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Impact of chemical fertilizers on diversity and abundance of soil-litter arthropod communities in coffee and banana plantations in southern Rwanda
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Few studies explored effects of chemical fertilizers on diversity and abundance of soillitter arthropods in the tropics. To fill this gap, a study focussed on the abundance of soil-litter arthropods and selected soil physicochemical properties in coffee plantations treated with chemical fertilizers and in plantations of coffee and banana treated with organic fertilizers and organic mulches in southern Rwanda. Each land use was replicated three times. Soil-litter arthropods were collected using pitfall traps and hand collection. They were identified to the family level using dichotomous keys. Soil have been collected using auger and taken to the laboratory for the analysis of soil pH, soil organic carbon, total nitrogen, phosphorus, and cation exchange capacity. Findings indicated a total of 12,945 individuals distributed into 3 classes, 16 orders, 50 families and 92 morphospecies, with higher abundance and diversity in coffee plantations treated with organic fertilizers and organic mulches. Collected soil-litter arthropods were mainly classified in the class Insecta, dominated in numbers by ants (Hymenoptera: Formicidae), while Coleoptera and Hemiptera had more families. However, soil under coffee plantations treated with organic fertilizers and organic mulches was acidic compared with the soil under coffee plantations treated with inorganic fertilizers and banana plantations treated with organic fertilizers and organic mulches. The relationships between soil-litter arthropods and soil physicochemical properties suggest that soillitter arthropods respond to the land use independently from soil physicochemical properties. We recommend further studies in coffee and other crop plantations in other regions of Rwanda to verify the findings of this study.
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RBINS Staff Publications 2023
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Impact of Laying Date and Fire Ants on Hatchlings of Chelonoidis porteri on Santa Cruz Island, Galápagos, Ecuador
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Chelonoidis land tortoises are iconic species endemic to the Galápagos Islands of Ecuador. Their populations have been dramatically reduced by human activities in the last three centuries, including indirect effects such as the introduction of invasive species. We investigated the mortality of eggs and hatchlings in 48 nests of Chelonoidis porteri on Santa Cruz Island with regard to various mortality causes such as the occurrence of fire ants and the date of laying. The average mortality rate was 0.56. Tropical Fire Ants (Solenopsis geminata) were present within 1 m of 75% of the C. porteri nests, and we encountered fire ants in 12.5% of excavated nests. We found no relationship between Tropical Fire Ant abundance and C. porteri egg and hatchling survivorship. We observed no signs of mold inside the nests. We determined that early deposition dates were associated with lower clutch survival and identified egg development as the critical life stage. Finally, we discuss the potential impacts of fire ants and climate change on tortoise survival and reproduction and stress the importance of taking these factors into account for the conservation of the endemic land tortoises of the Galápagos
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RBINS Staff Publications 2018
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Impacts and Risks of Deep Sea Mining, Funded Through JPI-Oceans, Final Report, August 2018 – Febuary 2023
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RBINS Staff Publications 2023
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Inclusiveness and Diversity in Citizen Science
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RBINS Staff Publications 2021
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Incorporating data uncertainty in 3D voxel modelling and the importance in decision making
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Geological databases resulting from the merging of various data sources and time periods jeopardize harmonization of data products. Data standardization is already common practice and a first step in avoiding semantic overlap. European marine data management infrastructures provide such standards, e.g., Geo-Seas (http://www.geo-seas.eu/) for geological data and SeaDataNet (https://www.seadatanet.org/) for marine metadata in general. In addition, metadata quality control is important, though data uncertainty is seldom quantified and to be used in modelling. Preliminary uncertainty analyses were worked out to provide an extra dimension to the cross-border 3D voxel models of the geological subsurface of the Belgian and southern Netherlands part of the North Sea (http://odnature.naturalsciences.be/tiles/). Starting from simple quality flagging in geological databases and model uncertainty calculations (probability and entropy) in the 3D modelling, data uncertainty (e.g., related to qualities in positioning, sampling and vintage) is now quantified. Combining all uncertainties remains a challenge, as well as communicating their importance in decision making. A demonstration will be given on the status of the uncertainty analyses and how these are incorporated in a newly developed decision support tool allowing interactive querying of the 3D voxel model, now comprising geological, as well as entropy, probability and data uncertainty attributes (figure 1).
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RBINS Staff Publications 2018
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Increased food availability at offshore wind farms affects trophic ecology of plaice Pleuronectes platessa
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Offshore wind farms (OWFs) and their associated cables, foundations and scour protection are often constructed in soft- sediment environments. This introduction of hard substrate has been shown to have similar effects as artificial reefs by providing food resources and offering increased habitat complexity, thereby aggregating fish around the turbines and foundations. However, as most studies have focused their efforts on fish species that are typically associated with reef structures, knowledge on how soft sediment species are affected by OWFs is still largely lacking. In this study, we analysed the trophic ecology and condition of plaice, a flatfish species of commercial interest, in relation to a Belgian OWF. The combination of a stomach and intestine content analysis with the use of biomarkers (i.e. fatty acids and stable isotopes) identified a clear shift in diet with increased occurrences of typical hard-substrate prey species for fish in the vicinity of the foundations and this both on the short and the long term. Despite some condition indices suggesting that the hard substrate provides increased food availability, no clear increases of overall plaice condition or fecundity were found. Samples from within the wind farm, however, contained larger fish and had a higher abundance of females compared to control areas, potentially indicating a refuge effect caused by the cessation of fisheries activities within the OWF. These results suggest that soft-sediment species can potentially benefit from the presence of an OWF, which could lead to fish production. However, more research is still needed to further elucidate the behavioral ecology of plaice within OWFs to make inferences on how they can impact fish populations on a larger spatial scale.
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RBINS Staff Publications 2023
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Increasing detections of the invasive mosquito Aedes albopictus in Belgium
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Aedes albopictus is an invasive mosquito species expanding its territory in Europe, posing a health risk as the species is a competent vector of dengue, chikungunya and Zika virus. In European countries autochthonous transmission of these viruses are reported in localities where the species is established. In Belgium the introduction of Ae. albopictus was first monitored through active surveillance at Points of Entry (PoEs). Since 2018, the increased observation of Ae. albopictus at parking lots located along the highways suggested a rise in introduction through route traffic. Hence, in 2022, a passive surveillance based on citizen science was implemented to complement the active surveillance and expand the coverage of the monitoring countrywide. We present the current situation for Ae. albopictus in Belgium based on the results of both active and passive surveillance. Via an online platform (web/app), citizens uploaded pictures of potential Ae. albopictus specimens after answering filtering questions about morphological characteristics of the mosquito related to its size, color and stripes on the hind legs. Subsequently, pictures were then analysed to determine whether or not it is Ae. albopictus. When Ae.albopictus was confirmed on the picture, a field inspection was performed. This inspection included larval sampling and the set-up of ten oviposition traps for one or two weeks around the notification point. Additionally, in 2022 and 2023, ten oviposition traps were set-up at eight parking lots between May and October. In 2023, a longitudinal surveillance was also implemented to monitor overwintering and potential spread at two locations where the presence of Ae. albopictus was confirmed in 2022. In 2024, overwintering monitoring happened through larval sampling at four locations where Ae. albopictus was detected in 2023. DNA-based validation of all life stages of Ae. albopictus collected during field visits from several locations was performed to validate the identification of the species, and to investigate the haplotype composition of the population. We received 12 notifications of Ae. albopictus from citizens from nine locations in 2022, 29 from 15 new locations in 2023 and 47 from 12 new locations in 2024. Overall, Ae. albopictus was detected at 36 locations in Belgium over these three years. Further, the exotic species was detected in 2022 at three, and in 2023 at seven parking lots. Longitudinal surveillance in 2023 confirmed the presence of Ae. albopictus at two locations, indicating local establishment and overwintering. In 2024, overwintering was confirmed at another three locations. Prior to 2022, Aedes albopictus was in the early stage of its invasion process in Belgium, with confirmed occurrences limited to PoEs. Since 2022, the implementation of citizen surveillance has led to a steep increase in detections, including in residential areas, alongside numerus findings at parking lots. Additionally, the confirmation of overwintering at five locations, indicates that the species is being increasingly imported into Belgium via ground vehicular traffic and has become locally established in recent years.
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RBINS Staff Publications 2025
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INDI67: Developments of Indicators to improve monitoring of MSFD descriptors 6 and 7. Contract – BR/143/A2. Final Report. Brussels: Belgian Science Policy Office 2020, Brain-be, Belgian Research Action through Interdisciplinary Networks
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RBINS Staff Publications 2020
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Indices d’extraction minière néolithique à Obourg - Le Village
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RBINS Staff Publications
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Influence of Natural Oxygenation of Baltic Proper Deep Water on Benthic Recycling and Removal of Phosphorus, Nitrogen, Silicon and Carbon
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At the end of 2014, a Major Baltic Inflow (MBI) brought oxygenated, salty water into the Baltic proper and reached the long-term anoxic Eastern Gotland Basin (EGB) by March 2015. In July 2015, we measured benthic fluxes of phosphorus (P), nitrogen (N) and silicon (Si) nutrients and dissolved inorganic carbon (DIC) in situ using an autonomous benthic lander at deep sites (170–210 m) in the EGB, where the bottom water oxygen concentration was 30–45 μM. The same in situ methodology was used to measure benthic fluxes at the same sites in 2008–2010, but then under anoxic conditions. The high efflux of phosphate under anoxic conditions became lower upon oxygenation, and turned into an influx in about 50% of the flux measurements. The C:P and N:P ratios of the benthic solute flux changed from clearly below the Redfield ratio (on average about 70 and 3–4, respectively) under anoxia to approaching or being well above the Redfield ratio upon oxygenation. These observations demonstrate retention of P in newly oxygenated sediments. We found no significant effect of oxygenation on the benthic ammonium, silicate and DIC flux. We also measured benthic denitrification, anammox, and dissimilatory nitrate reduction to ammonium (DNRA) rates at the same sites using isotope-pairing techniques. The bottom water of the long-term anoxic EGB contained less than 0.5 μM nitrate in 2008–2010, but the oxygenation event created bottom water nitrate concentrations of about 10 μM in July 2015 and the benthic flux of nitrate was consistently directed into the sediment. Nitrate reduction to both dinitrogen gas (denitrification) and ammonium (DNRA) was initiated in the newly oxygenated sediments, while anammox activity was negligible. We estimated the influence of this oxygenation event on the magnitudes of the integrated benthic P flux (the internal P load) and the fixed N removal through benthic and pelagic denitrification by comparing with a hypothetical scenario without the MBI. Our calculations suggest that the oxygenation triggered by the MBI in July 2015, extrapolated to the basin-wide scale of the Baltic proper, decreased the internal P load by 23% and increased the total (benthic plus pelagic) denitrification by 18%.
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