In this new post, Clea van de Ven—a PhD candidate at the Royal Netherlands Institute for Sea Research—presents her recently published article ‘Establishing cordgrass plants cluster their shoots to avoid ecosystem engineering’. She presents her experience conducting ecological research in European shores, encourages us to dig into salt marshes, and shares the joy behind coincidences in life.

On March 1^st, 2019, I first entered the Royal Netherlands Institute for Sea Research as an employee. I was starting a PhD in coastal ecology in the group of Valérie Reijers and Tjisse van der Heide, and couldn’t be more excited about working at an institute located right next to sea. Arriving to Texel by boat was (back then) still wildly exotic. On the first day, I met Carlijn Lammers who had also just started and would become a great office mate and partner in crime for experiments and field work. Together with Valérie and Carlijn, we visited 18 salt marshes and 9 dune areas in northwestern Europe. This all happened in the summer of 2019, while travelling in a campervan.

Coastal vegetated ecosystems, like dunes and salt marshes, are shaped by grasses that improve their own growing conditions by trapping and stabilizing sediment particles with their canopies. It is these grasses that create the first buffer from seaborne storms and floods and form an entire ecosystem with their presence.

Shoots are made for walking

Clonal grasses can influence habitat engineering via particle trapping with the positions of their shoots. Below the surface, shoots are connected by rhizomes that can grow into new shoots. Through this method, grass can clonally increase in size and the position of shoots directly result from the ‘rhizomal steps’ that plants take.

Imagine for a moment growing on a salt marsh—a muddy swamp that is swallowed by the sea during high tide, where waves and currents can reach you. Growing your shoots closely together may hypothetically increase your chance to trap and stabilize sediment, but you also increase resistance to the water flow. This means trouble, as the obstructed water will find a way along your edges where it accelerates and causes erosion. With your roots now half out of the sediment, you are close to being dislodged and lost. This is a serious risk for young grasses in the salt marsh, compared to grasses growing higher and drier on the beach or dunes. How do grasses balance growth, sediment capture and risk?

Better safe than sorry

The answer to this question is now published in two articles, one discussing dunes and one discussing salt marshes. In short, we compared if grasses in harsh environments had different shoot organizations compared to sheltered areas. We found that some dune grasses change their shoot positions depending on the environment. However, to our surprise, young cordgrass plants growing in the salt marsh, always showed the same clustered pattern. With a follow-up experiment we were able to understand why this occurred: salt marsh plants always follow a stress avoiding shoot pattern, even in ‘good’ conditions. Our results highlight that young plants initially minimize their engineering effect to avoid physical stress, instead of aiming to immediately try to modify the environment to their own benefit.

Coincidence or not?

The trajectories of the articles since submission to different journals was completely different (one was rejected twice on the desk of editors). So, what a coincidence that, after nearly four years of work, both papers were published on the exact same day! We are very happy that they are out and public and thank all co-authors and reviewers.

These results help us understand how plant characteristics interact with their environment. Knowing how plants facilitate their own growth can help us to improve restoration practices.

About the author

I am currently a PhD student at the Royal Netherlands Institute for Sea Research (NIOZ) and I am generally just an absolute ocean enthusiast! I enjoy swimming, diving, snorkeling, and surfing when possible!

Enjoyed the blogpost? Read the research here!