Data from: Misuse of bird digital distribution maps creates reversed spatial diversity patterns in the Amazon

It is well known that bird richness in the Amazon is greater in upland
forests and that seasonally flooded forest is particularly species poor.
However, the misleading pattern of greater bird richness in seasonally
flooded forest has emerged seemingly unnoticed numerous times in richness
maps in the literature. We hypothesize that commission errors in digital
distribution maps (DDMs) are the cause behind the misleading richness
pattern. In the Amazon, commission errors are a consequence of the
different methodological treatment given to large-ranged versus
small-ranged habitat specialists when mapping distributions. DDMs of 1007
Amazonian birds were examined, and maps that had commission errors were
corrected. We generated two richness maps, one from the overlay of
original DDMs and another from the overlay of the corrected ones. We
identified 291 species whose distribution maps had errors. In the original
data, seasonally flooded forests showed higher species richness than
upland forest, but this pattern was reverted in the corrected richness
map. Commission errors were 35 times more likely in the seasonally flooded
forest. We conclude that DDMs accurately portray the distribution of
single species in the Amazon. Commission errors in individual maps,
however, accumulate when they are overlaid, explaining the misleading
pattern for birds in the Amazon. DDMs can continue to be used mapping
richness, as long as, at a regional scale: (1) basic map refinements are
carried, or (2) only small-range species are used for mapping species
richness.