Data from: More salt, please: global patterns, responses, and impacts of foliar sodium in grasslands

Sodium is unique among abundant elemental nutrients, because most plant
species do not require it for growth or development, whereas animals
physiologically require sodium. Foliar sodium influences consumption rates
by animals and can structure herbivores across landscapes. We quantified
foliar sodium in 201 locally abundant, herbaceous species representing 32
families and, at 26 sites on four continents, experimentally manipulated
vertebrate herbivores and elemental nutrients to determine their effect on
foliar sodium. Foliar sodium varied taxonomically and geographically,
spanning five orders of magnitude. Site‐level foliar sodium increased most
strongly with site aridity and soil sodium; nutrient addition weakened the
relationship between aridity and mean foliar sodium. Within sites, high
sodium plants declined in abundance with fertilisation, whereas low sodium
plants increased. Herbivory provided an explanation: herbivores
selectively reduced high nutrient, high sodium plants. Thus, interactions
among climate, nutrients and the resulting nutritional value for
herbivores determine foliar sodium biogeography in herbaceous‐dominated
systems.