Centro de Investigación para el Territorio y el Hábitat Sostenible

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Universidad Indoamérica

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Risk assessment of unlined oil pits leaking into groundwater in the Ecuadorian Amazon: A modified GIS-DRASTIC approach
(2022)
Durango-Cordero J.
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Saqalli M.
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Ferrant S.
;
Bonilla S.
;
Maurice L.
This study evaluates the risk of groundwater contamination from unlined oil pits, in the Northern Ecuadorian Amazon (NEA). Applying spatial analysis, several maps were provided for its integration in land use planning, public health improvement and future site-specific investigations. Two main maps were produced: (1) a vulnerability indexed map using a modified DRASTIC model and (2) a hazard map based on the past (1995–1997) and present (2018) contamination using a weighted density equation. The hazard was derived from hydrocarbon contained in oil pits associated with a cost-distance analysis to obtain different maximum distance ranges (MDR), to model the surface of potentially impacted groundwater. The results indicate a total calculated hydrocarbons of 39 052 tons. A MDR from 500–10 000 km was retained to map aquifers at risk, the maximum surface potentially at risk covers 13% of the NEA, while 83% of the area represents low to medium-low vulnerability. This study led to several recommendations, such as the level of suitability of the available information, and what gaps should be filled to improve future research. A surface of 271–766.5 km in the 500-2000-m distance range should be prioritised for finer scale risk assessment. © 2021 Elsevier Ltd
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Sentinel satellite data monitoring of air pollutants with interpolation methods in Guayaquil, Ecuador
(2023)
Mejía C. D.
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Alvarez H.
;
Zalakeviciute R.
;
Macancela D.
;
Sanchez C.
In Ecuador, there is a limitation on air quality monitoring due to the cost of monitoring networks. Although air quality monitoring stations are instruments for air measurement, they do not cover an entire city due to their scope. Satellite remote sensing is now an effective tool to study atmospheric pollutants and has been applied to continuously assess a region and overcome the limitations of fixed stations. Despite the application of satellite data for air quality monitoring, there are some limitations, such as measurement frequency, cloud cover and wide spatial resolution, which do not allow the assessment of air pollution in cities. Therefore, downscaling, applying interpolation methods, is essential for continuous air quality monitoring at smaller scales. For this research, Nitrogen Dioxide (NO2) data from the Sentinel-5 satellite percussor was used in the city of Guayaquil for January–December 2020, which is considered before, during and after the COVID-19 quarantine. This mid-size port city does not have a permanent monitoring network, which prevents us from knowing the air quality. Due to the limitation of pixel size, this study used satellite data to apply interpolation techniques and reduce pixels to assess air quality. Two categories of interpolation were selected: deterministic and stochastic. The empirical Bayesian kriging (EBK) interpolation obtained a R2 of 0.9546, which was superior to the other methods applied. Therefore, the EBK method had the best accuracy for tropospheric NO2 concentration. Finally, the method used in this research can help monitor air quality in cities lacking continuous monitoring networks, as the reduction of the pixel size gives us a better pattern of pollutants. © 2023 The Authors
38
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Microalgal Diversity in the Ecuadorian Tropical Andes and Its Association with Abiotic Factors
(2025)
María Cristina Guamán-Burneo
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Nory González-Romero
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Santillán Sarmiento, Alex
The Ecuadorian Tropical Andes serve as vital biodiversity hotspots, crucial for hosting and preserving unique endemic species. While numerous taxonomic groups within these hotspots have been extensively studied, microalgae remain relatively unknown. This study aimed to document the microalgal diversity of Tropical Andean lakes in Ecuador and its relationship with abiotic environmental factors. Water samples were collected from 28 lakes throughout 10 conservation areas, spanning different altitudes in the Ecuadorian Tropical Andes, along with water physical/chemical data. A total of 92 microalgal genera were identified, spanning Bacillariophyta, Chlorophyta, Glaucophyta, Ocrophyta, Cyanophyta, and Euglenophyta. Lakes such as Rodeococha, Anteojos, Chinchillas, Toreadora, Magdalena, and La Mica exhibited the highest richness of microalgal genera. A positive association between temperature and the majority of microalgal phyla, except Glaucophyta, was observed. On the other hand, negative correlations were observed between total dissolved solids and water conductivity with microalgal biodiversity. Additionally, all groups displayed negative associations with pH, except Glaucophyta. The Jaccard similarity index was low among lake communities in agreement with the uniqueness of genera found in some lakes. This study represents a fundamental baseline for future investigations into Ecuador’s microalgal diversity and its relationship with abiotic environmental factors in the delicate freshwater ecosystems of Tropical Andean lakes.
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Mapping 50 years of contribution to the development of soil quality biological indicators
(2023)
Bonilla Bedoya, Santiago
;
Valencia K.
;
Herrera M.Á.
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López-Ulloa M.
;
Donoso D.A.
Biological indicators of soil quality express the capacity of a soil to maintain its ecosystem functions and services between socio-ecosystem inflection thresholds; therefore, they are determinants in management and land use decisions. However, their development until a few decades ago was limited for several reasons: reductionism and early development of other dimensions, such as physical and chemical indicators or their methodological complexity, thus affecting the importance given to biological factors and the integral evaluation of soil quality or health. Thus, this review presents a mapping of the scientific contributions of the last 50 years oriented to the theoretical and methodological development of biological indicators of soil quality, identifying their development and application in these decades. We conducted a bibliometric analysis that allowed us to present an overview of the field with respect to scientific production: temporality, geographical origin, institutional origin, journals that promote the development of the field, articles with greater influence by citation in the field of study, and the co-occurrences of these indicators in research. This analysis was complemented at the second stage by a systematic review of the literature with the greatest impact by citation. We found 2320 scientific papers distributed mainly in the United States (17.8%), China (12.2%), Brazil (8.3%), India (6.3%), and European Mediterranean countries, such as Spain, France, and Italy (14.2%). Our review showed 25 biological indicators with the highest occurrence; for example, microbial biomass (1 1 8), enzymatic activity (90), and organic matter (78); other indicators, such as earthworms, nematodes, or springtails, are also reported. All indicators showed relationships, to a greater or lesser extent, with soil biodiversity and its functions in the landscape. Important advances in soil indicators have developed gradually in the last few decades, with scientific efforts mainly concentrated in developed and emerging countries. In the last decade, the production curve continues with a growth trend., and research questions in the field revolve around the linkage of diversity and function from a molecular point of view. The scope goes beyond productivity, manifesting the real need to conserve and manage the ecosystem services of a limited and non-renewable natural resource. Pioneering research should begin to report on the scope of soil biological monitoring and its influence on policy, management, and land use. Finally, the promotion of research networks with developing countries can foster the development of regional and local soil monitoring policies in these regions. © 2023 The Author(s)
Scopus© Citations 5 33
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Urban–Rural Gradients Predict Educational Gaps: Evidence from a Machine Learning Approach Involving Academic Performance and Impervious Surfaces in Ecuador
(2021)
Santos-García F.
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Valdivieso K.D.
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Rienow A.
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Gairín J.
Academic performance (AP) is explained by a multitude of factors, principally by those related to socioeconomic, cultural, and educational environments. However, AP is less understood from a spatial perspective. The aim of this study was to investigate a methodology using a machine learning approach to determine which answers from a questionnaire-based survey were relevant for explaining the high AP of secondary school students across urban–rural gradients in Ecuador. We used high school locations to construct individual datasets and stratify them according to the AP scores. Using the Boruta algorithm and backward elimination, we identified the best predictors, classified them using random forest, and mapped the AP classification probabilities. We summarized these results as frequent answers observed for each natural region in Ecuador and used their probability outputs to formulate hypotheses with respect to the urban–rural gradient derived from annual maps of impervious surfaces. Our approach resulted in a cartographic analysis of AP probabilities with overall accuracies around 0.83–0.84% and Kappa values of 0.65–0.67%. High AP was primarily related to answers regarding the academic environment and cognitive skills. These identified answers varied depending on the region, which allowed for different interpretations of the driving factors of AP in Ecuador. A rural-to-urban transition ranging 8–17 years was found to be the timespan correlated with achievement of high AP. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Scopus© Citations 1 14
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Exploring Wardriving Potential in the Ecuadorian Amazon for Indirect Data Collection
(2021)
Santos F.
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Pesantes P.
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Bonilla Bedoya, Santiago
Digital inclusion in the Ecuadorian amazon is known as a problem, which intensified with the pandemic. Since social distance is now the norm, we constructed a WiFi access point (WAP) scanner to map and analyze its data. We correlated it with ancillary geoinformation to observe its potential and limitations as a method for indirect data collection. Our result indicate that WAP correlate weakly but positively with nightlight, young population, accessibility to economical centres, and negatively with slope. Moreover, we differentiated vulnerability naming patters from Service Set Identifiers (SSDI) and differentiated the number of WAPs according to land cover for differentiate urban from rural areas. This output is now offering increasing applications to get updated rought estimates of internet activity and indirectly correlations to socio-economic conditions, technology practices, and opportunities for natural language processing. Therefore, we conclude that wardriving offer interesting opportunities for mapping social data but also concerns as an indirect data collection method. © Published under licence by IOP Publishing Ltd.
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Evaluating night-time light sources and correlation with socio-economic development using high-resolution multi-spectral Jilin-1 satellite imagery of Quito, Ecuador
(2023)
Watson C.S.
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Elliott J.R.
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Córdova M.
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Menoscal J.
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Bonilla Bedoya, Santiago
Artificial light at night (ALAN) has positive and negative effects on social, economic, environmental, and ecological systems, and will increase with urban expansion. In this study, we used a multi-spectral 1.5 m resolution night-time acquisition from a Jilin-1 satellite over the city of Quito, Ecuador, to evaluate spatial lighting patterns in an expanding and topography complex-built environment. We demonstrated a requirement for robust georeferencing and orthorectification due to the complex topography, with errors on the order of 4–6 pixels (5.8–8.4 m CE95). We also quantified differences in observed brightness due to the image acquisition and local geometry. Street light type was distinguishable between high-pressure sodium (HPS) and light emitting diode (LED) sources (F1-score = 0.72–0.83) using a shark random forest decision tree approach. Additionally, street lights could be located within 10 m (F1-score = 0.71) with balanced omissions and commissions. Spatial trends revealed that the road network was the dominant source of illumination, accounting for 45% of illuminated pixels, whereas built-up areas accounted for 23%. Overall, 68% of all illuminated pixels were on or within 10 m of the road. Higher socio-economic development was associated with higher proportions of LED lighting, greater road network lighting and density of street lights, higher overall radiance for built-up areas and the road network, and greater coverage and illumination of designated green spaces. The broad impacts of ALAN mean that addressing the causes and consequences of lighting inequalities is a complex issue. Nonetheless, Jilin-1 night-time imagery offers a low-cost way to map and monitor light sources at high-resolution that will be beneficial to city-planners and progressing Sustainable Development Goals. © 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Scopus© Citations 4 35
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Urban Air Pollution in the Global South: A Never-Ending Crisis?
(2025)
Rasa Zalakeviciute
;
Jesus Lopez-Villada
;
Alejandra Ochoa
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Valentina Moreno
;
Ariana Byun
Among the challenges the human population needs to address are threats of global pandemics, increasing socioeconomic inequality, especially in developing countries, and anthropogenic climate change. The latter’s effect has been amplified with the arrival of 2023/24 El Niño, causing an exceptional drought in the Amazon basin, significantly affecting fire conditions and hydroelectric power production in several South American countries, including Ecuador. This study analyzes five criteria pollutants—carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and particulate matter ≤ 2.5 µm (PM2.5)—during 2019–2024 in Quito, Ecuador, a high-elevation tropical metropolis. Despite long-term efforts to regulate emissions, air pollution levels continue to rise, driven by overlapping crises, including energy shortages, political unrest, and extreme weather events. The persistent failure to improve air quality underscores the vulnerability of developing nations to climate change-induced energy instability and the urgent need for adaptive, diversified, and resilient future energy planning. Without immediate shifts in climate adaptation policies, cities like Quito will continue to experience worsening air quality, with severe implications for public health and environmental sustainability.
25
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Loss and fragmentation of native forest ecosystems and its influence on habitat diversity in the Tropical Andes hotspot [Pérdida y fragmentación de ecosistemas boscosos nativos y su influencia en la diversidad de hábitats en el hotspot Andes tropicales]
(2021)
Rodríguez-Echeverry J.
;
Leiton M.
It is necessary to evaluate the degree of forest landscape transformation for a proper conservation and restoration planning. The aim of this study was to evaluate the spatio-temporal changes of native forest ecosystems and the influence of these changes on habitat diversity in the Mira River watershed, Ecuador, from 1991 to 2017. The evaluation was carried out using satellite images and landscape metrics. A loss of 9% of native forest ecosystems was recorded at a deforestation rate of 0.57% year-1, which was associated with the increase in agricultural crops. The highest native forest loss was for thorny dry forest, inter-andean dry forest, low-montane dry forest, and premontane very-wet forest. Changes in the spatial patterns of forest ecosystems revealed a severe fragmentation. The Shannon diversity index decreased by 0.20, reflecting the loss of native forest habitats relative to the loss and fragmentation of the ecosystems studied. This study suggested to landscape-scale conservation and restoration planning, using the patch-corridor-matrix model, which must be complemented with land use planning and supported within a framework of environmental policies. © 2021 Universidad Nacional Autonoma de Mexico. All rights reserved.
Scopus© Citations 9 25
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Variation of Foliar Calcium and Magnesium in Six Fern Species at Different Elevations
(2021)
Salazar, Laura
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Paez-Vacas M.
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Kessler M.
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Kluge J.
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Homeier J.
Several efforts have been made to understand nutrient ecology worldwide. However, Ca and Mg have received less attention, despite their function in important biological processes of plants, such us growth and photosynthesis. Few studies focus on fern nutrient ecology of foliar Ca and Mg. Moreover, none has investigated the variation of these elements along elevational gradients. Herein, we analysed if there were differences of the foliar Ca and Mg contents of six species of ferns along a tropical elevational gradient: Adiantum humile, Cyathea tortuosa, Cyclodium meniscioides, Danaea moritziana, Maxonia apiifolia, and Thelypteris biformata. We found significant differences at the interspecific and intraspecific level variation of foliar Ca and Mg contents at each elevation. In terms of the relationship between elevation and nutrient content, we found that two species showed contrasting trends of foliar Ca with elevation. Content of Ca decreased with elevation in Adiantum humile, while it increased in Maxonia apiifolia. Regarding Mg, it decreased with elevation in Adiantum humile, Thelypteris biformata and Maxonia apiifolia. However, these results were not statistically supported. An exhaustive sampling effort will provide insight on variation of foliar Ca and Mg along tropical elevation gradients and the factors influencing patterns of variation. © Published under licence by IOP Publishing Ltd.
Scopus© Citations 2 25

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