Correlation between distribution-based and CBC-based values of community composition metrics based on categorical traits.

<p>For each of the two categorical traits considered – migratory behaviour and diet – maps were generated of community-weighted mean trait value (CWM; a, d, f, i), functional richness (FRICH; b, g) and functional divergence (FDIV; c, e, h, j). For the categorical traits, community-weighted mean was calculated as the proportion of birds in each of the trait classes. Observed values were calculated from recorded abundances at 68 evaluation Christmas Bird Count (CBC) sites. Distribution-based estimates of the metrics were generated using four methods, with the best two shown here, as in Fig. 3. Lines represent y = x. Full results for all four methods are presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044019#pone-0044019-t001" target="_blank">Table 1</a>.