The last peri-urban rivers of the Mexico Basin: establishment of potential reference conditions through the evaluation of ecological quality and biological indicators

Resumen

In assessing the health of rivers, the standardization of environmental and biological information as a baseline is essential in order to determine the set of conditions that are closest to the natural state of ecosystems. This is the case especially in peri-urban rivers where anthropogenic transformations occur rapidly and constantly. The objective of this work was to determine hydromorphological, physicochemical and biological parameters in 10 mountain rivers of the Mexico Basin, in order to establish a network of potential reference conditions and to validate the regional ecological quality. The potential reference conditions in this study are defined as oligotrophic water bodies with well-oxygenated concentrations and low ion concentrations. These conditions were recorded in 4 sub-basins with high hydromorphological quality. These results were corroborated through a base assembly composed of the macroinvertebrate families Baetide, Chrironomidae, Dugesiidae, Heptageniidae, Limnephilidae, Tipulidae and the class Arachnida (Acarina). The algal community was represented by Nostoc parmelioides, Placoma regulare, Batrachospermum gelatinosum, Paralemanea mexicana, Draparnaldia mutabilis, Prasiola mexicana and Vaucheria bursata. The major disturbances were structural changes in the riverbed that affect the structure and function of rivers.