Current distribution and invasion potential of the American Bullfrog, Lithobates catesbeianus in Central Europe

Breanna Emerson

Master's thesis

Abstract:

Invasive species have become a growing concern worldwide, and predicting their further dispersal is crucial for developing effective management strategies. The American bullfrog (Lithobates catesbeianus) is a widespread invasive species known to cause substantial ecological impacts, most especially on native amphibian species. Despite the organism’s global distribution, it has yet to establish populations within the central European ecoregion. To evaluate the possible risk of invasion of this species, this study aims to analyze the potential suitability of L. catesbeianus in this region based on climatic conditions, primarily temperature and precipitation. This assessment was performed using a Species Distribution Model (SDM), which is a maximum entropy modeling system that incorporates known species distribution patterns and associated climatic conditions to determine suitability within central Europe. The results showed the highest suitability in Germany as well as parts of Czechia and Poland, with varying degrees. The analysis showed a higher influence from temperature in determining suitable localities for this species than precipitation. According to the study, L. catesbeianus favored habitats with a wider annual temperature range, showing highest suitability in regions experiencing fluctuations in temperature of up to 25⁰C. The results from this study indicate suitable conditions within the currently uninhabited central European region for potential establishment and spread of this invasive species. By identifying areas where invasion risk is high, we can be proactive in developing essential prevention measures from this harmful organism, thus protecting the integrity of the native ecosystem.

Keywords

Species Distribution Model (SDM), American bullfrog (L. catesbeianus), Central Europe, Suitability Maps, invasive species

Language used: English

Date on which the thesis was submitted / produced: 2. 4. 2023

Thesis defence

• Date of defence: 17. 5. 2023
• Supervisor: doc. Ing. Jiří Vojar, Ph.D.
• Reader: Petr Chajma, Ph.D.

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme:
Nature Conservation