Functional estimates from surface pollen samples in North America

Surface pollen samples were transformed from relative abundances to ecological function by linking plant functional traits to pollen datasets in North America to test the ability of the transformation to track ecological function at present. Trait measurements of all native plant species were log-transformed and scaled, and trait values were then assigned to each pollen taxon. Trait values are presented as the mean and standard deviations of all associated values. These values were then used to quantify the range of occupied trait space at each surface sample that were then averaged in 0.5º X 0.5º grid cells to reconstruct the latitudinal functional diversity gradient.