Triangle model for evaluating species invasions

Background/Question/Methods

Despite many years of study, many proposed hypotheses, and many theories of the factors that contribute to invasion, invasion ecology still has no unified paradigm to evaluate the risk of species invasion. A growing consensus acknowledges that invasion is not a result of a single factor; most invasions occur due to a combination of factors. In this poster, we describe a triangle model that encompasses the multifactor process of invasion. The invasion triangle model serves as an integrated framework to evaluate the risk of species invasion in a particular site.

Results/Conclusions

Factors that influence invasion are grouped into three categories: the attributes of the potential invader, the biotic characteristics of a potential invaded site, and the environmental conditions of a potentially invaded site. The model also incorporates external influences that have the ability to dramatically alter the invasibility of the site such as climate change. Our invasion triangle model is an adaptation of the disease triangle used by plant pathologists to help envision and evaluate the interactions among a host, a pathogen and an environment, whose interaction determine the extent of disease development. The definitive characteristic of the invasion triangle model is the graphical representation of all the factors involved in invasion.

In this poster, we present a description of the invasion triangle model and include examples illustrating the application for real-world invasions. First, we summarize hypotheses that correspond to each side of the triangle, and present the concept of external influences. Second, we describe how the invasion triangle model may be used and provide some examples using published data. This poster is not intended to be a definitive guide to invasion ecology, but an introduction to the invasion triangle model.