In 2014, 12 experimental islands were built in the back-barrier tidal falts of Spiekeroog, and since serves as a test of metacommunity theory predictions across the marine and terrestrial interface. The experiment is supplemented with enclosed plots within the salt marsh. The experimental islands representing dispersal-limited conditions of species, while the salt marsh plots represent areas with unlimited rapid dispersal treatments. Six reference plots in each salt marsh zone continue to serve as undisturbed controls. Each of the experimental islands is a replicate with three elevation levels. Each level has the same elevation as the vegetation zones of the nearby salt marsh: pioneer zone, lower and upper salt marsh zone. Half of the experimental islands and salt marsh plots were transplanted with plants of the lower salt marsh communities from the nearby salt marsh. The other half was filled exclusively with mudflat sediment. This setup enables to study the effect of already present species on the arrival of new species. Species dynamics and abiotic conditions have been recorded since the experiment was set up. A detailed description of the experiment can be find here.