Fire Ecology of Salt and Brackish Marshes

Salt Marsh

Salt and brackish marshes are found in all southeastern states with marine coasts. They are defined by periodic tidal inundation, dominance of salt-tolerant herbaceous plants and a rate of net primary production that is among the highest of all the world’s ecosystems. Coastal marshes support a rich fauna, and are important habitat for coastal birds, fur-bearing species, and as a nursery for some species of marine fishes. In recent years, there has been a special interest in conservation of seaside sparrows and other species of special concern.

Although little documentation exists on the natural fire regime in salt and brackish coastal marshes, lightning-ignited fires in other communities were likely to spread into the coastal marshes during the growing-season. There is also a long history of human ignition of fire in southeastern coastal marshes. People often burned these sites to promote wildlife resources (especially for waterfowl), increase forage for cattle and enhance ease of access for hunting and trapping. 

To date, almost all research on fire effects in coastal marsh habitats has focused on burns during the dormant season. Although effect of dormant season fire on marsh vegetation appears to be short-lived, it remains unclear how growing season burns affect marsh vegetation. Growing-season burns may alter vegetation structure and/or availability of insects compared to the results of dormant season fires. These resources may be important for nesting success of many marsh birds.

Prescribed fire is a common management tool used in coastal marsh ecosystems of the southeastern U.S. It is often used as a cost-effective way to reduce fuel and, when coupled with impoundments, is viewed as an important tool for coastal waterfowl. Although research has explored the effects of season of burn and fire frequency in adjoining upland ecosystems and, under some conditions, has determined advantages of varying fire regimes, these topics remain largely unstudied in coastal marsh areas of the Southeast. Agencies continue to use mostly dormant-season burns in coastal marshes, in part due to concerns about potential negative effects on wildlife, especially seaside sparrows. Due to the lack of research on season and frequency of burn, large gaps still exist in the scientific knowledge required to develop and implement fire management programs in coastal marshes of the southeast United States.