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

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 eJec- tive in showing the ecosystem quality of the rivers in the basin. This study proposes a multimetric Index adapted to the Ayuqui- la-Armería River Basin (ICAYAR) using aquatic insects at the taxonomic family level. To build the index, 35 sites were sampled in 2018. 0ƒ the 10 sampled sites classified as reƒerences, 10 were not conserved, and the remaining 15 were used to validate the index. A stress gradient was constructed from the RDA analysis of the abundance values of the organisms and the environmental variables. Thirty metrics of richness, abundance, tolerance/intolerance, diversity indices, functional groups, and composition were calculated. Using Spearman correlations and discriminative eßciency, the final metrics oƒ 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). The three final metrics ƒor the ICAYAR were HilsenhoJ's Family Biotic Index (FBI), % Crushers, and % Diptera. The ICAYAR shows a good Discriminative Eßciency between the reƒerence sites and the not conserved sites. The ICAYAR was able to reÀect the conditions oƒ the best-conserved sites among the non-conserved ones. The me- thodology used to prepare the index can be replicated and used ƒor scientific and community monitoring purposes in other basins.