Aim: Global flux data analyses have shown a significant positive and linear relationship between site-scale photosynthetic optimum temperature (Topt-s) and averaged temperature variables. However, as existing studies have not fully considered species composition, it remains unclear to what extent the change in Topt-s is derived from intraspecific plasticity or from a difference in species with a consistent species-specific Topt-s. We tested these two hypotheses using the satellite-derived enhanced vegetation index (EVI).