The Functional Response Ratio (FRR): advancing comparative metrics for predicting the ecological impacts of invasive alien species

• DOI: 10.1007/s10530-019-02002-z
• Publication Date: 2019-05-11T15:44:30Z
• Authors: Ross N. Cuthbert; James W. E. Dickey; Neil E. Coughlan; Patrick W. S. Joyce; Jaimie T. A. Dick
• Keywords: Alien species

The Functional Response (FR) has been identified as a powerful predictive tool to forecast the ecological impacts of existing, emerging and future invasive alien species. In particular, parameters attack rate handling time h may be invaders when utilised in comparison with trophically analogous natives. However, researchers many cases face somewhat contradictory impact predictions based on use one parameter or other. Here, we thus propose new metric, Ratio (FRR), which is simply divided by h: that is, FRR = a/h. Given high values low should associate impact, vice versa, metric balances information from both parameters. This also resolves contradictions gives opposite Using multiple examples obtained literature, find indeed such are consistently higher than those natives, irrespective experimental environmental context. Accordingly, provides novel reliable for scientists, stakeholders practitioners predict species across taxa trophic groups.