Statistical challenges of evaluating diversity patterns across environmental gradients in mega-diverse communities

Ibanez etal. (Journal of Vegetation Science, this issue) applied sample size- and coverage-based rarefaction to analyse the elevational richness pattern in New Caledonian tree communities. We comment on the statistical assumptions behind rarefaction/extrapolation and suggest pooling small plot data to effectively assess/detect the diversity pattern. Broadening the analysis to include abundance-sensitive diversity measures and phylogenetic information can provide important additional insights.