Marsh Terracing as a Restoration Technique for Creating Nekton Habitat
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PRESENTATION
Bryan P. Gossman1, Megan K. La Peyre1, and J. Andrew Nyman2
1 USGS Louisiana Fish and Wildlife Cooperative Research Unit
School of Renewable Natural Resources
Louisiana State University AgCenter
2 School of Renewable Natural Resources
Louisiana State University AgCenter
Abstract
Marsh terracing is a wetland restoration technique that has rapidly gained in popularity in recent years. Terraces are assumed to benefit coastal restoration by providing areas for emergent plant growth, reducing wave energies, and increasing edge habitat to support nekton communities. This study was designed to examine the effectiveness of terraces in restoring nekton habitats in the coastal zone. Three hydro-logically-separate study sites located in southwest Louisiana at Sabine National Wildlife Refuge (1 study site) and Rockefeller State Wildlife Refuge (2 study sites) were selected for the study. Each study site consisted of a terraced pond and a nearby un-terraced reference pond. Sampling of nekton, submerged aquatic vegetation, and environmental variables occurred bi-monthly from April, 2004 through April, 2005. Nekton was quantitatively sampled at 4 habitat types using a 1-m2 throw trap. The habitat types sampled were un-terraced marsh edge, terrace edge, terraced pond open water and un-terraced pond open water. ANOVA revealed significant differences in nekton density (P = 0.0001), sample biomass (P = 0.0005), and species richness (P = 0.0008) between edge and open water habitats. No significant difference was observed in nekton density (P = 0.23), sample biomass (P = 0.38), or species richness (P = 0.13) between terraced and un-terraced ponds. However, more specific contrasts indicated significantly greater nekton density, biomass, and species richness at terrace edge habitats as compared to un-terraced open water habitats, while terrace edge and un-terraced marsh edge habitats were similar.
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