Evaluación de la diversidad biológica de macroinvertebrados acuáticos sobre el gradiente altitudinal de la microcuenca del río Pachanlica, provincia de Tungurahua

Abstract

This research aimed to evaluate the biological diversity of aquatic macroinvertebrates on the altitudinal gradient of the Pachanlica river micro-watershed. Ten monitoring points were determined and sampled in March - August 2022, corresponding to a rainy and dry season. At each sampling station, physical, chemical and microbiological parameters were measured, and ecological indices were estimated, such as the Quality index of the Riparian Forest (QBR), Andean Biotic Index (ABI), Fluvial Habitat Index (IMF), along with diversity indices: Shannon - Wiener, Margalef, Simpson. Protocols for collecting and identifying aquatic macroinvertebrates and standardisation methods for analysing water quality were applied. According to the application of the diversity indices in the identified aquatic macroinvertebrates, they presented an abundance of 1211 species in the rainy season and 1067 species in the dry season, with the most predominant families being Oligochaeta (38%) and Chironomidae (50%). , these individuals have an ABI and BMWP score of 1 and 2, respectively, which indicates the poor quality of the water in the micro-basin. The ecological indices present a more significant degradation, obtaining quality ranges from good to poor in the first sampling points and from bad to very critical in the last sections, contrasting with the water's physical, chemical and microbiological quality throughout the fluvial system. With the results obtained in the investigation, it is verified that the altitudinal range is a determinant in the biological diversity of aquatic macroinvertebrates of the aquatic ecosystem, being reduced at lower altitudes; this is mainly associated with anthropogenic activities. Therefore, it is recommended to take the necessary environmental measures to reduce pollution and thus improve the water quality of the Pachanlica river micro-basin.