Abstract
Invasive species, such as the mainly aquatic African clawed frog Xenopus laevis, are a main threat to global biodiversity. The identification of dispersal corridors is necessary to restrict further expansion of these species and help to elaborate management plans for their control and eradication. Here we use remote sensing derived resistance surfaces, based on the normalised difference vegetation index (NDVI) and the normalised difference water index (NDWI) accounting for behavioural and physiological dispersal limitations of the species, in combination with elevation layers, to determine fine scale dispersal patterns of invasive populations of X. laevis in Portugal, where the frog had established populations in two rivers. We reconstruct past dispersal routes between these two invaded rivers and highlight high risk areas for future expansion. Our models suggest terrestrial dispersal corridors that connect both invaded rivers and identify artificial water bodies as stepping stones for overland movement of X. laevis. Additionally, we found several potential stepping stones into novel areas and provide concrete information for invasive species management.
Highlights
Invasive species are a main threat to biodiversity (e.g. Fritts and Rodda 1998; Rosenzweig 2001; Chornesky and Randall 2003; Davis 2003; Doherty et al 2016), having played a role in global amphibian decline (e.g. Gibbons et al 2000; Chornesky and Randall 2003; Falaschi et al 2020)
The first record of X. laevis in western Portugal occurred in Laje River, which runs through a densely-urbanised part of Oeiras County ca. 20 km west of Lisbon, in 2006 (Sousa et al 2018) (Fig. 1A)
Our results explain the current distribution of the species, including its absence from nearby streams and locate the probable contact route between the two invaded basins, supporting the hypothesis of a natural colonisation of Barcarena by overland dispersal
Summary
Invasive species are a main threat to biodiversity (e.g. Fritts and Rodda 1998; Rosenzweig 2001; Chornesky and Randall 2003; Davis 2003; Doherty et al 2016), having played a role in global amphibian decline (e.g. Gibbons et al 2000; Chornesky and Randall 2003; Falaschi et al 2020). The African clawed frog (Xenopus laevis) is native to southern Africa and has been moved worldwide as a model organism for laboratory research (Measey et al 2012; van Sittert and Measey 2016) This species has unique physiological and demographical traits, including a tolerance to saltwater and eutrophic conditions and behavioural adaptations, such as terrestrial migration or the ability to burrow into substrate to persist in drought and extreme temperature events. This trait combination confers it with an enormous invasive potential (for a thorough review, see Measey et al 2012; Sousa et al 2018; Scalera et al 2019). It was ranked second amongst all invasive amphibian species considering its environmental and socio-economic impacts (Measey et al 2016)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
