ICAYAR, un Índice multimétrico basado en insectos acuáticos para evaluar el estado ecológico en la cuenca del río Ayuquila-Armería, México

Abstract

Aquatic macroinvertebrates are the organisms most used to evaluate river ecosystems due to their sensibility to environmental changes. The indices previously used to evaluate the Ayuquila-Armería basin with macroinvertebrates have not been very effective in showing the ecosystem quality of the rivers in the basin. Aim. This study proposes a multimetric Index adapted to the Ayuquila-Armería River Basin (ICAYAR) using aquatic insects at the taxonomic family level. Methods. To build the index, 35 sites were sampled in 2018. Which 10 sampled sites were classified as references, 10 were not conserved, and the remaining 15 were used for the validation of the index. A stress gradient was constructed from the RDA analysis of the abundance values of the organisms and the environmental variables. 30 metrics of richness, abundance, tolerance/intolerance, diversity indices, functional groups, and composition were calculated. Using Spearman correlations and discriminative efficiency, the final metrics of the index were selected. The ICAYAR results were compared with the Biotic Integrity Index for Aquatic Macroinvertebrate Associations (IIBAMA) and the Biological Monitoring Working Party (BMWP). Results. The three final metrics for the ICAYAR were Hilsenhoff's Family Biotic Index (FBI), % Crushers and % Diptera. The ICAYAR shows a good Discriminative Efficiency between the reference sites and the not conserved sites. Conclusions. The ICAYAR was able to reflect the conditions of the best-conserved sites among the non-conserved ones. The methodology used to prepare the index can be replicated and used for scientific and community monitoring purposes in other basins.