Maturation of a constructed tidal marsh relative to two natural reference tidal marshes over 12 years

Habitat functions of a constructed tidal marsh and two adjacent natural tidal marshes were compared between marshes and with similar data collected in the same marshes 7 years earlier. The marshes were sampled for fish, blue crabs, benthic infauna, vegetation community type, stem density and cover, salinity, temperature, dissolved oxygen, organic carbon, and bird utilization. The constructed marsh has progressed to a general level of function similar to that of nearby natural marshes. Some morphological differences remain, such as the differences in community type ratios. Significant differences in habitat function remain in three areas: sediment organic carbon at depth, mature saltbush density, and bird utilization (related to saltbush density). The addition of organic soil amendments and mature saltbush in the construction of tidal marshes will help in the progression of constructed marshes to functional equivalency with natural marshes. Specific functions can be enhanced for fish utilization (more subtidal habitat) and for birds (more shrub habitat) depending on management priorities.