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New OBN report : This report brings together knowledge on how to preserve biodiversity in old dune grasslands

Behoud van biodiversiteit in oude duingraslanden | Natuurkennis IN dutch with 2Pg english summary with al translation option interesting stuff for wider dune community

Summary
This report brings together knowledge on how to preserve biodiversity in old dune grasslands along the Dutch coast and in similar areas. It looks at vegetation, mushrooms (mycoflora) and soil life, and links these to soil processes, succession, and management. The study combines literature research, analysis of existing datasets, field measurements, DNA-analyses and interviews with site managers. The goal is to gain insight into the factors that maintain species-rich dune grasslands and what management actions are effective for their conservation and restoration. Dune grasslands belong to the Natura 2000 habitat type Grey Dunes (H2130) and form an important refuge for rare plants, lichens, and mushrooms. Their biodiversity is determined by natural processes such as drift, succession, and groundwater influence. In the past, the emphasis was on restoring natural dynamics, which primarily focused on young stages. Older successional stages, often species rich, have so far remained understudied. This report investigates why some older dune grasslands remain species rich while others lose species, what role nitrogen deposition plays, and how management can contribute to conservation and restoration. The report focuses on the following questions: • How is biodiversity related to the age of dune grasslands? • What factors determine high species richness? • How does nitrogen deposition influence biodiversity and scrub formation? • Which management measures are effective for conservation and restoration? To answer these questions, a broad approach was chosen: dune grassland data was analyzed from vegetation and soil chemistry time series of PQs and chronosequences from different soil ages, research on mushroom and soil life, scrub removal experiments, interviews with managers, and a synthesis of literature and practical experience. The time series of PQs shows that lime-poor and moderately lime-rich dune grasslands are more stable than those that are calcareous (lime-rich), which more often transition into scrub or forest. Since 2001, almost a quarter of the calcareous dune grasslands have been converted into scrubs, forests, heathland, or species-poor grasslands. Acidification, where lime-rich dune grasslands transition into lime-poor ones, occurs in some areas, particularly in the Wadden district. The buffering effect caused by sand deposition can promote local recovery. Chronosequence measurements show that soil organic matter increases with the dune grassland’s age, while pH decreases due to decalcification. Calcareous (lime-rich) dunes start at around a pH of 7 and drop to around 6; lime-poor dunes drop below a pH of 5. Moisture content, based on Ellenberg values, increases with age, especially in lime-poor dunes; the organic matter in the soil retains moisture. Nutrient richness, also based on Ellenberg values, increases, but the patterns differ by type and are influenced by nitrogen deposition. The species richness of vascular plants increases in the first ten years as vegetation develops but then becomes more variable. Calcareous dune grasslands have more vascular plants on average, and more mosses and lichen are found in lime-poor dune grasslands. The proportion of characteristic dune species decreases with succession, partly due to an increase in common species. The diversity of vascular plants correlates positively with pH and negatively with soil organic matter. The species richness of lichen also declines when soil organic matter is higher. 11 Old dune grasslands are crucial for waxcaps and allies, a group of grassland mushrooms (Hygrocybe, Entoloma, Clavaria, Geoglossaceae) indicating rather nutrient poor conditions. These species are highly threatened: 87% are on the Red List. In the Netherlands, approximately 98% of these grasslands have disappeared; a large portion of the remaining habitats is present in coastal dunes nowadays. Well-developed waxcap grasslands are primarily found in locations with long-term grazing and stable sward. Indicator species include Hygrocybe coccinea and Dermoloma cuneifolium. Threats include nitrogen deposition, renewed sand shifts, overgrowth, scrub formation, decline in rabbit populations, and climate change. A case study in the Middel- and Oostduinen (Goeree) includes 15 locations that have been grazed for over 100 years. Some 157 species were documented: 88 mushrooms, 58 plants, and 11 mosses/lichens. Four types of grasslands were distinguished: well-developed (more than 10 waxcaps and 10–15 Red List species), fairly well-developed (6–10 waxcaps), moderately developed (4–5 waxcaps, many saprophytes), and acidified (hardly any waxcaps). Correlations show that buffering (Ca) and pH are crucial: below a pH (NaCl) of 3.8, waxcaps disappear. Phosphate appears not to be limiting; well-developed grasslands with a relatively high pH and organic matter content contain relatively high amounts of plant-available phosphate. Nitrate levels in the soil are very low, which may indicate nitrogen limitations, despite still high deposition. Experiments suggest that ammonium is primarily absorbed by fungi. DNA-analysis of soil life reveals that thousands of species of bacteria and fungi exist in the soil. The fungal community is dominated by saprotrophs; species from the waxcap group are particularly prevalent in calcareous soils with low Al:Ca ratios. The fungal:bacterial ratio is higher in calcareous areas, which may indicate a greater role for fungi in nutrient cycling. The interviews and the literature study confirm that buffering, water supply, and grazing are crucial. Grazing is the most important measure against grass encroachment, overgrowth, and the development of scrub, but its effectiveness depends on the timing, intensity, and type of grazer. Mowing can be effective in wet areas. For the restoration of old successional stages, sod cutting should only be applied on a small scale and at shallow depths. Scrub removal appears to be effective for calcareous dunes, provided it is combined with grazing. Fire is not regularly used, but if it occurs accidentally, it can convert sea buckthorn scrub into dune grassland. Sand drift can counteract acidification and increase habitat diversity, but is negative for the mycoflora of old dune grassland. Reintroduction of rabbits can contribute to the restoration of open dune grassland. Old dune grasslands are essential for biodiversity, especially for mushrooms. Their stability depends on the lime content, pH, buffering capacity, and management. Nitrogen deposition remains a major threat. Its reduction does not automatically lead to recovery, partly due to the long term soil changes persisting. Management requires tailored approaches: grazing, mowing, scrub removal, and small scale sand deposition. Continuity in management is also crucial, as the restoration of mycoflora can take decades. Additional research is needed into the effects of reducing nitrogen deposition, sod cutting depth, dynamics, and interactions between soil life and vegetation.

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LIFE INSULAR

As one of the networking actions of the LIFE INSULAR project, they have the fourth bulletin, regarding the project activity during 2025 year.
Download it from the website.

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Keeping cows behind a virtual fence

In the Amsterdam Water Supply Dunes, water authority WATERNET is keeping a small herd of cows behind a virtual fence. "This way, we don't have to build forty kilometers of real fencing, and we still keep the animals out of the areas we don't want them in," says Maarten Jan van der Meulen.

The secret lies in a special collar from the young Dutch tech startup "Collie" (named after the dog breed often used for herding flocks of sheep). The collar is connected to the GPS system. As soon as the animals get too close to a programmed property boundary, the cow first hears a beep.

If the animal does cross the boundary, it receives a tiny electric shock through the collar. "That shock is ten to a hundred times weaker than the shock from an electric fence," explains Daniel Reisman of Collie. "But it's enough to train the animals to stay away from that virtual fence within a few days."

https://www.bnnvara.nl/vroegevogels/artikelen/koeien-houden-achter-een-virtueel-hek

Animal welfare: If a cow stays outside the area - because she's "stubborn" or perhaps being chased by a dog - she'll receive a maximum of three such shocks. Afterward, a message is automatically sent to the manager informing them that an animal has "escaped." "Animal welfare is priority," says Reisman. "You don't want to keep bothering an animal with such an electric shock."
Project leader Maarten Jan van der Meulen has been experimenting with this system on a small herd of grazers in the dunes since last spring. However, he has never tested the system himself. When he does so at our request, he confirms that it's a fairly subtle stimulus. "It feels like someone is giving you a sharp pinch," he says.

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Squeezed sands: Human footprints in coastal land

Eva M. Lansu

People are drawn to the coast. About one-third of the world’s population lives within 50 kilometers. This popularity brings development of infrastructure and buildings. Meanwhile, sea levels are rising, but this ‘hardening’ leaves no space for coastal ecosystems to retreat inland. This phenomenon, known as coastal squeeze, causes ecosystems to become trapped between rising sea levels on one side and infrastructure development on the other. However, it remains unclear what coastal squeeze means for dune ecosystems. This thesis therefore addresses two central questions: what is the minimal width of a biodiverse dune landscape? And how does that required width compare to the actual space available?
To answer these questions, I first quantify to what extent beaches and dunes are being squeezed on a global scale. On average, I find the first paved road or building within 400 meters of the sea. Then, based on field observations, I estimate how much space a biodiverse dune landscape needs. In the Netherlands, dune areas appear to require a width of approximately 3.8 kilometers to reach their full biodiversity potential. However, on average, Dutch dune areas are no wider than one kilometer. As a result, species diversity reaches only 56% of its potential.
Thus, coastal squeeze is causing a large-scale loss of dune biodiversity. This, in turn, reduces the resilience of dune ecosystems and threatens their functioning. This is concerning, as human populations depend on these ecosystems for services such as clean drinking water supply and flood protection. To preserve these valuable ecosystems in the long term, it is essential to give dunes space to adapt to rising sea levels. This requires preventing further coastal hardening and, where possible, widening the already narrowed dune areas.

https://research.rug.nl/en/publications/squeezed-sands-human-footprints-in-coastal-lands?utm_source=email

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Foredune Dynamisation Manual

Authors: Bas Arens et al., Editorial staff: Albert Oost, Bas Arens and Sonja van der Graaf, Editorial staff English edition: John Houston and Kenneth Pye

A must for all freaks of dynamic dunes...