I have recently registered for the Public Library of Science's Biology feed alerting me to new articles of interest. I have chosen to focus on PLOS as they provide the full content of the published scientific papers to the public. The other science journals restrict public access to the material for some period of time, unless you pay to be a member. Since I am not ready to take that step yet, I have been watching PLOS instead. You might have noticed that it was impossible to get at the original articles referenced in some of my recent favorite science stories of the week.
A recent article that caught my attention was:
Bulleri, F., Bruno, J.F., Benedetti-Cecchi, L. (2008). Beyond Competition: Incorporating Positive Interactions between Species to Predict Ecosystem Invasibility. PLoS Biology, 6(6), e162. DOI: 10.1371/journal.pbio.0060162
The paper is a theoretical paper exploring an alternative model for looking at ecosystem invasion than is in common use today. According to the paper, most studies of invasive species are focusing on the resource availability or species diversity within the ecosystem as a predictors for invasibility.
The paper argues that facilitation of the invasive species by native or other non-native species could have a much larger impact on potential invasibility than pure resource availability. They argue that facilitation can counter balance the effects of competition. This aspect could explain the conflicting results of small scale experimental studies showing that high native species diversity is a deterrent to invasibility and large scale observational studies which often shows the opposite.
The paper provides a compelling argument for the theory which has broadened my understanding of the interaction between an invasive species and the ecosystem. While no direct experimental results were presented, the theory seems intuitive enough that it warrants consideration in invasive species analysis. I would have preferred to see more observational examples of the concept in action to illustrate that facilitation is more than a minor impact in the overall equation.
This paper further supports one of my complaints about most ecosystem intervention. We too often believe we understand all of the intricate interactions of wild systems, but once we intervene, we realize that we don't.