Low cross-taxon congruence among aquatic organisms in artificial tropical ponds: implications for biomonitoring
We intended to choose an indicator group to better represent the biodiversity in man-made tropical ponds. For these propose we tested the congruence pattern among several aquatic communities. Two explanations have been previously proposed for the congruence among different taxa: (i) that different taxa have the same responses to environmental gradients (Padial et al., 2012a); or (ii) that congruence occurs because of ecological interactions among different groups, for instance, the relationships between predators and prey (Larsen et al., 2012). We hypothesized that the communities that depend directly on both water and land are likely more congruent with each other (e.g., amphibians, Odonata (in part), and macrophytes) than those that live in only one of these habitats (e.g., phytoplankton, aquatic insects, and birds). Although the congruency found for them was weak, amphibians were able to partially represent patterns in the abundance of Coleoptera, Heteroptera, and macrophytes. In terms of richness, macrophytes were able to partially represent patterns in Odonata, Coleoptera and birds. In this way, at least for abundance, our results partially supported the hypothesis that the biotic communities that depend directly on both water and land (e.g., amphibians and macrophytes) are more congruent with each other than those living only in one of these environments.Ultimately, we do not recommend the use of a single surrogate taxon to measure biodiversity: weak overall congruence between taxa; limited biological knowledge about tropical artificial ponds; and numerous taxa whose diversity patterns could not be represented by any surrogate group (phytoplankton, Heteroptera, and birds) illustrate the unsuitability of this approach.