In collaboration with colleagues from Bar-Ilan University in Israel we have just published a new paper in Ecology Letters critically examining key aspects of Modern Coexistence Theory—a theory that seeks to understand which mechanisms allow large numbers of species to coexist in nature. Specifically, we examine the theory’s reliance on using a species’ mean invasion growth rate as a measure of its ability to persist in a community.

Modern Coexistence Theory assumes that higher invasion growth rates imply greater persistence. We found that although the sign of the mean invasion growth rate correctly characterises two qualitatively different domains of species persistence, the magnitude of the mean invasion growth rate is not a reliable indicator of species persistence. The underlying reason is that the mean invasion growth rate ignores the effects of temporal variations in species abundances on species persistence. We suggest further investigation of metrics of species persistence that incorporate temporal variations in species abundances.

The project was led by Jayant Pande, a post-doctoral researcher in Nadav Shnerb’s lab at Bar-Ilan University. It is part of our collaborative grant with Shnerb’s lab under the Singapore–Israel research grants programme.

Pande, J., T. Fung, R. A. Chisholm, N. M. Shnerb (2019). Mean growth rate when rate is not a reliable metric for persistence of species. Ecology Letters. [link: https://onlinelibrary.wiley.com/doi/full/10.1111/ele.13430]

UPDATE: Ellner et al. wrote a technical comment on our paper, and our response is here.