Plant Community Composition and Biomass in Gulf Coast Chenier Plain Marshes: Responses to Winter Burning and Structural Marsh Management

Abstract

Many marshes in the Gulf Coast Chenier Plain, USA, are managed through a combination of fall or winter burning and structural marsh management (i.e., levees and water control structures; hereafter SMM). The goals of winter burning and SMM include improvement of waterfowl and furbearer habitat, maintenance of historic isohaline lines, and creation and maintenance of emergent wetlands. Although management practices are intended to influence the plant community, effects of these practices on primary productivity have not been investigated. Marsh processes, such as vertical accretion and nutrient cycles, which depend on primary productivity may be affected directly or indirectly by winter burning or SMM. We compared Chenier Plain plant community characteristics (species composition and above- and belowground biomass) in experimentally burned and unburned control plots within impounded and unimpounded marshes at 7 months (1996), 19 months (1997), and 31 months (1998) after burning. Burning and SMM did not affect number of plant species or species composition in our experiment. For all three years combined, burned plots had higher live above-ground biomass than did unburned plots. Total above-ground and dead above-ground biomasses were reduced in burned plots for two and three years, respectively, compared to those in unburned control plots. During all three years, belowground biomass was lower in impounded than in unimpounded marshes but did not differ between burn treatments. Our results clearly indicate that current marsh management practices influence marsh primary productivity and may impact other marsh processes, such as vertical accretion, that are dependent on organic matter accumulation and decay.

Man-induced habitat changes and sensitive species: a GIS approach to the Eurasian Bittern (Botaurus stellaris) distribution in a Mediterranean wetland

“…Indeed, fires are a regular occurrence at Massaciuccoli, as in many Mediterranean wetlands. Consequently, winter burning may represent a valid tool for management, and not only for Bittern conservation: indeed, positive effects on the vegetation and invertebrate populations have been reported to stem from the winter burning of limited wetland areas in both England (Hawke and Jose1 996) and America (Gabrey and Afton 2001). In marshy areas customarily exploited by human population, an effective management strategy should involve both public administrators and landowners, planning a burn or mow rotation of 2-5 years on predefined plots.…”

Effects of a drawdown on plant communities in a freshwater impoundment at Lacassine National Wildlife Refuge, Louisiana

“…These findings suggested that reduced sediment deposition in the impounded marshes would result in a shorter life expectancy for those marshes. Other studies have also identified lower sedimentation and lower surface elevation in impounded marshes compared to marshes that retained hydrologic connectivity (Reed and others, 1997;Bryant and Chabreck, 1998;Gabrey and Afton, 2001). Bryant and Chabreck (1998), however, found that a permanently flooded freshwater impoundment (that is, no active water management was applied) had greater accretion than did a nearby natural marsh.…”

Above- and below-ground vegetative responses to prescribed fire regimes in a Chesapeake Bay tidal brackish marsh

“…Previous studies have shown increases in vegetative biomass production for several species in coastal marshes by prescribed burns (de la Cruz and Hackney 1980, Johnson and Knapp 1995, Gabrey and Afton 2001, Flores 2003. However, the literature also reports a wide range of site specific and/or species-specific biomass responses to fire (de la Cruz and Hackney 1980, Dudley and Lajtha 1993, Schmalzer and Hinkle 1993, Gabrey and Afton 2001. Production of Juncus roemerianus and Spartina spp.…”

“…The removal of accumulated litter by burning has been found to maximize the annual production and reproductive effort of a wetland plant that is a viable food source for wildlife (Ward 1968, Johnson andKnapp 1995). In addition, the removal of overshadowing vegetation by burning often stimulates primary plant production by increasing light penetration to the ground (Gabrey and Afton 2001). Zontek (1966) found that prescribed fire not only increased food supplies for wildlife, but improved habitat conditions by controlling tree diseases in coastal.…”