A recently released voxel model quantifying aggregate resources of the Belgian part of the North Sea includes lithological properties of all Quaternary sediments and modelling-related uncertainty. As the underlying borehole data come from various sources and cover a long time-span, data-related uncertainties should be accounted for as well. Applying a tiered data-uncertainty assessment to a composite lithology dataset with uniform, standardized lithological descriptions and rigorously completed metadata fields, uncertainties were qualified and quantified for positioning, sampling and vintage. The uncertainty on horizontal positioning combines navigational errors, on-board and off-deck offsets and underwater drift. Sampling-gear uncertainty evaluates the suitability of each instrument in terms of its efficiency of sediment yield per lithological class. Vintage uncertainty provides a likelihood of temporal change since the moment of sampling, using the mobility of fine-scale bedforms as an indicator. For each uncertainty component, quality flags from 1 (very uncertain) to 5 (very certain) were defined and converted into corresponding uncertainty percentages meeting the input requirements of the voxel model. Obviously, an uncertainty-based data selection procedure, aimed at improving the confidence of data products, reduces data density. Whether or not this density reduction is detrimental to the spatial coverage of data products, will depend on their intended use. At the very least, demonstrable reductions in spatial coverage will help to highlight the need for future data acquisition and to optimize survey plans. By opening up our subsurface model with associated data uncertainties in a public decision support application, policy makers and other end users are better able to visualize overall confidence and identify areas with insufficient coverage meeting their needs. Having to work with a borehole dataset that is increasingly limited with depth below the seabed, engineering geologists and geospatial analysts in particular will profit from a better visualization of datarelated uncertainty.
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RBINS Staff Publications 2020
Litter ant communities constitute an important component of biodiversity in tropical regions. They are currently used in several ecosystem management programmes to as- sess forest health. The aim of this study was to uncover the ant diversity across forest successional stages (fallow land, secondary forest and primary forest) in the Yangambi Biosphere Reserve, the Democratic Republic of the Congo. These habitats were sam- pled at six localities using pitfall traps and Winkler extractions. In total, 190 ant species belonging to 50 genera and eight subfamilies were recorded in the Yangambi Biosphere Reserve. Ant diversity increased significantly along the successional gradient, being lowest in fallow land, intermediate in secondary forest, and highest in primary forest. Sixty ant species were shared across all three habitats, while each habitat supported a distinct assemblage of species. Primary forests contained the greatest number of exclu- sive species, followed by secondary forests and fallow land. Winkler extractors captured substantially more ant species than pitfall traps, recording nearly 50% greater species richness. However, a significant portion of the ant fauna in the Yangambi Biosphere Re- serve likely remains unrecorded, and additional sampling methods (like arboreal traps, net sweeping and baiting) could provide a more complete picture of its biodiversity.
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RBINS Staff Publications 2026 OA
