Text by Lauri Laanisto
“The relevance of species pool in the global relationship between productivity and plant species richness” was the initial title of a reanalysis paper, that was changed after accepted in Science to “Comment on “Worldwide evidence of a unimodal relationship between productivity and plant species richness””. The title is not as good anymore, but I guess it makes sense to have such policy for comments titles.
The object of the reanalysis was paper by Fraser and others published in summer also in Science (link to full text), which has generated quite a lot of rebuttals as I´ve heard. And we (I did it together with Mike Hutchings, former Editor in-Chief of Journal of Ecology) got into this game as well.
Fraser claims to have found the global proof that the relationship between (herbaceous) plant richness and productivity (it´s actually above-ground biomass in this case) in unimodal. Yet this humped-backed curve explains only a fraction of the relationship. And our reanalysis showed that it´s actually the local species pool that strongly drives the richness, and when local species pool is taken into account, the humped-backed curve is lost.
I´ll have a more comprehensive overwiev of this topic when the paper will be published and available.
(Not yet) full citation: Laanisto, Lauri & Hutchings, Michael J. (2015) Comment on “Worldwide evidence of a unimodal relationship between productivity and plant species richness”. Science (in press)
Fraser et al. (Research Article, 17 July 2015, p. 302) report that a hump-backed model describes the worldwide relationship between productivity and plant species richness in grassland communities. We reanalyze their data from a larger-scale perspective, using a local species pool. This influences richness far more strongly than productivity, and, when this is taken into account, the hump-backed richness-productivity relationship disappears.