Water Quality and Macroinvertebrate Community in Dryland Streams: The Case of the Tehuacán-Cuicatlán Biosphere Reserve (México) Facing Climate Change

Abstract

The Tehuacán-Cuicatlán Biosphere Reserve (TCBR), the southernmost semi-arid zone of North America, includes two dryland streams, the Río Salado (RS) and Río Grande (RG); it is surrounded by high vegetation diversity, a cacti diversification center, and the densest columnar cacti forest worldwide. However, no scientific knowledge is currently available on these dryland streams. We evaluated water quality, its relationship with the local geological characteristics, land uses, and the composition of aquatic macroinvertebrates (AM), analyzing their bioindicator potential. These results were discussed in relation to climate change predictions. The RS showed higher mineralization, salinity, hardness, water and air temperature, and low water quality index (WQI), relative to the RG. A discriminant analysis showed spatial (mineralization, salinity, and hardness in the RS) and temporal patterns (higher nitrogen compounds and temperature in the rainy season). The RS showed a lower AM diversity (40 taxa) compared to the RG (73 taxa); Ephemeroptera-Plecoptera-Trichoptera reached higher values in the RG. A co-inertia analysis identified five groups of sites with different AM assemblages and water quality characteristics. Climate change predictions for the TCBR suggest increased aridity, higher temperature, and lower rainfall, leading to reduced river flow and increased salinity and mineralization. These could alter habitat features and connectivity, with loss of AM diversity, highlighting the vulnerability of these unique ecosystems to climate change.

Aquatic macroinvertebrate assemblages in rivers influenced by mining activities

“…Despite the relatively low diversity and poor habitat conditions in the Extoraz River, we identified 32 different taxa (mostly at family level). By comparison, López-López et al 42 found 40 macroinvertebrate families in the Salado River, which flows across another Mexican PNA with similar vegetation, using the same sampling methods. However, in the Salado River, studies were conducted in two sampling sites, whereas our study was conducted in four study sites (Extoraz River).…”

Biotic Integrity, Water Quality, and Landscape Characteristics of a Subtropical River

“…This is related to the entry of clean water, where greater diversity is related to higher values of physicochemical parameters such as dissolved oxygen, water temperature, and transparency [59]. Different studies have described significant differences and important changes from the upper to the lower basin in the aquatic macroinvertebrate taxa, which could be related to changes in the physicochemical characteristics of the water by wastewater inputs, changes in habitats, and physical modifications to the channel, including nearby roads [60][61][62]. The values of the BMWP and the % EPT-B indices better reflected the general quality of the river, an aspect also described in other studies [45,[63][64][65].…”

A comparing vision of the lakes of the basin of Mexico: from the first physicochemical evaluation of Alexander von Humboldt to the current condition

“…Variables such as chlorides, conductivity, and total hardness can bring down the WQI scores, as pointed out by López-López et al (2019), who recorded low WQI scores in a river with high values of these parameters. Maansi et al (2022), estimating various water quality indices in Lake Sukhna, in India, found that higher hardness and alkalinity influenced the water quality.…”