Distribución geográfica y temporal de incendios en colombia utilizando datos de anomalías térmicas

Patrones de distribución en el tiempo y en el espacio de las anomalías térmicasdetectadas por el sensor MODIS son analizadas para el territorio colombiano entrediciembre 2000 y Febrero 2009. Se presenta un estudio de la dinámica inter-anuale intra-anual de la superfi cie afectada por los incendios para distintas coberturasde vegetación. También se analiza los patrones al interior de áreas protegidas,reservas forestales, reservas indígenas y territorio de comunidades negras, con lafi nalidad de analizar el posible rol como barrera a los incendios de estas fi guras demanejo en Colombia. Adicionalmente se analiza la distribución temporal y espacialpor regiones naturales, Corporaciones Autónomas Regionales y Departamentos.La información proporcionada por este tipo de análisis puede ser de gran utilidadpara la toma de decisiones en el manejo de los recursos naturales en el país. Losresultados obtenidos indican que los Llanos de Colombia es el área más afectadaanualmente por los incendios, seguida del Caribe y de la zona Andina, en particularel piedemonte amazónico. Estos análisis muestran el potencial para identifi car ymodelar la distribución de los incendios en el país y la identifi cación de patronesen función tanto de las características de la vegetación como del manejo que se estérealizando en un lugar determinado y pueden ser de utilidad para mejorar la gestiónde riesgo de incendios en el país, así como para entender los cambios de uso que sehan dado en Colombia en la última década

Land use and vegetation structure in forest remnants of fragmented landscapes in Amazonia, Colombia

Monitoring land use and knowledge about the vegetation state in forests remnants which are in a rapid fragmentation process are essential to support decision-making on land planning. We undertook a multitemporal analysis of land use change and landscape configuration for the period 1990-2016. Vegetation sampling transects were established in three forest relicts. Our results indicate a loss of 56.34% of forest area, an increase in the patches number, area reduction and a distance increase between the forest fragments. In the sampled forests, the dominance of generalist heliophyte species from disturbed ecosystems was found. Also, we observed a structural complexity reduction of the forest associated with an individuals low density with a DBH ≥ 10 cm in the upper tree layer, showing that landscape fragmentation has led to the forest degradation

Uso del suelo y estructura de la vegetación en paisajes fragmentados en la Amazonia, Colombia

Monitoring land use and knowledge about the vegetation state in forests remnants which are in a rapid fragmentation process are essential to support decision-making on land planning. We undertook a multitemporal analysis of land use change and landscape configuration for the period 1990-2016. Vegetation sampling transects were established in three forest relicts. Our results indicate a loss of 56.34% of forest area, an increase in the patches number, area reduction and a distance increase between the forest fragments. In the sampled forests, the dominance of generalist heliophyte species from disturbed ecosystems was found. Also, we observed a structural complexity reduction of the forest associated with an individuals low density with a DBH ≥ 10 cm in the upper tree layer, showing that landscape fragmentation has led to the forest degradation.El seguimiento al uso del suelo y el conocimiento del estado de la vegetación en remanentes de bosques de paisajes representan una metodología fundamental para la planificación del territorio ante la acelerada fragmentación. Por ello, se realizó un análisis multitemporal de la composición y configuración del paisaje (1990-2016) y se establecieron transectos de muestreo de la vegetación. Se identificó una pérdida del 56.34% de áreas de bosque, aumento en el número de parches, reducción de su área y ampliación de la distancia entre relictos, lo que evidencia procesos activos de fragmentación. En los bosques muestreados se registró la dominancia de especies heliófitas generalistas de ecosistemas perturbados y se encontró una reducción en la complejidad estructural asociada a una baja densidad de individuos (DAP≥ 10 cm) en el estrato superior arbóreo, mostrando que la fragmentación del paisaje ha conllevado a la degradación de estos bosques

A new algorithm for mapping burned areas in colombia

Every year, between 2.5 and 4.0 million km2 of vegetation are burned around the world, emitting an annual average of 2,013 Tg of C, at least 50% of which is estimated to represent net emissions that are not compensated for by the regeneration of vegetation. In Colombia, the official statistics of burned areas are not well known, but it is estimated that burned areas vary between 15,000 and 20,000 km2 per year. The main objective of this study was the development and application of a new algorithm for mapping burned areas in Colombia, using a synergistic combination of reflectance images and thermal anomalies detected by the MODIS sensors installed on NASA’s TERRA and AQUA satellites. Upon applying the developed algorithm, a burned surface area in Orinoquía of 998,473 ha was obtained for the month of February, 2007. The validation of the algorithm was performed using high spatial resolution Landsat images and the comparison of the data with the global MODIS MCD45A1 burned area product. The developed algorithm performed very similar to MCD45A1, with an overall accuracy of 79% in both cases. The new algorithm, which was developed for the mapping of burned areas in Colombia, can be used to complement deforestation and forest degradation monitoring procedures that are being implemented in Colombia in the context of the REDD+ mechanism initiation

Dynamics, Patterns and Causes of Fires in Northwestern Amazonia

According to recent studies, two widespread droughts occurred in the Amazon basin, one during 2005 and one during 2010. The drought increased the prevalence of climate-driven fires over most of the basin. Given the importance of human-atmosphere-vegetation interactions in tropical rainforests, these events have generated concerns over the vulnerability of this area to climate change. This paper focuses on one of the wettest areas of the basin, Northwestern Amazonia, where the interactions between the climate and fires are much weaker and where little is known about the anthropogenic drivers of fires. We have assessed the response of fires to climate over a ten-year period, and analysed the socio-economic and demographic determinants of fire occurrence. The patterns of fires and climate and their linkages in Northwestern Amazonia differ from the enhanced fire response to climate variation observed in the rest of Amazonia. The highest number of recorded fires in Northwestern Amazonia occurred in 2004 and 2007, and this did not coincide with the periods of extreme drought experienced in Amazonia in 2005 and 2010. Rather, during those years, Northwestern Amazonia experienced a relatively small numbers of fire hotspots. We have shown that fire occurrence correlated well with deforestation and was determined by anthropogenic drivers, mainly small-scale agriculture, cattle ranching (i.e., pastures) and active agricultural frontiers (including illegal crops). Thus, the particular climatic conditions for air convergence and rainfall created by proximity to the Andes, coupled with the presence of one of the most active colonisation fronts in the region, make this region differently affected by the general drought-induced fire patterns experienced by the rest of the Amazon. Moreover, the results suggest that, even in this wet region, humans are able to modify the frequency of fires and impact these historically well preserved forests

Changes in soil organic carbon after burning in a forest-savanna edge

Soils are one of the largest terrestrial pools of carbon, yet there is still little understanding of spatial variability for ecosystems in the tropics. Fire plays an important role in Neotropical savannas ecosystems and significantly contribute to global greenhouse gas (GHG) fluxes. Nevertheless, the impacts of burning on soil carbon is still uncertain in Latin America. We compared soil organic carbon (SOC) in the first 20 cm depth in savannas in pre and post fire conditions along a forests-savanna edge typically present in these landscapes of the northern South America. We established 8 transects of 20 m longitude along the border with 1m2 plots sampled every 4 m. SOC pre-disturbance was on average 1.794 (±SE 0.043) and the minimum value found (1.08%) was registered 6 months after the burning. Our results show that both the influence of the distance to the edge and the time of burning affect negatively the SOC and also there is a significant interaction between both variables. Our results provide improved estimates of the effect of fire on soil carbon stocks and its highly dynamic nature. We believe these finding will be a step to help better estimate GHG in this type of heterogeneous landscapes. Further it provides a tool for understanding C dynamics under a climate change context with predicted increased fire frequency, extent and severity.Soils are one of the largest terrestrial pools of carbon, yet there is still little understanding of spatial variability for ecosystems in the tropics. Fire plays an important role in neotropical savannas ecosystems and significantly contribute to global greenhouse gas (GHG) fluxes. Nevertheless the impacts of burning on soil carbon is still uncertain in Latin America. We compared soil organic carbon (SOC) in the first 20 cm depth in savannas in pre and post fire conditions along a forests-savanna edge typically present in these landscapes of the northern South America. We established 8 transects of 20 m longitude along the border with 1m2 plots sampled every 4 m. SOC pre-disturbance was on average 1.794 (±SE 0,043) and the minimum value found (1.08%) was registered 6 months after the burning. Our results show that both the influence of the distance to the edge and the time of burning affect negatively the SOC and also there is a significant interaction between both variables. Our results provide improved estimates of the effect of fire on soil carbon stocks and its highly dynamic nature . We believe these finding will be a step to help better estimate GHG in this type of heterogeneous landscapes. Further it provides a tool for understanding C dynamics under a climate change context with predicted increased fire frequency, extent and severity

Changes in soil organic carbon after burning in a forest-savanna edge

Soils are one of the largest terrestrial pools of carbon, yet there is still little understanding of spatial variability for ecosystems in the tropics. Fire plays an important role in neotropical savannas ecosystems and significantly contribute to global greenhouse gas (GHG) fluxes. Nevertheless the impacts of burning on soil carbon is still uncertain in Latin America. We compared soil organic carbon (SOC) in the first 20 cm depth in savannas in pre and post fire conditions along a forests-savanna edge typically present in these landscapes of the northern South America. We established 8 transects of 20 m longitude along the border with 1m2 plots sampled every 4 m. SOC pre-disturbance was on average 1.794 (±SE 0,043) and the minimum value found (1.08%) was registered 6 months after the burning. Our results show that both the influence of the distance to the edge and the time of burning affect negatively the SOC and also there is a significant interaction between both variables. Our results provide improved estimates of the effect of fire on soil carbon stocks and its highly dynamic nature . We believe these finding will be a step to help better estimate GHG in this type of heterogeneous landscapes. Further it provides a tool for understanding C dynamics under a climate change context with predicted increased fire frequency, extent and severity

Interceptación y escorrentía del bosque altoandino en la reserva forestal protectora “El Malmo”

Los bosques tropicales son importantes a nivel mundial por su biodiversidad y los servicios ecosistémicos que proveen, son claves en el ciclo global del agua. Los cambios y presiones de origen antrópico que afectan a los bosques tropicales inciden en el papel fundamental de estos en la provisión de agua. En este trabajo se evalúa la relación de las coberturas vegetales presentes en el Bosque altoandino de la Reserva Forestal Protectora “El Malmo” con la calidad y cantidad de interceptación y escorrentía; la zona de vida analizada comprende cuatro tipos de coberturas: bosque denso altoandino, vegetación secundaria baja, plantación de latifoliadas y mosaico de pastos con espacios naturales. Se instalaron ocho montajes (dos por cobertura) compuestos cada uno de una parcela de escorrentía y un medidor de precipitación bajo el dosel; el levantamiento de datos se efectúo cada ocho días durante 24 semanas. Los resultados indican que la interceptación de la precipitación no difiere en cada cubierta, mientras que si se ve afectada la escorrentía superficial y su calidad respecto a sedimentos, cambios que obedecen fuertemente a las diferencias en las condiciones físicas del suelo. La cobertura que permite las mejores dimensiones de calidad y cantidad de agua es el bosque denso altoandino. La influencia de la intervención antrópica en el área y la presencia de invasoras afectan negativamente estas variables. Este trabajo aporta conocimiento sobre el comportamiento hidrológico de la Reserva, para su uso en la gestión forestal. Así mismo, genera información, hasta el momento inexistente, sobre la relación interceptación/escorrentía en bosques de la región Cundiboyacense, convirtiéndose en punto inicial de comparación para nuevas investigaciones en ecosistemas altoandinos