Lust for Salt in the Western Amazon

Abstract

Although the use of mineral licks by diverse Amazonian birds and mammals is well-known, the ultimate motivation for such behavior remains unclear. As aerosol deposition of salts declines with distance from oceanic sources, lick visitation in the western Amazon can be explained by demand for sodium, given the low concentration of this micronutrient in the plant tissues consumed by these taxa. Sodium limitation also influences ant foraging behavior, and impinges on ecosystem rates of carbon cycling. The biogeographical context of sodium availability has been largely overlooked, but has substantial pantropical implications for herbivore and decomposer performance in inland rain forests.