Continuous measures of leaf mottling in five North American Erythronium species (Liliaceae), Eastern U.S., 2015-2023

iNaturalist observations of five species of Erythronium (E. albidum, E. americanum, E. mesochoreum, E. rostratum, and E. umbilicatum) were used to quantify variation in leaf-level mottling with forest canopy cover and deer abundance across central and eastern North America. Only research-grade observations made between 2015 and 2023 were included. For each visible leaf surface, 11 metrics of leaf-level mottling were quantified (six on the continuous leaf surface and five on the leaf surface categorized into two patches). The continuous mottling metrics included the root mean square reflectance roughness, the average surface roughness, the average and median surface ruggedness index, and the average and median surface roughness index. The categorical mottling metrics included (all at the leaf level) the Simpson's evenness index, the Shannon's diversity index, the joint entropy, the aggregation index, and the contagion. For each observation, mottling metrics were calculated for reflectance values in both the blue and green bands of the RGB image. Analysis of variance and regression modeling were used to relate mottling indices to canopy cover (as a proxy for leaf background) and deer abundance (as a proxy for herbivore pressure).