Data from: Can latitudinal richness gradients be measured in the terrestrial fossil record?

Studying the deep-time origins of macroecological phenomena can help us to
understand their long-term drivers. Given the considerable spatiotemporal
bias of the terrestrial fossil record, it behooves us to understand how
much biological information is lost. The aim of this study is to establish
whether latitudinal diversity gradients are detectable in a biased
terrestrial fossil record. I develop a simulated fossilization approach,
weighting the probability of terrestrial mammal species appearing in the
fossil record based on body size and geographic-range size; larger species
with larger range sizes are more likely to enter the fossil record. I
create simulated fossil localities from the modern North American mammal
record. I vary the percentage of species successfully fossilized and
estimate the magnitude of the latitudinal diversity gradient (slope of the
richness gradient and degree of species turnover). I find that estimates
of the latitudinal diversity gradient are sensitive to the loss of species
with small body size and geographic-range sizes. In some cases, simulated
fossil-record bias completely obliterates evidence of declining richness
with latitude, a phenomenon that is not ameliorated by the application of
nonparametric richness estimation. However, if the rate of preservation is
medium (50% of species) to high (75% of species), the magnitude of the
latitudinal diversity gradient can be reliably estimated. Similarly,
changes in the diversity gradient estimates are largely explained by
differences in the diversity–climate relationship among iterations,
suggesting that these relationships may be measurable in the fossil
record.