Marjolijn Christianen

How does ecosystem functioning change now megaherbivores are returning? In our new paper today in Global Change Biology  we show that the return of the green turtle has strong effects on seagrass ecosystem functions and can even reduce multifunctionality with ~25%. Read the short & simple summary below. 

Continue reading “Seagrass ecosystem multifunctionality under the rise of a flagship marine megaherbivore”

— Update, Sept 2022 — The documentary won the “Gouden Hert” competition 2022 at the International Short Films Festival in Arnhem.

In 2021 I was happy to be involved in the making of a documentary with Artist Mirthe Dokter, together with Rian van den Boom and others.

This unconventional docu shows an intriguing portrait of the leatherback sea turtle, threatened with extinction. In Ghana, artist Mirthe meets ‘Uncle Raf’, the leader of a turtle conservationists team in a small fishing town. Slowly, she gets entangled in the web of all the difficulties that come with protecting this ancient animal. Virtual artists Mirthe records her story in a painted diary, that she shares with a marine ecologist, Marjolijn, from the Netherlands.

Continue reading “Documentary ‘Leatherback’”

Seagrass and Mangroves on Bonaire can use a helping hand. Water quality, tourists (trampling), Sargassum tides and more, have caused rapid decline of seagrasses and mangroves. Based on results from an earlier pilot, last week we launched a larger scale seagrass restoration project to help counter this decline. And also set up pilots to test the use of a new method for mangrove restoration alongside other ongoing methods. We used biodegradable mats that need only a little amount of donor material. The structure of these mats stabilize the sediment for the young plants to facilitate settlement, mimicking the natural effect of nature root mats.

Continue reading “Restoring Bonaire’s seagrasses and mangroves a checkerboard at a time”

One grazer is not like another. Where sea turtle grazing gives way to invasive eelgrass, fish grazing has the opposite effect. “Protected areas with abundant native grazing fish may be more resistant to expansion of invasive eelgrass.

Continue reading “Fish can protect ecosystems from invasive seagrass”

WUR press release:

Seagrasses are important for our coastal protection, biodiversity and carbon sequestration. But contrary to popular belief, dense, waving seagrass meadows with long foliage are not necessarily more natural. In a new publication in Nature Ecology & Evolution, researchers from Wageningen University & Research and Radboud University argue for a more nuanced picture of natural seagrass meadows being dense vegetation interspersed with areas grazed by sea turtles. This calls for a change in our nature management practices.

Continue reading “Savannas of the sea: “Pristine seagrass meadows were often heavily grazed””

_{Coastal ecosystems are in rapid decline around the world. Restoring them is very expensive and is often unsuccessful. But together with an international team of researchers we discovered a way of increasing restoration success of salt marshes and seagrass meadows, using biodegradable mats. Our findings are just published in Nature Communications (22 July 2020)}

Continue reading “Can we improve coastal restoration by temporarily imitating nature? Yes we can!”