Scale dependence of canopy trait distributions along a tropical forest elevation gradient

• Published in: The New phytologist Vol. 214; no. 3; pp. 973 - 988
• Main Authors: Asner, Gregory P., Martin, Roberta E., Anderson, Christopher B., Kryston, Katherine, Vaughn, Nicholas, Knapp, David E., Bentley, Lisa Patrick, Shenkin, Alexander, Salinas, Norma, Sinca, Felipe, Tupayachi, Raul, Quispe Huaypar, Katherine, Montoya Pillco, Milenka, Ccori Álvarez, Flor Delis, Díaz, Sandra, Enquist, Brian J., Malhi, Yadvinder
• Format: Journal Article
• Language: English
• Published: England New Phytologist Trust 01-05-2017; Wiley Subscription Services, Inc
• Subjects: Altitude; Analytical methods; Canopies; Canopy; canopy chemistry; Carbohydrates; Carnegie Airborne Observatory; Climate change; Dependence; Ecological monitoring; Ecological studies; Elevation; Environmental changes; Forests; Geography; Imaging techniques; Landscape; Leaves; Linear Models; Mineral nutrients; Nutrients; Peru; Photosynthesis; Photosynthetic pigments; Pigments; plant functional traits; Plant Leaves - physiology; Polyphenols; Quantitative Trait, Heritable; Remote sensing; Sampling; Skewed distributions; Spectroscopy; Spectrum Analysis; trait distributions; trait scaling; Tropical Climate; Tropical forests; Weighting; Weighting methods; trait scaling; plant functional traits; Peru; Carnegie Airborne Observatory; canopy chemistry; trait distributions
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.14068

Average responses of forest foliar traits to elevation are well understood, but far less is known about trait distributional responses to elevation at multiple ecological scales. This limits our understanding of the ecological scales at which trait variation occurs in response to environmental drivers and change.
We analyzed and compared multiple canopy foliar trait distributions using field sampling and airborne imaging spectroscopy along an Andes-to-Amazon elevation gradient. Field-estimated traits were generated from three community-weighting methods, and remotely sensed estimates of traits were made at three scales defined by sampling grain size and ecological extent.
Field and remote sensing approaches revealed increases in average leaf mass per unit area (LMA), water, nonstructural carbohydrates (NSCs) and polyphenols with increasing elevation. Foliar nutrients and photosynthetic pigments displayed little to no elevation trend. Sample weighting approaches had little impact on field-estimated trait responses to elevation. Plot representativeness of trait distributions at landscape scales decreased with increasing elevation. Remote sensing indicated elevation-dependent increases in trait variance and distributional skew.
Multiscale invariance of LMA, leaf water and NSC mark these traits as candidates for tracking forest responses to changing climate. Trait-based ecological studies can be greatly enhanced with multiscale studies made possible by imaging spectroscopy.