Australia-wide photosynthetic trait dataset

“Least-cost theory” posits that C3 plants should balance rates of photosynthetic water loss and carboxylation in relation to the relative acquisition and maintenance costs of resources required for these activities. Here we investigated the dependency of photosynthetic traits on climate and soil properties using a new Australia-wide trait dataset spanning 528 species from 67 sites.
We tested the hypotheses that plants on relatively cold or dry sites, or on relatively more fertile sites, would typically operate at greater CO2 drawdown (lower ratio of leaf internal to ambient CO2, Ci:Ca) during light-saturated photosynthesis, and at higher leaf N per area (Narea) and higher carboxylation capacity (Vcmax 25) for a given rate of stomatal conductance to water, gsw. These results would be indicative of plants having relatively higher water costs than nutrient costs.
In general, our hypotheses were supported. Soil total phosphorus (P) concentration and (more weakly) soil pH exerted positive ..., Data collection/generation of data: Light-saturated rates of photosynthesis were measured at ambient CO2 levels using a portable gas exchange system. Stomatal conductance to water vapor and Ci:Ca correspond to light-saturated rates of photosynthesis. Carboxylation capacity, Vcmax, was estimated via the one-point method when it was not provided from A-ci curves. Concentrations of leaf nitrogen and phosphorus were measured using an elemental analyzer.  LMA was measured by dividing the leaf dry mass by the surface area of a fresh leaf. 
Climate data were extracted for each site from the eMAST data project. Soil data were measured for a subset of sites and extracted from the CSIRO SoilGrids for the remaining sites. 
Data processing: Raw data were used to calculate species means for all sites, which were then compiled to produce one data file. This was done using RStudio Version 1.3.959.
Environmental/experimental conditions: All data were collected on native plant species growing under natu..., Microsoft Excel