title: Sources of variability in canopy reflectance and the convergent properties of plants.
abstract: How plants interact with sunlight is central to the existence of life and provides a window to the functioning of ecosystems. Although the basic properties of leaf spectra have been known for decades, interpreting canopy-level spectra is more challenging because leaf-level effects are complicated by a host of stem- and canopy-level traits. Progress has been made through empirical analyses and models, although both methods have been hampered by a series of persistent challenges. Here, I review current understanding of plant spectral properties with respect to sources of uncertainty at leaf to canopy scales. I also discuss the role of evolutionary convergence in plant functioning and the difficulty of identifying individual properties among a suite of interrelated traits. A pattern that emerges suggests a synergy among the scattering effects of leaf-, stem- and canopy-level traits that becomes most apparent in the near-infrared (NIR) region. This explains the widespread and well-known importance of the NIR region in vegetation remote sensing, but presents an interesting paradox that has yet to be fully explored: that we can often gain more insight about the functioning of plants by examining wavelengths that are not used in photosynthesis than by examining those that are.
authors.affiliation: Complex Systems Research Center, Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, NH 03824, USA. scott.ollinger@unh.edu
authors.forename: S V
authors.initials: SV
authors.lastname: Ollinger
mesh_terms: D005075:Biological Evolution; D002734:Chlorophyll / Q000378:metabolism; D008027:Light; D018515:Plant Leaves / Q000502:physiology* / Q000528:radiation effects*; D010944:Plants / Q000528:radiation effects*; D019655:Quantitative Trait, Heritable
chemical_list: D002734:Chlorophyll