Identifier

etd-05162015-201418

Degree

Master of Science (MS)

Department

Renewable Natural Resources

Document Type

Thesis

Abstract

The Atchafalaya River Delta system along with the Wax Lake Outlet Delta and the Mississippi River Delta are the only three areas in Louisiana where land is being gained. Beneficial use of dredge spoil from shipping channel maintenance is used on the Atchafalaya River Delta to supplement natural accretion. These dredge spoil islands have the ability to provide valuable nesting habitat for a variety of waterbirds, including Mottled Ducks. Previous studies on these islands reported mammalian predation to be a significant cause of nest failure for Mottled Ducks. I tested the hypothesis that predator reduction through trapping would increase Mottled Duck nesting success. I selected six islands based on vegetative conditions optimal for nesting vegetation and separated them into three trapped and three control islands. I found mammalian depredation of Mottled Duck nests to be rare and was not successful in detecting or trapping any predators. Instead, I found that flooding, which had been a minor issue in a previous study, to be the major cause of nest failure during the 2012 and 2013 nesting seasons. I found that Mottled Ducks strongly preferred nesting on islands that were isolated from the main delta complex. I used LIDAR elevation data as well as NOAA and pressure transducer data logger water level data to evaluate the relationship between nest elevation and nest success. I found no apparent relationship between nest elevation and nest success. Mayfield nest success for Mottled Duck nests was 20.5% in 2012 and 11.5% in 2013 with 34.5% of nests destroyed by flooding. Further research into the effects of flood duration, frequency, and incubation stage at flooding as well as considering partial loss of clutches may show a clearer relationship between nest success and the effects of flooding

Date

2015

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Rohwer, Frank

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