How the litter-feeding bioturbator Orchestia gammarellus promotes late successional salt marsh vegetation

1.Traditionally, studies on vegetation succession have focused either on plant-plant interactions, or on interactions between plants and their physical environment, e.g. through organic matter build-up and increased nutrient cycling. These interactions can change conditions for macrodetritivores that feed on plant litter, but their role in vegetation succession is rarely studied. In this paper we explore whether the bioturbating crustacean macrodetritivore Orchestia gammarellus alters soil conditions in a salt marsh ecosystem in such a way that it promotes late successional, less stress-tolerant plant species at the expense of early successional species. 2.To answer this, we performed a field and a laboratory experiment in which we manipulated abundances of O. gammarellus, and studied the consequences for soil physical and chemical parameters and for vegetation community composition. 3.Our field experiment showed that O. gammarellus stimulated nitrogen mineralization, likely resulting...