Kaspari, Michael;Yanoviak, Stephen P.;Dudley, Robert
On the biogeography of salt limitation: A study of ant communities
Proceedings of the National Academy of Sciences of the United States of America
2008
Journal Article
105
46
17848-17851
Los Amigos;large spatial scales;invertebrates;ants;ecology;colpas;mineral licks;sodium
Sodium is an essential nutrient whose deposition in rainfall decreases with distance inland. The herbivores and microbial decomposers that feed on sodium-poor vegetation should be particularly constrained along gradients of decreasing sodium. We studied the use of sucrose and NaCl baits in 17 New World ant communities located 4-2757 km inland. Sodium use was higher in genera and subfamilies characterized as omnivores/herbivores compared with those classiï¬ed as carnivores and was lower in communities embedded in forest litter than in those embedded in abundant vegetation. Sodium use was increased in ant communities further inland, as was preference for the baits with the highest sodium concentration. Sucrose use, a measure of ant activity, peaked in communities 10-100 km inland. We suggest that the geography of ant activity is shaped by sodium toxicity near the shore and by sodium deï¬cit farther inland. Given the importance of ants in terrestrial ecosystems, changing patterns of rainfall with global change may ramify through inland food webs.