Comment on "Worldwide evidence of a unimodal relationship between productivity and plant species richness".
Tredennick AT., Adler PB., Grace JB., Harpole WS., Borer ET., Seabloom EW., Anderson TM., Bakker JD., Biederman LA., Brown CS., Buckley YM., Chu C., Collins SL., Crawley MJ., Fay PA., Firn J., Gruner DS., Hagenah N., Hautier Y., Hector A., Hillebrand H., Kirkman K., Knops JMH., Laungani R., Lind EM., MacDougall AS., McCulley RL., Mitchell CE., Moore JL., Morgan JW., Orrock JL., Peri PL., Prober SM., Risch AC., Schütz M., Speziale KL., Standish RJ., Sullivan LL., Wardle GM., Williams RJ., Yang LH.
Fraser et al. (Reports, 17 July 2015, p. 302) report a unimodal relationship between productivity and species richness at regional and global scales, which they contrast with the results of Adler et al. (Reports, 23 September 2011, p. 1750). However, both data sets, when analyzed correctly, show clearly and consistently that productivity is a poor predictor of local species richness.