ABSTRACT
This chapter focuses on two ecosystems developed along the intertidal zone: tidal salt marshes, dominated by herbaceous or low shrubby halophytic vegetation; and mangrove communities dominated by halophytic trees. The interaction between abiotic (stress gradients) and biotic components results in a shore-parallel zonation of species. Physical stress determines the lower limit of a species, and the upper limit is set by competition with less tolerant species. Positive interactions are common under more stressful conditions. The concept of outwelling is used to describe the exportation of nutrients and organic detritus from salt marshes and mangroves. Herbivory has been thought to be relatively unimportant in salt marshes and mangroves, as most consumers would follow an indirect trophic pathway by grazing the detritus-associated microbial community. However, herbivores may have the potential to control plant productivity and predators top-down regulate the abundance of herbivores. Thus, trophic cascades can control productivity. Coastal wetlands deliver essential services that benefit human societies and sustain global biodiversity. They sequester large amounts of inorganic carbon from the atmosphere and oceans and store large stocks of organic carbon in their soils/sediments, for what they are known as coastal blue Carbon ecosystems.
