Animal ecosystem engineers much stronger driver of salt marsh accretion than expected

The fate of coastal ecosystems depends on their ability to keep pace with sea-level rise-yet projections of accretion, the process by which marshes build up vertically, have widely ignored effects of animal ecosystem engineers. Researchers at the University of Florida (UF), the Royal Netherlands Institute for Sea Research (NIOZ) and Utrecht University combined observational, experimental, digital mapping and modelling work to show that ecosystem engineering by mussels in Southeastern US salt marshes is a much stronger driver of accretion rates than expected, as shown in a new study recently published in Nature Communications.   "This result suggests that animals may have a far greater role in helping coastal systems adapt to climate change than previously thought," said lead author Sinéad M. Crotty, associate director of science of the Carbon Containment Lab at Yale University. "Up to now, there's been no study showing this connection."  Relocating 200,000 mussels by hand. Using fieldwork data and a model, the researchers aimed to predict the effect of mussels on marsh accretion. They then conducted a large-scale mussel experiment, which involved removing over 200,000 mussels by hand, and moving them to a new location. "We found that, in reality, the effects of mussels are far greater than predicted by the models, and occur at large, landscape scales," said Crotty. The present study provides new insight into the mechanisms by which coastal ecosystems that are highly valuable for flood defense, such as salt marshes, can cope with sea-level rise.