We propose an integrated sampling, rarefaction, and extrapolation methodology to compare species richness of a set of communities based on samples of equal completeness (as measured by sample coverage) instead of equal size.
A sibling replication showed modern GBIF "biodiversity hotspots" for Iberian birds are inflated by survey effort: richest-ranked cells track where observers go, not where birds are densest, and even an EU Article 12 expert rangemap doesn't close the gap. Effort-rich cells reach higher completeness than effort-poor ones, so comparing raw per-cell richness is exactly the equal-size comparison this paper warns against. This study tests whether coverage-based rarefaction removes that effort bias.
Paper annotation: We propose an integrated sampling, rarefaction, and extrapolation methodology to compare species richness of a set of communities based on samples of equal completeness (as measured by sample coverage) instead of equal size.