Tom Ysebaert

Wageningen University & Research | WUR · Wageningen Marine Research

Heatwaves affect tidal flat ecosystems by altering the bioturbating behavior of benthic species, with potential consequences for sediment oxygenation, particle mixing, and erodibility. Although the frequency and duration of heatwaves are expected to increase under global warming scenarios, we lack insights into how heatwaves' temporal dynamics affe...

Understanding the sensitivity of tidal flats to environmental changes is challenging. Currently, most studies rely on process-based models to systematically explain the morphodynamic evolution of tidal flats. In this study, we proposed an alternative empirical approach to explore tidal flat dynamics using statistical indices based on long-term time...

Storm‐induced erosion events may alter the diversity of tidal flat communities by selecting species that can better tolerate such disturbances. Introduced and invasive species are highly adaptable to a wide range of abiotic characteristics, and this adaptability may make them better able to withstand erosion events. With a novel flume method, we co...

Mechanical disturbance from waves and sediment dynamics is a key bottleneck to mangrove seedling establishment. Yet, how species vary in tolerance to sediment dynamics has not been quantified. We identified how tolerance to sediment dynamics differs for three mangrove propagule traits: propagule size, successional stage, and type of embryo developm...

The intensity of marine heatwaves is increasing due to climate change. Heatwaves may affect macroinvertebrates' bioturbating behavior in intertidal areas, thereby altering the deposition-erosion balance at tidal flats. Moreover, small-scale topographic features on tidal flats can create tidal pools during the low tide, thus changing the heat capaci...

Coastal areas are especially vulnerable to habitat loss, sea-level rise, and other climate change effects. Oyster-dominated eco-engineered reefs have been promoted as integral components of engineered habitats enhancing coastal resilience through provision of numerous ecological, morphological, and socio-economic services. However, the assessed ‘su...

Benthic animal populations inhabiting intertidal flats provide important ecosystem functions and services that may be disrupted by physical disturbances such as tropical cyclones, which are predicted to increase in frequency and intensity under future climate change. However, the spatial reach at which tropical cyclones impact macrobenthos populati...

Benthic macrofauna are a key component of intertidal ecosystems. Their mobility and behavior determine processes like nutrient cycling and the biogeomorphic development of intertidal flats. Many physical drivers of benthic macrofauna behavior, such as sediment grain size, have been well-studied. However, little is known about how sediment bulk dens...

Modelling spatial and temporal patterns in bioturbator effects on sediment resuspension: a biophysical metabolic approach APPENDIX B – Distribution model

Modelling spatial and temporal patterns in bioturbator effects on sediment resuspension: a biophysical metabolic approach APPENDIX A - Re-analysis of mesocosm observations

Modelling spatial and temporal patterns in bioturbator effects on sediment resuspension: a biophysical metabolic approach APPENDIX C – Alternative tidal profiles

Tidal flats are biogeomorphic landscapes, shaped by physical forces and interaction with benthic biota. We used a metabolic approach to assess the overarching effect of bioturbators on tidal landscapes. The benthic bivalve common cockle (Cerastoderma edule) was used as model organism. The effect of C. edule on sediment resuspension was approximated...

Use of mangrove ecosystems for coastal flood protection requires reliable predictions of mangrove wave attenuation, especially if this capacity lessens due to storm‐induced forest damage. Quantifying and understanding the variation in drag forces and mechanical properties of mangrove vegetation can improve assessment of mangrove protective capacity...

Sand waves are dynamic and regular bedforms that are ubiquitous in sandy shelf seas. However, information about the ecological characteristics (e.g., benthic community structure) and their spatial variability within these habitats is very limited. To address this knowledge gap, we undertook a field campaign in summer 2017 to investigate the macrofa...

The Sand Motor is a very large (20 million m3) nourishment constructed along the coast in The Netherlands. The huge volume of sand is redistributed along the coast by natural forces stemming from tidal currents and waves. For environmental evaluation of this large construction, the benthic subtidal fauna has been sampled prior to the construction o...

Backscatter data from multibeam echosounders are commonly used to classify seafloor sediment composition. Previously, it was found that the survey azimuth affects backscatter when small organized seafloor structures, such as sand ripples, are present. These sand ripples are too small to be detected in the multibeam bathymetry. Here, we show that su...

The development of the Smartsediment Ecosystem Services QGIS tool enables users to make a first numerical evaluation of the impact of sediment management on ecosystem services in an estuary. This article is of interest to everyone involved in the management of estuaries and coastal areas. Read more to find out how the Smartsediment tool can be us...

Functional trait approaches advance the understanding of biodiversity–ecosystem function (BDEF) relationships and its control by the environmental context. Application of these insights into management remains constrained due to lack of evidence from real-world ecosystems that capture the natural spatial and temporal gradients at which biodiversity...

Coastal plants have unique adaptability to cope with strong hydrological stresses in tidal wetlands. A fundamental understanding of the establishment and maintenance of coastal plants is needed for conservation and restoration. In the Yangtze Estuary, the plasticity of the morphological and reproductive traits of a pioneer Scirpus species (sedge),...

Whether pristine ecosystems with intact trophic structures are more resilient to anthropogenic pressures than ecosystems facing human exploitation is a pressing question to ecological theory and management. For coastal vegetated ecosystems such as kelp forests and seagrass meadows, a number of studies recently highlighted that under eutrophic condi...

Predictive models accounting for the effect of bioturbation on sediment resuspension must be based on ecological theory as well as on empirical parametrizations. The scaling trend of individual metabolic and activity rates with body mass may be a key to the mechanistic understanding of the observed patterns. With this study we tested if general siz...

Bioirrigation, the exchange of solutes between overlying water and sediment by benthic organisms, plays an important role in sediment biogeochemistry. Bioirrigation either is quantified based on tracer data or a community (bio)irrigation potential (IPc) can be derived based on biological traits. Both these techniques were applied in a seasonal stud...

High-resolution surveying techniques of subtidal soft-bottom seafloor habitats show higher small-scale variation in topography and sediment type than previously thought, but the ecological relevance of this variation remains unclear. In addition, high-resolution surveys of benthic fauna show a large spatial variability in community composition, but...

In this study, we analysed the benthic effects of two in situ fisheries disturbance experiments using a combination of side-scan sonar, high definition underwater video, sediment profile imagery, and box core sampling techniques after conventional beam trawling and box core sampling after electric pulse trawling in a southern North Sea habitat. Aco...

Oyster breakwater reefs used for coastal protection have shown to enhance local biodiversity. Particularly, macro-invertebrate and fish assemblages can benefit directly from reefs providing structurally complex habitats and indirectly through alteration of soft-sediment environment near the reef areas. To test this hypothesis, a manipulative field...

De natuurlijke dynamiek van zoet-zout-overgangen is de basis voor een grote ecologische diversiteit. Door activiteiten als inpolderingen, aanleg van dammen en baggerwerkzaamheden zijn de dynamische zoet-zout-overgangen (estuaria) in de Nederlandse delta grotendeels of geheel verdwenen. Dit artikel zoomt in op de Zuidwestelijke Delta, waar sinds de...

Plant species can be characterized by different growth strategies related to their inherent growth and recovery rates, which shape their responses to stress and disturbance. Ecosystem engineering, however, offers an alternative way to cope with stress: modifying the environment may reduce stress levels. Using an experimental study on two seagrass s...

Although the consideration of socio-economic demands with biodiversity conservation is now high on the environmental policy agenda, it is not yet standard practice in spatial planning. This is argued to be related, amongst others, to a lack of awareness among stakeholders and practitioners of the underpinning role of ecosystem functioning and biodi...

Abstract. Bio-irrigation, the exchange of solutes between overlying water and sediment by benthic organisms, plays an important role in sediment biogeochemistry. Quantification of bio-irrigation is done either through measurements with tracers, or more recently, using biological traits to derive the community (bio-) irrigation potential (IPc). Both...

Onderzoek naar de historische ontwikkeling van het watersysteem en inschatting van de autonome ontwikkeling vergeleken met getijscenario's en effecten op Natura 2000-soorten en habitats bij gedempt getij Auteur(s):

Bioturbating benthic organisms have typically been characterised by how they modify the vertical sediment erosion thresholds. By means of several annular flume experiments, we aimed to understand how benthic organisms may affect grain-size sediment properties over time, and how this depends on the sediment type and the sediment loading of the water...

Oyster reefs have the potential as eco-engineers to improve coastal protection. A field experiment was undertaken to assess the benefit of oyster breakwater reefs to mitigate shoreline erosion in a monsoon-dominated subtropical system. Three breakwater reefs with recruited oysters were deployed on an eroding intertidal mudflat at Kutubdia Island, t...

There is growing interest to restore oyster populations and develop oyster reefs for their role in ecosystem health and delivery of ecosystem services. Successful and sustainable oyster restoration efforts largely depend on the availability and selection of suitable sites that can support long-term growth and survival of oysters. Hence, in the pres...

A Dynamic Energy Budget (DEB) model for the intertidal rock oyster (Saccostrea cucullata) is presented and applied for three different sites (Sonadia, Kutubdia and Inani) located in the south-eastern coast of Bangladesh, covering a distinct environmental gradient. At the three sites, field observations of oyster growth, temperature, total particula...

Bioturbation (i.e. particle reworking and bio-irrigation) is a key process in benthic coastal and estuarine ecosystems, and act as crucial control on important ecosystem functions, such as nutrient cycling. Particle reworking and bio-irrigation are affected by a wide array of environmental and biological factors and are therefore expected to be hig...

Understanding the environmental context where heterogeneous ecological processes affect biotic interactions is a key aim of ecological research. However, mechanisms underlying spatial variation in trophic interactions linked to resource availability across ecosystem gradients remains unclear. We experimentally manipulated the interactive effects of...

Macrozoobenthos may affect sediment stability and erodibility via their bioturbating activities, thereby impacting both the short- and long-term development of coastal morphology. Process-based models accounting for the effect of bioturbation are needed for the modelling of erosion dynamics. With this work, we explore whether the fundamental allome...

Reef-building bivalves like oysters and mussels are conspicuous ecosystem engineers in intertidal and subtidal coastal environments. By forming complex, three-dimensional structures on top of the sediment surface, epibenthic bivalve reefs exert strong bio-physical interactions, thereby influencing local hydro- and morphodynamics as well as surround...

The tube-building polychaete Sabellaria spinulosa (Ross worm) can form conspicuous biogenic reefs that stabilize the seabed and increase biodiversity by providing a habitat for a multitude of other species. These reefs, however, are assumed to be vulnerable to human-induced physical disturbances of the seabed. In the Greater North Sea, S. spinulosa...

Building man-made structures in coastal seas are often preceded by dredging operations, inducing turbid plumes of suspended sediment. To study the effects of such high-concentration sediment plumes on the suspension-feeding polychaete Lanice conchilega, a laboratory experiment was performed, in which individuals of L. conchilega were exposed to nat...

Dynamic Energy Budget (DEB) models describe the energy flow in organisms focusing on food assimilation and utilization for maintenance, growth and reproduction. In this paper, specific DEB parameters were obtained for the intertidal rock oyster Saccostrea cucullata, which has culture potential and important ecological functions in estuarine and coa...

Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna controls sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the str...

We propose an empirical framework to scale the effects of bioturbation on sediment resuspension to population bioturbation activity, approximated as population metabolic rate. Individual metabolic rates have been estimated as functions of body size and extrapolated to population level. We used experimental flumes to test this approach across differ...

Salt marshes are in danger of degradation due to human impact and climate change. A thorough understanding of mechanisms controlling sedimentation and erosion in salt marshes is essential for their conservation and restoration. To understand short-term dynamics of sediment availability and deposition around marsh edges, two contrasting marshes, Rat...

Some of the results of our research at the Oesterdam was recently published in the national popular science magazine Land en Water

Ecosystem-based coastal protection by means of conserving, restoring or creating intertidal ecosystems that attenuate waves and stabilize shorelines, offers a promising way to climate proof coastlines for the future. The Pacific oyster (Crassostrea gigas) is an ecosystem engineering species, which is known for its wave attenuating and sediment trap...

An ecosystem vision for the Flemish coastal zone (Belgium) that integrates socio-economic demands (ecosystem services) with nature values. Report describes the vision and the methodology developed to integrate ecosystem services with nature values. Additionally, an evaluation framework was developed to assess impacts on the coastal ecosystem.

Variations in abundance and diversity of estuarine benthic macrofauna are typically described along the salinity gradient. The influence of gradients in water depth, hydrodynamic energy and sediment properties are less well known. We studied how these variables influence the distribution of subtidal macrofauna in the polyhaline zone of a temperate...

The American razor clam, E. directus, makes up 85% of the benthic biomass in the Dutch shoreface (1-12m deep). The impact of E. directus populations is unknown. Does the species carry out biostabilisation by partially protruding from the sediment or bioturbation through burrowing activity. Flume studies determined that the species is capable of bot...

Abstract The natural coastal hydrodynamics and morphology worldwide is altered by human interventions such as embankments, shipping and dredging, which may have consequences for ecosystem functionality. To ensure long-term ecological sustainability, requires capability to predict long-term large-scale ecological effects of altered hydromorphology....

Only a handful of non-human animals are known to grow their own food by cultivating high-yield fungal or algal crops as staple food. Here we report an alternative strategy utilized by an omnivorous marine worm Hediste diversicolor to supplement its diet: gardening by sprouting seeds. In addition to having many other known feeding modes, we showed u...

Species invasions are known to change biotic and abiotic ecosystem characteristics such as community structure, cycling of materials and dynamics of rivers. However, their ability to alter interactions between biotic and abiotic ecosystem components , in particular bio-geomorphic feedbacks and the resulting landscape configuration in tidal wetlands...

The Delta Works, a series of dams and barriers constructed in the 1960's–1980's changed the estuarine landscape of the Rhine-Meuse-Scheldt delta (SW Netherlands) into more stagnant and disengaged freshwater, brackish water or saltwater lakes. The remaining tidal systems were adapted by building a storm surge barrier in the Oosterschelde and dike re...

The Dutch shore is threatened by erosion and invasive species.The invasive non-native species, the American razor clam- Ensis directus, was first reported the Netherlands in 1977. It is currently the most abundant bivalve along the Dutch coast occupying the hydrodynamic transition zone. The habitat and the density of E. directus in the Netherlands...

Baggett et al. (2015) identified a set of three universal environmental variables to be monitored for evaluating all oyster habitat restoration projects: salinity, temperature, and dissolved oxygen. Perhaps evidencing a bias toward subtidal reefs, this set of parameters omits another first-order environmental factor, tidal emersion. Intertidal oyst...

The Delta Works, a series of dams and barriers constructed in the 1960's-1980's changed the estuarine landscape of the Rhine-Meuse-Scheldt delta (SW Netherlands) into more stagnant and disengaged freshwater, brackish water or saltwater lakes. The remaining tidal systems were adapted by building a storm surge barrier in the Oosterschelde and dike re...

The tidal flats in the Eastern Scheldt tidal basin (The Netherlands) are eroding as a result of the construction of the storm surge barrier. These intertidal areas are important foraging grounds for birds and therefore it is important to mitigate the negative effects of erosion. As a pilot, a small part (20 ha) of the Galgeplaat tidal flat in the m...

This report (in Dutch) investigates a procedure to establish the Ecological status of the Westerschelde estuarine system following the classification according to the Water Framework Directive

Seed burial (i.e. vertical seed dispersal) has become increasingly valued for its relevance for seed fate and plant recruitment. While ecosystem engineers have been generally considered as the most important drivers of seed burial, the role of physical forces, such as wind or water flow, has been largely overlooked. Using tidal habitats as a model...

Marine species characterized as structure building, autogenic ecosystem engineers are recognized worldwide as potential tools for coastal adaptation efforts in the face of sea level rise. Successful employment of ecosystem engineers in coastal protection largely depends on long-term persistence of their structure, which is in turn dependent on the...

Rijkswaterstaat voert vooroeverbestortingen uit op het deel van de dijk dat onder water ligt in de Ooster- en Westerschelde. Dit is nodig om de stabiliteit van de dijk en daarmee de waterveiligheid te kunnen blijven garanderen. Eerst werd hierbij alleen op veiligheidsdoelen gelet. Nieuw inzicht is echter dat je door gebruik van bepaalde materialen...

Projectbureau Zeeweringen verbetert de dijkbekledingen langs de Oosterschelde en Westerschelde. Daarbij kan helaas niet voorkomen worden dat kwetsbare schorren en slikken verstoord en deels vernietigd worden tijdens de dijkverbeteringswerkzaamheden. Het doel van deze studie was om na te gaan onder welke omstandigheden herstel en groei van schorvege...

Eco‐engineering or the so‐called Building with Nature, also often referred to Living Shoreline, is a novel soft‐engineering approach that combines with existing coastal defence structures for protecting coastal areas and communities from erosion, and enhancing the natural defense of the coast using living organisms, at the same time providing vario...

Salt marshes are highly valuable ecosystems that provide numerous important ecosystem services. Given the global marsh decline, there is a pressing need to understand the natural bottlenecks and thresholds to their establishment and long-term ecological maintenance. Seed presence in the right place and time is a prerequisite for pioneer establishme...

Intertidal benthic macroalgae are a biological quality indicator in estuaries and coasts. While remote sensing has been applied to quantify the spatial distribution of such benthic macroalgae, it is generally not used for their monitoring. We examined the day-to-day and seasonal dynamics of macroalgal cover on a sandy intertidal flat using visible...

Ecosystem engineers that inhabit coastal and estuarine environments, such as reef building oysters, do not only stabilise the sediment within their reefs, but their influence might also extend far outside their reefs, affecting tidal flat morphology and protecting the surrounding soft-sediment environment against erosion. However, quantitative info...

Human infrastructures can modify ecosystems, thereby affecting the occurrence and spatial distribution of organisms, as well as ecosystem functionality. Sustainable development requires the ability to predict responses of species to anthropogenic pressures. We investigated the large scale, long term effect of important human alterations of benthic...

At the transition between mudflat and salt marsh, vegetation is traditionally regarded as a sustaining factor for previously incised mudflat channels, able to conserve the channel network via bank stabilization following plant colonization (i.e., vegetation-stabilized channel inheritance). This is in contrast to recent studies revealing vegetation...

The risk of flood disasters is increasing for many coastal societies owing to global and regional changes in climate conditions, sea-level rise, land subsidence and sediment supply. At the same time, in many locations, conventional coastal engineering solutions such as sea walls are increasingly challenged by these changes and their maintenance may...

The use of static indicator species, in which species are expected to have a similar sensitivity or tolerance to either natural or human-induced stressors, does not account for possible shifts in tolerance along natural environmental gradients and between biogeographic regions. Their indicative value may therefore be considered at least questionabl...

Many exploited fish and macroinvertebrates that utilize the coastal zone have declined, and the causes of these declines, apart from overfishing, remain largely unresolved. Degradation of essential habitats has resulted in habitats that are no longer adequate to fulfil nursery, feeding, or reproductive functions, yet the degree to which coastal hab...

The aim of this field study was to investigate the role of mussels on near-bed layer characteristics at different hydrodynamic regimes in a micro-tidal system. At Logstor Broad, the Limfjorden, Denmark, we deployed 'siphon mimics' to sample chlorophyll a (chl a), particulate organic carbon (POC) and inorganic nutrients at different distances above...