Salt marshes are among the most productive ecosystems on the planet, producing more organic matter per unit area than forests, grasslands, and cultivated fields. Marsh landscapes typically fringe low-energy coastal environments, but in places they may extend inland tens to hundreds of kilometers.
As a consequence of their high productivity and interactions with the coastal ocean, salt marshes provide numerous benefits to society. For example, salt marshes are critical habitats for commercially harvested marine and estuarine biota; they filter nutrients and sediment from the water column; and they provide recreational opportunities. In addition, salt marshes help dissipate erosive tide and wave energy and they have intrinsic aesthetic values. All of these societal benefits have a quantifiable economic value, and salt marsh impairment and degradation have associated costs.