Maps derived from remote sensing of canopy nitrogen (N) provide a potential avenue to make spatially explicit, regional-scale predictions of the vital forest ecosystem services that are coupled to the cycling of N and carbon. Yet, to fully use canopy N maps in this capacity, it is necessary to understand how canopy species with differing leaf functional traits will adjust foliar N in response to environmental variability. In this study, I relate a regional survey of foliar N data from a functionally-diverse set of forest tree species in the Adirondack Park, NY to a holistic matrix of environmental gradients thought to control spatial variability of foliar N.
Results/Conclusions
Stepwise multiple regression models developed for each species indicate that while neighboring species and abiotic gradients of resource availability play a lesser role, anthropogenic influences (caused by historic disturbances and atmospheric N deposition) upon ecosystem N capital form the dominant dimension of variability in foliar N. Moreover, we find that the plasticity of the total foliar N response to measured environmental variability is strongly related to leaf functional traits describing each species’ strategy for foliar N investment. Collectively, these results further demonstrate the utility of an environmental matrix approach to studying complex ecosystems while also emphasizing the dominant role of humans in controlling future nutrient cycling, even within this “forever wild” forest ecosystem. Finally, since these results also suggest that spatially-explicit measurements of leaf functional traits and environmental gradients may provide a pathway to map and forecast ecosystem services at regional scales, I conclude the presentation by providing a study design and overview of preliminary results from a subsequent, and ongoing field and remote sensing study conducted throughout forests of eastern North America.