Study

Effects of structural marsh management and winter burning on plant and bird communities during summer in the Gulf Coast Chenier Plain

  • Published source details Gabrey S.W., Afton A.D. & Wilson B.C. (2001) Effects of structural marsh management and winter burning on plant and bird communities during summer in the Gulf Coast Chenier Plain. Wildlife Society Bulletin, 29, 218-231

Actions

This study is summarised as evidence for the following.

Action Category

Use prescribed fire to control problematic plants: brackish/salt marshes

Action Link
Marsh and Swamp Conservation

Actively manage water level: brackish/salt marshes

Action Link
Marsh and Swamp Conservation
  1. Use prescribed fire to control problematic plants: brackish/salt marshes

    A replicated, randomized, paired, controlled study in 1995–1998 in 11 brackish and salt marshes in Louisiana, USA (Gabrey et al. 2001) found that prescribed winter burning typically had no significant effect on summer plant species richness but had mixed effects on the cover of two dominant plant species and caused only a temporary reduction in cover of dead vegetation. Averaged over the three summers following intervention, burned and unburned plots had statistically similar plant species richness in three of four marsh types (for which burned: 4.2–5.7 species/plot; unburned: 5.0–5.5 species/plot; other marsh type higher richness in burned plots). Cover of saltmeadow cordgrass Spartina patens was similar in burned and unburned plots in three of four marsh types, but greater in burned plots in the other marsh type. Cover of saltgrass Distichlis spicata was greater in burned plots in two of four marsh types, lower in burned plots in one marsh type and similar in burned and unburned plots in the other marsh type (see original paper for data). Averaged over all marsh types, cover of standing dead vegetation was lower in burned plots in the first summer (burned: 45%; unburned: 69%) but did not significantly differ between treatments in the following two summers (burned: 64–78%; unburned: 71–72%). Methods: The experiment was carried out in 11 coastal marshes (of four types based on salinity and tidal influence). In winter 1995/1996, one random half of each marsh was burned. The “unburned” half of one marsh experienced a lightning fire in summer 1997. In May–June 1996–1998, vegetation was surveyed at 40 points in each half of each marsh. This study was based on the same experimental set-up as (2).

    (Summarised by: Nigel Taylor)

  2. Actively manage water level: brackish/salt marshes

    A replicated, site comparison study in 1996–1998 of five coastal brackish marshes in Louisiana, USA (Gabrey et al. 2001) found that impounded marshes in which water levels were actively managed had similar summer plant species richness to open unmanaged marshes, and typically had similar cover of vegetation overall and dominant saltmeadow cordgrass Spartina patens. In three of three years, impounded marshes had statistically similar plant species richness (5.3–5.5 species/marsh) to open marshes (4.3–4.8 species/marsh). In two of three years, impounded marshes had statistically similar vegetation cover (total: 82–85%; cordgrass: 45–64%) to open marshes (total: 79–81%; cordgrass: 51–57%). The exception was in the first summer of the study, six months after prescribed burns, when impounded marshes had greater vegetation cover (total: 83%; cordgrass: 55%) than open marshes (total: 69%; cordgrass: 38%). Methods: In May–June 1996–1998, vegetation was surveyed at 80 points in each of five brackish marshes (salinity 5–10 ppt). Two marshes had been impounded since the late 1950s, meaning water levels could be controlled (e.g. maintained relatively high in winter). Water levels were not controlled in the other three marshes (i.e. open to natural tidal influence). In each marsh, 40 points had been burned earlier in winter 1995/1996 and 40 had not. This study used a subset of the marshes from (4).

    (Summarised by: Nigel Taylor)

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