CONICET | Buscador de Institutos y Recursos Humanos

The relationships between functional traits andenvironmental gradients are useful to identify different community assemblyprocesses. In this work, we used an approach based on functional traits toanalyse if changes in hydroperiod and tree covers of ponds are relevant forlocal amphibian community assembly processes. Ephemeral ponds with lowvegetation cover are expected to impose constraints on different species withparticular trait combinations and, therefore, to exhibit communities with lowerfunctional diversity than more stable ponds with greater tree cover. Samplingwas conducted in 39 temporary ponds located along vegetation and hydroperiodgradients in the most arid portion of the Chaco ecoregion. Seven functionaltraits were measured in each species present in the regional pool. Associationsbetween those traits and environmental gradients were detected usingmultivariate ordination techniques and permutation test (RLQ and fourth-corneranalyses respectively). Functional diversity indices were then calculated andrelated to variations in the environmental gradients. The results obtainedallowed us to identify different sets of traits associated with hydroperiod andtree cover, suggesting that those environmental variables are relevant forstructuring amphibian communities according to interspecific variations infunctional traits from both, larval and adult stages. Contrary to ourexpectations, communities associated with more stable ponds and with greatertree cover exhibited lower functional diversity tan expected by chance (andwere the ponds with highest species richness). This result indicates that thereduction in relative importance ofenvironmental restrictions imposed by a very short hydroperiod and the lack oftree cover, favours different species of the regional pool that are similar inseveral functional traits. Accordingly, com munities associated with stableponds with high tree cover exhibited a high functional redundancy.

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