Population trends of Adelie penguin (Pygoscelis adeliae) breeding colonies: a spatial analysis of the effects of snow accumulation and human activities

Many of the Adelie penguin colonies used for long-term demographic studies are located near research stations, and there is a need to disentangle the effects of human activities and environmental variability on Adelie penguin population trends. This study used Geographic Information Systems and decision trees to examine whether potential changes in snow cover and/or proximity to human activities were able to explain the varying population trends of colonies at two breeding localities near Casey, East Antarctica. At the less visited site, Whitney Pt, wind exposure and snow accumulation correctly predicted the broad trends of colonies in most (84%) instances, whereas at Shirley I their predictive accuracy fell to 58%. At Shirley I, proximity to human activity correctly predicted the broad trends for 84% of colonies. While snow accumulation patterns are a primary driver of variation in population trends among colonies, the effect of snow accumulation is outweighed by proximity to human activities near Casey.