Estimates of abundance are critical to manage and conserve waterfowl and their habitats. Most surveys of wintering waterfowl do not use probability sampling; therefore, development of more rigorous methods is needed. In response, I designed and evaluated an aerial transect survey to estimate abundance of wintering ducks in western Mississippi during winters 2002?2004. I designed a probability-based survey using stratified random and unequal probability sampling of fixed-width transects. To correct for visibility bias inherent in aerial surveys, I conducted an experiment to model bias and incorporated correction factors into estimation procedures to produce adjusted estimates. Bias-corrected estimates were most accurate. Precision of abundance estimates of total ducks met a priori goals (CV ≤ 15%) in 10 of 14 surveys. Based on a simulation study, the implemented survey design provided the most precise estimates, yet certain refinements remained possible. I also illustrated potential applications of survey results in the context of conservation and management of wintering waterfowl populations and habitats. I described patterns of abundance within and among winters, including a comparison with surveys conducted during winters 1988?1990 that revealed mallard abundance decreased 65% from the late 1980s. I developed a method to illustrate population abundance spatially for scientific and public education. I attempted to explain temporal variation in abundance estimates relative to variables potentially representing hypotheses explaining regional distributions of ducks. I concluded the data provided stronger support for factors related to energy conservation by ducks than factors related to energy acquisition. Finally, I determined associations between duck distributions and habitat and landscape features in accordance with the habitat-complex conceptual model. Landscapes with greater interspersion and diversity of wetlands attracted increased numbers of ducks, a though other factors such as wetland area also were important. I concluded that this study advanced methodologies to survey wintering waterfowl. Although improvements were warranted, I recommend this survey design for continued monitoring of wintering ducks in western Mississippi. Furthermore, I suggest habitat management on public and private lands should include complexes of seasonally flooded cropland, moist-soil, forested, and permanent wetlands to potentially increase wintering duck numbers in western Mississippi.
| Identifer | oai:union.ndltd.org:MSSTATE/oai:scholarsjunction.msstate.edu:td-2316 |
| Date | 05 May 2007 |
| Creators | Pearse, Aaron Todd |
| Publisher | Scholars Junction |
| Source Sets | Mississippi State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
Page generated in 0.0025 seconds