Fire and Wetlands

Fire was early recognized as important for the development and maintenance of many wetland communities in the Southeast (Penfound and Hathaway 1938, Viosca 1928, 1931, Wells 1942, Garren 1943). As such, prescribed fire has been a useful management tool in wetland ecosystems throughout the south. Fire can reduce fuel loads and promote diverse plant and animal assemblages. Other advantages of fire in wetlands include (Kirby et al. 1988):

• removal of dead herbaceous cover, thus reducing the risk of debris build-up on the marsh floor
• reduction of the marsh floor by burning into the mineral soil
• reduction or elimination of woody vegetation that has invaded areas
• destroys sphagnum moss and promotes succession of sedges and grasses, thus increases habitat and food for waterfowl
• reduced build-up in basins to reduce the effects of flooding
• provides open areas for spring grazing of waterfowl
• increased nutrient mineralization and improved forage quality and
• altered albedo (i.e., light environment) promoting earlier spring growth.

If fires are used in wetlands, they should mimic historical fire frequencies to prevent native vegetation losses and community shifts. For more in-depth discussions of the fire ecology and management of fire in specific wetland systems of the southeast, please see: Pocosins, Cypress ponds, Shrub bogs, Freshwater marshes, and the Everglades.

If fire is inappropriately used in wetlands it can lead to a loss of diversity and native plant communities. For example, fires too frequent can contribute to weed infestations and loss of native plants, whereas infrequent fires can lead to the build-up of dense fuel loads that may lead to high intensity fires which favor particular plant communities (Water and Rivers Commission, 2000). Other disadvantages of fire in wetlands include (Water and Rivers Commission, 2000):

• loss of seed source due to improperly timed fires
• degradation or loss of organic rich (peat) soils
• increased predation on seeds
• reduced nutrient uptake or sediment filtration if vegetation is lost
• exposed plant roots
• change in vegetation structure and composition

Where prescribed fires cannot be used in wetlands, reduction of fuels or understory growth may be done using alternative mechanical methods, such as hand tools or machinery. Also, non-native vegetation or weed problems may be controlled using herbicides that are formulated for water use (Water and Rivers Commission, 2000).