Identifier

etd-11162006-111100

Degree

Master of Science (MS)

Department

Renewable Natural Resources

Document Type

Thesis

Abstract

Terracing is a novel technique used to combat coastal marsh loss in Louisiana and Texas. Terraces are assumed to slow marsh erosion, decrease pond depth, and encourage vegetation expansion. Terraced ponds have never been evaluated as habitat for waterbirds, which heavily depend on Louisiana�s coastal marshes. From April 2005 to April 2006, I monitored waterbird species richness and density through time to estimate effects that terracing has on habitat quality. Water quality (turbidity, salinity, conductivity, water temperature, and water depth) also was measured. Submerged aquatic vegetation (SAV) biomass and nekton density were measured from April 2005 to September 2005. I monitored paired terraced and unterraced ponds in three sites within Louisiana�s Chenier Plain. Observations and samples were taken in two microhabitat types within ponds: marsh edge and open water. Terracing ponds increased the proportion of marsh edge, but did not alter water quality variables measured. SAV and nekton were denser at the marsh edge than in open water, but did not differ significantly when compared at the whole-pond level between pond types. Waterbirds also were denser at the marsh edge. Waterbird density was consistently greater in terraced ponds. Waterbird species richness was greater in terraced ponds in winter and during spring and summer was generally greater in terraced ponds. Additionally, bird density in ponds varied by foraging guild. During spring and summer, aerialists, shorebirds, and dabbling foragers were consistently denser in terraced ponds. Wading forager densities varied in ponds with time, but were generally denser in terraced ponds. Diving foragers were not dense and did not differ between pond types. During winter, only dabbling and wading foragers were significantly denser in terraced ponds, but these two guilds represented 83% of birds observed. Other foraging group densities did not differ between pond types. Several species of conservation concern were observed. Trends in density for most species of concern were similar to those seen for the foraging guild in which that species was classified. Marsh edge is a biologically prolific habitat. The amount of edge necessary to achieve pond level effects for nekton and SAV has not been evaluated.

Date

2006

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

J. A. Nyman

DOI

10.31390/gradschool_theses.2277

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