Project

URBANCOST

Goal: Efectos de la Urbanización en la conservación de la Biodiversidad de Humedales Costeros (2015-2018)

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Carolina Alejandra Rojas
added a research item
In an urbanized world, the sustainability of cities will depend on their form and urban structure. In this sense, fabrics that are compact, dense, green, and suitable for non-motorized transport methods are more environmentally efficient. For the purpose of contributing new tools to the design, urban planning, and sustainability of nature in residential areas, this study characterizes the urban fabrics of six urban wetlands in the Latin American city of Concepción (Chile), which is known for its blue–green spaces. In a wetland city, we model urban patterns through spatial relationship using a statistical regression model (OLS—ordinary least squares) with the urban variables of density, distance, population, housing, highways, green areas, and building permits. Concepción shows predominantly low- to medium-density fabrics, and it is not integrated with the urban wetlands. In fact, it was observed that the residential areas do not take advantage of the blue–green spaces and that the urban fabrics do not favor proximity, with a transportation network that promotes the use of cars, leading to the wetlands being inaccessible and fragmented. However, as they are still surrounded by open spaces with abundant vegetation, there are highly feasible opportunities for the future development of blue–green infrastructure.
Carolina Alejandra Rojas
added a research item
The coastal evolution of the microtidal Tubul-Raqui wetland in south-central Chile (36° S), which historically has been affected by large earthquakes and tsunamis, particularly the 1960 (Mw = 9.5) and 2010 (Mw = 8.8) subduction earthquakes and their associated tsunamis, is analyzed. Historical aerial photographs and topographic and bathymetric surveys from the 1961–2017 period, as well as salinity, sediment, and flora data obtained following the 2010 earthquake were used for comparison with data from prior to the event. A steady state of the shoreline was established, with an average erosion rate of −0.016 m/year in the 1961–2017 period. However, erosion predominated in the period between these two large earthquakes (1961–2009), with an average rate of −0.386 m/year. The wetland dried up, partially recovered saline intrusion a year later, and recovered the salinity conditions it had before the earthquake two years later. The postearthquake effects on the floristic composition were not significant, with the species Spartina densiflora, which presented a high tolerance to these types of changes, predominating. Moreover, 75 percent of the taxa in pre- and postearthquake conditions coincided, with the halophyte species Spartina densiflora, Sarcocornia fructicosa, and Cotula coronopifolia predominating, while the best-conserved community was Spartina-Sarcocornia association located in the saltmarsh. Seven years after the earthquake, the shoreline presented an accretion rate of 2.935 m/year; if the current tectonic conditions prevail, an erosive trend can be expected in the coming decades. The morphological variability and the changes associated with the shoreline in this wetland are strongly controlled by tectonic factors. Criteria aimed at integrated coastal management to promote its occupancy and use in accordance with its evolutionary dynamics are proposed.
Carolina Alejandra Rojas
added a research item
Rojas, C (2020). Humedales Urbanos en Chile: Impacto en políticas públicas y el Desarrollo Sostenible. En:Alfonso De Urresti Senado de Chile.Vicepresidencia del Senado, Ediciones Centro de Extensión del Senado, Ediciones Universitarias de Valparaíso, Pontificia Universidad Católica de Valparaíso. Humedales Urbanos Historia de una ley pionera y ciudadana de portección ambiental, 42-50.
Octavio Rojas
added a research item
Coastal wetlands are ecosystems that provide multiple benefits to human settlements; nonetheless, they are seriously threatened due to both a lack of planning instruments and human activities associated mainly with urban growth. An understanding of their functioning and status is crucial for their protection and conservation. Two wetlands with different degrees of urbanization, Rocuant-Andalién (highly urbanized) and Tubul-Raqui (with little urbanization), were analyzed using temperature, salinity, dissolved oxygen, pH, turbidity, granulometry, fecal coliform, and macroinvertebrate assemblage variables in summer and winter. In both wetlands marked seasonality in salinity, temperature and sediment texture classification, regulated by oceanic influence and changes in the freshwater budget, was observed. In the Rocuant-Andalién wetland, the increases in pH, dissolved oxygen, gravel percentage, and coliform concentration were statistically significant. Urbanization generated negative impacts on macroinvertebrate assemblage structure that inhabit the wetlands; greater richness and abundance (8.5 times greater) were recorded in the Tubul-Raqui wetland than in the more urbanized wetland. The multivariate statistical analysis reflects the alteration of these complex systems.
Carolina Alejandra Rojas
added a research item
Resumen Se analizaron los patrones espaciales del crecimiento urbano sobre las principales geo-formas costeras de la llanura de San Pedro de La Paz, ribera sur del río Biobío, durante el período 1955-2015. A través del uso de fotografías aéreas e imágenes satelitales recientes se identificaron estas geoformas costeras y se relacionaron con su contexto morfogenético. Utilizando fotografías aéreas correspondientes a los años 1955, 1978, 1992 y 1998 e imágenes satelitales de 2006 y 2015, se determinó la evolución de las manchas urbanas sobre estas geoformas. Para el análisis de las manchas resultantes se aplicaron indicadores de distancias, los cuales permitieron observar al-gunas características físicas de dispersión urbana. Se determinó que las geoformas costeras más intensamente ocupadas por el crecimiento urbano correspondieron a la planicie litoral, humedales, campos dunares y terrazas bajas. Se observó principalmente un crecimiento lineal, alrededor de la red de transporte entre San Pedro y Coronel. La dispersión urbana se acentuó desde 1992 producto de la periferización y urbanización en zonas altas, además se ha intensificado la ocupación en la costa reduciendo la distancia de los asentamientos al centro de Concepción en 1.2 km. Se constató un fenómeno de conurbación costera en un área metropolitana. Palabras claves: costa, crecimiento urbano, planificación territorial, dispersión urbana, geomorfología URBAN GROWTH ON THE PLAINS OF SAN PEDRO, METROPOLITAN AREA CONCEPCION Abstract Spatial patterns of urban growth of San Pedro de La Paz coastal landforms (south of the Biobío river Banks) are analyzed for the period 1955-2015. Using aerial photographs and satellite images are identified the coastal landforms and relate to their morphogenetic context. Aerial photographs from 1955, 1978, 1992 and 1998 and satellite images from 2006 and 2015 were used to determined of the urban forms evolution over the landforms. For the analysis of the urban forms distances indicators were applied, which allowed to observe some physical patterns of urban sprawl. It was determined that the coastal landforms zones more intensely occupied by urban growth corresponded to the coastal plains, wetlands, dune fields and low terraces. It is mainly observed tentacular growth around the transport infraestructure network between San Pedro and Coronel. Urban sprawl is accentuated from 1992 product of peripheralization, and urbanization in high slopes zones, addition the coastal occupation has intensified in reducing the distance the coast of settlements from central business district in 1.2 km. The coastal conurbation of medium in metropolitan area is observed.
Carolina Alejandra Rojas
added 2 research items
Latin American cities have experienced rapid urbanization with social and environmental challenges caused by urban sprawl. Over the last decades, the increase in urbanization has lead to strong wetland area loss and fragmentation and has negatively impacted their ecological value and biodiversity, ignoring their role in protection against flooding. The present study analyses wetland urbanization patterns as part of recent urban sprawl in the Metropolitan area of Concepción (South of Chile). It proposes a characterization of the urban fabrics using the urbanization variables of density, distances, population, dwellings, roads and green areas surrounding the wetland, and evaluating which urban variable explains the increase of urbanization over wetlands, reducing recreation services for the well-being of residents from the different urban fabric. Usually, urban wetlands in Chilean cities, are not protected. They are normally built on with architecture dwellings that are not friendly with the natural environment. The urban variables are modelled with statistical spatial model or Linear Regression Ordinary Least Squares (OLS). OLS was applied to detect the most intense urbanized area, as well as generate predictions or model a dependent variable in terms of its relationships to a set of explanatory urban variables. The variables were mapped on a grid cell analysis 250x250m and 6.25ha in size to determine the intensification of the urbanized area. The built-up area (BA) is the dependent variable and the remaining urbanization variables of density, distance, green areas, roads are independent. A discussion about the assessment of effect of spatial urbanization on urban wetlands is generated, and the intensity of urbanization is determined. The study contributed to increasing the discussion about spatial patterns and urban process in urban landscapes; the results are inputs for planning and design nature for people who intend to use urban wetlands in cities as nature-based solutions.
Se analizan los efectos del crecimiento urbano sobre el estado de conservación del humedal palustre Los Batros, en San Pedro de la Paz. Estos efectos son abordados a través de la pérdida de superficie y fragmentación del humedal. Para ello se consideraron las características físico-naturales del humedal e hitos de expansión urbana en el área, documentados por literatura. El perímetro del humedal y el crecimiento urbano a través de la mancha urbana, fueron delimitados mediante fotointerpretación utilizando fotografías aéreas e imágenes satelitales de los años 1955, 1978, 1998 y 2015. Se analizó la fragmentación del humedal a través de métricas del paisaje, a través del software FRAGSTATS. Este análisis fue complementado con índices espectrales para determinar la variación temporal de la cobertura vegetal (NDVI) y su relación con cambios en la precipita- ción anual. Se estableció una pérdida de superficie progresiva del humedal desde 1955 a 1998, mientras que la superficie urbana se triplicó en igual período pasando de 526 ha en 1978 a 1.712 has en 2015, generando una importante fragmentación del humedal, con un peak de proyectos inmobiliarios en el año 2000 que marcan una dominancia irreversible de la cobertura urbana en el paisaje.
Carolina Alejandra Rojas
added a research item
En el Área Metropolitana de Concepción existe una gran variedad de humedales altamente presionados por la urbanización, por tanto, se vuelve importante dar a conocer y disponer de indicadores espaciales capaces de generar datos que revelen el grado de naturalidad, biodiversidad y el efecto de los humedales urbanos. Desde esa perspectiva, se diseñó colaborativamente una plataforma Web-SIG con una interface y contenidos correspondientes a los requerimientos de los usuarios potenciales. A partir de encuestas aplicadas a la población, fue posible observar la necesidad de información sobre indicadores, diversidad de especies y servicios ecosistémicos asociados a estas áreas; por lo cual se realizó una revisión bibliográfica para integrar dichas sugerencias a la plataforma. En cuanto a la construcción, esta se llevó a cabo en el entorno de los Sistemas de Información Geográfica (ArcGIS online) y luego se publicó como visor de mapas en una página web. Finalmente, la herramienta facilita la interacción con datos espaciales y contribuye a difundir investigaciones científicas en áreas de conflictos socioambientales en un lenguaje cercano a toda la comunidad. Se espera que la información sea de utilidad para los encargados de tomar decisiones en estos temas, como también para determinados actores locales y la comunidad a favor de la conservación de humedales urbanos.
Carolina Alejandra Rojas
added 2 research items
La Vía Medioambiental. Desafíos y Proyecciones para un Chile Futuro, es el primer escrito que aborda multidisciplinarmente el problema medio ambiental y el anhelo de un desarrollo sustentable. Académicos, investigadores de di-versas áreas del saber, políticos y autoridades de Gobierno dan cuerpo a un volumen que reúne variadas realidades, problemáticas y visiones de futuro, desde una perspectiva crítica, creativa y comprometida con los destinos del país. Los contenidos aquí condensados constituyen una lectura ineludible para quienes quieran in-formarse tanto de las complejas aristas que el diagnóstico actual del medio ambiente presenta como de las acciones que personas, instituciones y gobiernos pueden llevar acabo para resguardar el más delicado de los fenómenos del planeta: la vida y toda su diversidad en entornos naturales y urbanos.
La planificación territorial en Chile avanza, a pesar del aumento en la cobertura e implementación del Sistema de Evaluación Ambiental Estratégica, sigue en deuda en la conservación de los espacios naturales en la ciudad. Se identifican cinco grandes desafíos de cara a un futuro de urbanización creciente, entre los cuales destaca el definir normativas y metodologías específicas en los instrumentos de planificación territorial para ecosistemas vulnerables y/o suelos de alto valor ambiental, procurando medidas concretas para los humedales urbanos, debido a que se han visto muy perjudicados por la ocupación del suelo, ignorando completamente sus múltiples servicios ecosistémicos. Los humedales urbanos son sensibles a la comunidad, por tanto son una oportunidad enorme para abrir espacios de participación ciudadana, inclusión y gestión territorial; en su conservación por medio de planes serán claves los vínculos entre sociedad, gobernanza y academia, así construir juntos ciudades más sustentables y resilientes.
Carolina Alejandra Rojas
added a research item
RESUMEN La urbanización en Concepción metropolitano (36°S) en las últimas décadas ha impactado áreas de valor ecológico, tales como humedales y lagunas. Aquí anali-zamos la perturbación de parámetros de biodiversidad en seis humedales urbanos, mediante la exploración y uso de indicadores. Se proponen tres indicadores: na-turalidad y riqueza de macrolepidópteros y plantas, los que se evalúan mediante modelos de regresión múltiple. Los resultados indican que los humedales con menor grado de perturbación antrópica se encuentran ubicados dentro de una reserva protegida y rodeados de una matriz de paisaje seminatural; mientras que los más perturbados están más próximos a la urbanización. Además, la riqueza de macrolepidópteros se ve más afectada por la distancia a carreteras, en cambio la riqueza de plantas por la densidad de viviendas. Se genera una herramienta para la evaluación de efectos de la urbanización en humedales urbanos. ABSTRACT Urbanization of the Metropolitan region of Concepción (36°S) in the last decades has impacted on the ecological value of areas such as wetlands and lagoons. Here, we analyse the disturbance to biodiversity indicators in six urban wetlands. Three measures are proposed: a naturalness indicator and two Macrolepidoptera plant indicators of species richness. Multiple regression models were developed for the assessment of indicators. Results show that the wetlands with the lowest degree of human interference are located in a protected area and surrounded by a matrix of semi-natural landscapes, whereas the more disturbed wetlands are those closer to areas of urbanization. Results indicate that macrolepidopterans richness is more affected by the distance to roads, in contrast with the richness of plants, which is affected by housing density. We generated a tool for the assessment of urbanization effects in urban wetlands.
Carolina Alejandra Rojas
added a research item
La urbanización de paisajes naturales y seminaturales genera consecuencias en ciudades latinoamericanas de tamaño medio. En Chile, el crecimiento urbano y el desarrollo de actividades forestales han afectado la funcionalidad y biodiversidad del paisaje. El Área Metropolitana de Concepción (en adelante AMC) es representativa de la combinación de ambos procesos dado que su paisaje circundante está mayormente cubierto por plantaciones forestales. En este trabajo se evalúan los cambios en la "conectividad ecológica" del AMC, como atributo significativo para la conservación del paisaje. Se analizan los cambios en la conectividad a través de una metodología de tipo paramétrica, calculando indicadores a nivel de paisaje y a nivel de ecosistemas. Las métricas aplicadas se basan en principios de ecología del paisaje y en el procesamiento de imágenes satelitales clasificadas en sistemas de información geográfica (SIG). Los resultados obtenidos indican que, los cambios en el paisaje del AMC han generado un paisaje rural-urbano con una alta fragmentación de los ecosistemas Abstract “Effects of urbanization on the ecological connectivity in metropolitan landscapes” The landscape’s urbanization has effects in medium-size cities of Latin America. In Chile, the urban growth and the development of forestry activities are affecting the functionality and biodiversity of the landscape. Concepcion Metropolitan Area (hereinafter CMA) is representative of the combination of both processes since it is surrounded by Forest Plantations. In this work, the changes of “Ecological Connectivity” in the CMA are evaluated as a significant landscape conservation attribute. They are analyzed through a parametric methodology computing indicators for landscape and ecosystem levels. Landscape metrics applied are based on principles of landscape ecology and processing of satellite images classified in geographic information systems (GIS). The results show that changes in the landscape of the CMA have generated a rural-urban landscape with high fragmentation of the valuable ecosystems for biodiversity and wetlands. At the same time, these ecosystems have low connectivity, especially those close to highly urbanized sectors
Carolina Alejandra Rojas
added an update
 
Carolina Alejandra Rojas
added a research item
Natural disasters can cause abrupt disturbances in coastal wetlands, affecting the social perception of ecosystem services (ES). The Tubul-Raqui coastal wetland is one of the most important wetlands in south-central Chile. Rich in biodiversity, these wetlands provide ES to a population of 2238 inhabitants. The recent MW = 8.8 earthquake of 2010 caused a coastal uplift of 1.4 m and substantial morphological, social, and environmental changes. This paper analyzes the social perceptions of the inhabitants of the village of Tubul-Raqui following a large earthquake disturbance with regards to ES provision frequency and their future changes. A statistically representative semi-structured survey was conducted (175 valid surveys) and the data interpreted through factor analysis and statistical tests for independent categorical variables. The perception of cultural and regulating services was significantly greater than that of provisioning services, which were probably the most affected by the earthquake. Residents identified habitat for species, recreation, and hazard regulation as the most important ES. Perception was influenced by the categorical variables of gender, age, and ethnicity; for example, hazard regulation services varied strongly by gender. According to the respondents, the availability of ES will remain stable (50%) or decrease (40%) in the next 50 years, mainly due to anthropogenic drivers; the effect of natural disasters was not mentioned among the main drivers of change.
Carolina Alejandra Rojas
added a research item
El humedal costero tipo marisma Tubul-Raqui, se localiza en el Golfo de Arauco (37°13’S-73°26’O), a 71 km al sur de Concepción, Región del Biobío. Formado en una gran llanura fluvial cuaternaria reciente, su pendiente débil y abierta hacia el NE produce que los principales ríos (Tubul y Raqui), presenten un marcado gradiente de salinidad (mixohalinas), con influencia de la pleamar hasta 6 km. El sistema se caracteriza por presentar una alta biodiversidad (83 tipos de aves y 4 micromamíferos), razón por la cual se considera sitio prioritario para la conservación de la biodiversidad. Corresponde a una zona de creciente población urbana (2.238 habitantes) concentrados en un 75% en la localidad de Tubul. El 70% de la población realiza actividades vinculadas al sector económico primario (extracción de productos del mar). El terremoto Mw=8.8 del año 2010, provocó fuertes cambios morfológicos, sociales y medioambientales. En la zona fue reportado un alzamiento de 1,4m, que condujo, a la desecación parcial de la marisma. Golpeando económicamente a la población del sector, dependiente de los servicios ecosistémicos de aprovisionamiento. El presente trabajo analiza la percepción social de los habitantes de la caleta Tubul sobre los servicios ecosistémicos (SS.EE) ligados al humedal Tubul-Raqui localizado en la costa sur de la Región del Biobío.
Carolina Alejandra Rojas
added 2 research items
Urbanization in the Concepción metropolitan area (36° S) has historically impacted valuable ecological areas such as wetlands and lagoons. We built indicators to analyze disturbance of biodiversity in six urban wetlands. We propose three measures: a Naturalness indicator and two indicators for Plants and Macrolepidoptera species richness. Multiple regression models were developed for the assessment of indicators. Results show that the wetlands with the lowest degree of human interference are located in a protected area and surrounded by a matrix of semi-natural landscape, whereas the more disturbed ones are closer to urbanization. Results indicate that Macrolepidoptera richness is more affected by the distance to roads, in contrast with the richness of plants, which is affected by housing density. A tool for the prevention of loss of species and the conservation of these ecosystems in urbanized areas is generated.
Urbanization of the Metropolitan region of Concepción (36°S) in the last decades has impacted on the ecological value of areas such as wetlands and lagoons. Here, we analyse the disturbance to biodiversity indicators in six urban wetlands. Three measures are proposed: a naturalness indicator and two Macrolepidoptera plant indicators of species richness. Multiple regression models were developed for the assessment of indicators. Results show that the wetlands with the lowest degree of human interference are located in a protected area and surrounded by a matrix of semi-natural landscapes, whereas the more disturbed wetlands are those closer to areas of urbanization. Results indicate that macrolepidopterans richness is more affected by the distance to roads, in contrast with the richness of plants, which is affected by housing density. We generated a tool for the assessment of urbanization effects in urban wetlands. © 2015, Revista de Geografia Norte Grande. All rights reserved.
Octavio Rojas
added a research item
Urban flooding is an increasing problem in developing countries, thus understanding flood dynamics is necessary to establish guidelines on urban development and flood management. This paper studied the lower reaches of the Andalien River basin, situated on the coast of the Greater Concepcion Metropolitan Area (CMA), the second most urbanized area in Chile. This basin experienced a record 21 flood events in the last 50 years. Patterns in the evolution of urban growth were evaluated using a historical analysis (1943–2011) that specifically focused on how these patterns interact with zones that are prone to flooding over different return periods. Our model applied to the CMA, but is sufficiently transversal to be applied in similar areas. It was determined that the built-up area increased by 1457 ha and had an urban form vulnerable to future flooding due to its location on landforms exposed to flood risk, with altitudes of <8 m and slopes of <0.5°. The bankfull channel of the Andalien River lost 18.4% of its area. Upstream, management of the river decreased smaller floods for a return period of two, five, and 10 years; however, for a return period of 500 years, risk remained at high levels. These findings help to rethink and improve urban planning and the response of Chilean cities in relation to flood hazard.
Carolina Alejandra Rojas
added a research item
Este proyecto surge como resultado del Primer Seminario de difusión de Urbanización en Humedales, realizado el 24 de Mayo de 2016 en el CEAT Centro Educacional de Alta Tecnología de San Pedro de la Paz en la región del Bíobío. El seminario nace como una iniciativa del equipo de investigación del Proyecto FONDECYT 1150459 “Efectos de la Urbanización en la conservación de la Biodiversidad de Humedales Costeros (URBANCOST)” (2015-2018). Uno de los humedales en estudio precisamente es el Humedal Los Batros, localizado en San Pedro de la Paz (Región del Biobío), un espacio de biodiversidad urbana que se encuentra muy presionado a las dinámicas de urbanización e infraestructura de transporte. Como equipo de investigación, conscientes de esta problemática, estamos muy interesados en difundir a la comunidad la investigación científica del proyecto debido a la importancia de conservar el Humedal Los Batros.
Carolina Alejandra Rojas
added a project goal
Efectos de la Urbanización en la conservación de la Biodiversidad de Humedales Costeros (2015-2018)