Beta-diversity of ant assemblages in the Paraguayan dry Chaco and its implication for conservation

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Spatial and temporal foraging overlaps in a Chacoan ground-foraging ant assemblage

In arid habitats ant temporal foraging results from a set of trade-offs between species food discovery and food domination ability and between species thermal tolerance and behavioral dominance. We investigated how this set of trade-offs structures the spatial co-occurrence of ants during foraging, hence focusing on interspecific competition. The consequences of food type on the spatio-temporal foraging structure were also studied because food preferences were expected to optimize the restricted foraging time and space of thermophilic species. The food partitioning between 24 species attracted to protein or carbohydrate baits was studied in a dry forest of the Paraguayan Chaco. Baits were spaced at one meter intervals and inspected every 15 min over 90-min sessions conducted during mornings and afternoons. Null model analyses revealed a temporal food partitioning during afternoon sessions and a spatial partitioning, influenced by both thermal conditions and interspecific competition. Bait type did not influence the spatio-temporal foraging. Unexpectedly, evidence of interspecific competition was scarce and avoidance rather than overt conflicts appeared to be the rule of thumb. Overall, the spatio-temporal food exploitation at a small scale was affected by temperature and stochastic processes. This demonstrates that chance structures ant foraging even in constraining arid environments. © 2007 Elsevier Ltd. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Temporal foraging overlaps in a Chacoan dry forest ant assemblage

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Ant diversity along a wide rainfall gradient in the Paraguayan dry Chaco

Aridity is expected to affect ant diversity by limiting the availability of resources and causing physiological distress to the ant populations. Studies conducted so far on such relationships are few and results are inconsistent due to confounding factors. Our aim was to survey an area that had an extended rainfall gradient, with minimal temperature and topography variations, to determine whether ant diversity was negatively correlated to aridity. The study was carried out in 11 localities along a 400 km-long transect in the Paraguayan dry Chaco. Mean annual rainfall ranged from 460 to 887 mm. In total, 197 ant species were collected. At the studied regional scale, our results did not confirm that aridity constitutes an environmental filter reducing ant diversity, neither at specific nor at higher-phylogenetic levels. Based on our results and of those extracted from the literature, rainfall seems to have either no influence or a negative one on ant alpha-diversity at both regional and larger geographical scales, except when rainfall is very low (e.g <200 mm). This pattern contrasts with what is classically observed for a large majority of other taxa. © 2010 Elsevier Ltd.SCOPUS: ar.jinfo:eu-repo/semantics/published[IF2008 = 1.589

Stable isotope analysis: from individual diet determination to complex food web disentanglement

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Influence of aridity and soil on the distribution and diversity of ant assemblages and dominant plant species in the Paraguayan dry Chaco

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Termites in Santo: lessons from a survey in the Penaoru area

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Soil properties only weakly affect subterranean ant distribution at small spatial scales

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