In the Future Dikes project, research is being conducted on how Dutch dikes can be strengthened with species-rich grass coverings. The first phase of the project showed that flower-rich dikes are safe, and the High Water Protection Program and water boards have expressed the ambition to achieve "Strong species-rich dikes as standard."
In Phase 2, work is being done to realize this ambition. Research is being conducted on how species-rich dikes can be constructed, transformed, and managed so that they are both strong and biodiverse. The development of practical guidelines for construction, transformation, and management is central to this effort. To support dike managers in constructing and developing species-rich dikes, the team is developing a Functional Vegetation Typology and Opportunity Scan for species-rich dikes in the Netherlands.
Functional Vegetation Typology
The basis for the opportunity scan is a functional vegetation typology, based on thousands of already available vegetation surveys that are available within the National Vegetation Database and that have been recorded by project partners in recent years. Each survey includes a description of the species composition and the relative proportion of that species on a defined area. This data can additionally be linked to locally measured soil data, site factors, and strength parameters.
Plant species don't grow anywhere randomly, and especially the combination of plant species can give us information about the local environment. The appearance or disappearance of plant species tells us which processes are taking place locally. This could be drought or moisture, excess or shortage of nutrients, whether sheep graze or whether mowing takes place, or a particular soil composition. This means each section of dike has its own fingerprint determined by a unique species combination. With the functional typology, we want to map these fingerprints and give dike managers the ability to read and translate the information that plants provide to us regarding the status of the grass covering and whether or not to modify management.
The overview of this information is included in the functional typology. Basic principles from syntaxonomic science are applied here, creating comprehensive overviews in which characteristic species form the guideline. The data behind the typology and the types that can be assigned to different vegetation can serve as a basis for new automated monitoring of dike covering using remote sensing and AI in the near future.
But above all, this way all dikes in the Netherlands can be mapped. A lot of information can be derived from this map. For example, where we can easily realize strong species-rich dikes with certain measures.
The opportunity scan
The opportunity scan is a tool for dike managers that provides simple insight into the possibilities of their dikes for developing strong, species-rich, and herb-rich dike vegetation. Water boards have a great need for such a tool for all their dikes. They have many questions about how they can construct and develop species-rich dikes, how they can manage them sustainably, and whether and how a species-poor dike can be transformed into a species-rich dike.
The opportunity scan is based on the functional vegetation typology for Dikes. From the overview of different dikes in the Netherlands, we can make an assessment within the project of which dikes are directly suitable for species-rich grass coverings and at which locations there are opportunities through management interventions.
To get not only a safe dike but also a beautiful, naturally valuable dike, it would be very useful if it could be determined in advance how promising transformation to species-rich grass covering is for a dike section. What circumstances must be taken into account, how to intervene or adjust. There are still many questions about steering visible and less visible effects to maintain a safe, beautiful, valuable dike for a long time. That's where the opportunity scan should help us!
Peter Boone, grasregisseur, STOWA; Waterschap Vallei en Veluwe
Taking the typology to the dike
Both the functional vegetation typology and the opportunity scan are being created to be directly applied by dike managers. This means that within Future Dikes we are committed to making this knowledge available on the dike as well. In a (web)app, a dike manager can practically discover what vegetation type a particular dike has, what he/she should pay attention to during transformation, and how the dike can best be managed (mowing, overseeding, fertilizing, etc.). Fed by data from the Future Dikes project, dike managers can estimate not only the vegetation type and desired management but also the civil engineering quality and erosion resistance of the dike covering. The tool thus offers the possibility to identify unwanted processes early that can be corrected with relatively small management interventions.
The management of grass covering on dikes looks simple: we mow and then it will be fine. But within that grass covering, many complex processes are taking place. These are determined by a large number of ecological factors. It is important for a dike manager to get an instrument with which he or she can determine what the possibilities are with that vegetation, how it stands, what can be steered. The opportunity scan can contribute to this.
Jaap Bronsveld, vakspecialist waterkeringen, Waterschap Rivierenland
