Wetland restoration is widely promoted as a complementary nature-based climate solution, but its net carbon and GHG effects across wetland types and interventions remain poorly quantified at the global scale. We address this gap with a global meta-analysis spanning all major wetland types and restoration strategies. We conducted a global meta-analysis of 617 restored-altered pairs from 149 studies on five continents to assess how restoration influences major carbon stocks and greenhouse gas (GHG) fluxes relative to altered wetlands. Overall, across all wetland types studied, restoration significantly increased aboveground biomass, belowground biomass and soil carbon. Restored wetlands also exhibited significantly lower CO₂ fluxes, consistent with increased primary production and reduced aerobic decomposition following hydrological and vegetation recovery, but also higher CH₄ emissions particularly in peatlands where rewetting enhances anaerobic conditions. By contrast, neither N₂O flux (though close to) nor, particularly dissolved organic carbon concentration showed statistically significant overall changes. These global patterns were robust to sensitivity and leave-one-out analyses but varied strongly among wetland types and restoration approaches. Restored mangroves and peatlands more clearly exhibited significant biomass and soil carbon gains, whereas restored freshwater wetlands and peatlands significantly displayed strong belowground biomass and and decreases in both CO2 fluxes, though the later showed significant CH₄ flux increases. Other wetland types displayed more variable responses to restoration, if any. Hydrological restoration (mainly rewetting) produced the strongest improvements in aboveground biomass, soil carbon and N₂O flux reductions, though it significantly increased CH₄ flux. Vegetation recovery was significantly effective action increasing above- and belowground biomass, soil carbon, and decreasing CO2 fluxes. Data were dominated by studies from Asia, Europe and North America, by far made in the Northern hemisphere, highlighting major geographical gaps in Southern areas. Overall, our synthesis shows that wetland restoration reliably regenerates carbon stocks and reduces CO₂ emissions, supporting its inclusion in climate mitigation portfolios and nature-based solution frameworks. Short-term CH₄ emission increases and ecosystem-specific responses highlight the need for long-term monitoring, context-dependent restoration design and improved global coverage to optimise carbon benefits and inform on climate’s friendly restoration policies and actions.

Ecosystem restoration is a paramount policy priority for this decade, with ambitious global and European targets requiring unprecedented levels of data-driven implementation. Achieving effective and equitable restoration, particularly for coastal wetlands, hinges on spatially explicit socio-ecological information - maps that integrate habitats, ecosystem services, human activities, and pressures to guide prioritization, stakeholder negotiation, and adaptive management. This study, grounded in the RESTORE4Cs initiative, introduces an innovative multilayered dataset that bridges science and policy for six emblematic European coastal wetlands: Ria de Aveiro (Portugal), Valencian Wetlands (Spain), Camargue (France), Southwest Dutch Delta (Netherlands), Curonian Lagoon (Lithuania), and the Danube Delta (Romania). The dataset consolidates ecological mapping (EUNIS 2021, 2022), human activity and pressure documentation (aligned with EU Habitats Directive, Water Framework Directive, Marine Strategy Framework Directive), comprehensive ecosystem services mapping (CICES v5.1), alongside robust participatory community and stakeholder data. Altogether, the database encapsulates 97 habitat records, 23,160 activity-pressure associations, and 1,668 ecosystem service records-enabling robust cross-regional analyses and direct integration into evidence-based decision support tools. By illustrating practical pathways for participatory engagement, trade-off negotiation, and cross-scale integration, this research equips scientists, policymakers, practitioners, and communities with the scientific foundation to propel the Nature Restoration Regulation and Biodiversity Strategy 2030 objectives, fortifying Europe's climate adaptation trajectory. The approach showcased signals a new era for restoration science - where spatially explicit, multi-actor data supports policy, mobilizes citizen stewardship, and accelerates the transformative ambitions of Europe's restoration decade.

Coastal wetlands play a substantial role in regulating Earth’s climate through exchanges of greenhouse gases (GHGs). Current European policies promote widespread coastal wetland restoration to reverse historical losses and ongoing pressures. However, substantial uncertainty remains regarding how CO₂ and CH₄ fluxes respond to restoration across different coastal wetland types and whether these responses translate into net climate mitigation in terms of CO₂ equivalents (CO₂-eq). We measured simultaneous CO₂ and CH₄ fluxes using static chambers across four seasons at multiple locations spanning preserved, altered and restored sites within each of six European coastal wetlands of different ecological types. By comparing GHG exchanges and resulting CO₂-eq balances across wetlands, we identified the dominant biogeochemical drivers of CO₂ and CH₄ dynamics and assessed the climate mitigation potential of conservation and restoration actions. CO₂ fluxes were primarily controlled by landscape-scale vegetation cover and inundation, whereas CH₄ emissions responded to more subtle changes in water quality, salinity and wetland hydrodynamics. Comparisons of CO₂-eq balances between altered and restored sites revealed that seagrass replantation and eutrophication reversal generated significant mitigation benefits, driven by enhanced CO₂ uptake and reduced CH₄ emissions, respectively. In contrast, other restoration measures modified CO₂ and CH₄ fluxes in opposing directions, resulting in non-significant net climatic effects of CO2-eq balances. Overall, our results demonstrate that climate mitigation outcomes of coastal wetland restoration are both GHG-specific and wetland-type dependent, underscoring the need for tailored restoration strategies and robust, multi-GHG monitoring to detect and accurately quantify potential climatic benefits.

Due to the benefits to the ecosystem there is a growing incentive to limit management interventions of stranded whales. This study was conducted to test the impact of a stranded whale carcass decomposing in a natural dune ecosystem and to gain experience in managing a beached whale carcass. A 4.70 m male juvenile minke whale Balaenoptera acutorostrata carcass washed up on the western side of the uninhabited island Rottumerplaat, the Netherlands. The carcass was moved the same night into the dunes to prevent it from washing back into the sea. Regular field visits were undertaken and wildlife trail cameras were placed to document the decomposition stages and the attraction of avifauna. Pitfall traps were placed to monitor insect fauna next to the carcass. Vegetation plots were surveyed to document changes to the dune vegetation and soil cores were taken to determine the increase in metal, carbon and nutrient contents. Decomposition of the carcass until the bare skeleton within the temperate dune ecosystem took about two years. The carcass was highly beneficial for beetle biodiversity, attracting different beetle species at various stages of decomposition. In total, 129 species of beetles were found near the carcass, of which eight species are specific for carcasses. For scavenging birds such as gulls, magpies and carrion crows the skin of the minke whale was too tough to break open. While the initial nutrient leakage from the carcass was toxic to dune plants immediately around the carcass, it eventually promoted lush vegetation growth due to increased fertility. The bioavailable metal contents in the soil for potassium (K) and nickel (Ni) showed a significant increase due to the presence of the whale carcass up to six months. Significantly increased levels of arsenic (As), cobalt (Co) and vanadium (V) were found up to one and a half years later and sodium (Na) and manganese (Mn) persisted in elevated levels up to two years later. Recommendations were given on management interventions when leaving a whale carcass on site.

Salt marshes are known as one of the world’s most efficient ecosystems for carbon sequestration. At the same time they are vulnerable to ecosystem degradation due to climate-induced sea level rise (SLR). It is relatively poorly understood how marsh response to SLR may affect carbon sequestration rates. Here we present work based on some global to local-scale studies on organic carbon accumulation rates (OCAR, g C m-2 yr-1) in salt marsh sediment beds. First, based on a global dataset including 477 marsh sites, we find that the local SLR rate is the most important driver of OCAR among 12 investigated environmental variables. Overall, faster SLR favors higher OCAR values, which is interpreted to result from a positive feedback between SLR, more tidal inundation of marshes, higher tidal supply and deposition of sediments, and hence higher rates of sediment organic carbon (SOC) burial. Yet our global analysis shows OCAR values are also related to several other environmental variables. This illustrates the limits of global or regional-scale meta analyses to identify OCAR response to SLR, as also other environmental drivers vary between geographically distant sites. Therefore, secondly, we present results from two local-scale studies on OCAR, one in a so-called minerogenic marsh complex (i.e. SOC contents 35 %) in Maryland, USA. In the minerogenic system we quantified OCAR over the past four decades in two nearby marsh systems, with similar environmental conditions, but largely varying local relative SLR rates: one reference marsh with a SLR rate of ~2 mm.yr-1 versus a nearby marsh with accelerated relative SLR rate (~10 mm.yr-1) due to local land subsidence through gas extraction. Our results show OCAR values are on average twice as high in response to the accelerated SLR, with a more pronounced response (i.e. 63 % increase) on marginal marsh zones 30 m from creeks. We explain this as increased tidal sediment deposition and OCAR in response to faster SLR is more pronounced closer to creeks, as these are the source of tidal sediment supply. Further, in the organogenic marsh, we find OCAR values at 30 m from creeks. Moreover, our local case studies show interior marsh zones may experience vegetation die-back and conversion to shallow water ponds, which we interpret as a result of too low sediment accretion to keep pace with SLR. We highlight that the SOC response after marsh to pond conversion remains a key question. First analyses show lower SOC stability in response to higher SOC contents, suggesting that marsh degradation in response to SLR may trigger potentially higher SOC losses in organogenic marshes as compared to minerogenic marshes.

Coastal wetland restoration is widely promoted as a tool for climate change mitigation, but its effect on the carbon cycle is not well constrained. We conducted a systematic review and meta-analysis of peer-reviewed field studies that directly contrasted restored with altered sites, covering carbon stocks and greenhouse gas fluxes across mangroves, saltmarshes, seagrass meadows, brackish systems, and coastal freshwater wetlands. Literature searches yielded 66 studies and 257 pairwise restored versus altered site comparisons. Multilevel random-effects models with nested study effects showed significant increases after restoration in soil carbon, aboveground biomass, and belowground biomass. Mean greenhouse gas flux changes after restoration were non-significant for CO₂, CH₄, and N₂O. Meta-regressions detected no significant differences among wetland types, though this result is constrained by unbalanced evidence across systems and studied parameters. The available data are geographically biased toward tropical and subtropical Asia, with minimal coverage in Africa and limited data from temperate and cold coastal regions. Among the covered variables dissolved organic carbon is critically underrepresented, constraining whole-system impact estimates. Overall, the data examined in this study show that restoration consistently rebuilds biomass and soil carbon without a detectable systematic “cost” from methane or nitrous oxide, indicating positive outcomes for greenhouse gas fluxes. To translate these findings into policy-ready estimates, monitoring of greenhouse gases and dissolved organic carbon should be expanded, altered versus restored designs should be prioritized, and underrepresented regions and wetland types should be targeted.

Salt marshes are known as key ecosystems for nature-based climate mitigation through organic carbon sequestration into their sediment beds, but at the same time they are affected by accelerating sea level rise induced by climate warming. Consequently, an important question is how organic carbon accumulation rates (OCAR) of salt marshes will respond to future accelerating rates of relative sea level rise (RSLR). To date, existing insights are either based on (1) comparison of geographically distant marsh sites, differing in local RSLR rates but also in other environmental conditions that additionally can affect OCAR, or (2) experiments in given marsh sites, in which proxies for RSLR are manipulated, but run over periods of years instead of decades, the latter being the relevant time scale of marsh responses to RSLR. Here we bridge these shortcomings by studying the OCAR over four decades at two nearby salt marsh sites in the Netherlands, with similar environmental conditions, but with one site experiencing an accelerated RSLR rate of 9.7–11.7 mm yr−1 (i.e., within the range of projected global mean sea level rise rates by 2100) due to local land subsidence induced by gas extraction, while the other site does not experience subsidence and has a low background RSLR rate of 2.0 mm yr−1 (i.e. close to the current global mean sea level rise rate). Our results reveal that the salt marsh site experiencing the accelerated RSLR rates shows OCAR values that are on average twice as high as those found in the marsh site experiencing the low background RSLR rates. Moreover, the increase of OCAR in response to faster RSLR was even more pronounced (i.e. 63 % increase) on marsh levees within 10 m from tidal creeks, while this was more subtle (i.e. 27 % increase) in marsh basins at a distance of 30–40 m from the creeks. These observations of increased OCAR are mainly attributed to increased sediment accretion rates (SAR) in response to (1) increased tidal inundation due to accelerated RSLR and (2) larger sediment supply due to closer proximity to creeks, while sediment organic carbon content was relatively little affected. Our findings support expectations that nature-based climate mitigation actions, through salt marsh conservation and restoration, are sustainable on the long term of the coming decades, and are even likely to become more effective with future accelerations in global sea level rise, at least for macrotidal sites not limited by sediment supply.

A global concern for coastal ecosystems is the predicted rise in sea-level for which salt marshes must keep pace by increasing in surface elevation sufficiently. Variables that control this elevation change need to be identified to predict the adaptability of marshes to future sea-level rise. Many European marshes are grazed by livestock and these heavy grazers can biocompact the soil, a process often underestimated in studies assessing the long-term survival of marshes. We measured elevation changes for thirteen years in the field in grazed and non-grazed marshes. With a statistical model the most important factors controlling rates of surface elevation change were identified and provided the input for a mathematical model to study future elevation change of grazed and non-grazed salt marshes up to 2100 under three Sea Level Rise and sediment supply scenarios. We found that trampling by grazing cattle significantly reduced the annual rates of elevation gain from 11.9 mm yr-1 in the non-grazed marsh to 3.6 mm yr-1 in the grazed marsh. Next to biocompaction by livestock, precipitation deficit and extreme drought resulted in extra compaction. Our model results showed that cattle presence had a negative impact on the future adaptability of salt marshes to grow vertically for rising sea levels. Biocompaction reduced the total elevation change by 42% if the current linear SLR does not accelerate. For an accelerating and high SLR to 109 cm +NAP in 2100, biocompaction reduced elevation changes by 12% and the grazed marsh can no longer outcompete the rise in sea level from around 2050 onwards, compared to the non-grazed marsh. The grazed marsh will slowly drown but this will not lead to a significant change in vegetation composition yet. For an extreme SLR to 195 cm +NAP in 2100 the elevation changes in both the grazed and non-grazed marshes cannot keep pace with the rise in sea level and the marsh vegetation is expected to show regression to plants typical for a low marsh. A reduction in sediment supply will aggravate the effects of SLR and may result in highly increasing inundation frequencies and subsequent disappearance of the marsh vegetation.

Seasonal movements between the summer and winter areas are a widespread phenomenon in bats So far, most information on the migration ecology of bats has been obtained by studies in terrestrial habitats, whereas scientific knowledge on migration over sea is scarce. We performed continuous ultrasonic acoustic monitoring at 13 locations in the southern North Sea during four consecutive years (2017–2020) and analysed the spatiotemporal occurrence of Nathusius’ pipistrelle Pipistrellus nathusii during autumn migration in relation to weather parameters and lunar phase. Our analysis showed that the main autumn migration of Nathusius’ pipistrelle at the southern North Sea occurs from mid-August until late October and most bats within the study area occur off the Noord Holland coast. North Sea crossings frequently last longer than one night; the day is spent roosting at an offshore structure. The strongest migration occurs during nights with tailwinds from the east-northeast, but bats are also recorded offshore with low to moderate headwinds or crosswinds. Bat presence decreased between the full moon and the last quarter and increased just before the new moon. Finally, our observations show that the occurrence of bats at sea was reduced in 2020 in comparison to the previous years. The results of this study show clear spatiotemporal patterns of migratory bat occurrence at the southern North Sea. The spatial distribution can be used in spatial planning of future offshore wind farms, whereas the temporal occurrence and environmental factors that shape offshore migration can be used to develop mitigation measures to reduce the number of bat fatalities.

Intertidal salt marshes provide a range of valuable ecosystem services which typically increase with marsh width. Understanding the drivers for salt marsh expansion versus retreat is thus key to managers. Previous research highlights the influence of short-term (daily/event) bed level dynamics on germination and establishment and subsequent vegetation presence. However, more recent literature suggests the importance of medium-term seasonal bed level dynamics on viable seed availability and subsequent vegetation presence. This study aims to assess event-based and seasonal bed level dynamics for vegetation presence in natural and semi-natural salt marshes and to provide generic thresholds for vegetation presence. To gain insight into bed level dynamics, data was used from autonomous Optical and Acoustic Surface Elevation Dynamics sensors (O-SED and A-SED) around the edge of natural and semi-natural salt marshes. Sensors were installed at vegetated and unvegetated measurement station Field observations from 22 O-SEDs deployed at 4 well-established natural salt marshes in the Western Scheldt estuary and 4 O-SEDs at a well-established semi-natural salt marsh in the Wadden Sea were reanalyzed. Six novel A-SEDs were deployed at a pioneer semi-natural salt marsh in the Ems-Dollard Estuary. The measurement duration at all salt marshes was at least 1 year. The A-SED sensor was successfully validated against manual measurements. Furthermore, vegetation data and water level data were obtained. No significant difference was observed between natural and semi-natural salt marshes. However, a significant difference between vegetated and unvegetated measurement stations for short-term bed level dynamics was observed. Vegetation was found to be present at locations restricted by short-term bed level variability smaller than or equal to 12 mm, emphasizing the presence of a short-term threshold. Although trends in the non-growing season were significantly different between vegetated and unvegetated stations, seasonal thresholds for vegetation presence were not found. The findings imply that knowledge of bed level-dynamics in well-established natural marshes can be used to predict vegetation presence in constructed semi-natural marshes. The importance of local short-term dynamics for vegetation presence instead of longer-term dynamics highlights possibilities for developing favorable conditions for vegetation presence in marsh restoration projects and the construction of new salt marsh ecosystems.

De Pilot Kleirijperij is onderdeel van het programma Eems-Dollard 2050 (ED2050) dat is gestart om de slibproblematiek in het Eems-Dollardestuarium aan te pakken. Als een voor de hand liggende oplossing voor het verbeteren van de ecologische kwaliteit geldt slibonttrekking. Inmiddels ligt er de ambitie om langdurig minimaal één miljoen ton droge stof per jaar uit het Eems-Dollardestuarium te verwijderen. Voor dat slib wordt binnen het ED2050-deelprogramma Nuttig Toepassen Slib naar bestemmingen gezocht die ook in economisch opzicht rendabel zijn. De Pilot Kleirijperij is een van de verkennende projecten binnen dat deelprogramma, en kent een separaat uitvoeringsproject met twee hoofdactiviteiten: 1) onderzoek naar manieren van kleirijping in slibdepots op land met behulp van zowel diverse fysische als biologische bewerkingsmethoden; en 2) het toeleveren van 70.000 m3 gerijpte klei aan het demonstratieproject Brede Groene Dijk (BGD) - een ander ED2050-innovatie-project. De praktische uitvoering van de Pilot Kleirijperij vond plaats op twee terreinen: één nabij het zeehavenkanaal van Delfzijl (Oterdum; Kleirijperij Delfzijl) en een kwelderlocatie langs de Dollarddijk (Kleirijperij Kwelder), waar in 2022 ook het 750 m lange proeftracé van de BGD is aangelegd. De voorliggende rapportage van Wageningen Marine Research (WMR) gaat enkel over de biologische bewerkingen in de kleirijperen en levert toe aan de EcoShape-rapportage over alle toegepaste bewerkingsmethoden. In die overkoepelende rapportage wordt ook de vergelijking gemaakt tussen de effecten van de fysische en de biologische bewerkingen. In het projectdeel van WMR stond de vraag centraal wat het effect van vegetatie is op het kleirijpingsproces, waarbij ook de praktische vraag aan de orde was: is actieve inzaai van vegetatie wel nodig of voldoet spontane vestiging van vegetatie? Als derde speelde de vraag of een kleirijperij extra (tijdelijke) natuurwaarde kan hebben als broedgebied voor vogels. Om de inrichting c.q. inzaai van de biologische vakken in de slibdepots nader te kunnen bepalen, is een literatuurstudie uitgevoerd. De wijze van monitoren van de vegetatie en van de natuurwaarden c.q. broedvogels is afgestemd op de uitvoering van de fysische bewerkingen. In 2020 en 2021 zijn vervolgens beide proeflocaties meerdere keren bezocht voor opname van de gevestigde vegetatie in het eerste jaar en de biomassabepaling en bedekking van de vegetatie. Beide locaties zijn op een verschillend moment en met een ander bronmateriaal in gebruik genomen en kenden derhalve een verschillende opnamecyclus. De meest relevant geachte abiotische factoren (vocht-, zout-, zuurstof- en organisch-stofgehalte) zijn gemeten. Ook zijn broedvogelinventarisaties uitgevoerd in de kleirijperijen als geheel. De aanwezigheid van vegetatie in een kleirijperij is niet doorslaggevend voor de rijping van zilt slib tot dijkenklei in een depot met relatief grote diepte (zoals bij deze proef), maar heeft wel bepaalde effecten. Twee jaar doorlooptijd is echter te kort om effecten van vegetatie op de langzame rijping van slib eenduidig te bepalen. Wel kon worden vastgesteld dat er in de bovenste 30 cm van de bodem enige invloed van vegetatie is. − Ten opzichte van onbegroeide bodem zorgt een vegetatiedek in de zomermaanden voor een lagere bodemtemperatuur, in de toplaag (0-14 cm) voor een lager vochtgehalte en in zowel de toplaag als de diepere laag (14-28 cm) voor een hoger zoutgehalte. − In de diepere laag (14-28 cm) zien we een toename van oxidatie in de bodem en een (kleine) toename van organische stof. − Inzaai van vegetatie is niet per se noodzakelijk. Vegetatie komt op uit reeds in het slib aanwezige en aangewaaide zaden; een zaadbank en/of zaadbron in de omgeving zijn daarvoor wel een voorwaarde.

Constructed salt marshes as a Nature-Based Solution for coastal defense offer additional benefits over conventional engineering, but project realization is often hampered by practical and governmental obstacles. We assessed the execution of a local-scale salt marsh construction project as a Nature-Based Solution (NBS) with respect to the regional-scale Social-Ecological System (SES) in an explicitly linked NBS-SES framework. A local municipality came up with various plans to develop its waterfront but these proved unrealizable without wider stakeholder participation. Crucial for success was that the local initiative was turned into an NBS integrating livability, biodiversity and flood safety, and that it was linked to the governance systems and actors in a regional SES. The chosen NBS consists of a city beach and two salt marshes, a salt marsh park that is open to the public and a pioneer salt marsh that is only accessible for research. The pioneer salt marsh was constructed by raising the seabed to around mean high tide with sand obtained from a capital dredging project. It was used as a large-scale natural experiment in salt marsh construction. To test the effect of enrichment with silt and clay on initial salt marsh development, six hectare-scale compartments were created in which mud was mixed with sand in the top 1.0 m of the bed to three mud contents of on average 8%, 25% and 48%. Heavy machinery was needed to mix mud through the upper meter of the sandy bed. Mixing mud was softening the sediment causing the machines to sink into the 48% mud enriched bed. To test whether seeding with a pioneer plant species accelerates salt marsh development, fragments of Salicornia procumbens plants were seeded in half of three compartments. Field observations between November 2018 to September 2020 showed that seeding of Salicornia plant fragments resulted in significant differences in vegetation cover and species richness in the first growing season. Mud content showed significant positive effects on vegetation cover and species richness in the two monitored growing seasons, where the compartments with on average 7–9% mud had the lowest vegetation cover and species numbers. When constructing a salt marsh by raising sand and mixing mud, a mud content of 25% is practically feasible and results in high vegetation cover and species richness.

The project Samenwerking Kustverontreiniging na Maritieme Incidenten (Cooperation Coastal Pollution after Maritime Incidents) explores how Rijkswaterstaat can better assist municipalities in cleaning up pollution that washes up on the coast after maritime incidents. In this context, an inventory has been made of methods that can be used to clean up the coastline from microplastics (particularly industrial pellets) that have ended up in the sea as a result of an incident. Broadly speaking, there are three methods used to remove microplastics, namely raking, shovelling or vacuuming, after which a sieve may or may not be used to separate materials. Shovelling or raking are suitable methods for removing plastics from soft sediments without vegetation, such as beaches and possibly tidal flats. On hard substrates, and on moist sand, the 'hoover' is an effective way to collect microplastics reasonably selectively, especially as long as the pellets are still on top of the sand. If the sand is dry, a combination with a sieving system is needed to separate the microplastics from the sand that is also collected. Vacuum cleaning can also be applied to overgrown areas, but as the overgrowth becomes denser, the efficiency with which microplastics are collected decreases. For the vacuum method to work effectively, it is also important to avoid vacuuming coarse (plant) material, as this can quickly clog the vacuum hose. All methods can be used on a small scale, manually, or on a large scale, motorised. Vacuum cleaning seems to be the most suitable method for cleaning up washed-up microplastics from the various substrates. There are a few companies that offer vacuum cleaning systems for the removal of microplastics on the market. These may or may not be equipped with systems that separate the waste, although separating microplastics and plant remains within a size fraction is not possible at present. It is inevitable that organisms will be damaged or removed during clean-up operations. However, if this takes place in a limited area, quick recovery from the surrounding terrain is possible, provided that the structure of the subsurface has not been changed by the clean-up operations. Therefore, vacuuming is preferable to excavating and mowing. To minimise the area that needs to be cleaned up, a fast response after an incident is important, as the plastic can then be cleared while still concentrated in the flood mark. Ideally, an affected beach should be closed to the public so that plastics do not end up deeper in the sand through foot traffic or vehicles. For salt marshes, it is important to act quickly if the plastics are still low on the marshes where the vegetation is less dense. Densely vegetated salt marshes (and silty tidal flats) are difficult to clean without substantial impact on the local system. Ideally, contamination of these areas is prevented by collecting the plastics from the water at an early stage, for example by using oil screens. If microplastics do end up in these areas, 'doing nothing' seems to be the best option, as the impact of the presence of plastic pellets on the ecosystem seems small. However, without specific research, this remains an assumption. It is possible that the ecological effects of pellets are too subtle to be observed under field conditions, but from an ethical and aesthetic point of view, lost waste should always be cleaned up as much as possible. For the further development of knowledge on how best to react after an incident with microplastics, the exchange of knowledge and experience in this field should be promoted within the Netherlands and possibly Europe. If various prototypes of clean-up systems can be tested in this context, a better picture of their actual effectiveness can be obtained. This cooperation may also provide the market perspective that can encourage commercial parties to invest in improving the clean-up methods.