Born to be wild? Response of an urban exploiter to human-modified environment and fluctuating weather conditions

Abstract

Human-driven environmental changes affect behavior, morphology, life history, and population dynamics of wild species. Artificial food sources in anthropogenic environments benefit some species and may lead to faster somatic growth and larger body size, which affects survival and reproduction, thus contributing to a species’ success in modified environments. Using raccoons (Procyon lotor (L., 1758)) as a model, we documented age-specific body-mass pattern and evaluated the influence of human activities (human density, area with artificial food sources, edges of forested area bordering corn (Zea mays L.) fields) and weather (index of winter severity and mean annual precipitation) on body-mass variation at multiple spatial scales. The effect of human-driven changes on raccoon mass varied with age, sex, and spatial scale, suggesting that anthropogenic changes affect raccoons differentially according to gender and life stages. Human activity had consistently opposing effects between the sexes. Weather covariates represented >50% of the total variance in body mass explained by our models. Previous winter severity and mean annual precipitation affected body mass negatively and positively, respectively. Our results emphasize the importance of multiscale, sex- and age-specific analyses when studying influences of human activity on wildlife.