STRONG EFFECTS OF ENVIRONMENTAL CONDITIONS ON REPRODUCTIVE SUCCESS OF PENGUINS AT KING GEORGE ISLAND

Generalized linear and additive models suggest that large proportions of inter-annual variability in the reproductive success of Adélie, gentoo, and chinstrap penguins can be explained by simple linear predictors based on local weather conditions and winter sea ice extent. Local weather variables selected by step-wise model fitting procedures corresponded to the incubation periods for each species. Sea ice extent measured during the winter prior to breeding also appears to be an important predictor of reproductive success in all species. Biological variables measured during the chick-rearing phase, like krill size, krill density at sea, and chlorophyll a concentrations appear less important, except for chinstrap penguins which breed later in the season than gentoo and Adélie penguins. In most cases, the final predictor variables detected in this analysis have exhibited directional trends, implying important effects of directional climate change on the future of reproductive success in monitored populations.