17. Prolonged 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. 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 sampled from northern Georgia in the year of 2019 will display lower N:L ratios and a higher body mass than those sampled in the year of 2021 due to the increasing and ongoing presence of human disturbances in their environment. The American toad, Anaxyrus americanus, a species native to the eastern United States, was used in this study due to their common occurrence in the northern Georgia region. Here, we present data from the 2019-2021 field seasons from a densely forested residential neighborhood which has been experiencing new development. Morphological measurements and blood smears were taken from toad’s native to this site. Leukocyte profiles were then taken by counting 100 leukocytes and all red blood cells located and were used to assess and compare stressor prevalence between the two years of interest. This study provides data on amphibian health conditions that can be compared to human disturbance effects in environments over a prolonged duration of time.