14. Human disturbance effects on white blood cell profiles of Anaxyrus americanus in northern Georgia

Abstract

As human development in the northern Georgia region extends into natural environments, toxins and pollutants from agriculture, construction, and industrial runoff have increased in aquatic and terrestrial ecosystems. These toxins can negatively impact animals by disrupting their individual health and population dynamics. Amphibians, which rely on cutaneous respiration through semi-permeable skin, are especially susceptible to environmental toxins, making them a favorable candidate to study the effects of human development on the health of native fauna. Toxins present in the environment may negatively affect amphibian immune system function and cause stress. Quantifying the neutrophil to lymphocyte (N: L) ratios from blood smears has been shown to correlate with increased stress in vertebrates. We hypothesize that amphibians in an environment with increased human disturbance will have higher N: L than those in less polluted environments. The American toad, Anaxyrus americanus, a species native to the eastern United States, is used in this study due to their common occurrence in the northern Georgia region. Blood samples and morphological measurements will be taken from toads at two different sites: a newly constructed neighborhood (high human disturbance) and an established, forested neighborhood (low human disturbance). Blood smears will be used to determine leukocyte profiles and N: L. Morphological measurements will also be used to assess differences in body condition and health in toads. This study will provide data on amphibian health conditions that can be compared to human disturbance effects in environments.