Search publications of the members of the Royal Belgian institute of natural Sciences
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Guide pour l'évaluation des services écosystémiques dans les réserves de biosphère africaines : vers un développement durable
- Le rapport de 2020 de « l’évaluation mondiale de la biodiversité et des services écosystémiques » de la Plateforme intergouvernementale scientifique et politique sur la biodiversité et les services écosystémiques (IPBES) indique que la nature et ses contributions aux populations jouent un rôle important non seulement pour la santé de la planète, mais aussi pour atteindre les objectifs de développement durable. Il souligne notamment la nécessité d'améliorer la compréhension des interactions entre les services écosystémiques et les objectifs et cibles visant à mettre fin à la pauvreté et à la faim, et à améliorer le bienêtre des populations. Les services écosystémiques, nous le savons, englobent toutes les contributions de la nature aux humains. Il peut s'agir de matières premières telles que l'eau ou le bois, mais aussi de véritables services comme la pollinisation des cultures ou la séquestration du carbone. Être capable d'évaluer ces services écosystémiques est, pour les communautés, une autre étape dans la compréhension de la région dans laquelle elles vivent et de la manière de vivre durablement, en harmonie avec leur environnement direct. Pour la première fois, un manuel spécifique et convivial consacré à l'évaluation des services écosystémiques adapté au contexte des réserves de biosphère africaines a été créé pour les gestionnaires de réserves de biosphère et pour les décideurs. En comblant une lacune dans la communauté de l'Homme et de la Biosphère et au-delà, ce manuel fournira à ses lecteurs les outils et les connaissances nécessaires pour engager leurs communautés à atteindre les objectifs de développement durable.
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2nd international conference on biodiversity in the Congo Basin
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Generalized changes of benthic communities after construction of wind farms in the southern North Sea
- Over the last years, the development of offshore renewable energy installations such as offshore wind farms led to an increasing number of man-made structures in marine environments. Since 2009, benthic impact monitoring programs were carried out in wind farms installed in the southern North Sea. We collated and analyzed data sets from three major monitoring programs. Our analysis considered a total of 2849 sampling points converted to a set of biodiversity response metrics. We analyzed biodiversity changes related to the implementation of offshore wind farms and generalized the correlation of these changes with spatial and temporal patterns. Our results demonstrate that depth, season and distance to structure (soft-bottom community) consistently determined di- versity indicators and abundance parameters, whereas the age and the country affiliation were significantly related to some but not all indices. The water depth was the most important structuring factor for fouling communities while seasonal effects were driving most of the observed changes in soft-sediment communities. We demonstrate that a meta-analysis can provide an improved level of understanding of ecological patterns on large- scale effects of anthropogenic structures on marine biodiversity, which were not visible in single monitoring studies. We believe that meta-analyses should become an indispensable tool for management of offshore wind farm effects in the future, particularly in the view of the foreseen development of offshore renewable energies. This might lead to a better picture and more comprehensive view on potential alterations. However, this requires a modern open-source data policy and data management, across institutions and across national borders.
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Goniatietenkerkhof Lompret fini
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Frasnian cephalopods from the newly discovered Carrière de Lompret section, Lompret, Belgium
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Nautiloid turnover across the Cretaceous/Paleogene boundary: Chixculub impact, Deccan volcanism and Europe as key?
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La mort des ammonites, délice turc : quatre nouveaux sites de la limite Crétacé/Tertiaire documentant deux faunes d'ammonoïdes finmaastrichtiennes très différentes et contemporaines du volcanisme du Deccan
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A Step Towards Accurate Integrated Monitoring of The Sinking Zones in the Coastal Area of Antwerp Due to Possible Hydrogeological and Geomechanical Processes
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A Summary Review Based on Case Studies of the Challenges Related to the Comparison of Displacements Measured by PS-InSAR and Simulated by Geomechanical Coupled to Groundwater Models.
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Difficulties arising when PS-InSAR displacement measurements are compared to results from geomechanical and groundwater flow computations
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Subsidence Evolution of Antwerp Region, Belgium over 77 Years, Using Historical Levelling and GNSS Data and Recent Persistent Scatterers Interferometry Observations
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Contrasting saltmarsh vegetation impacts under increasing sea level rise rates
- The resilience of saltmarshes mainly depends on their ability to gain elevation by sediment accretion to keep pace with sea level rise. While vegetation is known to facilitate sediment accretion at the plant scale by trapping mineral sediments and producing organic matter, the long- term impact at the landscape scale is still poorly understood. Here we use the biogeomorphic model Demeter to reveal contrasting vegetation impacts on spatial patterns of sediment accretion under different sea level rise regimes. Under contemporary sea level rise rates (2-10 mm/yr), vegetation inhibits sediment transport from tidal channels to platform interiors and creates levee- depression patterns. Hence, intertidal platforms accrete slower with vegetation than without, but this trend attenuates with increasing sea level rise rate, as water depth increases, and vegetation drag decreases. Under extreme sea level rise rate (20 mm/yr), platform interiors don’t keep up and turn into open water, while vegetation allows to preserve intertidal levees. Our results help to better understand some basic biophysical mechanisms that will control the fate of coastal wetlands under global climate change.
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North Sea Hydrodynamics With Nested Models
- The North Sea is an epeiric sea on the European continental shelf, which connects to the Atlantic Ocean through the English Channel in the South and the Norwegian Sea in the North. It hosts key north European shipping lanes, and it is a major fishery and a rich source of energy resources, including wind, wave and solar power. Here we present a nested hydrodynamics model that is calibrated against in situ data for the year 2009, and validated for the years 2010, 2011 and 2015, which present a large range of contrasting North Atlantic Oscillation (NAO) indices. Our results are openly available and provide 10+ years of hydrodynamics data (sea surface elevation, sea water velocity, potential temperature and salinity) with a resolution of 30 arcseconds in the Southern Bight of the North Sea, and 2 arcminutes elsewhere. With our model and resulting dataset, we aim at supporting marine research and policy in a highly, anthropogenically impacted system, allowing stakeholders to take informed decisions to sustainably manage its valuable resources.
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Ecosystem Modeling in the North Sea
- The North Sea is an epeiric sea on the European continental shelf, which connects to the Atlantic Ocean through the English Channel in the South and the Norwegian Sea in the North. It hosts key north European shipping lanes, and it is a major fishery and a rich source of energy resources, including wind and wave power. Here we present a multi-year effort at developing a modeling infrastructure to support research in marine ecology and biogeochemistry in such highly, anthropogenically impacted system, and allow stakeholders taking informed decisions to sustainably manage its valuable resources. Our approach is fully open-source and mainly based on the numerical model COHERENS to simulate hydrodynamical and biogeochemical processes in three spatial dimensions and time. Our model is specifically validated against relevant in situ data in view of its main applications, for which it provides a large-scale virtual laboratory. For example, our model is used to investigate the impact of floating solar panel farms on primary production, but also to assess the efficiency of enhanced silicate weathering to serve as negative emission technology.
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Dense Vegetation Hinders Sediment Transport Towards Saltmarsh Interiors
- The resilience of saltmarshes mainly depends on their ability to gain elevation by sediment accretion to keep pace with sea level rise, and tidal channels play a crucial role in the supply of sediments towards their interiors. While feedbacks between vegetation and geomorphology are increasingly recognized as key drivers shaping a variety of tidal channel network structures, the resulting impact on long-term sediment accretion over the vegetated platforms remains poorly studied. At the plant-scale, vegetation facilitates sediment accretion by trapping mineral sediments and producing organic matter. At the landscape-scale, vegetation promotes the formation of dense, branching, and meandering tidal channel networks, which reduce the distance between saltmarsh interiors and their source of suspended sediments. In this presentation, we use a biogeomorphic model validated against data to reveal two mechanisms by which vegetation also hinders sediment transport towards saltmarsh interiors. First, vegetation concentrates tidal flow and sediment transport inside channels, which reduces sediment availability for deposition on saltmarsh platforms. Secondly, vegetation enhances sediment deposition close to channels, which deprives saltmarsh interiors of suspended sediments, creating levee-depression patterns and leading to pond formation. In the present context of accelerating sea level rise and human-induced decrease of sediment supply, our findings suggest that saltmarshes are more vulnerable than previously thought.
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How does landscape vegetation configuration regulate local channel initiation in rapidly expanding marsh?
- Biogeomorphic interactions between tidal channels and marsh plants play a crucial role in enhancing coastal resilience to climate change. Previous studies linking the channel formation with vegetation dynamics predominantly focused on the early initiation, characterized by local-scale plant-flow feedbacks. However, the influence of rapid changes in landscape-scale vegetation pattern on the channel initiation remains poorly understood, especially in micro-tidal system. In this study, we investigated this relationship through biogeomorphic modeling combined with the analysis of satellite images in a rapidly expanding marsh in China under Spartina alterniflora invasion. The satellite images demonstrated the increase in drainage density and the decrease in unchanneled path length following plant encroachment. Our modeling results showed that local flow acceleration between vegetation patches was insufficient to initiate channels rapidly before the merging of isolated patches under micro-tidal conditions. With plant expansion, the continuous marsh caused landscape flow diversion from homogenous platform flow to concentrated channel flow, which promoted evident tributary channel initiation in the landward marsh zone. The vegetation removal scenarios further highlighted that the flow divergence from adjacent platforms due to the spatial heterogeneity in plant configuration amplified the magnitude of local hydrodynamics and further channel incision. Our findings emphasize that the initiation of tidal channels not only depends on local plant-flow interaction but is largely driven by landscape vegetation configuration under micro-tidal conditions.
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Coastal marsh resilience: a study on the role of bio-geomorphic self-organization
- Tidal marshes are valuable coastal ecosystems that are threatened by global climate warming and the resulting sea level rise. Whether they drown or continue to exist, depends on the trapping of sediments that builds up the land surface. Tidal channel networks, which typically occur within tidal marshes, are the major supply routes for sediments towards the marshes and hence are expected to affect the capacity of marshes to keep up with sea level rise by sediment trapping. The development and evolution of tidal channel networks and the sediment trapping are locally determined by so-called bio-geomorphic interactions between plants, water flow and sediment transport. However, the effect of different environmental variables on channel network formation remains poorly understood. In this research, we investigated the impact of spatio-temporal plant colonization patterns by means of flume experiments. Four scaled landscape scale experiments were conducted in the Metronome tidal facility, a unique flume that tilts periodically to generate tidal currents. Two control experiments without vegetation, a third experiment with a channel-fringing vegetation colonization pattern, and a fourth with patchy vegetation colonization pattern. Seeds were distributed by water in the channel-fringing experiment, while a manual sowing method was used to obtain laterally expanding circular patches in the patchy experiment. Our results show that vegetation and their respective colonization pattern affect channel network formation both on a landscape scale and local scale. More extensive and effective channel networks are found in vegetation experiments. These results indicate that channel-fringing or patchy recruitment strategies might produce landscapes that are more resilient to sea level rise.
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Contrasting saltmarsh vegetation impacts under increasing sea level rise rates
- The resilience of saltmarshes mainly depends on their ability to gain elevation by sediment accretion to keep pace with sea level rise. While vegetation is known to facilitate sediment accretion at the plant scale by trapping mineral sediments and producing organic matter, the long-term impact at the landscape scale is still poorly understood. Here we use the biogeomorphic model Demeter to reveal contrasting vegetation impacts on spatial patterns of sediment accretion under different sea level rise regimes. Under contemporary sea level rise rates (2-10 mm/yr), vegetation inhibits sediment transport from tidal channels to platform interiors and creates levee-depression patterns. Hence, intertidal platforms accrete slower with vegetation than without, but this trend attenuates with increasing sea level rise rate, as water depth increases, and vegetation drag decreases. Under extreme sea level rise rate (20 mm/yr), platform interiors don’t keep up and turn into open water, while vegetation allows to preserve intertidal levees. Our results help to better understand some basic biophysical mechanisms that will control the fate of coastal wetlands under global climate change.
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Observations of tidal attenuation and amplification in a mangrove forest: channels as conduits
- Mangroves are increasingly recognized as an effective nature-based coastal defence strategy. Mangrove trees are proven to reduce the height of propagating long-period waves such as storm tides and extreme sea levels. Existing empirical studies, however, are limited to small scales (~10²-10³ m) or only cover continuous belts of mangroves. Here we present water level measurements along a 20 km channel and in the surrounding mangrove forests for regular neap- and spring tides in a natural mangrove forest in the Guayas Delta, Ecuador. For tides with peak water levels which are high enough to flood the surrounding mangroves, inundation levels reached 45 cm with attenuation rates up to 40 cm/km. Along the entire 20 km channel, however, no attenuation occurred. Instead, we measured amplification with rates varying between 4.3 and 4.6 cm/km. Amplification rates increased with peak water level until water levels were high enough to flood the surrounding mangroves, upon which amplification rates decreased with peak water level. The latter implies that with higher peak levels, such as during an extreme sea level event, the capacity of mangroves to dampen amplification or even attenuate increases.
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Revision of the Eurybrachidae (XV). The Oriental genus Purusha Distant, 1906 with two new species and a key to the genera of Eurybrachini (Hemiptera: Fulgoromorpha: Eurybrachidae)
