A recent paper by a group of researchers, led by C·I·B core team member Prof Cang Hui, proposed a framework
to help explain why some invasive alien species are so successful in invading the new areas, while it is not so easy for others.
The success of an organism to become invasive and the impacts of the invasion depend on the potential of the species
itself (also called the invasiveness) and on the susceptibility of the ecosystem (invasibility) they invade. Yet, the two concepts are
not defined under a common framework.
In their paper, Prof Hui and colleagues used invasion fitness as a common framework for their definition. The invasion
fitness of a species is a measure of the invading potential of a species and depends both on the phenotypic traits of the invading species
and those of the species that exist in the ecosystem they invade. Phenotypic traits are observable traits for example body size,
competitive ability, life-history and foraging strategies, etc.
Invasiveness and invisibility are not easy to be empirically measured or quantified. However, they are shown to be
correlated with the stability and structure properties of the invaded ecosystem. Such metrics are easily computed from the interaction
network of the invaded ecosystem, being it measured through field experiments or guessed through expert opinion, thus providing an
estimate of invasiveness and invasibility.
In their paper, Prof Hui and colleagues demonstrated the framework using both a theoretical model of a food-web ecosystem
and observed interaction networks before and after the invasion of the harlequin ladybird (Harmonia axyridis) in agricultural and
“Information on invasiveness and invasibility can be useful for the prevention and management of invasions by
alien species, and can play a crucial role in the conservation of endemic biodiversity and ecosystem services” according to
Dr Pietro Landi, co-author of the paper published in a special issue of the journal, Biological Invasions.
This paper had its origin at a workshop on “Drivers, impacts, mechanisms and adaptation in insect invasions”
hosted by the DST-NRF Centre of Excellence for Invasion Biology in November 2014 (Read more
about the workshop).
Discussions at the workshop led to a special issue in the journal Biological Invasions. The special issue is
available as the April 2016 volume of Biological Invasions (View the Biological Invasions special issue articles).
Read the paper by Hui et al.
Hui, C., Richardson, D.M., Landi, P,
Minoarivelo, H.O., Garnas, J. and Roy, H.E. (2016). Defining invasiveness and invasibility in ecological networks. Biological
Invasions, Volume 18, Issue 4, pp 971-983
For more information, contact Prof Cang Hui at email@example.com