PARENT SESSION
Oral Session # 17: Avian Ecology I.
Presiding: J Arnold
Tuesday, August 5. 8:00 AM to 11:30 AM, SITCC Meeting Room 103.

Wood ducks of the Savannah River Site: Indicators of changing environments.

Kennamer, Robert^*,1, ¹ Savannah River Ecology Laboratory, Aiken, SC, USA

ABSTRACT- Knowledge of the dynamics of biological populations and of their specific responses to varying environmental conditions provides a foundation for assessing the potential for projected climate change to reshape ecosystems and their member components. Critical in the search to understand how species might adapt to unfolding climate change will be the data from long-term population studies, as in this example using wood ducks (Aix sponsa) breeding on the upper Atlantic Coastal Plain in west-central South Carolina. In one investigation, surface waters in local wetlands that are the primary habitats of wood ducks are shown to be under the influence of global-scale climatological systems such as the El Niño-Southern Oscillation in the tropical Pacific. Annual productivity of the breeding population then is related to an annual index of wetland conditions across the 78,000-ha Savannah River Site, exemplified as higher duckling production in wetter years. High levels of population productivity in wet years is realized through increased production by individual females, attempted female breeding at an earlier age, and a lessening of certain nest predation pressures. Wood ducks, like many organisms, rely on environmental cues to time reproduction with resource availability. In a second investigation, the timing of wood duck breeding is examined, showing that since the early 1970s, the annual onset of breeding has shifted almost a month earlier. This shift in timing of reproduction appears to coincide with a general warming of the late-fall and winter months over the period of study.

Key words: long-term population study, timing of reproduction, Aix sponsa, wetland conditions and population productivity