People and Projects Solving Freshwater Restoration Challenges

EcoAdvance European Project

Showcase category ➤ Star Scientists

BELGIUM

Prof Dr Jonas Schoelynck

Professor, University of Antwerp, ECOSPHERE Research Group

Scientists & Researchers
My Projects
  • Key project facts

    Over the past 20 years, together with a team of researchers, I have contributed to the monitoring of the Sigmaplan restoration project in the Demer Valley, as well as to the restoration of freshwater tidal habitats at Lippenbroek and other Sigmaplan sites in Flanders, Belgium. My input reflects the collective efforts of the research team, and I do not claim all merits individually.

  • What impact did these projects have on biodiversity, if any?

    These projects had a demonstrably positive impact on both freshwater and riparian biodiversity, particularly in the restored sections. The improved lateral connectivity with floodplains, enhanced habitat heterogeneity, and the re-establishment of natural sedimentation and erosion processes contributed significantly to habitat creation and improved water quality. As a result, biodiversity increased, alongside the carrying capacity, robustness, and resilience of the ecosystems.

  • What work challenges did you face and what approach did you take to solve them?

    One of the main challenges we faced was monitoring under difficult field conditions, such as steep riverbanks, deep waterbeds, and strongly fluctuating water levels. To address this, we tested and evaluated several monitoring methods before selecting the most effective approaches. Another technical challenge was the introduction of tidal influence in embanked sites with low elevation, which were not suitable for managed realignment. We resolved this by integrating flood defense and nature restoration through the construction of flood control areas (FCA) with a controlled reduced tide (CRT), applying a system of high inlet and low outlet sluices.

  • What lessons learned are transferable to other places/projects?

    Among the most transferable technical lessons we learned are the use of the FCA-CRT system, which effectively combines flood protection with the restoration of tidal habitats, and the pre-treatment of compacted polder soils prior to the reintroduction of tidal influence. These approaches can be applied in other contexts to enhance both ecological restoration and long-term site functionality.

  • What is your biggest barrier and what are you trying to do about it?
    Our biggest technical barrier was creating the right tidal conditions to establish tidal nature without compromising flood safety or encouraging nuisance species such as biting midges. We overcame this challenge by implementing the FCA-CRT system and by carefully designing the site topography to balance ecological objectives with safety requirements.
My Focus and Approach
  • Lessons Learnt - Some recommendations for others?
    1. What’s most important:

      What we consider most important is clear communication with the public, both professionals and local residents, to ensure understanding and support for restoration efforts. In addition, it is essential not to base project evaluation on a single metric, but to assess the functioning of the entire ecosystem. Finally, adopting a multidisciplinary approach is key to achieving sustainable and widely supported outcomes.

    2. Do this, not that: 

      Cooperate.

    3. Always start by:

      We always start by engaging in dialogue and identifying the basic requirements needed for the ecosystem to function properly.

    4. The biggest barrier and what I am trying to do about it:
      Time and money.
My Journey
  • My journey:

    I obtained my MSc in Biology in 2007 and defended my PhD in 2011. Since then, I have been affiliated with the University of Antwerp. In 2020, I started my Tenure Track, and in 2025, I was appointed Full Professor.

  • My Education:

    BSc, MSc, PhD Biology.

  • The Big Change:

    Our work has had a significant impact by advising policymakers on strategies for future river restoration projects aimed at enhancing ecosystem health, drawing on insights from extensive monitoring campaigns. Moreover, through the realization of the Sigmaplan, more than 2,000 hectares of new tidal nature are being created in Flanders, contributing substantially to biodiversity and climate resilience.

  • Favourite part of the work I do:

    One of our favourite aspects of the work is witnessing how ideas and concepts are translated into practice in the field. Equally rewarding are the small wins along the way, such as encountering rare species that depend on natural river dynamics and that have reappeared thanks to the restoration projects.

Interview

Key Topics:

Key Topics

These relate to specific topics (e.g. technical solutions; restoration activities etc.) addressed within the showcase materials.

  • Wetland restoration
  • Hydrological restoration
  • Freshwater estuary
  • Water quality
  • Tidal marshes
Prone2Success Factors Demonstrated:

Prone2Success Factors Demonstrated

These are the Prone2Success checklist factors which are highlighted within this showcase. More information on the Prone2Success checklist can be found here.

  • Measurable goals to improve ecological status
  • Measurable goals to improve ecosystem services
  • Supports WFD, NRL and other restoration policy goals
  • Communicate/engage with stakeholders from the outset
  • Engage with the local community from the outset
  • Obtain sufficient finance for all project stages
  • Restoration works (design) are self-sustaining 
  • Local planning processes are transparent / clearly understood
  • Include long term monitoring
  • Include adaptive management approaches (combined with monitoring)
  • Ensure stakeholder understanding / education of restoration goals & benefits
  • Demonstrate specific ecological improvements/legal compliance / communicating results during and after the project
  • Take climate change into account
NRL Restoration Categories:

NRL Restoration Categories

These are the restoration categories (listed under Annex VII of the European Nature Restoration Law (NRL) which are relevant to this showcase.

  • [2] Improve hydrological conditions
  • [5] Re-establish river meandering
  • [7] Re-naturalise river beds
  • [8] Restore natural sedimentation
  • [9] Establish riparian buffers
  • [22] Improve connectivity across habitats
  • [26] Restore fish spawning / nursery areas
Resources
Articles
  • Costanza, R., d’Arge, R., de Groot, R., Farber, S., Grasso, M., Hannon, B., Limburg, K., Naeem, S., O’Neill, R. V., Paruelo, J., Raskin, R. G., Sutton, P., & van den Belt, M. (1997). The value of the world’s ecosystem services and natural capital. Nature, 387(6630), 253–260. https://doi.org/10.1038/387253a0 
  • Jones, C. G., Lawton, J. H., & Shachak, M. (1994). Organisms as ecosystem engineers. Oikos, 69(3), 373–386. https://doi.org/10.2307/3545850 
  • McClain, M. E., Boyer, E. W., Dent, C. L., Gergel, S. E., Grimm, N. B., Groffman, P. M., Hart, S. C., Harvey, J. W., Johnston, C. A., Mayorga, E., McDowell, W. H., & Pinay, G. (2003). Biogeochemical hot spots and hot moments at the interface of terrestrial and aquatic ecosystems. Ecosystems, 6(4), 301-312. https://doi.org/10.1007/s10021-003-0161-9
Videos

Sigmaplan Flood Control Area Reduced Tide

Aansluiten Demermeander Betekom mei 2020

Er stroomt opnieuw Demerwater door de meander in Aarschot

De Demer mag weer kronkelen

Demervallei Werchter Betekom 2 4K

These are just a snapshot of some videos; many more are available online. Please note that all of them were produced by the official SIGMAPLAN authorities (De Vlaamse Waterweg). Our contribution lies in monitoring and providing advice, so there are no specific videos featuring us directly.

Peer reviewed papers
  • Hons, M. ; Maris, T. ; Schoelynck, J. (2025). The effects of meander reconnection and deflector installation on the physicochemical water quality. River Research and Applications 56 - 67. https://doi.org/10.1002/rra.4384
  • Amadei Martínez, L.; Sabbe, K.; D'Hondt, S.; Dasseville, R.; Daveloose, I.; Verstraete, T.; Chaerle, P.; Brion, N.; Maris, T.; Meire, P.; Vyverman, W. (2025). Freshwater discharge and salinity drive taxonomic and functional turnover of microbial communities in a turbid macrotidal estuary. Environmental Microbiology Reports 17(4): e70135. https://dx.doi.org/10.1111/1758-2229.70135, meer
  • Hons, M. ; Maris, T. ; Schoelynck, J (2024). Short-term effects of a summer flash flood on the physiochemical water quality in a restored river. Journal of Coastal and Riverine Flood Risk 3: 1-20. https://doi.org/10.59490/JCRFR.2024.0013
  • Mouth, C.; Tackx, M.; Azémar, F.; Bou, E.; Meire, P.; Maris, T.; Legal, L.; Bernard, A. (2024). Environmental factors as drivers of the spatial distribution of the copepods Eurytemora affinis affinis and Eurytemora velox in the Scheldt tributaries. Est., Coast. and Shelf Sci. 303: 108802. https://dx.doi.org/10.1016/j.ecss.2024.108802
  • Stoorvogel, M.; Temmerman, S.; Oosterlee, L.; Schoutens, K.; Maris, T.; van de Koppel, J.; Meire, P.; Bouma, T. (2024). Nature‐based shoreline protection in newly formed tidal marshes is controlled by tidal inundation and sedimentation rate. Limnol. Oceanogr. 69(10): 2377-2390. https://dx.doi.org/10.1002/lno.12676
  • Amadei Martínez, L.; Sabbe, K.; Dasseville, R.; Daveloose, I.; Verstraete, T.; D'Hondt, S.; Azémar, F.; Sossou, A.C.; Tackx, M.; Maris, T.; Meire, P.; Vyverman, W. (2023). Long-term phytoplankton dynamics in the Zeeschelde estuary (Belgium) are driven by the interactive effects of de-eutrophication, altered hydrodynamics and extreme weather events. Sci. Total Environ. 860: 160402. https://dx.doi.org/10.1016/j.scitotenv.2022.160402
  • Lauryssen, F.; Crombé, P.; Maris, T.; Van Maldegem, E.; Van de Broek, M.; Temmerman, S.; Smolders, E. (2022). Estimation of the natural background of phosphate in a lowland river using tidal marsh sediment cores. Biogeosciences 19(3): 763-776. https://dx.doi.org/10.5194/bg-19-763-2022
  • Saintilan, N.; Kovalenko, K.E.; Guntenspergen, G.; Rogers, K.; Lynch, J.C.; Cahoon, D.R.; Lovelock, C.E.; Friess, D.A.; Ashe, E.; Krauss, K.W.; Cormier, N.; Spencer, T.; Adams, J.; Raw, J.; Ibáñez, C.; Scarton, F.; Temmerman, S.; Meire, P.; Maris, T.; Thorne, K.; Brazner, J.; Chmura, G.L.; Bowron, T.; Gamage, V.P.; Cressman, K.; Endris, C.; Marconi, C.; Marcum, P.; St. Laurent, K.; Reay, W.; Raposa, K.B.; Garwood, J.A.; Khan, N. (2022). Constraints on the adjustment of tidal marshes to accelerating sea level rise. Science (Wash.) 377(6605): 523-527. https://dx.doi.org/10.1126/science.abo7872
  • Minguez, J.; Maris, T.; Tackx, M.; Gers, C.; Meire, P.; Legal, L. (2020). Genetics of the estuarine copepod Eurytemora affinis with regard to improving water quality. Est., Coast. and Shelf Sci. 246: 107037. https://dx.doi.org/10.1016/j.ecss.2020.107037
  • Van Putte, N.; Temmerman, S.; Verreydt, G.; Seuntjens, P.; Maris, T.; Heyndrickx, M.; Boone, M.; Joris, I.; Meire, P. (2020). Groundwater dynamics in a restored tidal marsh are limited by historical soil compaction. Est., Coast. and Shelf Sci. 244: 106101. https://dx.doi.org/10.1016/j.ecss.2019.02.006
  • Cox, T.J.S.; Maris, T.; van Engeland, T.; Soetaert, K.; Meire, P. (2019). Critical transitions in suspended sediment dynamics in a temperate meso-tidal estuary. NPG Scientific Reports 9(1): 10 pp. https://dx.doi.org/10.1038/s41598-019-48978-5
  • Oosterlee, L.; Cox, T.J.S.; Vandenbruwaene, W.; Maris, T.; Temmerman, S.; Meire, P. (2018). Tidal marsh restoration design affects feedbacks between inundation and elevation change. Est. Coast. 41(3): 613-625. https://dx.doi.org/10.1007/s12237-017-0314-2
  • Geerts, L.; Cox, T.J.S.; Maris, T.; Wolfstein, K.; Meire, P.; Soetaert, K. (2017). Substrate origin and morphology differentially determine oxygen dynamics in two major European estuaries, the Elbe and the Schelde. Est., Coast. and Shelf Sci. 191: 157-170. https://dx.doi.org/10.1016/j.ecss.2017.04.009 
  • Le Coz, M.; Chambord, S.; Meire, P.; Maris, T.; Azémar, F.; Ovaert, J.; Buffan-Dubau, E.; Kromkamp, J.C.; Sossou, A.C.; Prygiel, J.; Spronk, G.; Lamothe, S.; Ouddane, B.; Rabodonirina, S.; Net, S.; Dumoulin, D.; Peene, J.; Souissi, S.; Tackx, M.; Sossou, A.C. (2017). Test of some ecological concepts on the longitudinal distribution of zooplankton along a lowland water course. Hydrobiologia 802(1): 175–198. https://dx.doi.org/10.1007/s10750-017-3256-6
  • Chambord, S.; Maris, T.; Colas, F.; van Engeland, T.; Sossou, A.-C.; Azémar, F.; Le Coz, M.; Cox, T.; Buisson, L.; Souissi, S.; Meire, P.; Tackx, M. (2016). Mesozooplankton affinities in a recovering freshwater estuary. Est., Coast. and Shelf Sci. 177: 47-59. http://dx.doi.org/10.1016/j.ecss.2016.04.016
  • Cox, T.J.S.; Maris, T.; Soetaert, K.; Kromkamp, J.C.; Meire, P.; Meysman, F.J.R. (2015). Estimating primary production from oxygen time series: A novel approach in the frequency domain. Limnol. Oceanogr., Methods 13(10): 529-552. http://dx.doi.org/10.1002/lom3.10046 
  • Jacobs, S.; Wolfstein, K.; Vandenbruwaene, W.; Vrebos, D.; Beauchard, O.; Maris, T.; Meire, P. (2015). Detecting ecosystem service trade-offs and synergies: a practice-oriented application in four industrialized estuaries. Ecosystem Services 16: 378-389. http://dx.doi.org/10.1016/j.ecoser.2014.10.006 
  • Gasmi, S.; Ferval, M.; Pelissier, C.; D'Amico, F.; Maris, T.; Tackx, M.; Legal, L. (2014). Genetic diversity among the Eurytemora affinis species complex in the Scheldt estuary and its tributaries using ISSR-PCR marker assay. Est., Coast. and Shelf Sci. 145: 22-30. http://dx.doi.org/10.1016/j.ecss.2014.04.005 
  • Korsman, J.C.; Schipper, A.M.; de Hoop, L.; Mialet, B.; Maris, T.; Tackx, M.L.M.; Hendriks, A.J. (2014). Modeling the impacts of multiple environmental stress factors on estuarine copepod populations. Environ. Sci. Technol. 48(10): 5709–5717. http://dx.doi.org/10.1021/es5004439 
  • Teuchies, J.; Vandenbruwaene, W.; Carpentier, R.; Bervoets, L.; Temmerman, S.; Chen, W.; Maris, T.; Cox, T.J.S.; Van Braeckel, A.; Meire, P. (2013). Estuaries as filters: The role of tidal marshes in trace metal removal. PLoS One 8(8): e70381. http://dx.doi.org/10.1371/journal.pone.0070381
  • Beauchard, O.; Jacobs, S.; Cox, T.J.S.; Maris, T.; Vrebos, D.; van Braeckel, A.; Meire, P. (2011). A new technique for tidal habitat restoration: Evaluation of its hydrological potentials. Ecol. Eng. 37(11): 1849-1858. http://dx.doi.org/10.1016/j.ecoleng.2011.06.010 
  • Mialet, B.; Gouzou, J.; Azémar, F.; Maris, T.; Sossou, C.; Toumi, N.; Van Damme, S.; Meire, P.; Tackx, M. (2011). Response of zooplankton to improving water quality in the Scheldt estuary (Belgium). Est., Coast. and Shelf Sci. 93(1): 47-57. http://dx.doi.org/10.1016/j.ecss.2011.03.015 
  • Vandenbruwaene, W.; Maris, T.; Cox, T.J.S.; Cahoon, D.R.; Meire, P.; Temmerman, S. (2011). Sedimentation and response to sea-level rise of a restored marsh with reduced tidal exchange: Comparison with a natural tidal marsh. Geomorphology (Amst.) 130(3-4): 115-126. https://dx.doi.org/10.1016/j.geomorph.2011.03.004
  • Azemar, F.; Maris, T.; Mialet, B.; Segers, H.; Van Damme, S.; Meire, P.; Tackx, M. (2010). Rotifers in the Schelde estuary (Belgium): a test of taxonomic relevance. J. Plankton Res. 32(7): 981-997. http://dx.doi.org/10.1093/plankt/fbq030
  • Mialet, B.; Azémar, F.; Maris, T.; Sossou, C.; Ruiz, P.; Lionard, M.; Van Damme, S.; Lecerf, A.; Muylaert, K.; Toumi, N.; Meire, P.; Tackx, M. (2010). Spatial spring distribution of the copepod Eurytemora affinis (Copepoda, Calanoida) in a restoring estuary, the Scheldt (Belgium). Est., Coast. and Shelf Sci. 88(1): 116-124. http://dx.doi.org/10.1016/j.ecss.2010.03.018
  • Cox, T.J.S.; Maris, T.; Soetaert, K.; Conley, D.J.; Van Damme, S.; Meire, P.; Middelburg, J.J.; Vos, M.; Struyf, E. (2009). A macro-tidal freshwater ecosystem recovering from hypereutrophication: the Schelde case study. Biogeosciences 6(12): 2935-2948. https://www.vliz.be/nl/imis?module=ref&refid=143698 
  • Jacobs, S.; Beauchard, O.; Struyf, E.; Cox, T.J.S.; Maris, T.; Meire, P. (2009). Restoration of tidal freshwater vegetation using controlled reduced tide (CRT) along the Schelde Estuary (Belgium). Est., Coast. and Shelf Sci. 85(3): 368-376. http://dx.doi.org/10.1016/j.ecss.2009.09.004 
  • Jacobs, S.; Struyf, E.; Maris, T.; Meire, P. (2008). Spatiotemporal aspects of silica buffering in restored tidal marshes. Est., Coast. and Shelf Sci. 80(1): 42-52. dx.doi.org/10.1016/j.ecss.2008.07.003, meer
    Lionard, M.; Muylaert, K.; Hanoutti, A.; Maris, T.; Tackx, M.; Vyverman, W. (2008). Inter-annual variability in phytoplankton summer blooms in the freshwater tidal reaches of the Schelde estuary (Belgium). Est., Coast. and Shelf Sci. 79(4): 694-700. http://dx.doi.org/10.1016/j.ecss.2008.06.013
  • Maris, T.; Cox, T.; Temmerman, S.; De Vleeschauwer, P.; Van Damme, S.; De Mulder, T.; Van den Bergh, E.; Meire, P. (2007). Tuning the tide: creating ecological conditions for tidal marsh development in a flood control area. Hydrobiologia 588(1): 31-43. https://dx.doi.org/10.1007/s10750-007-0650-5
  • Cox, T.; Maris, T.; De Vleeschauwer, P.; De Mulder, T.; Soetaert, K.; Meire, P. (2006). Flood control areas as an opportunity to restore estuarine habitat. Ecol. Eng. 28(1): 55-63, https://www.vliz.be/nl/imis?module=ref&refid=109881 
  • Soetaert, K.; Middelburg, J.J.; Heip, C.H.R.; Meire, P.; Van Damme, S.; Maris, T. (2006). Long-term change in dissolved inorganic nutrients in the heterotrophic Scheldt estuary (Belgium, The Netherlands). Limnol. Oceanogr. 51(1): 409-423. http://dx.doi.org/10.4319/lo.2006.51.1_part_2.0409
  • Meire, P.; Ysebaert, T.J.; Van Damme, S.; Van den Bergh, E.; Maris, T.; Struyf, E. (2005). The Scheldt estuary: a description of a changing ecosystem. Hydrobiologia 540(1-3): 1-11. https://dx.doi.org/10.1007/s10750-005-0896-8
  • Van Damme, S.; Struyf, E.; Maris, T.; Ysebaert, T.J.; Dehairs, F.A.; Tackx, M.; Heip, C.H.R.; Meire, P. (2005). Spatial and temporal patterns of water quality along the estuarine salinity gradient of the Scheldt estuary (Belgium and The Netherlands): results of an integrated monitoring approach. Hydrobiologia 540(1-3): 29-45. https://dx.doi.org/10.1007/s10750-004-7102-2
Best solutions I have found

We have increasingly adopted drones to map vegetation, which has made this task considerably faster and less labor-intensive compared to the traditional manual field surveys. This innovation allows us to cover larger areas in less time and to collect more consistent data. At the same time, ground truthing in the field remains indispensable to validate drone-based observations, to capture ecological nuances, and to maintain the researcher’s direct connection with the ecosystem. In this way, technology supports and complements, rather than replaces, our fieldwork.

 

Acknowledgements & Links

Funding by Sigmaplan (funded by DVW and ANB).

For more information see https://www.sigmaplan.be/en. 

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