussions and to initiate collaborations with other researchers in this field.

The Centre for Invasion Biology (C·I·B) has undertaken research on a wide range of topics relating to tree invasions and is internationally regarded as one of the leading research institutes in the field of invasion biology. This and its location within one of the world’s hotspots of tree invasions make the C·I·B the ideal host institution for the workshop.

Expected output

The main aim of this workshop is to publish the workshop contributions in a special issue of the international peer-reviewed journal AoB PLANTS which offers a dynamic, open-access environment for the publication of high-quality research in environmental and evolutionary plant biology. We encourage presentations of ongoing studies that are at an advanced stage based on theoretical, molecular and/or experimental approaches related to the research areas described above. Ideally participants should have a draft manuscript ready at the time of the workshop.

Sponsored by

We thank the following organisations for their support of this workshop:

Picture credits: (left and right) Acacia forestry trial – photo credit John Wilson; (top left) Acacia pycnantha also known as Golden wattle – photo credit Jaco Le Roux; (top centre) Acacias covering country road – photo credit Pablo Souza-Alonso; (top right) Acacia mearnsii commonly known as Black wattle; (bottom) Prosopis, Loeriesfontein – photo credit Ross Shackleton.