Measuring ecological impacts of alien species

Alien species cause a number of impacts in the ecosystems they live in, ranging from hardly detectable to dramatic change. Measuring such impacts is not always straightforward. Furthermore, a wide range of methods and variables has been used to describe these impacts, making comparison between species and habitats difficult. Impacts of some species are context-dependent, varying greatly depending on the exact circumstances. Measuring and comparing impacts is however crucial in order to prioritise the management of alien species. The better the understanding of context-dependency, the better equipped we will be to predict the impacts of new alien species.

In 2013, an international working group, named sImpact, was established to tackle some of the issues related to the impacts of alien species. Under the leadership of C·I·B researcher Sabrina Kumschick, the group published a paper that reviewed different methods (observational and experimental) for detecting and quantifying impacts for different groups (plants, vertebrates, invertebrates) and habitats (terrestrial, aquatic and marine).

The paper, published in BioScience, proposed a set of parameters on which to base the development of quantitative measurements to allow comparisons of impacts across alien species, sites, and time. “The systematically gathering and synthesizing of solid evidence of the impacts caused by alien species facilitate communication with the public and will better inform policy- and decision makers.” says Sabrina Kumschick, lead author of the paper.

Read the article:

Kumschick S, Gaertner M, Vilà M, Essl F, Jeschke JM, Pyšek P, Bacher S, Blackburn TM, Dick JTA, Evans T, Hulme PE, Kühn I, Mrugala A, Pergl J, Rabitsch W, Ricciardi A, Richardson DM, Sendek A & Winter M (2014) Ecological impacts of alien species: quantification, scope, caveats and recommendations. BioScience

For more information, contact Sabrina Kumschick at

sImpact participants of a workshop held in Leipzig in July 2013

The paper is one of the outcomes of a workshop held in Leipzig in July 2013 by the sImpact working group.