We are witness to the greatest loss of biodiversity; the rate of biodiversity loss is only comparable to the major extinction events registered in the fossil record. In light of these losses, developing new ways to characterize and monitor biodiversity that takes advantage of remote sensing technologies and products is critical to inform conservation actions and develop effective management strategies to address global change. In this study, I evaluate the strength of the relationships between functional and spectral diversity in the Southeast United States. Specifically, I tested the extent to which plot-based metrics of plant functional diversity and airborne-based spectral diversity metrics are related. The results showed both positive and negative relationships between metrics of plant functional diversity and remote sensing metrics of diversity. Overall, the strength and direction of the relationships vary with metric complexity, where simple metrics showed strong associations between functional with metrics derived from hyperspectral imagery. The results presented here contribute to the development of generalizable approaches for assessing plant biodiversity across multiple spatial and temporal scales.