Cross-taxon congruence of [alpha] and [beta] diversity among five leaf litter arthropod groups in Colombia

In this study [alpha] and [beta] diversity patterns of five leaf litter arthropod groups (ants, predatory ants, oribatid mites, spiders and other arachnids) were described and compared in 39 sampling patches of a transformed landscape in southwestern Colombia, that represented five vegetation types: secondary forest, riparian forest, giant bamboo forest, pasture and sugarcane crop. It was also assessed whether some taxa could be used as diversity surrogates. A total of 6,765 individuals grouped in 290 morphospecies were collected. Species richness in all groups was lower in highly transformed vegetation types (pasture, sugarcane crop) than in native ones (forests). In contrast, there were no clear tendencies of [beta] diversity among vegetation types. Considering sampling patches, 0.1-42% of the variation in [alpha] diversity of one taxonomic group could be explained from the [alpha] diversity of another, and 0.2-33% of the variation of [beta] diversity of a given taxon was explained by that in other groups. Contrary to recent findings, we concluded that patterns of [alpha] diversity are more congruent than patterns of [beta] diversity. This fact could be attributed to a sampling effect that promotes congruence in [alpha] diversity and to a lack of a clear regional ecological gradient that could promote congruent patterns of [beta] diversity. We did not find evidence for an ideal diversity surrogate although diversity patterns of predatory ants had the greatest congruencies. These results support earlier multi-taxon evaluations in that conservation planning should not be based on only one leaf litter arthropod group.