Newsletter 17 | 22 February 2019

Newsletter 17, 22 February 2019

We gladly present you a new Centre for Wetland Ecology (CWE) newsletter full of information concerning Wetland Ecology.

This newsletter will come to you twice per year to inform you about CWE symposia, STOWA activities and to announce other events and news.

Casper van Leeuwen (coordinator CWE)
Liesbeth Bakker (chair CWE)

Please e-mail us so we can spread news about any upcoming events, job offers, symposia, PhD defences or publications, either on our website, twitter or the next newsletter (released November 2018).

Newsletter contents

Upcoming events in the Netherlands

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  • The Netherlands Centre for Coastal Research organizes the NCK Annual conference, 22-23 March, Enkhuizen. More information.
  • Meeting ‘Meten aan vegetatie voor waterveiligheid bij waterkeringen’, 7 March, Wageningen. More information.
  • Symposium about microcontaminants in the water 'Al doende leren, al lerende doen', 8 March, Utrecht. More information.
  • Netherlands Ornithological Union congress, 8-10 March, Haren. More information.
  • Waterschapsdag 2019, 18 March, Den Haag. More information.

CWE Symposium

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Three upcoming CWE symposia in 2019
Registration (free) and more information on the CWE website.

Future of rivers and streams: ecology and restoration under global change
6 March 2019, Antwerp, Belgium

The aquatic environment is a very dynamic and complex metasystem that fulfills a large number of key services. It hosts an enormous diversity of plant and animal species, but is threatened by global change. The sustainable use, management and protection of the aquatic environment in all its diversity, is key to the success of a whole range of human activities and their long term sustainability. This CWE symposium lists present-day threats and opportunities in rivers, makes projections for the future and learns about 21st century river management.

Save the dates for two more upcoming symposia, more information soon:

Aquatic microbiomes: Impact in natural and man-made ecosystems
28 June 2019, Wageningen

Perspectives in Aquatic Ecology
Special CWE symposium for the retirement of Prof. dr. Ellen van Donk
10 October 2019, Wageningen

International conferences

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  • Symposium for European Freshwater Sciences (SEFS11), 30 June - 5 July, 2019, Zagreb, Croatia. More information.
  • XVII Congresso Brasileiro de Limnologia & 2 Congresso Ibero-americano de Limnologia, August 2019, Florianópolis, SC, Brazil More information.
  • 15th European Ecological Federation Congress: Embedding Ecology in Sustainable Development Goals, 29 July - 2 August, Lissbon, Portugal More information.
  • Meeting of the Ecological Society of America (ESA), 11-16 August 2019, Louisville, Kentucky, USA. More information.
  • Annual meeting of Ecological Society of Germany (GFÖ) 9 - 13 September 2019, Munster, Germany. More information.


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  • Merel Soons became Professor of Plant Dispersal Ecology & Conservation at the Faculty of Science. Prof. Soons is one of few scientists in the world specialised in the ecology and evolution of plant seed dispersal. Dispersal is becoming an increasingly important topic, as the ongoing modification of landscapes by humans is resulting in rapid alteration and fragmentation of plant and animal habitat. Soons also focuses on the application of scientific knowledge on plant dispersal and habitat fragmentation in nature conservation and restoration. More information.
  • Martina Vijver became professor of Ecotoxicology at Leiden University. Her research field is in Ecotoxicology. Obtaining realistic predictions and measurements of how existing and emerging chemical stressors potentially affect our natural environment and the organisms living therein is essential to provide the necessary tools to assess and mitigate ecosystem threats. More information.
  • There are upcoming elections for the waterboards in The Netherlands on the 20th of March. Read more on
  • There is a new movement called "Deltaplan for biodiversity in The Netherlands: changing loss of nature to recovery." A large number of knowledge institutes, agricultural representatives, companies and nature organizations recently teamed up with the shared aim to create more awareness for biodiversity loss in The Netherlands, which should lead to recovery of biodiversity. They invite the rest of the Netherlands to join. Read more on

Guest column: Aquatic plants and water quality

Liesbeth Bakker (NIOO-KNAW), Marloes van den Akker (RUN), Yvonne Kahlert (RUG) & Hui Jin (NIOO-KNAW)
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"The Marker Wadden is a large ecosystem restoration project, designed to improve the productivity of the Markermeer food web to the benefit of fish and water birds. The Marker Wadden form an archipelago of 5 islands, which are built with sediment from the Markermeer itself and emerged from the lake in 2016 and 2017. Starting from scratch, multiple partners of the Centre for Wetland Ecology are following the development of the Marker Wadden and its impact on the lake, including the project Nature in Production, a joint effort of Natuurmonumenten, the Netherlands Institute of Ecology (NIOO-KNAW), Radboud University and University of Groningen. The PhD students Marloes van den Akker (Radboud University), Yvonne Kahlert (University of Groningen) and Hui Jin (Netherlands Institute of Ecology (NIOO-KNAW)) spent the field season of 2018 on the Marker Wadden and give an update of the ecosystem developments."

Yvonne placed malaise traps on the Marker Wadden from mid-April through mid-August to study the abundance of insects – inspired by the insect decline study using similar methods. Furthermore, she placed transects with pitfall traps to collect the ground dwelling arthropods. In total she collected almost 1000 arthropod samples, which she is still sorting. Highlights so far: the Marker Wadden are a hotspot for insect abundance, of which >90% are chironomids – so the aquatic habitat fuels terrestrial productivity. The chironomids are likely local, as also in benthic samples there are many. Multiple ground beetles of the genus Bembidion were found that are typical of riverine habitats, the small beaches, for instance Bembidion velox. Furthermore, many Linphyiidae spiders were found and an explosion of ladybirds. Over the season the arthropod diversity is increasing and a lot of parasitic wasps were found that co-occur with their host fly species. The food web assembly progresses over the season, with particularly a high number of predators on land and a generally strong nutrient subsidy from the aquatic to the terrestrial habitat.

Left: Yvonne at work at one of the malaisetraps. Right: A close-up shows the huge amounts of chironomids – the non-stinging ones – that were present for most of the spring and summer.

Marloes studies the nutrient release from the Marker Wadden sediment that may stimulate ecosystem productivity, and how biota-water-sediment interactions influence this process. Originating as marine sediment from the Zuiderzee, the sediment with which the Marker Wadden are built consist of a mixture of marine clay, sand and some peat, which is very nutrient rich, as supported by the nutrient availability found in pore water extractions. As a result, Phragmites australis and Typha angustifolia, which are sown at Marker Wadden to jump-start reed marsh formation and prevent willow encroachment, are growing rapidly. This in turn is very attractive for grazing Greylag geese, hence at present, the Marker Wadden landscape is formed by an interaction between sediment, water level, plants and geese. This interaction does not only determine the vegetation development, but also soil subsidence, greenhouse gas emissions and food web assembly, which Marloes follows using exclosures and paired control plots.

Left: Starting from scratch: in May 2018 we planted reed in half of the exclosures and control plots on Marker Wadden. Right: in September 2018 the effect of grazing by Greylag geese was very visible: the reed grew fast, if protected from grazing.

The Marker Wadden part that emerges above the water level is most visible, but around the Marker Wadden a new underwater landscape has formed, with shallow parts among the islands and sheltered parts at the lee side, depending on the wind direction. Hui is measuring the response of the phytoplankton, zooplankton and benthic communities to these different habitats by comparing the shallow sheltered sites with the open water at the different exposed sites around Marker Wadden. He found that there is a strong increase in nutrient availability in the water among the islands, increasing phytoplankton abundance, but also phytoplankton quality as food source for zooplankton when considering its carbon: phosphorous ratio. This corresponds with high abundance of zooplankton, and in the sheltered sites which were still free of fish, huge Daphnia were found. There is strong sediment resuspension in the very shallow sites, but this seems favorable for the phytoplankton as the suspended sediment provides nutrients in the water column. Therefore the base of the food web seems to profit from the Marker Wadden so far, but the effect seems rather local at the moment and not to extent very far into the lake.

Left: Hui taking water samples. Right: Concentrated filtered zooplankton sample.

The findings of the PhD students are supported by an extremely productive breeding season of the common terns (up till 2500 breeding pairs) and avocet (200 breeding pairs) as reported by Jan van der Winden from his bird research supported by KIMA (the Knowledge and Innovation program Marker Wadden). Hence, the first year that all islands were present the restoration worked exactly as it was meant to be, by at least locally increasing the productivity of the food web, and a stimulation of the top of the food web, including the birds. Whether this is a first year effect, coincidence or will remain so for the coming years is to be seen and will be followed by the PhD students and other CWE partners.

Marker Wadden: a new wetland ecosystem in development.

PhD graduations

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  • Annieke Borst (RUN) 12 March 2019: "Food and furniture: disentangling trophic and non-trophic interactions within foundation species' communities"
  • Sven Teurlincx (NIOO-KNAW) 25 March 2019: "Connecting the ditches: a spatial perspective on biodiversity in Dutch polder landscapes"
  • Karen Brandenburg (NIOO-KNAW) expected 5 June 2019: "Harmful algal traits and bloom dynamics under climate change"
  • Antonella Petruzzella (NIOO-KNAW) expected 12 June 2019: "Biotic resistance to alien plant invasions in tropical and temperate freshwater ecosystems"


Recent key publications

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  • Bakker, E. S., Veen, C. G. F., Ter Heerdt, G. J. N., Huig, N., & Sarneel, J. M. (2018). High grazing pressure of geese threatens conservation and restoration of reed belts. Frontiers in Plant Science, 9, [1649].
  • Bakker, E.S. & Svenning, J.-C. (2018) Trophic rewilding: impact on ecosystems under global change. Philosophical Transactions of the Royal Society B: Biological Sciences, 373, 20170432.
  • Brinkmann, B.W., Vonk, J.A., van Beusekom, S.A.M., Ibanez, M., de Lucas Pardo, M.A., Noordhuis, R., Manders, E.M.M., Verspagen, J.M.H., & H.G. van der Geest (2018) Benthic hotspots in the pelagic zone: Light and phosphate availability alter aggregates of microalgae and suspended particles in a shallow turbid lake
  • de Baat, M.L., D.A. Bas, S.A.M. van Beusekom, S.T.J. Droge, F. van der Meer, M. de Vries, P.F.M. Verdonschot, M.H.S. Kraak (2018) Nationwide screening of surface water toxicity to algae. Science of the Total Environment 645:780-787
  • de Jager, M., Kaphingst, B., Janse, E.L., Buisman, R., Rinzema, S.G.T. & Soons, M.B. (2019) Seed size regulates plant dispersal distances in flowing water. Journal of Ecology, 107, 307-317.
  • dos Reis Oliveira, P.C., Kraak, M.H.S., van der Geest, H.G., Naranjo, S. & Verdonschot, P.F.M. (2018) Sediment composition mediated land use effects on lowland streams ecosystems. Science of the Total Environment, 631-632, 459-468.
  • Janssen, A.B.G., Janse, J.H., Beusen, A.H.W., Chang, M., Harrison, J.A., Huttunen, I., Kong, X., Rost, J., Teurlincx, S., Troost, T.A., van Wijk, D. & Mooij, W.M. (2019) How to model algal blooms in any lake on earth. Current Opinion in Environmental Sustainability, 36, 1-10.
  • Teurlincx, S., Kuiper, J.J., Hoevenaar, E.C.M., Lurling, M., Brederveld, R.J., Veraart, A.J., Janssen, A.B.G., Mooij, W.M. & de Senerpont Domis, L.N. (2019) Towards restoring urban waters: understanding the main pressures. Current Opinion in Environmental Sustainability, 36, 49-58.
  • Teurlincx, S., Heijboer, A., Veraart, A. J., Kowalchuk, G. A., & Declerck, S. A. J. (2018). Local functioning, landscape structuring: Drivers of soil microbial community structure and function in peatlands. Frontiers in Microbiology, 9, [2060].
  • Van Putte, N., Temmerman, S., Verreydt, G., Seuntjens, P., Maris, T., Heyndrickx, M., Boone, M., Joris, I. & Meire, P. (2019) Groundwater dynamics in a restored tidal marsh are limited by historical soil compaction. Estuarine, Coastal and Shelf Science.
  • van Zuidam, J.P., van Leeuwen, C.H.A., Bakker, E.S., Verhoeven, J.T.A., Ijff, S., Peeters, E.T.H.M., van Zuidam, B.G. & M.B. Soons (2019) Plant functional diversity and nutrient availability can improve restoration of floating fens via facilitation, complementarity and selection effects. Journal of Applied Ecology, 56, 235-245.
  • Zhang, P., van den Berg, R.F., van Leeuwen, C.H.A., Blonk, B.A. & Bakker, E.S. (2018) Aquatic omnivores shift their trophic position towards increased plant consumption as plant stoichiometry becomes more similar to their body stoichiometry. PLOS ONE, 13, e0204116.