Evaluation of the causes of error in the MCD45 burned-area product for the savannas of northern South America [Evaluación de las causas de error en el producto de área quemada MCD45 para las sabanas del norte de Suramérica]

Forest fires contribute to deforestation and have been considered a significant source of CO2 emissions. There are global maps that estimate the area affected by a fire using the reflectance variation of the surface. In this study, we evaluated the reliability and the causes of error of the MCD45 Burned Area Product, by applying the confusion matrix method to the Orinoco River Basin. This basin is located in the northern zone of South America, and consists mainly of savanna ecosystems. For the evaluation, we used as reference data five pairs of Landsat images, covering 165,000 km2. The Burned Area Product estimated a burned area of 7,576.43 km2, which is lower than the area of 12,100.16 km2 found with Landsat images, leading to an overall underestimation. The causes of error are associated to the spatial resolution of the map, and to some structures of the algorithm that generates the map

Identification of wetland areas in the context of agricultural development using remote sensing and GIS [Identificación de áreas de humedal en el contexto del desarrollo agrícola usando teledetección y SIG]

This study aims to determine the wetland potential on a pixel basis on the floodplain of the Leon River: hydrology, hydrophytic vegetation and hydromorphic soils were taken into account. Field measurements and spatially explicit models were used to model surface hydrology and piezometric levels. Satellite data were used to derive inundated areas and vegetation. Existing maps from the national geographic institute (IGAC) were used to define the spatial distribution of hydromorphic soils. Special attention was paid to agricultural infrastructure, levees and diversion channels used to modify surface hydrology in order to promote plantations and cattle grazing. A total of 536 km2 meet one or more wetland conditions according to biophysical variables, but only 393 km2 were selected, using logical rules, as wetland pixels. The combination of biophysical variables to define wetland potential is discussed in terms of the spatial distribution and the implications for environmental resource management. © The author; licensee Universidad Nacional de Colombia

Data for wetlandscapes and their changes around the world

Geography and associated hydrological, hydroclimate and land-use conditions and their changes determine the states and dynamics of wetlands and their ecosystem services. The influences of these controls are not limited to just the local scale of each individual wetland but extend over larger landscape areas that integrate multiple wetlands and their total hydrological catchment-the wetlandscape. However, the data and knowledge of conditions and changes over entire wetlandscapes are still scarce, limiting the capacity to accurately understand and manage critical wetland ecosystems and their services under global change. We present a new Wetlandscape Change Information Database (WetCID), consisting of geographic, hydrological, hydroclimate and land-use information and data for 27 wetlandscapes around the world. This combines survey-based local information with geographic shapefiles and gridded datasets of large-scale hydroclimate and land-use conditions and their changes over whole wetlandscapes. Temporally, WetCID contains 30-year time series of data for mean monthly precipitation and temperature and annual land-use conditions. The survey-based site information includes local knowledge on the wetlands, hydrology, hydroclimate and land uses within each wetlandscape and on the availability and accessibility of associated local data. This novel database (available through PANGAEA https://doi.org/10.1594/PANGAEA.907398; Ghajarnia et al., 2019) can support site assessments; cross-regional comparisons; and scenario analyses of the roles and impacts of land use, hydroclimatic and wetland conditions, and changes in whole-wetlandscape functions and ecosystem services.. © 2005 IEEE Computer Society. All rights reserved