Data from: The paleobiologic implications of modern nonmarine ecological gradients

In modern nonmarine settings, previous studies have demonstrated the
importance of elevation-correlated ecological gradients, but such studies
tend to focus on relatively small areas and only one higher taxon. Here,
we analyze GBIF occurrence records from a wide variety of taxa across the
southeastern United States coastal plain. Many taxa display ecological
gradients (gradients in proportional or relative abundance) correlated
with elevation, distance to the coast, and latitude. These gradients tend
to be steepest within a few tens of kilometers near the coast and at
elevations less than 25 m. Some taxa, notably terrestrial mammals, do not
display gradients correlated with elevation and distance to the coast. The
small sample sizes of these groups and their heterogeneous sampling raise
concerns about whether sufficient data exists. Coupled with previous
studies of these ecological gradients, their common presence over
distances of tens to hundreds of kilometers and elevations of tens to
hundreds of meters suggests they are likely important in the nonmarine
fossil record. Because elevation and distance to the coast change
predictably with cycles of accommodation and sediment flux, these
ecological gradients are predicted to occur in the nonmarine stratigraphic
record, especially through intervals that record transgression or
regression. Such gradients will affect the local composition of species
associations and occurrences, even in the absence of regional species
origination, immigration, and extinction and in the absence of regional
change in the structure of ecological gradients. The ordination of taxon
counts in stratigraphically limited samples has great potential for
establishing their existence.