In a paper published by C·I·B researchers, Rainer Krug and Dave Richardson examined a system consisting of two seed-attacking biocontrol agents (a midge, Dasineura dielsi and a weevil, Melanterius servulus) and one invasive alien plant (Acacia cyclops).
One of the major transformations of the planet from human activities is the redistribution of species to areas outside their native range. These “alien” species have in many cases caused substantial harmful impacts to the recipient environment.
All alien species cause changes to the ecosystems to which they are introduced. Such impacts are of many types - some are dramatic and obvious and can easily be classified as desirable or undesirable. However, for the vast majority of alien species, no information on impact is available. This greatly complicates the task of objectively assigning priority to management.
“If you can't measure it, you can't manage it” is, as with all such well-worn phrases, only partly true. But to adapt another such maxim, while we might be able to make progress without measurement, we do need proof to satisfy everyone else.
Invasive alien species are generally accepted as being one of the top three threats to biodiversity worldwide, but until now there has been no metric for assessing the magnitude problem globally, its impact and our responses to it.