INVESTIGADORES
CALCATERRA Luis Alberto
artículos
Título:
Habitat and Grazing Influence on Terrestrial Ants in Subtropical Grasslands and Savannas of Argentina
Autor/es:
LUIS A. CALCATERRA, SONIA M. CABRERA, FABIANA CUEZZO, IGNACIO JIMENEZ PEREZ, AND JUAN A. BRIANO
Revista:
ANNALS OF THE ENTOMOLOGYCAL SOCIETY OF AMERICA
Editorial:
ENTOMOLOGICAL SOC AMER
Referencias:
Año: 2010 vol. 103 p. 635 - 646
ISSN:
0013-8746
Resumen:
The maintenance of species diversity in modiÞed and natural habitats is a central focus of conservation biology. The Ibera´ Nature Reserve (INR) protects highly diverse ecosystems in northeastern Argentina, including one of the largest freshwater wetlands in South America. Livestock grazing is one of the major disturbances to these ecosystems; however, its effect on ant diversity is poorly known. The objective of this work was to study the effect of savanna versus grassland and grazing on the structure and composition of subtropical terrestrial ants focusing on the particular response of the native red imported Þre ant, Solenopsis invicta Buren. Unbaited pitfall traps were used to capture worker ants in 25 grazed and 20 nongrazed sites. Fifty ant species were collected. The savanna showed more species, individuals, biomass, and functional groups of ants than the grassland.´ Nature Reserve (INR) protects highly diverse ecosystems in northeastern Argentina, including one of the largest freshwater wetlands in South America. Livestock grazing is one of the major disturbances to these ecosystems; however, its effect on ant diversity is poorly known. The objective of this work was to study the effect of savanna versus grassland and grazing on the structure and composition of subtropical terrestrial ants focusing on the particular response of the native red imported Þre ant, Solenopsis invicta Buren. Unbaited pitfall traps were used to capture worker ants in 25 grazed and 20 nongrazed sites. Fifty ant species were collected. The savanna showed more species, individuals, biomass, and functional groups of ants than the grassland.Solenopsis invicta Buren. Unbaited pitfall traps were used to capture worker ants in 25 grazed and 20 nongrazed sites. Fifty ant species were collected. The savanna showed more species, individuals, biomass, and functional groups of ants than the grassland. S. invicta was the most frequently captured (61.4%) and numerically dominant species; however. invicta was the most frequently captured (61.4%) and numerically dominant species; however Camponotus punctulatus punctulatus Mayr showed the highest biomass. Grazing simpliÞed vegetation structure in both habitats, but its impact on vegetation seemed only to promote a higher total biomass especially in the grassland, and/or functional groups, favoring occurrence of hot-climate specialists in the savanna. This study revealed that habitat type strongly affected the organization of the terrestrial ant assemblages at the INR. However, as in other studies, we did not Þnd clear evidence that habitat modiÞcation by grazing signiÞcantly affected terrestrial ant assemblages. The weak grazing inßuence could be the consequence of the short enclosure time as to recover the original ant communities, the differential response of ant species to habitat type, and/or the resilience of ants.Mayr showed the highest biomass. Grazing simpliÞed vegetation structure in both habitats, but its impact on vegetation seemed only to promote a higher total biomass especially in the grassland, and/or functional groups, favoring occurrence of hot-climate specialists in the savanna. This study revealed that habitat type strongly affected the organization of the terrestrial ant assemblages at the INR. However, as in other studies, we did not Þnd clear evidence that habitat modiÞcation by grazing signiÞcantly affected terrestrial ant assemblages. The weak grazing inßuence could be the consequence of the short enclosure time as to recover the original ant communities, the differential response of ant species to habitat type, and/or the resilience of ants.