Aquatic macroinvertebrates as indicators of water quality in the wetlands of the Chimborazo Wildlife Reserve – Ecuador

The Chimborazo Wildlife Reserve (CR), located in central Ecuador, is home to 16 wetlands distributed in the provinces of Bolivar (7), Tungurahua (4) and Chimborazo (5), with altitudes ranging between 3 825 and 4 240 m above sea level (m.a.s.l.). The objective of the study was to analyse the ecological quality of the reserve's wetlands. Sampling units were established at three points per wetland to measure the physico-chemical variables of the water, which helped to validate the results obtained through macroinvertebrates, since if these organisms determine the ecological state of the wetlands, the physico-chemical analyses determine the reasons for pollution. Two methods were used to collect macroinvertebrates: direct capture and Surber net sampling. Three indices were calculated: Biological Monitoring Working Group for Colombia (BMWP/Col), Ephemeroptera, Plecoptera and Trichoptera (EPT), and Multimetric Index of Ecological Status for High Andean Rivers (IMEERA). A total of 8664 individuals belonging to 7 Classes, 12 Orders and 23 Families were identified, with the Family Hyalellidae being the most abundant. The physico-chemical variables indicated that the wetland water is suitable for agricultural irrigation and livestock use, but definitely not for human consumption. Similarly, the results of the 3 biological indices suggest that the waters should be classified as polluted and that therefore the catchment areas supplied by these ecosystems also constitute polluted aquatic systems. Hence the importance of adopting urgent and decisive measures for the conservation of these ecosystems, which constitute the main source of water supply for the communities that cohabit them.