Movements and habitat use of the invasive species Lithobates catesbeianus in the valley of the Grote Nete (Belgium)

Abstract

Nine adult American bullfrogs (Lithobates catesbeianus) were tagged with an internal radio transmitter and tracked during one year in the valley of the Grote Nete (Belgium). The mean ± SD core range area (KDE50) was 15.00 ± 22.41m2. The home range area (KDE95) had a mean ± SD of 429.78 ± 510.97m2. Shores of larger eutrophic ponds and small temporary pools in alluvial forest were chosen as habitat. The total area used (MCP95) had a mean of 11,086.73 ± 12,239.00m2. The study revealed a mean action radius of 270.78 ± 199.17m and individuals moved up to 742m in a single displacement. These results show that the dispersion of the American bullfrog in a valley system such as the Grote Nete can proceed very rapidly. A positive correlation between weight and distance covered within one movement was found, which could suggest that dominant individuals are capable of covering greater distances in search of optimal habitat for reproduction, foraging or hibernation.

Accurate detection and quantification of seasonal abundance of American bullfrog (Lithobates catesbeianus) using ddPCR eDNA assays

“…As temperatures decrease in autumn and cross the threshold of 15 °C, which generally occurs from October to March, bullfrogs enter winter torpor. They mostly hibernate semi-immersed in sediment at the bottom of a pond, but winter lethargy or adopting terrestrial hibernacula instead is not exceptional 52 , 67 . Therefore, the reduced metabolic rate, and hence eDNA release, during hibernation 39 , or the lowered abundance of juveniles in water bodies during winter could explain the observed decrease in measured eDNA concentrations following the peak in late summer.…”

“…1 a). This stream serves as a dispersal corridor for bullfrogs and facilitates the colonisation of the numerous suitable ponds in its immediate vicinity, making active control challenging 51 , 52 . Disposing of a comprehensive overview of its distribution and local abundance, especially at very low abundances, is an absolute prerequisite for successful control of AIS 23 .…”

Accurate Detection and Quantification of Seasonal Abundance of American Bullfrog (Lithobates Catesbeianus) Using ddPCR eDNA Assays

“…As temperatures decrease in autumn and cross the threshold of 15 °C, which generally occurs from October onwards, bullfrogs enter winter torpor. They mostly hibernate in the water at the bottom of a pond, semiimmersed in mud, but winter lethargy or adopting terrestrial hibernacula instead is not exceptional 49,61 .…”

“…1a). Apparently, this stream functions as an artery for bullfrog displacement providing access to plenty of suitable ponds, mostly private, which opposes active control 48,49 . Disposing of a reliable and comprehensive overview of the precise distribution and density of bullfrog populations, especially at very low abundances, in this and other cases is thus an absolute prerequisite for successful eradication, although currently one of the main shortcomings.…”

Risk assessment for the native anurans from an alien invasive species, American bullfrogs (Lithobates catesbeianus), in South Korea

“…We also observed the food habits, movement patterns, breeding sites, and breeding seasons to compare them with previous literature to purify and enrich the dataset. Because, the home range, movement patterns, breeding behavior, and breeding seasons of IAB can be different based on geo-climatic conditions 39 – 42 . After the field observations, we matched this dataset with existing information for all anurans of South Korea to rank them according to the risk from IAB.…”