2005 年 60 巻 6 号 p. 1157-1160
The concentration of nitrogen in leaves, or fbliar N, can be remotely measured from space-borne hyperspectral remote sensing instruments, and is theorized to be the best indicator of an ecosystem’s N status, or ability to retain inputs of N from atmospheric deposition. However, interpretation of foliar N measurements becomes increasingly complicated at broad scales due to its poorly-understood variability through space and time. We present an approach that minimized temporal variability in order to identify controls on the spatial variation in foliar N within diverse forested ecosystems along a two-fold N deposition gradient within the 2.5 million hectare Adirondack Park, NY. As an example of results obtained with this approach, we discuss the highly significant, positive relationships observed between foliar N and N deposition in five of seven major Adirondack forest species. From these relationships, we conclude that regional gradients of N deposition can explain a large part of the spatial variation in foliar N, but their ability to do so is species dependent. A species’ foliar N response to N deposition may be determined by its functional group and its position along a spectrum of shade tolerance.
