Water quality assessment methods of the highland Andean rivers: A scoping systematic review.

Water is a resource that influences sustainable development in different ways in social, economic, and environmental aspects, being the Andes the major provider of this resource. However, they have been affected mainly by anthropogenic activities due to the proximity of settlements in the watersheds, so they tend to have more significant contamination, and their evaluation is essential to mitigate problems for those who consume them. However, despite being a fundamental resource and one of the main contributors of water, it is not so studied, so the present study aims to determine the studies based on the water quality of the high mountain rivers of the Andes by using a PRISMA methodology with the scoping review extension, based on search techniques, inclusion and exclusion criteria, and monitoring tables, in order to maintain a line of research attached to the objective of the study. After using the methodology, ten articles were obtained, which were analyzed after a bibliometric analysis to determine features of interest, such as countries in which the studies were carried out, years of publication, methodologies used, and authors' consensus. High Andean rivers' importance, the need for more studies within these areas, and the lack of suitable indexes for these unique ecosystems are highlighted.

Behavioral and biochemical patterns in the Andean highland macroinvertebrate Nectopsyche sp. after chronic mercury exposure.

Environmental pollution by mercury (Hg) is of particular interest in Latin American countries like Ecuador, where artisanal and industrial gold mining has widely expanded. However, classic assessments, either based on water parameters or bioindicators, are not always effective in determining the effect of this type of pollutant on the ecological quality of the rivers. This study analyzed the behavioral and biochemical responses in benthic macroinvertebrate Nectopsyche sp. after sub-lethal Hg exposure emulating the maximum limits allowed by the current legislation in Ecuador (0.0002 mg L-1). Behavioral changes were significant, with an average decrease in the movement (measured as the number of strokes per 15 s of larvae) after 6 days of exposure to the maximum limit concentration of Hg. Furthermore, the antioxidant enzyme Glutathione S-Transferase activity significantly increased when exposed for 7 days to 0.0002 mg L-1 of Hg concentration. These results preliminarily proved that behavioral and biochemical patterns could function as biomarkers that efficiently identify ecological impairment caused by Hg, which would otherwise be neglected by a purely chemical-based or biomonitoring based on the presence/absence of macroinvertebrates type of assessment. Moreover, we demonstrate that the current limits allowed can impair aquatic life.

Effects of Pesticides on the Survival of Shredder Nectopsyche sp. (Trichoptera) and Leaf Decomposition Rates in Tropical Andes: A Microcosm Approach.

Andean streams are becoming increasingly impacted by agricultural activities. However, the potential effects of pesticides on their aquatic biodiversity remain unassessed. In order to address this knowledge gap, we conducted an experiment over 37 days in microcosms to assess the effect of two pesticides commonly used in Ecuador (Engeo and Chlorpyrifos) on the aquatic insect Nectopsyche sp. (Trichoptera: Leptoceridae) at 0, 0.10, 5 and 10 µg L-1 concentrations. The highest concentration corresponds to the maximum concentration allowed by the Equatorian legislation. We assessed insect mortality every 24 h, with leaf litter decomposition rates of organic matter determined by deploying Andean alder (Alnus acuminata) dry leaf packs in the microcosms. We found significant mortality of Nectopsyche sp. at high concentrations of Chlorpyrifos, whereas leaf litter was not significantly affected by any of the treatments. We conclude that the environmental legislation of Ecuador might not be fully protecting aquatic biodiversity from pesticide pollution. Further studies are needed, especially when considering that the maximum permitted concentration is very likely exceeded in many areas of the country. We also suggest that the maximum permissible values should be reviewed, considering each pesticide individually.

Long-term responses of macroinvertebrate assemblages to the 2011 eruption of the Puyehue-Cordón Caulle volcanic complex, Chile.

In June 2011 the Puyehue-Cordón Caulle volcanic complex (PCCVC) erupted, ejecting around 950 million metric tons of volcanic ash and pyroclastic rock, generating habitat destruction, environmental deterioration and devastation of ecological communities in rivers near the volcanic fissure. We evaluate the long-term effect of this eruptive event on the recovery of the diversity of aquatic macroinvertebrates, collecting biological and environmental information from 2011 to 2018 in visibly impacted Chilean rivers (Gol-Gol and Nilahue) and not visibly impacted rivers (Calcurrupe and Chanleufu). With the macroinvertebrate records we developed a recovery coefficient based on their diversity before and after the eruption. The results show that before the eruption (2009-2010), the accumulated family richness and mean diversity in the Gol-Gol River were higher than that observed post-eruption in rivers visibly impacted and not visibly impacted. Between 2013 and 2018, 17 families recolonized the Gol-Gol River, as well as 10 new families that were not recorded before the eruption. The richness of families post-eruption was negatively related to the increase in the concentration of total suspended solids, affecting the successional changes and recovery in the medium term. The recovery coefficient indicates that seven years after the eruption the diversity of macroinvertebrates still shows lower levels than those recorded before the eruptive event, with predominance of a slow recovery phase. Families of orders Ephemeroptera, Plecoptera and Trichoptera that were dominant before the eruption of the PCCVC began to recover the richness of taxa two years later, Plecoptera reaching 50% recolonization in 2018, Ephemeroptera 33.3% and Trichoptera 30%. In contrast, Diptera reached 100% recovery by 2018 and chironomids increased since 2015, becoming the dominant taxon during intermediate recovery in the Gol-Gol River. The recovery of macroinvertebrates in the Gol-Gol River is related to their modes of dispersal, feeding and the decrease in ash concentration.

Structure of the aquatic Diptera community in the upper basins of the Fucha and Bogotá rivers / Estructura de la comunidad de dípteros acuáticos en tramos de los cursos altos de los ríos fucha y bogotá

RESUMEN Los macroinvertebrados acuáticos son bien conocidos como bioindicadores de la calidad del agua. En Colombia, los estudios sobre este tema se han hecho principalmente a nivel taxonómico de familia. En este trabajo se analizan las respuestas en abundancia, riqueza y diversidad de los dípteros identificados a nivel de género en ríos altoandinos (río Bogotá y río Fucha), en épocas de aguas bajas y aguas altas. Los especímenes se recolectaron con tres métodos: red Surber, red de mano y lavado de rocas. La temperatura promedio fue de 12,9 °C y la saturación de oxígeno estuvo cerca del 100 % o más, con excepción del tramo bajo del río Bogotá antes de Villapinzón. Se colectaron 13 690 dípteros pertenecientes a diez familias y 40 géneros. La riqueza taxonómica fue alta, con una mayor variación en los tramos bajos de las dos corrientes. Las subfamilias de Chironomidae fueron las más abundantes. El análisis de correspondencia canónica (ACC) mostró que los Orthocladiinae se asociaron con la conductividad; el género Gigantodax (Simuliidae) no mostró una relación clara con ninguna variable; por el contrario, el género Simulium se vinculó con el caudal. En términos generales, la asociación entre taxones y variables ambientales fue más clara para los géneros que para las familias, pero no fue suficientemente robusta. Se sugiere que para encontrar un mayor grado de asociación biota-ambiente, es necesario realizar los análisis a nivel de especie, considerando las variaciones locales y temporales.

ABSTRACT Aquatic macroinvertebrates are recognized as bioindicators of water quality. In Colombia, the studies have mainly been addressed by the family taxonomic level. This work analyzes the responses in abundance, richness, and diversity of the Diptera at the genus level in high Andean rivers (Bogotá River and Fucha River), in periods of low and high waters. The specimens were collected with three methods: Surber net, hand net, and rock washing. The average temperature was 12.9 °C and oxygen saturation was close to 100 % or more, except for the lower section of the Bogotá River, before the Villapinzón town. 13 690 Diptera were collected from ten families and 40 genera. Taxonomic richness was high with the greatest variation in the lower sections of the two streams. The Chironomidae subfamilies were the most abundant. Canonical correspondence analysis (CCA) showed that Orthocladiinae were associated with water conductivity; the Gigantodax genus (Simuliidae) did not show a clear relationship with any variable; conversely, the genus Simulium was linked to the caudal. In general terms, the association between taxa and environmental variables was clearer for genera than for families, but it was not robust enough. It is suggested that to find a higher degree of biota-environment association, it is necessary to carry out analyzes at the species level, considering local and temporal variations.

SARS-CoV-2 in river water: Implications in low sanitation countries.

Since the beginning of COVID-19 pandemic studies on viral shedding have reported that this virus is excreted in feces in most patients. High viral loads are found at the sewage pipeline or at the entrance of wastewater treatment plants from cities where the number of COVID-19 cases are significant. In Quito (Ecuador) as in many other cities worldwide, wastewater is directly discharged into natural waters. The aim of this study was to evaluate SARS-CoV-2 presence in urban streams from a low sanitation context. Three river locations along the urban rivers of Quito were sampled on the 5th of June during a peak of COVID-19 cases. River samples were evaluated for water quality parameters and afterwards, concentrated for viral analysis using skimmed milk flocculation method. The viral concentrates were quantified for SARS-CoV-2 (N1 and N2 target regions) and Human Adenovirus as a human viral indicator. The results showed that SARS-CoV-2 was detected for both target regions in all samples analyzed in a range of 2,91E+05 to 3,19E+06 GC/L for N1 and from 2,07E+05 to 2,22E+06 GC/L for N2. The high values detected in natural waters from a low sanitation region have several implications in health and ecology that should be further assessed.

Response of epilithic diatom communities to environmental gradients along an Ecuadorian Andean River.

Epilithic diatom communities are particularly suitable for the evaluation of freshwater quality. In Ecuador, however, no water quality index includes this biotic parameter. This work is the first attempt in the country to determine the composition of epilithic diatom communities associated with different degrees of eutrophication. This was accomplished by measuring physical, chemical and microbiological variables at five sampling sites along the Pita River, Ecuador, from August to December 2016. The results indicate a clear gradient of eutrophication from sampling sites P1 (good water) in the upper reaches to P5 (bad water) located in the lower reaches. Concerning diatom analyses, the results indicated a high diversity for tropical areas in terms of species richness, varying from S=34 in headwaters to S=42 downstream. Moreover, the results obtained suggest a lack of concordance with the trophic values given to some of the epilithic diatoms in the literature. There were also species that seem to be sensitive to downstream nutrient increases that were not considered as bioindicators in previous studies. We concluded that the trophic values of diatom species available in the scientific literature are not directly applicable to their sites in the Pita River. Hence, it is necessary to establish a trophic diatom index for the Andean region of Ecuador.

Revision of Neacomys spinosus (Thomas, 1882) (Rodentia: Cricetidae) with emphasis on Peruvian populations and the description of a new species.

The large spiny mouse Neacomys spinosus (Thomas, 1882) has been considered the widest ranging species of the genus, occurring in southern Colombia, eastern Peru, western Brazil and northern Bolivia. The morphological variation between subspecies and populations of N. spinosus has been noted; nonetheless, this variation has not been assessed in a morphological or molecular context. Here, we present a taxonomic revision of Neacomys spinosus s.l. using qualitative and quantitative morphological analyses. These analyses were complemented with molecular analysis to reconstruct the phylogenetic relationships among species of Neacomys, based on sequences of the cytochrome b gene. Our results reveal that N. spinosus s.l. is a monophyletic group, and morphological and molecular evidence to differentiate three taxa: N. spinosus s.s., an endemic species from mountain cloud forests in Peru; N. amoenus s.l. from the Cerrado between Bolivia and Brazil to the Amazonia between Ecuador and northern Peru, and Neacomys sp. nov. from mountain cloud forests from southern Peru to Bolivia. Also, our molecular results indicate that Neacomys is still far from being completely known. For instance, there are three candidate species pending of taxonomic revision. Finally, we propose three species groups within Neacomys: "paracou", "tenuipes" and "spinosus", and discuss biogeographical scenarios of the genus within South America.

Freshwater fish faunas, habitats and conservation challenges in the Caribbean river basins of north-western South America.

The remarkable fish diversity in the Caribbean rivers of north-western South America evolved under the influences of the dramatic environmental changes of neogene northern South America, including the Quechua Orogeny and Pleistocene climate oscillations. Although this region is not the richest in South America, endemism is very high. Fish assemblage structure is unique to each of the four aquatic systems identified (rivers, streams, floodplain lakes and reservoirs) and community dynamics are highly synchronized with the mono-modal or bi-modal flooding pulse of the rainy seasons. The highly seasonal multispecies fishery is based on migratory species. Freshwater fish conservation is a challenge for Colombian environmental institutions because the Caribbean trans-Andean basins are the focus of the economic development of Colombian society, so management measures must be directed to protect aquatic habitat and their connectivity. These two management strategies are the only way for helping fish species conservation and sustainable fisheries.

Estado poblacional del orden Plecoptera (Insecta) en el Parque Nacional Sierra Nevada en Venezuela y sus implicaciones para planes de conservación

Population status of insects of Plecoptera order in Sierra Nevada National Park in Venezuela and its implications for conservation planning. Longitudinal distribution of Plecoptera species were examined along the Sierra Nevada National Park in the Andean region of Merida State, Venezuela. PNSN is one of the largest protected areas and consists of two major sub-basins. Quantitative samples were collected in 7 river tributaries along the PNSN from February to May of 2009, and a total of 135 individuals and 4 species of the genus Anacroneuria were collected. Only three rivers (Nuestra Señora, La Picón y Corcovada) found the presence of stoneflies, the principal component analysis show that the characterization of habitat, current velocity, dissolved oxygen and the absence of human disturbance sources of influence in a suitable habitat for populations. Stoneflies are endangered or have become extinct throughout much of its range due to human activities. Conservation plans must be implemented urgently, in order to avoid recreational areas and/or economic in vicinity thereof. Rev. Biol. Trop. 58 (4): 1299-1310. Epub 2010 December 01.

La distribución longitudinal de las especies de plecópteros fue examinada a lo largo del Parque Nacional Sierra Nevada en la región Andina del estado Mérida, Venezuela. El PNSN es uno de las más grandes regiones protegidas y abarca dos subcuencas hidrográficas importantes. Muestras cuantitativas fueron recolectadas en 7 ríos tributarios de estas cuencas a lo largo del PNSN desde febrero a mayo del 2009, con un total de 135 individuos de 4 especies del género Anacroneuria. Sólo en tres ríos (Nuestra Señora, La Picón y Corcovada) se encontró la presencia de plecópteros, los análisis de componentes principales muestran que la caracterización del hábitat, la velocidad de la corriente, el oxígeno disuelto y la ausencia de fuentes de perturbación antrópica influyen en un hábitat idóneo para las poblaciones. Los plecópteros se hallan en peligro de desaparición o incluso se han llegado a extinguir en gran parte de su área de distribución como consecuencia de actividades humanas. Planes de conservación deben ser implementados con urgencia, como evitar zonas recreacionales y/o económicas en las cercanías de los mismos.