Weak congruence between biological assemblages of streams and their relationship with the environmental gradient in the Cerrado-Amazon transition area, Brazil

Abstract

Congruence between taxa is the agreement between groups, it is used to find indicator taxa, being a quick and effective way to assess biodiversity. The objective of this work was to evaluate the congruence between fish assemblages, Heteroptera, Odonata in streams of the Amazon-Cerrado transition area. The study took place in 24 streams in the transition between the Cerrado and Amazon biomes, Brazil. The analysis results showed weak congruence between Odonata and Heteroptera for the two data sets. Disagree Odonata and fish showed weak congruence but signicant with abundance data, and with incidence data, the congruence was not significant. A similar result was obtained when analyzing fish and Heteroptera, which were not congruent with any of the datasets used. These findings were repeated when analyzing the suborder Zygoptera separately, instead of Odonata. The variance partition test, with abundance data, showed that both environmental variables and space are responsible for structuring the Heteroptera community, different fish, Odonata and Zygoptera did not respond to any of the analyzed variables, with incidence data no group showed a relationship with the environmental and spatial variables analyzed. The pRDA, with abundance data, confirmed the relationship of the Heteroptera assemblage with environmental and spatial variables, however, the other assemblages did not present significant results. With the incidence data, it was not significant for all assemblages. The weak congruence between the different groups can due to the different responses to the same environmental gradient, which was confirmed by the variance partition test.