The “salt gardens” of the Wadden Sea

Press release from
© Daphne van der Wal
Salt marshes at the intersection between land and sea.

The international SALTGARDEN consortium led by LUH is developing a sustainable salt-marsh management concept for coastal regions.

Can salt marshes in the Wadden Sea withstand the triple crisis of climate change, biodiversity loss and environmental pollution? Researchers from Germany, the Netherlands and Denmark want to jointly investigate the extent to which these ecosystems, which are extremely important in protecting coastal regions, are able to contend with the increasing ecological pressure.

Salt marshes in the transitional area between land and sea are valuable buffer zones that weaken the energy of the waves and can thus reduce the erosion and flooding of coastal areas. In this way, salt marshes contribute significantly to coastal protection, and they are also a habitat for many animals and plants found only in this ecosystem. Additionally, they play an important role as carbon reservoirs. But can salt marshes survive under future climatic conditions? Can they continue to accomplish their coastal protection function under the new conditions, with rising sea levels and increased CO2 pollution?

The SALTGARDEN research project investigates the extent to which the preservation and promotion of biodiversity in salt marshes can serve as a central component of a strategy for addressing the so-called triple ecological crisis of climate change, biodiversity loss and environmental pollution. German, Dutch and Danish research facilities are collaborating on the project, which is funded by the Federal Ministry of Education and Research (BMBF); the Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection; and the Dutch Research Council (NWO). The project is headed by the Ludwig Franzius Institute of Hydraulic, Estuarine and Coastal Engineering at Leibniz University Hannover (LUH) (PhD Maike Paul and Dr. Dorothea Bunzel). The co-spokesperson role is held by Twente University (Erik Horstmann) in the Netherlands. LUH has participated in previous research projects on salt marshes, which have delivered promising initial findings on the resilience of these ecosystems.

If the salt marshes at the interface between land and sea are examined more closely, it becomes clear that most of these areas are cultivated and, for the most part, tended landscapes. They are managed with a strong focus on their use for pasture and coastal-protection purposes. The artificial draining of the areas in front of dikes – originally for the purpose of obtaining land – is also a common practice. Although many types of use have been reduced or suspended over recent decades, many of the artificial landscape structures are still clearly evident today. As a result, the natural biodiversity of the salt marshes is impeded in a lasting way. But it is particularly the biological diversity and the vegetation dynamics of a salt marsh that drive the central ecosystem processes and are thus the prerequisites for the adaptability and resilience of these coastal ecosystems. Against this backdrop, the cultivated salt marsh landscapes would appear to be susceptible to the increasing impacts of the ecological crisis.  

The SALTGARDEN consortium aims to use laboratory experiments and field studies to evaluate the robustness of salt marshes in response to hydrodynamic impacts such as sea-level rise and storm surges and to investigate the reaction of salt marsh plants to altered climatic conditions such as heat and drought stress. An additional research focus is the examination of pollutant accumulation – for example, through microplastic and nutrient inputs. The Ludwig Franzius Institute of Hydraulic, Estuarine and Coastal Engineering at LUH has set itself the task of examining the resilience of real salt marshes extracted from the Wadden Sea – with varying structure and quality in terms of diversity – in its own wave basin.

In close cooperation with government organisations and administrative entities, NGOs and local interest groups in the three countries, all of which are located on the North Sea, the SALTGARDEN research team aims to develop strategies for the sustainable management of salt marshes. These strategies will be based on the fundamental principles of so-called nature-based gardening. The goal is to better understand the value of biodiverse and dynamic coastal ecosystems, to quantify the sensitivities and, based on these, to establish future-oriented foreshore management strategies at the sociopolitical level.

SALTGARDEN is one of five research projects on the topic “International research on the Wadden Sea: Understanding the complex stressors impacting the Wadden Sea and developing options for action” that have received funding. The SALTGARDEN consortium will receive a total of 2.8 million euros over four years.

The SALTGARDEN consortium: Leibniz University Hannover (LUH), Twente University (UT), Kiel University (CAU), Alfred Wegener Institute (AWI), Royal Netherlands Institute for Sea Research (NIOZ), Van Hall Larenstein University of Applied Sciences (VHL), University of Copenhagen (UCPH), Technical University of Denmark (DTU), Deltares, Waterschap Noorderzijlvest, Wetterskip Fryslân, EcoShape, Landscape Architects Office (LAMA), Nature and Biodiversity Conservation Union (NABU), Lower Saxony Wadden Sea National Park (NLPV).


Note to editors:

For further information, please contact Dr. Dorothea Bunzel, Ludwig Franzius Institute of Hydraulic, Estuarine and Coastal Engineering at Leibniz University Hannover (Tel. +49 511 762 3737, email