An important article

Its not often we highlight an article as 'exceptional', but we felt this refutation that eloquently counters some of the rather wild articles published recently which essentially tell us to stop making so much fuss about invasive species is an important one. 

The natives are restless, but not often and mostly whendisturbed.

D Simberloff, L Souza, MA Nuñez, MN Barrios-Garcia and W Bunn Ecology. 2012 Mar; 93(3): 598-607

Our Review: 

Parry H, Lonsdale M: 2012. F1000.com/717952323#eval793457754 

This paper provides some counter-evidence to the argument that native species are as likely to become problematic invaders as non-indigenous species. The authors examined the literature on plant invasions in the United States and found that a member of the naturalised non-native pool is 40 times more likely than the native species to be perceived as invasive.

It is important to note that, while 'invasive' means different things to different researchers in the literature, these authors are using it to mean spreading from the point of introduction into the natural or semi-natural habitat and having an effect on the resident species in the habitat. The authors used Web of Science literature searches to determine for the United States the proportion of native and non-native plant species that were recorded as invasive and to glean the reasons for invasions by native species. In addition to demonstrating that non-native species have far greater invasion risk than native species, they also found that the typical cause for invasiveness of native species was mainly anthropogenic environmental change, such as altered fire regimes and grazing regimes. In other words, it was unusual for native species to spontaneously invade under natural, unmodified environmental conditions.

All this provides an important counter-argument to the proposal that there is nothing special about non-native species per se, which has arisen in recent literature (e.g. [1]). According to Simberloff et al., non-native species clearly have a greater propensity to cause damage than natives, and we should use this information strategically, rather than ignore this important trait.

References:

[1] Don't judge species on their origins.

Davis MA, Chew MK, Hobbs RJ, Lugo AE, ..., Ehrenfeld JG, Grime JP, Mascaro J, Briggs JC Nature. 2011 Jun 9; 474(7350): 153-4