I am a coastal community ecologist that work in the interphase between land and sea, and currently I focus on putting marine fish ecology on the scientific agenda in the Netherlands. Coastal fish has always been an integrated part of coastal and riverine economies, but the ecological knowledge of coastal fish in the Netherlands is seriously neglected. At the same time, coastal fish are experiencing increased threats by a strong emerging necessity to adapt and transform our coastlines and rivers, in response to global climate change. These are likely to compound the current already high pressures on coastal fish populations by creating even more impermeable barriers. This calls for urgent action and attention to how coastal fish are managed and affected by climate change and resulting infrastructure developments. The past years we have started to map fish distributions and describe their web of interactions along the Dutch coast. The coming years mechanistic experiments will reveal the function of fish communities for the Dutch coastline. Looking five-ten years forward, I aim to provide advice on how we can manage a coastline that is resilient both for humans and coastal biodiversity.

Understanding consequences of the global erosion of species for the integrity of the biosphere is one of the grand challenges for biological sciences in the 21st century. Biodiversity determines the function of ecological communities, including how they respond to major threats to human welfare such as climate change and nutrient loading. For more than two decades, the overall aim of my research has therefore been to understand how biodiversity loss (in the broad sense) affects the function and resilience of natural communities.

Current projects

The destruction of coastal fish communities through modification of our coastlines is one of the largest ecological catastrophes in northern Europe. Fish in the Wadden Sea is in dramatic decline. Especially threatened are those fish that migrate and use the Dutch coasts for part of their life-cycle and that are constrained by barriers such as seawalls and dams. My prioritized research goals are currently therefore to understand the importance of coastal habitats for fish, why coastal fish is in decline, and how fish in turn shape their own habitat and its wider ecosystem.

The swimway of fish

In a five year project on fish we explore how fish use the Wadden Sea during different parts of their life-cycle. We have two main targets: 1) to document the function of foreshore salt-marshes for fish; and 2) to experimentally test the function of small-scale reef structures for fish.

Salt-marshes: The Netherlands have battled the sea for centuries and provide a template for the engineering solution to safe-guard highly populated coastal areas from rising sea levels. The Dutch solution is tempting because it provide instant safety by constructing a hard land-sea border that protects us from marine intrusion. At the same time it is an ecological catastrophe, transforming multi-functional wetlands that provide a portal between fresh and salt, into an impermeable barrier of land. Here we explore the function of the leftover salt-marches for fish. These man-made marshes outside the sea-wall are mainly managed for grazing livestock and birds, and are traditionally not acknowledged as valuable for marine organisms. We show that these foreshore marshes lack important aspects of habitat variability that occur in natural marshes, but that they still are valuable for fish and need to be accounted for when designing management plans for the failing coastal fish ecosystem in the Netherlands.

Reef restoration: Many fish use hard substrate habitat types during their life cycle for different functions; such as for spawning grounds, nurseries, hunting areas, and shelter. Historically, the Wadden Sea was connected to a large inland marsh landscape and was composed of a diversity of hard substrate types, including sublittoral shellfish and tube worm reefs, rocks of different sizes (from glacial deposits of boulders to gravel), driftwood, and hardened peat. The benthic habitats have been impacted by bottom-contact fisheries, including direct harvest of the hard substrates themselves, as well as coastal development and dredging practices homogenizing the bottom substrate. Consequently, the presence of sublittoral hard structures have  decreased dramatically in the Wadden Sea compared to historic records. In this project we test effects of different types of reef restoration on the fish community.

The soundscape of marine organisms

In this project we explore the sounds of mobile marine organisms. We deploy hydrophones to document the underwater soundscape with the purpose of documenting spatial and temporal distribution of fish and marine mammals. Our research questions include: Can we use sound to monitor fish and seal communities and their behaviour? What are the migration calls of fish? What do porpoise do in the Wadden Sea?  

Other current interests

We are still highly active in research regarding indicators of boiodiversity change and the stickleback wave – see below.

Major research accomplishments so far

Biodiversity change: One of the large enigmas in biodiversity research is that the documented erosion of species globally, is not reflected by decreasing number of species in local monitoring data. Baffled by this phenomenon, I have together with internationally leading biodiversity researchers addressed the mechanics of biodiversity change.  In 2017, we showed that individual coastal systems across the globe actually have gained species the past 50 years on average (Elahi et al. 2017). This indicated that local and regional processes react on different time-scales to global change. While human induced changes cause extinctions globally, they initiate dynamic processes locally, leading to changes in species composition rather than a decrease in species numbers. In response to this we developed a new species turnover metric (SER) and showed that in nature, biodiversity change is uncoupled from species richness trends (Hillebrand et al. 2018). These discussions led to a personal invitation to write a perspective in Science magazine highlighting that earth currently experience a rapid and large scale reorganization of biodiversity (Eriksson and Hillebrand 2019).

Thus, a major challenge for biodiversity research right now, is to predict the complex consequences of rapid compositional changes and turnover of species. Another current issue is to understand the limits of species ability to compensate for change by reorganising individuals – i.e. what is the potential for immigrating populations (new species, populations with different traits or unique genes) to replace the function of other populations that go extinct? For example, there is a large fear that equatorial marine communities currently are becoming depauperate due to climate migration. Recently, we have contributed to this field by demonstrating that historic (Pleistocene) legacy limit the adaptive potential of a key marine habitat forming species to climate change, by limiting its genetic potential (Duffy et al. 2022).

Landscapes of facilitation: Today we know that regime shifts are typically caused by external “shocks” or gradually changing environmental conditions that exceed critical thresholds, but that some also involve critical transitions, where novel feedbacks propel the system from one self-reinforcing and persistent regime (or stable state) to another. All regime shifts are difficult to manage, but critical transitions pose particular challenges because of inherent difficulties in both predicting and reversing them. It is therefore critical to identify and quantify the importance of biological feedbacks to manage regime shifts. In a series of papers, we have demonstrated how intertidal shellfish systems are shaped by feedbacks that reinforce particular biological configurations (van der Zee et al. 2012,  Donadi et al. 2013, Koppel et al. 2015). Recently, we have shown how these facilitation processes shape an intertidal landscapes of mussels and their associated species (Andriana 2020, 2021, van der Ouderaa 2021).

The stickleback wave: Regime shifts are commonly deducted from simple time-series data that average across a larger system. The temporal-only perspective is limiting and represent spatially heterogeneous (natural) systems poorly, because theory predicts that in large ecosystems with environmental gradients, shifts should start locally and gradually spread through space. Thus, despite well-developed theory, many empirical examples, and implementation of critical transitions in European policy and management legislation; we are still far from understanding how to detect and manage regime shifts. By compiling a dataset with both a long temporal perspective and a high spatial resolution, we have been able to empirically document a spatially propagating shift in the trophic structure of a large aquatic ecosystem, from dominance of large predatory fish (perch, pike) to the small prey fish (the three-spined stickleback) (Eklöf et al. 2021). This shift has propagated like a slow moving wave through the system for the past 30 years. Mechanistic experiments and modelling also showed that the different “trophic states” were reinforced by strong biological feedbacks. Our results demonstrate the need to incorporate the spatial component in the monitoring of complex natural systems; to better predict, detect and confront regime shifts within large ecosystems.

Educating the new generation of fellow academics is the single most important task of the University. It is also one of the most inspiring journeys of my profession. I have developed a number of courses throughout the years; currently I coordinate one field-based course in benthic reseaqrch methodology on the Marine Biology Master Program (Principles of Marine Biology ) and one bachelor course in Conservation Biology. I also participate as a lecturer in the bachelor course in Marine Biology.

I also supervise a number of Master students in various projects. Currenly we maily have projects related to fish in salt-marches, the function of artificial reefs (for fish) and soundscapes of fish and marine mammals. For an exhaustive list of alumni studnts and their projects - see below.

Students working on Schiermonnkoog 2022 in the Master course Principles of Marine Biology

Break during excursion in Sweden 2022 in the Master course Principles of Marine Biology

Finished Master projects, essays and presentations in the Marine Ecology Group:

Lukas Verbom, 2021-22 (45 ECTS). Effects of two benthic ecosystem engineers on sediment communities in the intertidal Wadden Sea. Master research project. Main supervisor

Lily Meade, 2021-22 (40 ECTS). Comparing fish communities in the Dutch Wadden Sea across three systems. Master research project. Main supervisor

Nino van Hees, 2021-22 (40 ECTS). The Effects of Creek Morphology on Saltmarsh Fish Communities in the Dutch Wadden Sea. Master research project. Main supervisor

Ann-Christin Ziebell, 2021-22 (40 ECTS). The effect of livestock grazing on the fish community in Dutch salt marshes. Master research project. Main supervisor

Joost van der Laan, 2021-22 (40 ECTS). Migration pathway, estuary or both?. Master research project. Main supervisor

Kjell Ratajczak, 2021-22 (40 ECTS). Using lateral plate morphotype distributions of three-spine sticklebacks (Gasterosteus aculeatus) to assess changes in an artificial estuary in “Noarderleech”. Master research project. Main supervisor

Javier Alexis Vincente Diaz, 2020-21 (40 ECTS). Differences in environmental habitat and fish composition between the bays of Curaçao. Master research project. Main supervisor

Christina Marampouti, 2020-21 (35 ECTS). Long-term ecosystem changes and temporal dynamics of invasive species in a Mediterranean MPA  . 2nd research project. Main supervisor

Fenna de Vries, 2020-21 (5 ECTS). Managing marine invasive species: is action needed?. Master colloqium. Main supervisor

Bram Nieuwenhuis, 2020-21 (40 ECTS). Effectivity of an artificial migration pathway for Gasterosteus aculeatus. Master research project. Main supervisor

Nadine Bleile, 2019-20 (30 ECTS). Restoration of transition zones. Master research project. Main supervisor

Brid OConnor, 2019-20 (40 ECTS). Data Deficient and Threatened Elasmobranch Species of Zavora Bay, Mozambique. Master research project. Examiner

Marcos Suárez Menéndez, 2019-20 (5 ECTS). Iron limitation in the Antarctic Ocean and the whale pump hypothesis. Master essay. Main supervisor

Ilse Winkel, 2019-20 (40 ECTS). Rapportage over beheer van visfauna in de Nederlandse Waddenzee. Master research - M variant. Co-supervisor

Manon de Haan, 2019-20 (5 ECTS). Sentinels of the Arctic facing global warming. Master colloqium. Main supervisor

Fabris van der Zee, 2019-20 (5 ECTS). Pacific oyster, friend or foe. Master colloqium. Main supervisor

Susanne Bähr, 2019-20 (5 ECTS). ‘Overlooked Photosymbioses’ – A Review of Research exploring Bleaching in non-cnidarian Hosts of Photosymbionts. Master essay. Examiner

Mariana Cunha Chiti Parente, 2019-20 (5 ECTS). Monitoring of marine organisms on Maio Island, Cape Verde. Individual research assignment. Main supervisor

Christina Marampouti, 2019-20 (40 ECTS). Ems Estuary: Fish Monitoring and Food web Reconstruction. 1st research project. Main supervisor

Yasmine Gatt, 2019-20 (5 ECTS). Ecological Effects of Crassostrea gigas in the Wadden Sea. Master colloqium. Main supervisor

Sacha Koning, 2019-20 (40 ECTS). The Effect of Morphology of the Three-Spined Stickleback (Gasterosteus aculeatus) on Migration Inside a Novel Ecosystem in Noarderleech. Master research project. Main supervisor

Raven Cammenga, 2019-20 (40 ECTS). Aquatic Fauna in Noarderleech: A Study into Marine Fauna Communities present in the Salt Marsh of Noarderleech after Finalization of Project Vijfhuizen. Master research project. Main supervisor

Giulia Leone, 2018-19 (45 ECTS). Methodology for examining trophic transfer of microplastic from herrrings (Clupea harengus) and salmon (Salmo salar) to grey seal pups (Halichoerus grypus). Master research project. Co-supervisor

Daniella Crowley, 2018-19 (40 ECTS). Fucus vesiculosus as a facilitator on the Eastern Schiermonnikoog mussel bed. Master research project. Main supervisor

Eleanor Greenway, 2018-19 (45 ECTS). Diet Composition and Feeding Strategy of the Thornback Ray, Raja clavata, (Linnaeus 1758) in the North Sea. Master research project. Co-supervisor

Sorcha Passmore, 2018-19 (45 ECTS). Ecological effects of stickleback morphotype differentiation: predation on gammarids. Master research project. Main supervisor

Fiona Colgan Carey, 2018-19 (40 ECTS). What determines the distribution of stickleback morphotypes in the Baltic Sea. Master research project. Main supervisor

Sara Doolittle, 2018-19 (40 ECTS). Plastic as a vector for Marine Invasive species in the Galapagos archipelago. Master research project. Main supervisor

Jorn Classen, 2018-19 (50 ECTS). The Ecological Importance of Pools in the Mussel Bed. Master research project. Main supervisor

Miranka van Breugel, 2018-19 (30 ECTS). Elasmobranch assemblages of Aruba’s coastal waters, discovering shark diversity among the islands of the Dutch Caribbean. Master research project. Co-supervisor

Stephan van Dijk, 2018 (30 ECTS). The diet of the Antarctic squid Psychroteuthis glacialis. Master research project. Co-supervisor

Eeke Haanstra, 2018 (30 ECTS). Ecosystem effects of Marine Protected Areas in the Western Baltic Sea. Master research project. Main supervisor

Aoife O'Sullivan, 2018 (40 ECTS). Investigating the effects of grazer exclusion and nutrient enrichment on a seagrass community in Zanzibar. Master research project. Main supervisor

Sil Piek, 2018 (40 ECTS). The effects of Bonnaire's three different conservation reserves on fish communities and biomass. Master research project. Co-supervisor

Gabriela Maldonado, 2018 (5 ECTS). Microplastics in Marine Food-webs. Master colloqium. Main supervisor

Eeke Haanstra, 2017 (40 ECTS). Parasitism & the intertidal: direct and indirect effects of trematode infection on the Wadden Sea community. Master research project. Co-supervisor

Luna van der Loos, 2017 (5 ECTS). Beta diversity of macroalgal communities around St. Eustatius, Dutch Caribbean. Master research assignment - writing a paper. Main supervisor

Stephan van Dijk, 2017 (5 ECTS). The state of seagrass in the Dutch Wadden Sea. Master colloqium. Main supervisor

Aoife O'Sullivan, 2017 (40 ECTS). Human impacts on macroalgae in the Baltic Sea. Master research project. Main supervisor

Javi Alegra, 2017 (30 ECTS). Bloom dynamics and propagation of the dinoagellate Alexandrium. Master research project (2nd). Main supervisor

Lucía Irazábal González , 2017 (5 ECTS). Effects of turbidity on fish mate choice. Master colloqium. Main supervisor

Youk Greeve, 2017 (5 ECTS). The bioremedial potential of large-scale macroalgae cultivation in dutch coastal waters. Master colloqium. Main supervisor

Manasweni Kilnagar Swaminathan , 2017 (40 ECTS). Effect of Reef-forming mussels on the productivity of the microphytobenthos in the Dutch Wadden Sea. Master research project. Main supervisor

Nina Fieten, 2017 (40 ECTS). The Effect of Habitat Complexity of Zostera marina on Predation Intensity in Northern Norway. Master research project. Main supervisor

Javi Alegra, 2017 (40 ECTS). Mussel beds shape the intertidal by reducing hydrodynamic stress, which change the conditions for associated organisms and promote the abundances of sediment-living species.. Master research project. Main supervisor

Lucía Irazábal González , 2017 (40 ECTS). Comparison of plastic content in grey and harbour seals in the North Sea and Wadden Sea . Master research project. Main supervisor

Youk Greeve, 2017 (35 ECTS). The Effect of Bivalve Ecosystem Engineers on the Meiobenthic Communities of the Wadden Sea. Master research project. Main supervisor

Aoife Osullivan, 2017 (5 ECTS). Trait based approaches for marine management. Does it work?. Master colloqium. Main supervisor

Marelle van der Snoek, 2017 (30 ECTS). Assessment of the artisanal hand line fisheries in Cape Verde. Master research project. Main supervisor

Joppe Visser, 2017 (40 ECTS). The possible effects of small scale structure (habitat choice) on the distribution of the different morphotypes of the three-spined stickleback (Gasterosteus aculeatus).. Master research project. Main supervisor

Jesse Jorna, 2017 (5 ECTS). The effect of climate change on pelagic macropredators in the arctic Bering- and Barents Sea.. Master scriptie. Main supervisor

Marelle van der Snoek, 2017 (5 ECTS). Artificial Reefs: Setting goals and gaining success. Master colloqium. Main supervisor

Sandra Strigel, 2016 (5 ECTS). In what ways can corals acclimatize or adapt to climate change?. Master colloqium. Main supervisor

David Swieringa, 2016 (40 ECTS). Seasonal Occurence, spatial variation, and anatomical differences in acorn barnacles. Master research project. Main supervisor

Sarah Bedolfe, 2016 (5 ECTS). If you can’t beat them, should you eat them? The Dutch fishery for invasive crayfish. Master Colloqium. Main supervisor

Luna van der Loos, 2016 (40 ECTS). Macroalgal communities around the tropical island of St. Eustatius. Master research project. Main supervisor

Sarah Bedolfe, 2016 (40 ECTS). Effects of invasive copepods on native blue mussles. Master research project. Co-supervisor

Michiel van Harten, 2016 (50 ECTS). Predation by Mnemiopsis leydi on bivalve veligers. Master research project. Main supervisor

Jildou Schotanus, 2015 (5 ECTS). Restoration of Mussel beds. Master colloqium. Co-supervisor

Karine Kirgosian, 2015 (40 ECTS). Chubby and chic, or lean and mean. Master research project. Main supervisor

Pim Boute, 2015 (5 ECTS). What is the impact of marine protected areas on finfish stocks. Master colloqium. Main supervisor

Stijn den Haan, 2015 (40 ECTS). Genetic diversity and ecological consequences: a global comparison of Zostera marina meadows. Master research project. Main supervisor

Javi Alegra, 2015 (10 ECTS). Humpback whales in the breeding grounds of Maio (Cape Verde). Master research project. Main supervisor

Floor Driessen, 2015 (30 ECTS). Opportunities to develop the Living North Sea Initiative. Master research - M variant. Beta supervisor

Anne Ausems, 2015 (5 ECTS). The human side of MPA's. Master colloqium. Main supervisor

Arjen Tilstra, 2015 (5 ECTS). Testing the bleaching resistance hypothesis: Genotype-specific response in the
scleractinian coral Stylophora pistillata. Master research. Main supervisor

Leonie Huiser, 2015 (40 ECTS). Coda repertoairs in sperm whales. Master research project. Main supervisor

Marelle van der Snoek, 2015 (40 ECTS). Effects of heat-waves on the production of diatoms. Master research project. Main supervisor

Sarah Bedolfe, 2015 (40 ECTS). Heat-waves decrease production in benthic diatoms. Master research project. Main supervisor

Marelle van der Snoek, 2015 (10 ECTS). Trophic cascades in the Baltic Sea. Master research project. Main supervisor

Nieck Kromkamp, 2015 (5 ECTS). Fishing and eutrophication. Master colloqium. Main supervisor

Marin van Regteren, 2014 (40 ECTS). The role of predation on Gammarus amphipods. Master research project. Main supervisor

Arjen Tilstra, 2014 (50 ECTS). Genotype-specific response to elevated temperatures of different light adapted colonies of the scleractinian coral Stylophora pistillata. Master research project. Main supervisor

Reinier Nauta, 2014 (50 ECTS). Parasites in Mylisus edulis of the Wadden Sea. Master research project. Co-supervisor

Anne Marie Jellema, 2014 (40 ECTS). Vooruitzichten na het IMP Eems-Dollard. Master research - M variant. Beta supervisor

Reinier Nauta, 2014 (10 ECTS). Artificial induction of sori in kelp species. Master research project. Co-supervisor

Jarco Havermans, 2014 (40 ECTS). Condition of mussels under different oyster densities. Insights for management of hand-fishing for Pacific oysters. Master research - M variant. Beta supervisor

Jelle Loonstra, 2014 (5 ECTS). The potential effect of human activities on the brown shrimp (Crangon crangon L.) in the Wadden Sea. Master scriptie. Main supervisor

Vera Caruso, 2014 (40 ECTS). Joint effects of temperature and dispersal on diatom communities. Master research project. Main supervisor

Angeliki Paspati, 2014 (5 ECTS). Gene expression as a tool in ecotoxicology. Master scriptie. Main supervisor

Marin van Regteren, 2013 (40 ECTS). Effects of trematode parasites on burrowing ability and winter. Master research project. Co-supervisor

Mike van het Land, 2013 (40 ECTS). Macroalgae as a physical barrier for sea lice: A way to promote integrated aquaculture?. Master research project. Main supervisor

Marin van Regteren, 2014 (6 ECTS). Distribution of reproductive modes in Aptinothrips species in the western Swiss Alps. Master research project. Co-supervisor

Audrey van Mastrigt, 2013 (40 ECTS). Fishery co-management; a sustainable management a sustainable way to develop fisheries: A multi-disciplinary assessment of the fisheries in Lake Vättern, Sweden.. Master research - M variant. Co-supervisor

AM Wallert, 2013 (5 ECTS). The Function of Biodiversity. Master scriptie. Main supervisor

Pablo de Vries, 2013 (40 ECTS). A short heat wave causes a shift in bacterial composition in Stauroneis constricta monocultures. Master research project. Main supervisor

Tom Wijers, 2013 (5 ECTS). The effect of salmon farming on wild salmon. Master scriptie. Main supervisor

Sophie Vergouwen, 2012 (5 ECTS). Sea Ice Melt effects on food web dynamics in the Arctic. Master scriptie. Main supervisor

Clare Divine, 2012 (40 ECTS). The effect of ecosystem engineers on functional composition of the soft-bottom intertidal community. Master research project. Main supervisor

Linda Planthof, 2012 (40 ECTS). Conditional facilitation and inhibition by ecosystem engineers on the tidal flats. Master research project. Main supervisor

JG Nijboer, 2012 (5 ECTS). The importance of shallow waters and mangrove forests for commercial fisheries. Master scriptie. Main supervisor

JG Nijboer, 2012 (1 ECTS). Using functional groups in Ecology. Master scriptie. Main supervisor

Ellen Duister, 2012 (30 ECTS). From vision to reality: The road towards a healthy ecosystem. Master research - M variant. Co-supervisor

Marieke van Woensel, 2012 (40 ECTS). Does shrimp affect the competition between oyster and mussel larvae. Master research project. Co-supervisor

Myra Boers, 2012 (30 ECTS). Ecosystem engineers on the Dutch mudflat: The effect on colonization and biodiversity of macrobenthos. Master research project. Main supervisor

Wouter Koch, 2011 (10 ECTS). Inventory of parasitic copepods and their hosts in the Western Wadden Sea in 1968 and 2010. Master research project. Co-supervisor

Linda Franken, 2011 (6 ECTS). Seals- Fisheries: A review of Operational and Biological interactions. Master essay. Main supervisor.

Marlijn de Grraf, 2011 (5 ECTS). The function of mangroove forests and shrimp farms. Master essay. Main supervisor.

Sietske van der Wal, 2011 (6 ECTS). The lionfish (Pterois volitans) - an invasive species in the Caribbean. Master colloqium. Co-supervisor.

Vincent Boer, 2011 (6 ECTS). Impact of Dredging Events on soft-bottoms. Master colloqium. Main supervisor.

Ellen Duister, 2011 (5 ECTS). Marine Spatial Planning. Master colloqium. Main supervisor.

Mike van het Land, 2011 (5 ECTS). MPAs as fishery management tools. Master colloqium. Main supervisor.

Dieuwke Hoeijmakers, 2011 (5 ECTS). Interlinked ecosystems: Ontogenetic habitat migration of reef fishes. Master colloqium. Main supervisor.

Marc Bartelds, 2011 (40 ECTS). How does cockle hand-raking affect sediment properties and non-target species in the Dutch Wadden Sea? Master research project. Main supervisor.

Udhi Hernawan, 2011 (35 ECTS). Intertidal mussel beds have long range effects on macrofauna by modifying hydrodynamic conditions. Master research project. Main supervisor.

Joelle Weenstra, 2011 (30 ECTS). Nutrient effects on microphytobenthos in the Wadden Sea. Main supervisor

Bastiaan Groot, 2011 (30 ECTS). Cascading effects of top predator decline on primary producers in a benthic Baltic Sea food web. Main supervisor

Imke van Gerwen, 2011 (40 ECTS). Interactive effects of eutrophication and ecosystem engineers on sediment properties of mudflats in the Dutch Wadden Sea. Master research project. Main supervisor.

Mica Herriot, 2011 (30 ECTS). Comparing effects of fish density and diversity on prey consumption in a coastal food web in the Baltic Sea. Master research project. Main supervisor.

Christiaan van Sluis, 2011 (30 ECTS). Plant biomass, not diversity controls primary productivity and spider abundance on a salt marsh. Master research project. Co-supervisor.

Lodewijk van Walraven, 2010 (8 ECTS). Effects of climate change on migration patterns between the North and Wadden Sea. Master essay. Main supervisor.

Franziska Stuke, 2010 (5 ECTS). The interaction between eutrophication and fishing in the Baltic Sea. Master colloqium. Main supervisor.

Libby Kochen, 2010 (6 ECTS). Wadden Sea Food-webs. Master colloqium. Main supervisor.

Thea Vries, 2010 (5 ECTS). The diversity stability debate. Master colloqium. Main supervisor.

Anouk Goedknegt, 2010 (5 ECTS). Seagrass: How we lost it and how to get it back. Master colloqium. Main supervisor.

Merlijn de Graaf, 2010 (10 ECTS). The effect of toxins on the development of Sole. Master research project. Co-supervisor.

Adriana Alzate, 2010 (35 ECTS). The influence of food distribution on mudsnail (Hydrobia ulvae) movement strategy. Master research project. Co-supervisor.

Alexandra Kausch, 2010 (44 ECTS). Effects of different mesopredator species on the invertebrate grazer community in the Baltic Sea. Master research project. Main supervisor.

Franziska Stuke, 2010 (38 ECTS). Policy regulation of eutrophication in the German Baltic Sea The European Framework Directives and the Baltic Sea Action Plan in focus. Master research project. Main supervisor.

Renee Koper, 2009 (6 ECTS). Parasites as an Indicator of marine Pollution. Master essay. Main supervisor.

Arno Kangeri, 2009 (6 ECTS). Effects of man-made structures on the marine life. Master essay. Main supervisor.

Joop Collem, 2009 (6 ECTS). Off shore mussel faring and Natura 2000. Master colloqium. Main supervisor.

Inge van den Beld, 2009  (5 ECTS). Working with GIS. Master research project. Co-supervisor.

Frederike Tirre, 2009 (16 ECTS). Mesopredator release effects on a coastal food web. Master research project. Main supervisor.

Christian van Sluis, 2009 (40 ECTS). Effects of an omnivore shrimp on trophic cascades in a Baltic food-web. Master research project. Main supervisor.

Anneke Rippen, 2009 (38 ECTS). Joint effects of declining top-predators and increasing nutrient levels on the composition of invertebrate grazer communities in the coastal Baltic Sea. Master research project. Main supervisor.

Anne Vos, 2008 (6 ECTS). Sustainability of marine fish farming. Master colloqium. Main supervisor.

Barbara van Genne, 2008 (24 ECTS). The effect of different currencies of eveness and diversity for environmental stress gradients. Master research project. Main supervisor.

Jurgen Batsleer, 2008 (24 ECTS). The effects of nutrients vs predation in the Baltic Sea food-web. Master research project. Main supervisor.

Hyugen van Steen, 2008 (18 ECTS). Predation effects on invertebrate grazer commuities in the Baltic Sea. Master research project. Main supervisor.

Barbara van Genne, 2008 (38 ECTS). Community richness in different trophic levels over environmental stress gradients. Master research project. Co-supervisor.

Judith Brauwer, 2008 (38 ECTS). Biodiversity and productivity of benthic algae on the mud flat of the Wadden Sea. Master research project. Main supervisor.

Joop Collem, 2008 (38 ECTS) Vindparken in de Noordzee. Effecten op vis and bodemfauna. Master research project. Main supervisor.

Jurgen Batsleer, 2007 (12 ECTS). Cascade effects by the loss of apex predators in the marine environment. Master essay. Main supervisor.

Peter Mulder, 2007 (6 ECTS). Comparison between ecological indicators of fresh and marine ecosystems. Master essay. Main supervisor.