High marsh

The high marsh depends on regular tidal activity and inundation to deposit sediments. Sediment deposition facilitates mineral and organic matter buildup and sediment accretion. The minerals and organic matter promote vegetation growth and the sediment accretion promotes heightened elevation growth.

The high marsh is also important to many habitat specialists such as the Saltmarsh Sparrow, Black Rail, American Black Duck, saltmarsh spike-grass, and salt-hay. These specialists rely on the high marsh ecosystem to provide for their biological needs to ensure stable productivity and abundance. Among these biological needs are foraging, mating, nesting, incubation, and brooding.

The Clean Water Act of 1972 was the first act to protect these ecosystems but, due to the absence of protection, many wetlands were converted into farmland and residential land.

Marsh Prevalence Worldwide

Saltmarshes are found in at least 99 countries, as mapped by scientists McOwen et al. in 2017. Similarly, in 43 countries/territories there are 5,495,089 mapped hectares of saltmarsh. The coterminous United States has many estimates for original wetland content, spanning from 211 to 217 million acres total. Alaska has the highest amount of wetlands, with an estimated 165 million acres originally. The U.S. Department of Interior and the U.S. Fish and Wildlife Service estimate that colonial United States had approximately 392 million acres, with 221 million in the 48 states, 170 million acres in Alaska, and 59,000 acres in Hawaii.

Thomas Dahl reports in Wetlands that from 1780 to 1980 there was a “53-percent loss from the original [wetland] acreage total." Further, United States wetlands experienced a net loss of approximately 60,000 acres per year spanning from 1998 to 2004. This increased to 80,000 acres per year between 2004 and 2009.