Variation in trait trade-offs allows differentiation among predefined plant functional types: implications for predictive ecology.
Plant functional types (PFTs) aggregate the variety of plant species into a small number of functionally different classes. We examined to what extent plant traits, which reflect species' functional adaptations, can capture functional differences between predefined PFTs and which traits optimally describe these differences. We applied Gaussian kernel density estimation to determine probability density functions for individual PFTs in an n-dimensional trait space and compared predicted PFTs with observed PFTs. All possible combinations of 1-6 traits from a database with 18 different traits (total of 18 287 species) were tested. A variety of trait sets had approximately similar performance, and 4-5 traits were sufficient to classify up to 85% of the species into PFTs correctly, whereas this was 80% for a bioclimatically defined tree PFT classification. Well-performing trait sets included combinations of correlated traits that are considered functionally redundant within a single plant strategy. This analysis quantitatively demonstrates how structural differences between PFTs are reflected in functional differences described by particular traits. Differentiation between PFTs is possible despite large overlap in plant strategies and traits, showing that PFTs are differently positioned in multidimensional trait space. This study therefore provides the foundation for important applications for predictive ecology.
Systems Ecology, Department of Ecological Science, VU University Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands.
Lieneke M
LM
Verheijen
Systems Ecology, Department of Ecological Science, VU University Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands.
Rien
R
Aerts
Max Planck Institute for Biogeochemistry, Hans Knoell Strasse 10, 07745, Jena, Germany.
Gerhard
G
Bönisch
Max Planck Institute for Biogeochemistry, Hans Knoell Strasse 10, 07745, Jena, Germany.
Jens
J
Kattge
Systems Ecology, Department of Ecological Science, VU University Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands.|Institute of Environmental Sciences, Leiden University, Einsteinweg 2, 2333 CC, Leiden, the Netherlands.
Peter M
PM
Van Bodegom
D004463:Ecology / Q000379:methods*; D008954:Models, Biological; D010641:Phenotype; D018521:Plant Physiological Phenomena; D010944:Plants / Q000145:classification*
kernel density estimation; plant functional types; plant strategies; plant traits; trade-offs; trait variation