Ordenación hidrológico forestal de la cuenca del río Guabalcón, Ecuador

La ordenación agrohidrológica de las cuencas se considera un pilar importante sobre el que basar las políticas territoriales de las comunidades que se integran en ellas. Así, estos proyectos son documentos que analizan desde la perspectiva física y socioeconómica, los recursos agua y suelo y recogen una serie de propuestas de manejo de las cuencas, que ayuden al desarrollo racional de estas comunidades y al aprovechamiento sustentable de los recursos naturales. Este proyecto fin de carrera se integra dentro del Programa Marco de la Comisión Europea EPIC FORCE (Evidence Based Policy for Integrated Control of Forested River Catchments in Extreme Rainfall and Snowmelt - Políticas basadas en la evidencia científica para la gestión integrada de cuencas hidrográficas forestadas frente a precipitaciones extremas y fusiones repentinas del manto de nieve), y su objetivo principal dentro de este es estudiar la defensa de la cuenca ante eventos torrenciales, cualquiera que fuera su intensidad, y encontrar las vías adecuadas para garantizar su aprovechamiento sustentable La cuenca del río Guabalcón (Ecuador), se encuentra situada en la Cordillera de los Andes, provincia del Chimborazo. En ella se ha realizado un estudio de su comportamiento hidrológico así como un estudio de sus usos de suelo y técnicas de manejo con el fin de identificar los principales problemas físicos. Para estos, y para los problemas socioeconómicos que la población misma detecta como acuciantes, la alta tasa migratoria de su población y los bajos precios de los productos agrícolas y ganaderos, se han intentado buscar unas alternativas que protejan a la población ante fenómenos relacionados con el geodinamismo torrencial, y otras, que representen para las comunidades una alternativa de futuro

Land cover dynamics and climate change implications on water resources in South Pacific Costa Rica

Water is fundamental to human life and the availability of freshwater is often a constraint on human welfare and economic development. Consequently, the potential effects of global changes on hydrology and water resources are considered among the most severe and vital ones. Water scarcity is one of the main problems in the rural communities of Central America, as a result of an important degradation of catchment areas and the over-exploitation of aquifers. The present Thesis is focused on two critical aspects of global changes over water resources: (1) the potential effects of climate change on water quantity and (2) the impacts of land cover and land use changes on the hydrological processes and water cycle. Costa Rica is among the few developing countries that have recently achieved a land use transition with a net increase in forest cover. Osa Region in South Pacific Costa Rica is an appealing study site to assess water supply management plans and to measure the effects of deforestation, forest transitions and climate change projections reported in the region. Rural Community Water Supply systems (ASADAS) in Osa are dealing with an increasing demand of freshwater due to the growing population and the change in the way of life in the rural livelihoods. Land cover mosaics which have resulted from the above mentioned processes are characterized by the abandonment of marginal farmland with the spread over these former grasslands of high return crops and the expansion of secondary forests due to reforestation initiatives. These land use changes have a significant impact on runoff generation in priority water-supply catchments in the humid tropics, as evidenced by the analysis of the Tinoco Experimental Catchment in the Southern Pacific area of Costa Rica. The monitoring system assesses the effects of the different land uses on the runoff responses and on the general water cycle of the basin. Runoff responses at plot scale are analyzed for secondary forests, oil palm plantations, forest plantations and grasslands. The Oil palm plantation plot presented the highest runoff coefficient (mean RC=32.6%), twice that measured under grasslands (mean RC=15.3%) and 20-fold greater than in secondary forest (mean RC=1.7%). A Thornthwaite-type water balance is proposed to assess the impact of land cover and climate change scenarios over water availability for rural communities in Osa Region. Climate change projections were obtained by the downscaling of BCM2, CNCM3 and ECHAM5 models. Precipitation and temperature were averaged and conveyed by the A1B, A2 and B1 IPCC climate scenario for 2030, 2060 and 2080. Precipitation simulations exhibit a positive increase during the dry season for the three scenarios and a decrease during the rainy season, with the highest magnitude (up to 25%) by the end of the 21st century under scenario B1. Monthly mean temperature simulations increase for the three scenarios throughout the year with a maximum increase during the dry season of 5% under A1B and A2 scenarios and 4% under B1 scenario. The Thornthwaite-type Water Balance model indicates important decreases of water surplus for the three climate scenarios during the rainy season, with a maximum decrease on May, which under A1B scenario drop up to 20%, under A2 up to 40% and under B1 scenario drop up to almost 60%. Land cover scenarios were created taking into account current land cover dynamics of the region. Land cover scenario 1 projects a deforestation situation, with forests decreasing up to 15% due to urbanization of the upper catchment areas; land cover scenario 2 projects a forest recovery situation where forested areas increase due to grassland abandonment on areas with more than 30% of slope. Deforestation scenario projects an annual water surplus decrease of 15% while the reforestation scenario projects a water surplus increase of almost 25%. This water balance analysis indicates that climate scenarios are equal contributors as land cover scenarios to future water resource estimations

Modifying harvesting time as a tool to reduce nutrient export by timber extraction: a case study in planted teak (Tectona grandis L.f.) forests in Costa Rica

Despite its low nutrient concentration, the high amount of biomass accumulated in the tree stem makes it an important nutrient sink. Hence, nutrient loss through timber removal at harvesting is a major cause of nutrient impoverishment at some forest sites. The present study was designed to test the following hypotheses: (a) nutrient allocation in the different tree tissues would be affected by (re)translocation processes related with leaf senescence; hence, (b) timber may have a higher nutrient concentration during the defoliated period (in deciduous species); and consequently, (c) modifying harvesting time could influence nutrient export. To test these hypotheses, the present study analyzes the intra-annual dynamics of foliar and trunk nutrient concentration in a planted teak (Tectona grandis L.f.) forest in Costa Rica. Samples from nine trees were taken at nine sampling times between June 2012 and August 2013. The results confirm the above-mentioned hypotheses and reveal that modifying harvesting time have different consequences: (1) when harvesting occurs between August and October, it reduces the N-P-K exported through timber harvesting by 24-29-43%; (2) when harvesting occurs in December, the reduction is 28-29-14%. Harvesting between August and October (rainy season) may involve logistical difficulties. Harvesting slightly earlier than usual (i.e., December, just after the rainy season but before leaf senescence) would therefore be an efficient approach to reducing nutrient export through timber extraction.Agencia Española de Cooperación Internacional para el Desarrollo/[]/AECID/EspañaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro de Investigaciones Agronómicas (CIA

Manejo Integral de Agua y Suelo en Centroamérica. Bases científicas para el desarrollo rural comunitario.

Este libro recoge los frutos de la colaboración y trabajo conjunto de un grupo de Universidades Iberoamericanas entre 2007 y 2012 el marco de las actividades del Programa de Cooperación Comunidad, Agua y Bosque en Centroamérica (CAB Centroamérica, http://www2.caminos.upm.es/Departamentos/imt/Topografia/Cab/cab.html ). Las actividades se han realizado con el apoyo del Programa de Cooperación Universitaria PCI-AECID IBEROAMÉRICA, de la Dirección de Cooperación para el Desarrollo de la Universidad Politécnica de Madrid y de los fondos propios de las Universidades latinoamericanas, con especial mención a la Universidad de Costa Rica, coordinadora de los trabajos en Centroamérica. El inicio de esta colaboración se produjo en 2007 a partir de la identificación de un objetivo común: profundizar la investigación sobre la dinámica agua-suelo-planta para mejorar la producción y la calidad del agua de los sistemas de abastecimiento comunitarios en Centroamérica

Implications of land use change on runoff generation at the plot scale in the humid tropics of Costa Rica

International audienceRecent land use changes in Central America have involved the abandonment of marginal farmland activities, the regeneration of secondary forest and the spread of high return crops such as oil palm plantations. The potential impacts of land use change on overland flow are evaluated using data from Tinoco Experimental Catchment (South Pacific Costa Rica). Our main hypothesis is that secondary forest overland flow is lower than the one generated under the other land cover types. For this purpose, runoff responses at plot scale are analyzed for different land uses: secondary forests, forest plantations, oil palm plantations and grasslands. Runoff plots were situated over former grasslands, abandoned 8-15 years prior to plot settlement Measurements were conducted at two complementary spatial scales i) the plot (150 m(2)) under natural precipitation and ii) rainfall simulation on microplots (0.0625 m(2)). The combination of natural and simulated rain runoff response measurements provides a more accurate picture of the overland flow generation in the study site. Secondary forest shows a significantly lower runoff response than grassland and oil palm plantations, although there are no significant differences among the plots in variables such as saturated hydraulic conductivity (Ks). The oil palm plantation plot presented the highest runoff coefficient (mean RC = 32.6%), twice that measured under grasslands (mean RC = 153%) and 20-fold greater than in secondary forest (mean RC = 1.7%). The runoff plots part of the Tinoco Experimental Catchment provide valuable data and coefficients for evaluating the influence on overland flow of secondary forest recovery and oil palm plantation expansion over hillsides, contributing to a better understanding of the effects of land cover dynamics on water resources in the humid tropics

Coincidencias conceptuales entre el pensamiento débil y fin del arte en Vattimo y arte poshistórico en Danto : el "acontecimiento" Warhol

This work develops the coincidences between the weak thinking in Vattimo and the posthistoric art in Danto, exemplified in the work of Warhol. Contemporary art and its philosophy emerge as a contestation movement against the canonical meta-narrative in art and show points of encounter with the postmodern philosophy that also criticized the metarrelates of history for its erection as totalizing ideologies. This research shows the closeness of Vattimo to Lyotard's analysis, and also to the Heideggerian concept of Dasein as to manifest and hide the truth; closeness to the Gadamerian concept of meaning as the possibility of achieving a collective experience of art without conceptualization. Vattimo indicates the possibility of access to the truth of the work of art through the ontology of non-being and shows the opportunity to be able to understand non-canonical art but historically. Danto characterizes contemporary art as post-historical art and considers the "Warhol event" as evidence, since what is after the history of the end of art can be "anything" capable of becoming a work of art and whose freedom of expression is unprecedented. Thus, Danto defines contemporary art as the propitious time for the philosophy of art.TesisEste trabajo desarrolla las coincidencias entre el pensamiento débil en Vattimo y el arte poshistórico en Danto, ejemplificado en la obra de Warhol. El arte contemporáneo y su filosofía surgen como movimiento contestatario ante el metarrelato canónico en el arte y muestran puntos de encuentro con la filosofía postmoderna que también criticaba los metarrelatos de la historia por su erección como ideologías totalizantes. Esta investigación muestra la cercanía de Vattimo al análisis que hace Lyotard, y también al concepto heideggeriano del Dasein como manifestarse y ocultarse la verdad; cercanía al concepto gadameriano de sentido como posibilidad de lograr una experiencia colectiva del arte sin conceptualización. Vattimo indica la posibilidad del acceso a la verdad de la obra de arte mediante la ontología del no-ser y muestra la oportunidad de poder comprender el arte no canónica sino históricamente. Danto caracteriza el arte contemporáneo como arte poshistórico y considera al “acontecimiento Warhol” como evidencia, ya que lo que está después de la historia del fin del arte puede ser “cualquier cosa” capaz de convertirse en una obra de arte y cuya libertad de expresión no tiene precedentes. Así, Danto define al arte contemporáneo como la época propicia para la filosofía del arte

An Operational Framework for Land Cover Classification in the Context of REDD+ Mechanisms. A Case Study from Costa Rica

REDD+ implementation requires robust, consistent, accurate and transparent national land cover historical data and monitoring systems. Satellite imagery is the only data source with enough periodicity to provide consistent land cover information in a cost-effective way. The main aim of this paper is the creation of an operational framework for monitoring land cover dynamics based on Landsat imagery and open-source software. The methodology integrates the entire land cover and land cover change mapping processes to produce a consistent series of Land Cover maps. The consistency of the time series is achieved through the application of a single trained machine learning algorithm to radiometrically normalized imagery using iteratively re-weighted multivariate alteration detection (IR-MAD) across all dates of the historical period. As a result, seven individual Land Cover maps of Costa Rica were produced from 1985/1986 to 2013/2014. Post-classification land cover change detection was performed to evaluate the land cover dynamics in Costa Rica. The validation of the land cover maps showed an overall accuracy of 87% for the 2013/2014 map, 93% for the 2000/2001 map and 89% for the 1985/1986 map. Land cover changes between forest and non-forest classes were validated for the period between 2001 and 2011, obtaining an overall accuracy of 86%. Forest age-classes were generated through a multi-temporal analysis of the maps. By linking deforestation dynamics with forest age, a more accurate discussion of the carbon emissions along the time series can be presented