Browsing by Author "Munizaga, Juan"

Now showing 1 - 6 of 6
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    Accessibility disturbances to the biodiversity of urban wetlands due to built environment
    (2022) Rojas Quezada, Carolina Alejandra; Sepúlveda Zúñiga, Einer Alexander; Jorquera Guajardo, Felipe Ignacio; Munizaga, Juan; Pino, Joan; CEDEUS (Chile)
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    Mapping coastal wetlands using satellite imagery and machine learning in a highly urbanized landscape
    (2022) Munizaga, Juan; García, Mariano; Ureta, Fernando; Novoa, Vanessa; Rojas, Octavio; Rojas Quezada, Carolina Alejandra; CEDEUS (Chile)
    Coastal wetlands areas are heterogeneous, highly dynamic areas with complex interactions between terrestrial and marine ecosystems, making them essential for the biosphere and the development of human activities. Remote sensing offers a robust and cost-efficient mean to monitor coastal landscapes. In this paper, we evaluate the potential of using high resolution satellite imagery to classify land cover in a coastal area in Concepción, Chile, using a machine learning (ML) approach. Two machine learning algorithms, Support Vector Machine (SVM) and Random Forest (RF), were evaluated using four different scenarios: (I) using original spectral bands; (II) incorporating spectral indices; (III) adding texture metrics derived from the grey-level covariance co-occurrence matrix (GLCM); and (IV) including topographic variables derived from a digital terrain model. Both methods stand out for their excellent results, reaching an average overall accuracy of 88% for support vector machine and 90% for random forest. However, it is statistically shown that random forest performs better on this type of landscape. Furthermore, incorporating Digital Terrain Model (DTM)-derived metrics and texture measures was critical for the substantial improvement of SVM and RF. Although DTM did not increase the accuracy in SVM, this study makes a methodological contribution to the monitoring and mapping of water bodies’ landscapes in coastal cities with weak governance and data scarcity in coastal management.
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    Urban development versus wetland loss in a coastal Latin American city : lessons for sustainable land use planning
    (2019) Rojas, Carolina; Munizaga, Juan; Rojas, Octavio; Martínez; Reyes, Carolina del Pilar; Pino, Joan; CEDEUS (Chile)
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    Urban Fabric Patterns on Urban Wetland
    (2021) Rojas Quezada, Carolina Alejandra; Díaz, Sebastián; Munizaga, Juan; Trapani, Ferdinando; Mohareb, Nabil; Rosso, Federica; Kolokotsa, Denia; Maruthaveeran, Sreetheran; Ghoneem, Mahmoud; CEDEUS (Chile)
    The Author(s), under exclusive license to Springer Nature Switzerland AG.Latin American cities have experienced rapid urbanization and with it the social and environmental challenges caused by urban sprawl. Over the last decades, this increase has led to strong wetland area loss and fragmentation. It has negatively impacted its ecological value and biodiversity, and ignored their ecosystems services. This study analyzes wetland urbanization patterns in the Metropolitan area of Concepción (South of Chile). It proposes a characterization of the urban fabrics using the urbanization variables of density of population and dwellings, distances to roads and city center, and % covered by roads and green areas surrounding the wetland, in order to evaluate which urban variable explains the increase in urbanization, reducing recreation services for the well-being of residents from the different urban fabrics. In Chilean cities, urban wetlands are typically built on with dwellings that are not friendly with the natural environment. The urbanization intensity is modeled with a linear regression ordinary least squares (OLS), and predictions or a model of the dependent variable in terms of its relationships to a set of explanatory urban variables is generated. The built-up area (BA) is the dependent variable, and the variables of densities, distances, green spaces, and roads are independent. A discussion about the effect of spatial urbanization on urban wetlands is achieved, and the urbanization intensity is determined. The study adds to the discussion about spatial patterns and urban processes in urban landscapes; the results are inputs for natural planning and designing for people who intend to use urban wetlands in cities as nature-based solutions
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    Water footprint and virtual water flows from the Global South: Foundations for sustainable agriculture in periods of drought
    (2023) Rojas Quezada, Carolina Alejandra; Novoa, Vanessa; Rojas, Octavio; Ahumada-Rudolph, Ramón; Arumí, José Luis; Munizaga, Juan; Cabrera-Pardo, Jaime R.; CEDEUS (Chile)
    Freshwater availability has decreased alarmingly worldwide, with agriculture playing a vital role in this trend. The assessment of the agricultural water footprint (WFagricultural) and virtual water flows (VWF) is fundamental not only in local water resources management and protection, but also in our understanding of the synergies between local water consumption and global markets. Thus, the WFagricultural – broken down into its components (blue, green, and gray) – of the leading 21 crops (grouped in fruit, legumes, cereals, and vegetables), grown in four basins with the most significant agricultural activity in central Chile was determined, estimated in two consecutive years 2017–2018. In addition, due to their great importance in exports, VWFs were assessed, establishing connections according to their origins and destinations. The results show that the green and gray water footprints increased significantly in the south-central basins, while blue water consumption increased in the basins of the central zone, reflecting an evident WFagricultural transition in accord with latitude and climate conditions. Furthermore, VWF showed an annual increase of 44 %, in about 116 destinations, with Asia, Europe, and North America being the preferred destinations, with annual variations of VWFblue- gray associated with increases in exports of apples, cherries, grapes, blueberries, and walnuts, market preferences and growing areas. The present study is an initial step toward sustainable agriculture in a commodity exporting country, one that is relevant in the exploitation of virtual water yet faces severe water deficit problems, distribution, and local water policies. Therefore, contributing to encouraging the efficiency and value of water in the process of a new institutional framework.