CONSERVATION BIOLOGY AND BIODIVERSITY Ground Ant Diversity (Hymenoptera: Formicidae) in the Iberá Nature Reserve, the Largest Wetland of Argentina

The Iberá Nature Reserve in northeastern Argentina protects one of the largest freshwater wetlands and reservoirs of species in South America. However, key invertebrate groups such as the ants (Hymenoptera: Formicidae) remain almost unknown.Themainobjective of thiswork was to study the ground ant diversity in four main habitats of Iberá: grasslands, savannas, forests, and ßoating islands. Pitfall traps were used to characterize ground foraging ant assemblages, compare ant diversity among environments, and establish habitat associations. We also used bait traps, manual collections, andWinkler and Berlese extractors on the ground, vegetation, and litter strata to increase the species inventory. In total, 94 species in 30 generawere captured, representing thehighest number of species reported from a survey of a protected area of Argentina. The richest genus was Pheidole Westwood with 23 species including three species reported for the Þrst time in Argentina. The most common species was Solenopsis invicta Buren. Overall, the savanna was the richest and most diverse habitat with the highest number of exclusive species and functional groups. The grassland showed the highest numberof rare species, but onlyhalf of the expected specieswere captured.The forest showed the lowest ant richness, diversity, and equitability, but one half of the species were exclusive to forest habitat.Generalizedmyrmicineswerepredominant anddominant in all habitats.OurÞndings indicate that habitat specialization could be an important factor determining the organization of ant assemblages in Iberá. The protection of each of these unique and threatened natural habitats of Argentina is needed to ensure the long-term preservation of their exclusive ant species.