Biodiversity metrics are affected by variation in sampling completeness, and notoriously underestimate the species’ diversity in a site. Recently, statistical tools have been developed to estimate and account for biases in sample coverage. These tools allow researchers to compare observed and expected diversity metrics and their change along gradients. This approach has been applied by Mareike Kortmann and co-authors, now published in the Journal of Applied Ecology. The results on bird communities were clear: sample coverage decreased with the age of regenerating forests (i.e., biodiversity is more underestimated in mature forests than in young ones). The observed bird diversity (both species and phylogenetic metrics) significantly decreased with forest age, but the corrected diversity did not. Changes in species composition and functional diversity were more pronounced and were unaffected by sample coverage correction.
