Napo River Basin Research Articles

Rediscovery of Rhyacoglanis pulcher (Boulenger, 1887) (Siluriformes: Pseudopimelodidae), a rare rheophilic bumblebee catfish from Ecuadorian Amazon.

Rhyacoglanis pulcher is a rare Neotropical rheophilic bumblebee catfish known only from the type locality in the Cis-Andean Amazon region, Ecuador, and the type-species of the genus. So far, the three syntypes collected in 1880 were the only specimens unambiguously associated to the name R. pulcher available in scientific collections. Recently, a specimen was discovered in a fast-flowing stretch of the Villano river, a tributary of the Curaray river, Napo river basin, Ecuador, representing a new record after nearly 140 years. Here, we present this new record, identified by morphology, provide the DNA barcode sequence of the specimen, and propose why the species of Rhyacoglanis are scarce in zoological collections. Additionally, we discuss the intraspecific variation in the color pattern observed in R. pulcher.

Diversity of fishes of the Napo and Arajuno rivers, with potential of handling, in the Parish Ahuano, Canton Tena, Napo Province

The study is carried out to establish the diversity of fish in the Napo and Arajuno rivers in the segments that cross the Ahuano parish of the Tena Canton, Napo Province in the Ecuadorian Amazon. Several studies indicate that the Napo River basin would have up to 680 species of fish (Barriga, 2012). A monitoring effort was carried out for 12 months. Trammel and trawl nets were used to collect the specimens. Sampling was carried out at five stations in each river, every 1,000 meters, once a month during the 11 months of study. As a general result, the record of 27 species of bony fish was obtained. Of the order Characiformes, 16 species were obtained, being the most diverse, while at the taxonomic family level, Characidae was more frequent with 9 corresponding species. Additionally, a survey was carried out among 5 indigenous and peasant communities on the banks of the two rivers to establish the preference for fish consumption and the potential species for management, which were: Prochilodus nigricans for 28%, followed by Pimelodus blochii 18%, Mylosoma duriventre, Leporinus pearsoni, Hypostomus oculeus, Aguarunichthys torosus, Leporinus friederici and Triportheus angulatus with 9% each.

Effects of intensive agriculture and urbanization on water quality and pesticide risks in freshwater ecosystems of the Ecuadorian Amazon

The Ecuadorian Amazon has experienced a significant land use change due to the demographic increase and the expansion of the agricultural frontier. Such changes in land use have been associated to water pollution problems, including the emission of untreated urban wastewater and pesticides. Here we provide the first report on the influence of urbanization and intensive agriculture expansion on water quality parameters, pesticide contamination and the ecological status of Amazonian freshwater ecosystems of Ecuador. We monitored 19 water quality parameters, 27 pesticides, and the macroinvertebrate community in 40 sampling locations of the Napo River basin (northern Ecuador), including a nature conservation reserve and sites in areas influenced by African palm oil production, corn production and urbanization. The ecological risks of pesticides were assessed using a probabilistic approach based on species sensitivity distributions. The results of our study show that urban areas and areas dominated by African palm oil production have a significant influence on water quality parameters, affecting macroinvertebrate communities and biomonitoring indices. Pesticide residues were detected in all sampling sites, with carbendazim, azoxystrobin, diazinon, propiconazole and imidacloprid showing the largest prevalence (>80% of the samples). We found a significant effect of land use on water pesticide contamination, with residues of organophosphate insecticides correlating with African palm oil production and some fungicides with urban areas. The pesticide risk assessment indicated organophosphate insecticides (ethion, chlorpyrifos, azinphos-methyl, profenofos and prothiophos) and imidacloprid as the compounds posing the largest ecotoxicological hazard, with pesticide mixtures potentially affecting up to 26–29% of aquatic species. Ecological risks of organophosphate insecticides were more likely to occur in rivers surrounded by African palm oil plantations, while imidacloprid risks were identified in corn crop areas as well as in natural areas. Future investigations are needed to clarify the sources of imidacloprid contamination and to assess its effects for Amazonian freshwater ecosystems.

Nuevos registros por científicos ciudadanos de Acanthicus hystrix Agassiz, 1829 (Siluriformes: Loricariidae) en la Amazonia ecuatoriana

Three new records of Acanthicus hystrix Agassiz, 1829 are reported for the Ecuadorian Amazon, based on photographs of adult specimens uploaded to the ICTIO database (https://www.ictio.org/) by artisanal fishermen using the ICTIO 3.1 mobile application and a specimen collected in the upper Napo River basin (Ecuador). This specimen is the first voucher deposited in a scientific collection in Ecuador. This report confirms the presence of this cryptic fish species in the Ecuadorian Amazon.

Andean headwater and piedmont streams are hot spots of carbon dioxide and methane emissions in the Amazon basin

Rivers substantially contribute to global greenhouse gas emissions, yet emissions from headwater streams are poorly constrained. Here, we report dissolved concentrations of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in Andean headwater and piedmont streams in the Napo River basin in Ecuador, part of the Amazon River catchment. Concentrations increased exponentially with elevation decrease between 3990 and 175 m above sea level. Concentration changes scaled with catchment slope, and were attributed to variations in gas transfer velocity, forest cover, inundation extent, and water temperature. We estimate river emissions across the whole Amazon basin using existing data for the lowland Central Amazon. We find that Andean mountainous headwater and piedmont streams are hotspots of CO2 and CH4 emission, with respective areal fluxes being 1.7 and 4.5 higher in headwater streams, and 1.2 and 6.6 higher in piedmont streams than in lowland streams. Together, Andean mountainous headwater and piedmont streams and rivers represented 35% CO2 and 72% CH4 of basin scale integrated fluvial diffusive emissions. Conversely, N2O emissions from headwater and piedmont streams were low compared to lowland streams.

Evidence for Landscape Transformation of Ridgetop Forests in Amazonian Ecuador

AbstractThe Napo River basin, which is situated within the Upper Amazon archaeological region, is one of the most speciose forests in Greater Amazonia. Standard thinking in scholarship and science holds that these forests are essentially pristine because any Indigenous impacts in the past would have been minimal, seedbanks would have been nearby, and natural forests would have reappeared after the humans left, died out, or dispersed. Inventory research in 2019 on three ridgetop forests in Waorani territory inside the Curaray basin (which drains to the right margin of the Napo River) and a comparable inventory on one control site forest along the Nushiño River (also in the Curaray basin) show human impacts from about the late nineteenth century to about 1960; they occurred during the period of wartime among Waorani themselves and between Wao people and outsiders. The human impacts resulted in the high basal-area presence of two long-lived species with important Waorani cultural uses: cacao (Theobroma cacao L.) and ungurahua palm (Oenocarpus bataua Mart.). These species have high frequency and dominance values and do not occur in the control site, which is comparable in terms of elevation above the flood zone of the rivers in the sample. These findings mean that alpha diversity in the right margin sector (or south) of the Napo River basin cannot a priori be explained by reference to traditionally, biologically accepted patterns of ecological succession but may require knowledge of historical patterns of Indigenous land use and secondary landscape transformation over time due to human (specifically Waorani) impacts of the past.

Human health risk assessment of metals and metalloids in mining areas of the Northeast Andean foothills of the Ecuadorian Amazon.

Gold mining (GM) is a major source of metals and metalloids in rivers, causing severe environmental pollution and increasing the exposure risks to the residents of surrounding areas. Mining in Ecuadorian Amazonia has dramatically increased in recent years, but its impacts on Indigenous local populations that make use of rivers are still unknown. The aim of this study was to assess the risks to adults and children caused by the exposure to metals and metalloids in freshwater ecosystems contaminated with tailings released by GM activities in 11 sites of the upper Napo River basin, Ecuador. We selected a carcinogenic and a noncarcinogenic risk assessment method to estimate the hazard index (HI) and total cancer risk (TCR). The concentration of Ag, Al, As, Cd, Cu, Fe, Mn, Pb, Zn, B, and V in water and sediment samples was considered to assess the risks to human health. The calculated HI was 23-352 times greater than the acceptable limits in all sites for both children and adults. Mn and Fe were the main contributors (75% in water and 99% in sediment) to the total calculated risk based on the HI. The calculated TCR for children and adults exceeded approximately one to three times the permissible threshold in all sites. As and Pb contributed up to 93% of the total calculated risk based on TCR for both children and adults. This study demonstrates that the emission and mobilization of metals and metalloids caused by mining activities increase the risk to human health, to which we recommend further monitoring of freshwater contamination in the area and the implementation of preventive health management measures. Integr Environ Assess Manag 2023;19:706-716. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Data-set of the partial pressure of CO2 and dissolved concentration of CH4 and N2O in the rivers and streams of the Napo River basin in Ecuador.

Data-set of the partial pressure of CO2 and dissolved concentration of CH4 and N2O in the rivers and streams of the Napo River basin in Ecuador.

Data-set of the partial pressure of CO2 and dissolved concentration of CH4 and N2O in the rivers and streams of the Napo River basin in Ecuador.

Data-set of the partial pressure of CO2 and dissolved concentration of CH4 and N2O in the rivers and streams of the Napo River basin in Ecuador.

Appropriate Technology for Access to Universal Basic Services: A Case Study on Basic Electricity Service Provision to Remote Communities in the Napo River Basin

Appropriate technologies (ATs) refer to technologies that are controlled by the communities that benefit from their implementation. Technologies have become a fundamental element in projects aiming to solve problems related to poverty and access to basic needs in some areas in emerging countries, and appropriation of these technologies is necessary to ensure effective transfer of knowledge and sustainability. However, due to the lack of consensus on the definition of ATs, there is a need to clarify and define the scope and boundaries of the term to facilitate the implementation of technology in projects in developing countries. This study addresses this gap by means of a scoping review, which presents a detailed analysis of 17 journal articles (from an initial selection of 95 articles) and provides a comprehensive definition of ATs. To guide AT-oriented interventions in technology-intensive cooperation projects, this study proposes an Action Framework based on that definition of ATs. The Action Framework provides guidance on how to implement technology in these projects to ensure that the technology is appropriated. To facilitate the understanding of the Action Framework, the study showcases its application in a real project of rural electrification in the Peruvian Amazon Rainforest.

Improving Hourly Precipitation Estimates for Flash Flood Modeling in Data-Scarce Andean-Amazon Basins: An Integrative Framework Based on Machine Learning and Multiple Remotely Sensed Data

Accurate estimation of spatiotemporal precipitation dynamics is crucial for flash flood forecasting; however, it is still a challenge in Andean-Amazon sub-basins due to the lack of suitable rain gauge networks. This study proposes a framework to improve hourly precipitation estimates by integrating multiple satellite-based precipitation and soil-moisture products using random forest modeling and bias correction techniques. The proposed framework is also used to force the GR4H model in three Andean-Amazon sub-basins that suffer frequent flash flood events: upper Napo River Basin (NRB), Jatunyacu River Basin (JRB), and Tena River Basin (TRB). Overall, precipitation estimates derived from the framework (BC-RFP) showed a high ability to reproduce the intensity, distribution, and occurrence of hourly events. In fact, the BC-RFP model improved the detection ability between 43% and 88%, reducing the estimation error between 72% and 93%, compared to the original satellite-based precipitation products (i.e., IMERG-E/L, GSMAP, and PERSIANN). Likewise, simulations of flash flood events by coupling the GR4H model with BC-RFP presented satisfactory performances (KGE* between 0.56 and 0.94). The BC-RFP model not only contributes to the implementation of future flood forecast systems but also provides relevant insights to several water-related research fields and hence to integrated water resources management of the Andean-Amazon region.

Vulnerability of Human Populations to Contamination from Petroleum Exploitation in the Napo River Basin: An Approach for Spatially Explicit Risk Assessment

Background: contamination of aquatic ecosystems by oil spills associated with petroleum exploitation represents a serious problem of environmental contamination that can affect human health. We developed a spatial model of contamination risk in the Ecuadorian Amazon, and evaluated the model using independent datasets on environmental contamination and clinical indicators of human health risk factors. Methods: the spatial risk of contamination for the Napo River basin was based on the calculation of a friction surface and the accessibility of possible oil contamination. Human health was evaluated using peripheral blood samples from 256 individuals. We used monitoring data on contamination to validate the spatial model of contamination risk and analyzed whether the estimated risk explained the incidence of human health risk factors. Results: our risk model showed a significant association with actual contamination detected in the study area. According to our risk model, around 30% of the territory has some level of contamination. Risk of contamination was associated with an increasing mean incidence in risk factors for human health in resident populations, but elevated contamination risk was not a significant predictor of the incidence of selected health indicators; only the incidence of inflammation was significantly increased. Conclusions: a large proportion of the populations in the Napo River basin has high vulnerability to contamination from petroleum exploitation, and this contamination risk may be traced in some indicators of health risk. Closer examination of health risk factors is warranted, and our spatial model of contamination risk can inform the design and analysis of such studies, as well as risk mitigation and management. Our approach to building the model of contamination risk could be applied in other catchments where petroleum exploitation is contemplated.

LENGTH-WEIGHT RELATIONSHIPS FOR 14 FISH SPECIES OF NAPO RIVER BASIN, PERUVIAN AMAZON


 
 
 This work presents the length-weight relationships of 14 species of fish of the Napo River basin. Fish collections were carried out between 2012 and 2014, using gill nets and seine. A total of 1896 specimens, belonging to 14 species and five orders were analyzed. The allometric coefficient b ranged from 2.69 to 3.78. A new record of length-weight relationship is presented for Curimata cisandina (Allen, 1942). The comparisons with other Amazonian studies indicated differences in the parameters a and b of LWR with this study for the species Triportheus angulatus (Spix & Agassiz, 1829), Mylossoma duriventre (Cuvier, 1818), Roeboides myersii Gill, 1870 and Pellona castenaena Valenciennes, 1847 and only parameter b for Psectrogaster amazonica. The results presented in this work contribute to a better knowledge of fish resources in the region of the Peruvian Amazon, especially in the Napo River basin.
 
 

Species and geographic distribution of Mylossoma Eigenmann & Kennedy, 1903 from Ecuador

A review of the species of the genus Mylossoma Eigenmann & Kennedy, 1903 found in the Ecuadorian Cis-Andean region was conducted. Two species were recognized: M. albiscopum (Cope, 1872) from the Putumayo, Napo, and Tigre river basins and M. aureum (Agassiz, 1829) from the Napo river basin. A map of geographical distribution and radiographs for both species are provided. Historical records of M. duriventre (Cuvier, 1818) were not confirmed in this geographical distribution.

Soccer in the integration and assimilation processes of Amerindian peoples

Has soccer favoured the integration processes of Amerindian peoples in the different national societies to which they belong, or has it rather permitted their cultural assimilation? Based on this general question, four different scenes are analysed: the ethnic through the Yanomami case; the regional with the populations of the Napo river basin; the national with the Pan-indigenous Games; and the international one with the America's Cup of the Indigenous Peoples. The methodology used for data production combines ethnographic work with documentaries, distributed in different places and periods of time. Among the conclusions, soccer has become one of the symbols of the new ages of the indigenous world, instrumentalized in different ways and used to expand and reinforce social links. By the moment, its practice is not directly denoting the abandonment of the cultural being of these towns.

Time Series Analysis for Predicting Hydroelectric Power Production: The Ecuador Case

Electrical generation in Ecuador mainly comes from hydroelectric and thermo-fossil sources, with the former amounting to almost half of the national production. Even though hydroelectric power sources are highly stable, there is a threat of droughts and floods affecting Ecuadorian water reservoirs and producing electrical faults, as highlighted by the 2009 Ecuador electricity crisis. Therefore, predicting the behavior of the hydroelectric system is crucial to develop appropriate planning strategies and a good starting point for energy policy decisions. In this paper, we developed a time series predictive model of hydroelectric power production in Ecuador. To this aim, we used production and precipitation data from 2000 to 2015 and compared the Box-Jenkins (ARIMA) and the Box-Tiao (ARIMAX) regression methods. The results showed that the best model is the ARIMAX (1,1,1) (1,0,0)12, which considers an exogenous variable precipitation in the Napo River basin and can accurately predict monthly production values up to a year in advance. This model can provide valuable insights to Ecuadorian energy managers and policymakers.

La arqueología del río Napo: noticias recientes y desafíos futuros

La arqueología del río Napo fue inicialmente conocida a través de los trabajos pioneros de Clifford Evans y Betty Meggers en territorio ecuatoriano. Estas investigaciones permitieron la formulación de una secuencia cerámica que aún continúa siendo la columna vertebral de nuestra comprensión arqueológica de la región. Sin embargo, nuevos datos arqueológicos han mejorado la reconstrucción del proceso de ocupación humana de la región en la época pre-colonial. Entre ellos se cuentan observaciones derivadas de la actividad coleccionista de misioneros, nuevas informaciones producidas por la arqueología de contrato en Ecuador y recientes datos producidos por investigaciones arqueológicas en el territorio peruano de la cuenca. En este artículo se sintetiza la información referida, se discuten los aspectos tecno-estilísticos de la cerámica arqueológica de la región, se presentan nuevos datos arqueológicos que evidencian ocupaciones de la fase Napo a lo largo de todo el curso del río por tierras bajas, y se evalúa el estado de avance del conocimiento de las ocupaciones pre-coloniales de la cuenca del río Napo.

Spatial prediction of stream physicochemical parameters for the Napo River Basin, Ecuador

Major threats to freshwater ecosystems in the Andean-Amazon region include agriculture, point and nonpoint source pollution, hydroelectric dams, oil extraction, mining and road building, yet little is known about the baseline values and current state of rivers and streams, or how expanding urban, industrial and agricultural activities could affect and change these freshwater ecosystems and their diversity. Therefore, there is a need to understand physicochemical parameters at the basin scale in many large river systems in the Andean-Amazon such as the Napo River, a world biodiversity hotspot. Establishing baselines for these parameters under less developed conditions will be impossible after development in the watersheds increases and hydroelectric projects reach completion. In addition to collecting data to fill in information gaps in geology, vegetation, disturbance, and other parameters that influence water quality, it is important to use existing data in the Napo to predict chemical parameters throughout the watershed to set a baseline from which deviations from development and climate change can be assessed and to guide data collection efforts. In this study, we provide the first basin-wide estimates of physicochemical parameters (pH, conductivity, dissolved oxygen and temperature) for the entire Napo River Basin using a recently developed geostatistical technique called top kriging. Basin-wide predictions aligned well with observed values and a model validation test showed a strong goodness-of-fit for parameter estimates. Furthermore, our predictions aligned well with observed values from independent datasets from the Napo Basin. These predictions could be useful in developing water quality reference baselines for the basin and for monitoring relative changes to parameters, assist in the identification of priority areas within the basin for management and conservation efforts, direct future research, and be applied in other data-scarce basins in remote regions worldwide.

Rural Social Networks along Amazonian Rivers: Seeds, Labor and Soccer among Communities on the Napo River, Peru

Research on Amazonian communities has focussed more often on rural‐urban linkages than on links among rural communities. This is unsurprising, given the low density of population, limited intercommunity commerce, and importance of direct city‐market relations. Social relations among rural communities are also important in shaping rural livelihoods and lifeways. We report on the findings of a large‐scale census of communities in the Napo River basin in northeastern Peru (n=174). Data were gathered on intervillage crop seed acquisition and cooperative labor sharing as two key inputs in agriculture, and on intervillage soccer matches, which are integral to rural social life. We analyze the socio‐spatial networks of each practice, paying attention to settlement patterns, community ethnicity, and differential access to the uplands. We find that seeds and labor flow along soccer network lines. Rural social networks appear to be structured strongly by ethnicity (homophily) and reflect important complementarities between upland and lowland communities (weak ties).

Distribution and Habitat Suitability of Andean Climbing Catfish in the Napo River Basin, Ecuador

Astroblepidae face numerous threats in Ecuador, and their range is thought to be decreasing in most basins due to urban development, agriculture, oil and mineral extraction, dams, and introduction of exotic species. In the Napo River Basin, one of the largest and most-diverse river basins in Ecuador, Astroblepus vaillanti is also potentially being displaced by rainbow trout (Onchorynchus mykiss) introductions at higher altitudes, yet no published information exists on the habitat requirements and distribution of the species. In this study, we developed species–habitat relationships for a suite of physico-chemical variables and compared abundances of A. vaillanti in streams heavily impacted by agriculture and less impacted streams. Interestingly, we found significantly higher abundances of A. vaillanti in heavily impacted streams. We also found that A. vaillanti abundance was positively related to stream temperature, whereas the inverse was true for rainbow trout. Our study highlights the need for further study to understand the habitat requirements and diet of A. vaillanti as well as the impacts of rainbow trout on the species to inform conservation efforts of the species.