Plants play dominant role in landscape formation of coastal areas

Introduction: Dutch and Flemish researchers studied the colonisation by coastal vegetation

Coastal vegetation interacts with water flow and the transport of sand and sediment: this interaction plays a key role in the rise of characteristic landscape forms in coastal habitats. Scientists from the University of Utrecht, the Netherlands Institute for Sea Research and University of Antwerp ( Global Change Ecology Centre , Research Group Ecosystem Management ) provide more insight in this interaction in their new paper that appeared recently. UAntwerp researchers Jim Van Belzen , Olivier Gourgue and Stijn Temmerman contributed to the study.

The new study shows that not only physical characteristics (root density, shoot thickness, plant size, …) are important. The colonisation ‘behaviour’ of the plants - the way the plants establish and proliferate - is playing an even more essential role.

The researchers studied the colonisation by multiple pioneer coastal plant species, and concluded that the speed at which the species can establish is the key to landscape formation. Research leader Christian Schwarz (lead researcher at Utrecht University): “Climate change can lead to changes in plant growth characteristics: our research shows this can impact whole coastal landscapes. The colonisation characteristics of different pioneer species can strongly differ. We can roughly divide between fast and slow colonizers. Fast colonizers show well-distributed growth patterns, while slow colonizers show a more stochastic soil and sediment coverage. The fast colonizers lead to landscape patterns that we currently observe. Slow colonizers however promote the rise of new formations and patterns in the landscape: deeper gulleys e.g., which have a strong influence on the ability of coastal marshes to cope with sea level rise.”

Earlier research already showed that fast colonizers seemed to result in a higher risk of loss of marshes due to sea level rise. “In the end, the distribution of slow and fast colonizers can thus determine the resistance of our coastal landscape to sea level rise”.

In their study, the reearchers combined ecological models with observations in two marsh areas along the Westerschelde: the ‘ Hooge Platen ’ and the ‘Platen van Walsoorden’. In the first marsh, Salicornia europaea dominates, a fast colonizer. In the second marsh, Spartina anglica is the dominant species, a slow colonizer. Both marshes are subjected to similar tidal conditions and have similar sediment characteristics, but landscape patterns strongly differ. This confirmed the modelling predictions by the researchers.

The research of Christian Schwarz and colleagues contributes to growing conscience on the relation between plant growth and landscape formation. This new research field can be practically applied through the concept of ‘Building with Nature’, where landscape management is applied to cope with the negative consequences of climate change.

Aerial view of the Hooge Platen (source Zeeuwseankers.nl)