Marjolijn J. A. Christianen

Marjolijn J. A. Christianen
Wageningen University & Research | WUR · Department of Aquatic Ecology and Water Quality Management

Dr

About

60
Publications
31,265
Reads
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2,050
Citations
Introduction
Associate Professor Marine Ecology @WUR, passionate about science & (marine) conservation issues, worked on various projects in Wadden Sea and >15 years in the tropics. PhD on sea turtle & seagrass ecology, Indonesia. Post-docs on food web research in the Wadden Sea, Sea turtle habitat connectivity in Caribbean, restoration of foundation species. Enjoys conducting large scale field experiment in challenging environments, avid diver & adventurer Check out my personal website: http://penyu.nl/
Additional affiliations
February 2013 - May 2015
University of Groningen
Position
  • PostDoc Position
January 2013 - present
Position
  • See my LinkedIn profile for a complete profile
October 2007 - October 2012
Radboud University
Position
  • PhD at Radboud Universiteit Nijmegen
Description
  • Fieldwork in East-Kalimantan, Indonesia

Publications

Publications (60)
Article
Full-text available
Marine protected areas (MPAs) are key tools for combatting the global overexploitation of endangered species. The prevailing paradigm is that MPAs are beneficial in helping to restore ecosystems to more 'natural' conditions. However, MPAs may have unintended negative effects when increasing densities of protected species exert destructive effects o...
Article
Full-text available
One of the most frequently quoted ecosystem services of seagrass meadows is their value for coastal protection. Many studies emphasize the role of above-ground shoots in attenuating waves, enhancing sedimentation and preventing erosion. This raises the question if short-leaved, low density (grazed) seagrass meadows with most of their biomass in bel...
Thesis
Full-text available
Despite their high economic and ecological value, seagrass meadows are experiencing chronic declining at a global scale (Waycott et al. 2009), predominantly due to eutrophication, high turbidity due to land use change, but also due to other factors such as mechanical disturbance (Short et al. 1996, Orth et al. 2006) and shifts in top-down controls...
Article
Fauna species living in seagrass meadows depend on different food sources, with seagrasses often being marginally important for higher trophic levels. To determine the food web of a mixed-species tropical seagrass meadow in Sulawesi, Indonesia, we analyzed the stable isotope (d 13 C and d 15 N) signatures of primary producers, particulate organic m...
Article
1. Populations of marine megaherbivores including green turtle (Chelonia mydas) have declined dramatically at a global scale as a result of overharvesting and habitat loss. This decline can be expected to also affect the tolerance of seagrass systems to coastal eutrophication. Until now, however, simultaneous effects of top–down control by megaherb...
Article
Full-text available
Worldwide, coastal ecosystems are rapidly degrading in quality and extent. While novel restoration designs include facilitation to enhance restoration success in stressful environments, they typically focus on a single life-stage, even though many organisms go through multiple life-stages accompanied by different bottlenecks. A new approach – life...
Article
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Pleistocene environmental changes are generally assumed to have dramatically affected species’ demography via changes in habitat availability, but this is challenging to investigate due to our limited knowledge of how Pleistocene ecosystems changed through time. Here, we tracked changes in shallow marine habitat availability resulting from Pleistoc...
Article
Full-text available
Coastal ecosystems provide vital ecosystem functions and services, but have been rapidly degrading due to human impacts. Restoration is increasingly considered key to reversing these losses, but is often unsuccessful. Recent work on seagrasses and salt marsh cordgrasses highlights that restoration yields can be greatly enhanced by temporarily mimic...
Article
Wetlands die worden gedomineerd door planten, zoals kwelderplanten, zeegras-sen en veenmossen, leveren belangrijke leefgebieden met een hoge biodiversiteit en veel belangrijke ecosysteemdiensten. Wereldwijd is het oppervlak van deze systemen afgelopen eeuw echter gehal-veerd door menselijke activiteiten zoals veranderd landgebruik, drainage of over...
Article
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Combining foreshore ecosystems like saltmarshes and mangroves with traditional hard engineering structures may offer a more sustainable solution to coastal protection than engineering structures alone. However, foreshore ecosystems, are rapidly degrading on a global scale due to human activities and climate change. Marsh-edges could be protected by...
Article
Full-text available
The success of invasive macrophytes can depend on local nutrient availability and consumer pressure, which may interact. We therefore experimentally investigated the interacting effects of nutrient (nitrogen and phosphorus) addition, the exclusion of large herbivorous fishes and mimicked grazing on the expansion rates of the invasive seagrass Halop...
Article
The occasional westward transport of warm water of the Agulhas Current, “Agulhas leakage”, around southern Africa has been suggested to facilitate tropical marine connectivity between the Atlantic and Indian oceans, but the “Agulhas leakage” hypothesis does not explain the signatures of eastward gene flow observed in many tropical marine fauna. We...
Article
Concerted conservation efforts have led to a remarkable recovery of multiple green turtle (Chelonia mydas) populations worldwide. The voracious feeding of these returning populations is radically transforming tropical seagrass habitats in ways that prompt a re-think of the reference state and management plans for seagrass meadows.
Data
Freely accessible field guide to improve and encourage determination and monitoring of the reproductive structures (flowers and fruits) of the dioecious seagrass species H. stipulacea, invasive in the Caribbean Sea. Link to accompanying paper: https://doi.org/10.1515/bot-2020-0046
Article
The dioecious seagrass species Halophila stip-ulacea reproduces mainly through fast clonal growth, underlying its invasive behavior. Here, we provide morphological evidence to show that the first findings of fruits in the Caribbean were misidentified. Consequently, H. stipulacea reproduction is likely still only asexual in the Caribbean. Therefore,...
Article
Full-text available
Mini-special over natuureiland Griend In het septembernummer van De Levende Natuur staat Griend in de schijnwerpers. De ongestoorde, centrale ligging in de Waddenzee, met hoogwatervluchtplaatsen en rondom foerageergronden, maakt van dit natuureiland een ideale stop-over voor trekvogels. In het broedseizoen broeden er bovendien 20 duizend paar kokme...
Article
Full-text available
Restoration is becoming a vital tool to counteract coastal ecosystem degradation. Modifying transplant designs of habitat-forming organisms from dispersed to clumped can amplify coastal restoration yields as it generates self-facilitation from emergent traits, i.e. traits not expressed by individuals or small clones, but that emerge in clumped indi...
Article
Full-text available
Seagrasses provide an important ecosystem service by creating a stable erosion‐resistant seabed that contributes to effective coastal protection. Variable morphologies and life history strategies, however, are likely to impact the sediment stabilisation capacity of different seagrass species. We question how opportunistic invasive species and incre...
Article
Full-text available
1. Vegetated marine and freshwater habitats are being increasingly lost around the world. Habitat restoration is a critical step for conserving these valuable habitats, but new approaches are needed to increase restoration success and ensure their survival. 2. We investigated interactions between plants and bivalves through a review and analysis of...
Article
Full-text available
Understanding the population composition and dynamics of migratory megafauna at key developmental habitats is critical for conservation and management. The present study investigated whether differential recovery of Caribbean green turtle (Chelonia mydas) rookeries influenced population composition at a major juvenile feeding ground in the southern...
Article
Increasing green turtle abundance will lead to increased grazing within seagrass habitats—ecosystems that are important for carbon sequestration and storage. However, it is not well understood how carbon dynamics in these ecosystems respond to grazing and whether a response differs among meadows or locations. We measured seagrass ecosystem metaboli...
Article
Full-text available
Increasing incubation temperatures may threaten the viability of sea turtle populations. We explored opportunities for decreasing incubation temperatures at a Caribbean rookery with extreme female-biased hatchling production. To investigate the effect of artificial shading, temperatures were measured under simple materials (white sheet, white sand,...
Article
Seagrass ecosystems are inherently dynamic, responding to environmental change across a range of scales. Habitat requirements of seagrass are well defined, but less is known about their ability to resist disturbance. Specific means of recovery after loss are particularly difficult to quantify. Here we assess the resistance and recovery capacity of...
Article
Full-text available
Food webs are an integral part of every ecosystem on the planet, yet understanding the mechanisms shaping these complex networks remains a major challenge. Recently, several studies suggested that non-trophic species interactions such as habitat modification and mutualisms can be important determinants of food web structure. However, it remains unc...
Article
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After being ecologically extinct for almost a century, the discovery of a shellfish reef with native European flat oysters (Ostrea edulis) in the Dutch coastal area of the North Sea by the authors of this study called for an extensive survey to better understand some of the key requirements for the return of the native oyster in coastal waters. We...
Article
Full-text available
1.Our knowledge of the functional role of large herbivores is rapidly expanding, and the impact of grazing on species co‐existence and non‐native species expansion has been studied across ecosystems. However, experimental data on large grazer impacts on plant invasion in aquatic ecosystems are lacking. 2.Since its introduction in 2002, the seagrass...
Technical Report
Full-text available
Native oyster restoration, North Sea, Ostrea edulisARK Nature and World Wildlife Fund Netherlands are working on shellfish bed restoration in the Haringvliet coastal zone (the so-called Voordelta). The project was started in 2016. Total project duration is at least 3 years. Results of 2017 monitoring and experiments are described in the current rep...
Article
Full-text available
The use of satellite systems and manned aircraft surveys for remote data collection has been shown to be transformative for sea turtle conservation and research by enabling the collection of data on turtles and their habitats over larger areas than can be achieved by surveys on foot or by boat. Unmanned aerial vehicles (UAVs) or drones are increasi...
Article
Full-text available
Seagrasses are hugely valuable to human life, but the global extent of seagrass meadows remains unclear. As evidence of their value, a United Nations program exists (http://data.unep-wcmc.org/datasets/7) to try and assess their distribution and there has been a call from 122 scientists across 28 countries for more work to manage, protect and monito...
Article
Knowledge on the role of seagrass leaf elements and in particular micronutrients and their ranges is limited. We present a global database, consisting of 1126 unique leaf values for ten elements, obtained from literature and unpublished data, spanning 25 different seagrass species from 28 countries. The overall order of average element values in se...
Article
Full-text available
The advent of Fastloc-GPS is helping to transform marine animal tracking by allowing the collection of high-quality location data for species that surface only briefly. We show how the improved location accuracy of Fastloc-GPS compared to Argos tracking is expected to lead to far more accurate home range estimates, particularly for animals moving o...
Article
Full-text available
The non-native seagrass species Halophila stipulacea has spread throughout the Eastern Caribbean since 2002, and could potentially impact the functioning of local seagrass ecosystems. Important characteristics for invasiveness, such as dispersal, recruitment and expansion of H. stipulacea at a local scale, are unknown. We assessed H. stipulacea exp...
Article
Full-text available
Coastal food webs can be supported by local benthic or pelagic primary producers and by the import of organic matter. Distinguishing between these energy sources is essential for our understanding of ecosystem functioning. However, the relative contribution of these components to the food web at the landscape scale is often unclear, as many studies...
Article
In conservation strategies of marine ecosystems, priority is given to habitat-structuring foundation species (e.g. seagrasses, mangroves and reef-building corals, shellfish) with the implicit goal to protect or restore associated communities and their interactions. However, the number and accuracy of community level metrics to measure the success o...
Article
Full-text available
The management of small rookeries is key to conserving the regional genetic diversity of marine turtle populations and requires knowledge on population connectivity between breeding and foraging areas. To elucidate the geographic scope of the populations of marine turtles breeding at Bonaire and Klein Bonaire (Caribbean Netherlands) we examined the...
Article
Full-text available
The diversity and structure of ecosystems has been found to depend both on trophic interactions in food webs and on other species interactions such as habitat modification and mutualism that form non-trophic interaction networks. However, quantification of the dependencies between these two main interaction networks has remained elusive. In this st...
Article
Full-text available
In many marine ecosystems, biodiversity critically depends on foundation species such as corals and seagrasses that engage in mutualistic interactions [1-3]. Concerns grow that environmental disruption of marine mutualisms exacerbates ecosystem degradation, with breakdown of the obligate coral mutualism ("coral bleaching") being an iconic example [...
Article
Conservation of seagrasses meadows is important, because these habitats are ecologically important and under threat. Monitoring and modelling are essential tools for assessing seagrass condition and potential threats, however there are many seagrass indicators to choose from, and differentiating between natural variability and declining conditions...
Technical Report
Full-text available
In dit document wordt verslag gedaan van de verschillende experimenten die gedaan zijn in het kader van het Waddenfonds project “Waddensleutels” in het Nederlandse deel van de Waddenzee (verderop in dit rapport aangeduid met ‘Waddenzee’). Dit onderzoeksproject is een samenwerking tussen Natuurmonumenten, Staatsbosbeheer, Rijksuniversiteit Groninge...
Article
Full-text available
Efforts to conserve globally declining herbivorous green sea turtles have resulted in promising growth of some populations. These trends could significantly impact critical ecosystem services provided by seagrass meadows on which turtles feed. Expanding turtle populations could improve seagrass ecosystem health by removing seagrass biomass and prev...
Article
Full-text available
From Bonaire, we here provide the first documented case of the green turtle feeding on the invasive seagrass, Halophila stipulacea, in the Caribbean. The seagrass is rapidly invading existing seagrass meadows and altering key foraging habitat of this endangered marine reptile throughout the eastern Caribbean. We expect that more records of green tu...
Technical Report
Full-text available
In this report we examined the proximate response of fish assemblages, queen conch, and sea turtles on H. stipulacea meadows in Lac Bay, Bonaire, Caribbean Netherlands. Here we primarily focused on the differences between the invasive species H. stipulacea and the principal species of native sea grass in Lac Bay, namely turtle grass Thalassia testu...
Data
Full-text available
In remote, tropical areas human influences increase, potentially threatening pristine seagrass systems. We aim (i) to provide a bench-mark for a near-pristine seagrass system in an archipelago in East Kalimantan, by quantifying a large spectrum of abiotic and biotic properties in seagrass meadows and (ii) to identify early warning indicators for ri...
Article
Full-text available
A new tunicate, Ascidia subterranea sp. nov., was found in burrows of the axiid crustacean Axiopsis serratifrons on De-rawan Island, Indonesia. It differs from other ascidians in its habitat as well as numerous morphological peculiarities which are described in detail. The shrimp Rostronia stylirostris Holthuis, 1952 was found inside A. subterranea...
Article
Full-text available
A new tunicate, Ascidia subterranea sp. nov., was found in burrows of the axiid crustacean Axiopsis serratifrons on De-rawan Island, Indonesia. It differs from other ascidians in its habitat as well as numerous morphological peculiarities which are described in detail. The shrimp Rostronia stylirostris Holthuis, 1952 was found inside A. subterranea...
Article
Full-text available
Land use changes in tropical regions such as deforestation, mining activities, and shrimp farming, not only affect freshwater and terrestrial ecosystems, but also have a strong impact on coastal marine ecosystems. The increased influx of sediments and nutrients affects these ecosystems in multiple ways. Seagrass meadows that line coastal marine eco...
Article
Seagrasses have declined at a global scale due to light reduction and toxicity events, caused by eutrophication and increased sediment loading. Although several studies have tested effects of light reduction and toxicants on seagrasses, there is at present no information available on their interacting effects. In a full-factorial 5-day laboratory e...
Article
In remote, tropical areas human influences increase, potentially threatening pristine seagrass systems. We aim (i) to provide a bench-mark for a near-pristine seagrass system in an archipelago in East Kalimantan, by quantifying a large spectrum of abiotic and biotic properties in seagrass meadows and (ii) to identify early warning indicators for ri...
Article
Full-text available
Motile fauna species in two mixed-species seagrass meadows with different canopy structure were studied on an uninhabited island in the Spermonde Archipelago, Sulawesi, Indonesia. The main focus of the study was to assess the edge effect and seasonal abundance of macrobenthic invertebrates. Fish and infauna densities were determined as well. Fauna...
Article
Full-text available
Pristine freshwater fens harbour many species of aquatic macroinver- tebrates. Effects of eutrophication and desiccation have strong negative impacts on macroinvertebrate assemblages. To restore degraded fens, the removal of accumulated organic sludge by dredging seems a neces- sary step. However, degraded fens may harbour relic populations of rare...
Article
Full-text available
There is a long-standing debate whether mangrove and seagrass habitats in the Indo-Pacific region function as nurseries for coral reef fishes. We studied the use of all major shallow-water habitat types by juvenile coral reef fish using visual census surveys at 4 islands along the Tanzanian coast (East Africa) and at the island of Grande Comoros (C...

Projects

Projects (7)
Project
In this project we aim to improve our understanding of the impact of herbivores as green turtles on the ecosystem services and resilience of Caribbean seagrass meadows
Project