A GIS approach to the study of colour anomalies in amphibians of Ukraine reveals the deleterious effect of human impacts

Our study provides a review of colour anomalies in amphibians from Ukraine during the 20th and early 21st centuries. Observations including melanism, flavinism, leucism, and blue axanthism were assembled from the published literature (1909–2018) and during field surveys (2000–2017). Blue colouration was the most common abnormal variant (81.5%; n = 106), and colour anomalies were recorded in 13 of Ukraine’s 24 administrative regions (oblasts), mainly along the Dnieper River and in the Carpathian Mountains. The largest number of anomalies was found in the Poltava (26.5%) and Kyiv (20.4%) Oblasts. We also explored the relationship between abnormal colouration and environmental variables using a GIS framework. Correlations existed mainly with geographic location and temperature-related parameters (e.g., reference evapotranspiration), as could be expected for interactions of morphological or physiological anomalies. However, the Human Footprint, an integrated index of anthropogenic impact, was also important. The connection of colour anomalies  and human activities shows once again the importance of amphibians as bioindicators for the early detection of pollution and other harmful effects in aquatic ecosystems.