Peter M.J. Herman

Delft University of Technology | TU

Seagrass meadows provide valuable ecosystem services of coastal protection and chemical habitat formation that could help mitigate the impact of sea level rise and ocean acidification. However, the intensification of hydrodynamic forces caused by sea level rise, in addition to habitat degradation threaten the provision of these ecosystem services....

As a response to climate change and sea-level rise, new nourishment strategies for low-lying sandy coasts are developed. These interventions affect the habitat quality of coastal ecosystems for benthic communities. Unraveling the relationship between benthic fauna and their environment facilitates the design of sustainable management strategies for...

Salt marshes can contribute to coastal protection, but the magnitude of the protection depends on the width of the marsh. The cross‐shore width of the marsh is to a large extent determined by the delicate balance between seaward expansion and landward retreat. The influence of the magnitude of daily occurring mild weather conditions and sediment av...

The intensity of major storm events generated within the Atlantic Basin is projected to rise with the warming of the oceans, which is likely to exacerbate coastal erosion. Nature-based flood defence has been proposed as a sustainable and effective solution to protect coastlines. However, the ability of natural ecosystems to withstand major storms l...

Shallow tropical bays in the Caribbean, like Orient Bay and Galion Bay in Saint Martin, are often sheltered by coral reefs. In the relatively calm environment behind the reefs, seagrass meadows grow. Together, these ecosystems provide valuable ecosystem services like coastal protection, biodiversity hotspots, nursery grounds for animals and enhanci...

Tropical beaches provide coastal flood protection, income from tourism, and habitat for flagship species. They urgently need protection from erosion, which is being exacerbated by changing climate and coastal development. Traditional coastal engineering solutions are expensive, provide unstable temporary solutions, and often disrupt natural sedimen...

Quantifying spatial variability in intertidal benthic productivity is necessary to guide management of estuaries and to understand estuarine ecological processes, including the amount of benthic organic carbon available for grazing, burial and transport to the pelagic zone. We developed a model to assess microphytobenthic (MPB) primary production u...

Ecosystem engineering species can affect their environment at multiple spatial scales, from the local scale up to a significant distance, by indirectly affecting the surrounding habitats. Structural changes in the landscape can have important consequences for ecosystem functioning, for example, by increasing retention of limiting resources in the s...

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...

Seagrass meadows form highly productive and valuable ecosystems in the marine environment. Throughout the year, seagrass meadows are exposed to abiotic and biotic variations linked to (i) seasonal fluctuations, (ii) short-term stress events such as, e.g., local nutrient enrichment, and (iii) small-scale disturbances such as, e.g., biomass removal b...

Extensive development of coastlines and climate change is increasing the vulnerability of beaches to erosion. Beach erosion increases the risk of flooding from storm surges, but also impacts the income from tourism, something of great significance in many tropical countries. Engineering solutions have been developed to combat beach erosion, however...

Migrating flow-transverse mesoscale intertidal bedforms (megaripples or dunes) may pose disturbance but may also provide heterogeneity in microhabitats to the inhabiting fauna. We investigated how the macrofauna community responds to these migrating intertidal bedforms, based on surveys in the Westerschelde estuary. Considering the entire estuary,...

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...

Salt marshes are valuable ecosystems that provide important ecosystem services. Given the global scale of marsh loss due to climate change and coastal squeeze, there is a pressing need to identify the critical extrinsic (wind exposure and foreshore morphology) and intrinsic factors (soil and vegetation properties) affecting the erosion of salt mars...

Significance Theoretical models suggest that spatial self-organization enhances the resistance of ecosystems to disturbance. However, experiments investigating this important prediction are lacking. Our paper provides clear experimental evidence that spatial self-organization profoundly increases the ability of ecosystems to persist in the face of...

Seagrasses are marine flowering plants distributed worldwide. They are however threatened, mostly due to the increase of human activities. Seagrasses have the capacity to adapt their morphological, physiological, and mechanical traits to their local conditions. Mechanical traits have been identified as a good tool to investigate a plant-species cap...

The time needed for ecosystems to recover from a disturbance has been proposed as a generic indicator of ecosystem resilience. The lengthening of the recovery time with increasing stress is referred to as “Critical Slowing Down” and has been proposed as an early warning of a nearing tipping point. Hence, methodologies for measuring recovery rates a...

Data bundle including code supporting the publication: van Belzen, J., van de Koppel,, J., Kirwan, M.L., van der Wal, D., Herman, P.M.J., Dakos, V., Kefi, S., Scheffer, M., Guntenspergen, G.R., Bouma, T.J. (2017). Vegetation recovery in tidal marshes reveals critical slowing down under increased inundation. Nature Communications 8, 15811 doi: 10.10...

A declining rate of recovery following disturbance has been proposed as an important early warning for impending tipping points in complex systems. Despite extensive theoretical and laboratory studies, this ‘critical slowing down’ remains largely untested in the complex settings of real-world ecosystems. Here, we provide both observational and expe...

Supplementary Figures, Supplementary Tables, Supplementary Notes and Supplementary References

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...

Fishery on subtidal mussel beds and subsequent relying on culture plots in the same system is a common practice in bottom mussel culture. We address factors that determine the population dynamics of subtidal blue mussels Mytilus edulis L. and to what extent total (natural plus cultured) subtidal mussel biomass in the system is affected by fishery p...

Long-term field observations of nitrogen [N] and phosphorus [P] concentrations were used to construct nutrient budgets for the western Dutch Wadden Sea between 1976 and 2012. Nutrients come into the western Dutch Wadden Sea via river runoff, through exchange with the coastal zone of the North Sea, neighbouring tidal basins and through atmospheric d...

Biological traits offer valuable approaches to understand species distributions and underlying mechanisms. Their use has received a growing interest in marine community ecology, for both fundamental and applied purposes. The need of ecological indicators as part of marine directives and conservation programmes has promoted the use of multiple trait...

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....

Fishery on subtidal mussel beds and subsequent relying on culture plots in the same system is a common practice in bottom mussel culture. We address factors that determine the population dynamics of subtidal blue mussels Mytilus edulis L. and to what extent total (natural plus cultured) subtidal mussel biomass in the system is affected by fishery p...

We would like to express our thanks to all commentators for their important and thought-provoking commentaries. We appreciate that commentators from a diverse array of expertise including mathematics [1], statistical physics and biological physics [2], biomathematics [1,3], computational and systems biology [4], evolutionary biology and ecology [5]...

Structure building, autogenic ecosystem engineers are worldwide recognized as potential tools for coastal protection, which depends on long-term sustainability and persistence of their structures. For reef-building oysters, reefs are maintained through accumulation of shell material, which depends on recruitment and growth and which provides substr...

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...

Our study aims to enhance process understanding of the long-term (decadal and longer) cyclic marsh dynamics by identifying the mechanisms that translate large-scale physical forcing in the system into vegetation change, in particular (i) the initiation of lateral erosion on an expanding marsh, and (ii) the control of seedling establishment in front...

Seagrasses need dissolved nutrients to maintain their productivity through uptake processes, from substrate pore-water via their roots and/or from the water column via their leaves. Here, we present the first study of exchanges of dissolved nutrients between pore water and the water column in the vicinity of seagrass canopies. We address the follow...

Many ecosystems develop strikingly regular spatial patterns because of small-scale interactions between organisms, a process generally referred to as spatial self-organization. Self-organized spatial patterns are important determinants of the functioning of ecosystems, promoting the growth and survival of the involved organisms, and affecting the c...

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...

Changes in the seascape often result in altered hydrodynamics that lead to coinciding changes in sediment dynamics. Little is known on how altered sediment dynamics affect long-term seagrass persistence. We studied the thresholds of sediment dynamics in relation to seagrass presence by comparing sediment characteristics and seagrass presence data o...

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...

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

We show in laboratory and field investigations that in the short-term seagrasses obtain most of their required nitrogen from the degradation of seagrass leaves, rather than degradation of leaves exported from adjacent mangroves. Mangrove forests at our Thailand site retain the majority of their nutrients, and therefore potentially buffer seagrasses...

Ecosystem engineering species can structure their environment at multiple spatial scales, locally where the organisms are found, but this can also extend to significant distance. Such structural change of the landscape can have important consequences for ecosystem functioning, increasing retention of valuable resources in the system, such as water...

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...

On intertidal mudflats, reef-building shellfish, like the Pacific oyster and the blue mussel, provide a myriad of ecosystem services. Monitoring intertidal shellfish with high spatiotemporal resolution is important for fisheries, coastal management and ecosystem studies. Here, we explore the potential of X- (TerraSAR-X) and C-band (Radarsat-2) dual...

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...

Hydrodynamic processes are an important agent of stress and facilitation in seagrass meadows, but little is known about the effects of the common phenomenon of heterogeneity of seagrass meadows on their interactions with hydrodynamic processes. To address this gap in knowledge, 4 heterogeneous configurations of Posidionia oceanica mimics were analy...

Ecosystems in the tropical coastal zone exchange particulate organic matter (POM) with adjacent systems, but differences in this function among ecosystems remain poorly quantified. Seagrass beds are often a relatively small section of this coastal zone, but have a potentially much larger ecological influence than suggested by their surface area. Us...

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...

Self-organized complexity at multiple spatial scales is a distinctive characteristic of biological systems. Yet, little is known about how different self-organizing processes operating at different spatial scales interact to determine ecosystem functioning. Here we show that the interplay between self-organizing processes at individual and ecosyste...

Environmental conditions during the larval phase (food concentration and temperature) impact recruitment success of marine bivalves by affecting growth and survival. We analysed the seasonal match between environmental conditions and larval presence of six coastal bivalve species over eight consecutive years (2006–2013) in the western Wadden Sea, t...

We study how organism traits and population densities of ecosystem engineering species, in combination with environmental factors, affect the formation and erosion rates of biogeomorphological structures, and focus on the widely distributed marine tube-building polychaete Lanice conchilega, which lives in patches that form mounds up to 80 cm high i...

Over the last decades, population densities in coastal areas have strongly increased. At the same time, many intertidal coastal ecosystems that provide valuable services in terms of coastal protection have greatly degraded. As a result, coastal defense has become increasingly dependent on man-made engineering solutions. Ongoing climate change proce...

Fluxes of energy, materials and organisms among ecosystems are consequences of their openness to exchange, and lead to consideration of reciprocal connections among adjacent ecosystems. This may have implications for ecosystem functioning and management, but is generally not studied for multiple factors. We ask to what extent these fluxes may apply...

Theoretical models highlight that spatially self-organized patterns can have important emergent effects on the functioning of ecosystems, for instance by increasing productivity and affecting the vulnerability to catastrophic shifts. However, most theoretical studies presume idealized homogeneous conditions, which are rarely met in real ecosystems....

There is extensive experience in adaptive management of exposed sandy coastlines through sand nourishment for coastal protection. However, in complex estuarine systems, coastlines are often shortened through damming estuaries to achieve desired safety levels. The Dutch Deltaworks illustrate that this approach disrupts natural sediment fluxes and ha...

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...

1.Vegetation recovery in disturbance-driven ecosystems is difficult to predict. We demonstrate a concept to analyse time series for short term variability in external forcing which can identify potential events for sudden vegetation recovery in biogeomorphic ecosystems such as salt marshes, mangroves, dunes or floodplains. 2.Time series of externa...

Within the DEVOTES project, a catalogue of existing indicators of marine biodiversity and closely related topics such as non-indigenous species, food-webs, and seafloor integrity (EU Marine Strategy MSFD Descriptors 1, 2, 4, 6) has been established. Currently, the catalogue includes 557 entries with information on metadata ranging from indicator de...

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...

Marine protected areas (MPAs) are key tools for combatting the global overexploitation of endangered species. The prevailing paradigm is that MPAs are beneficial in helping to restore ecosystems to more 'natural' conditions. However, MPAs may have unintended negative effects when increasing densities of protected species exert destructive effects o...

Ecological theory uses Brownian motion as a default template for describing ecological movement, despite limited mechanistic underpinning. The generality of Brownian motion has recently been challenged by empirical studies that highlight alternative movement patterns of animals, especially when foraging in resource-poor environments. Yet, empirical...

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 location of tropical mangrove forests and seagrass beds along coastlines and shallow water areas enables them both to receive and outwell particulate organic matter (POM), as well as inorganic and organic nitrogen in dissolved forms. Little is known about the potential importance of POM transfer between mangrove forests and seagrass beds as a n...

Mangrove forests and seagrass beds are thought to exchange particulate organic material especially in the form of leaves. However, relatively little is know about the trapping capacity of mangrove above-ground roots and seagrass plants for leaf segments. We aim at identifying the major factors controlling the leaf-trapping capacity of mangroves and...

Mangroves may grow in an active sedimentary en-vironment and are therefore closely linked to physical coastal processes. Seedlings colonize dynamic tidal flats, after which mangroves have the potential to change their physical envi-ronment by attenuating hydrodynamic energy and trapping sediments. Disturbance from hydrodynamic energy of waves or cu...

The origin of regular spatial patterns in ecological systems has long fascinated researchers. Turing's activator-inhibitor principle is considered the central paradigm to explain such patterns. According to this principle, local activation combined with long-range inhibition of growth and survival is an essential prerequisite for pattern formation....

Vegetated biogeomorphic systems (e.g. mangroves, salt marshes, dunes, riparian vegetation) have been intensively studied for the impact of the biota on sediment transport processes and the resulting self‐organization of such landscapes. However, there is a lack of understanding of physical disturbance mechanisms that limit primary colonization in a...

One of the most frequently quoted ecosystem services of seagrass meadows is their value for coastal protection. Many studies emphasize the role of above-ground shoots in attenuating waves, enhancing sedimentation and preventing erosion. This raises the question if short-leaved, low density (grazed) seagrass meadows with most of their biomass in bel...

The impact of ocean acidification on benthic habitats is a major preoccupation of the scientific community. However, the natural variability of pCO2 and pH in those habitats remains understudied, especially in temperate areas. In this study we investigated temporal variations of the carbonate system in nearshore macrophyte meadows of the western Ba...

Future choices about the realization of hydrodynamic infrastructures in estuaries should be based on solid forecast about the changes they will generate in the environment. While complex numerical models are available for simulating sediment transport on physical basis, biologic elements are still hard to predict. This research project is aimed tow...

The estuarine environment is strongly affected by the hydrodynamic forces from currents and waves, which often form both a resource and a stress to the organisms inhabiting these areas. Organisms that inhabit these areas interact with these physical forces, and may thereby modify their abiotic environment. This is referred to as ecosystem engineeri...