Global realized niche divergence in the African clawed frog Xenopus laevis

Abstract

Although of crucial importance for invasion biology and impact assessments of climate change, it remains widely unknown how species cope with and adapt to environmental conditions beyond their currently realized climatic niches (i.e., those climatic conditions existing populations are exposed to). The African clawed frog Xenopus laevis, native to southern Africa, has established numerous invasive populations on multiple continents making it a pertinent model organism to study environmental niche dynamics. In this study, we assess whether the realized niches of the invasive populations in Europe, South, and North America represent subsets of the species’ realized niche in its native distributional range or if niche shifts are traceable. If shifts are traceable, we ask whether the realized niches of invasive populations still contain signatures of the niche of source populations what could indicate local adaptations. Univariate comparisons among bioclimatic conditions at native and invaded ranges revealed the invasive populations to be nested within the variable range of the native population. However, at the same time, invasive populations are well differentiated in multidimensional niche space as quantified via n‐dimensional hypervolumes. The most deviant invasive population are those from Europe. Our results suggest varying degrees of realized niche shifts, which are mainly driven by temperature related variables. The crosswise projection of the hypervolumes that were trained in invaded ranges revealed the south‐western Cape region as likely area of origin for all invasive populations, which is largely congruent with DNA sequence data and suggests a gradual exploration of novel climate space in invasive populations.

Assessing the effect of landscape features on pond colonisation by an elusive amphibian invader using environmental DNA

“…Additionally, a recent study which modelled the potential distribution of X. laevis in western France by using bioclimatic data, showed that the maximal expected invasive range is much larger than our updated range (Rödder et al, 2017). The capacity of the species to cross major watercourses raises concerns about the occurrence of natural barriers to the expansion of X. laevis in western Europe.…”

A taxonomically and geographically constrained information base limits non-native reptile and amphibian risk assessment: a systematic review

“…One such initiative in Europe saw members from four EU countries funded to work jointly on the impacts of the invasive African clawed frog , X. laevis : INVAXEN ( ). This initiative has added 15 published articles on this species, nearly doubling the available data on their invasive populations ( Courant et al, 2017 ; Louppe, Courant & Herrel, 2017 ; Rödder et al, 2017 ). Funded by BIODIVERSA, this call did not include funding for studies on populations in non-participating EU countries (e.g.…”

Influence of temperature on reproduction and length of metamorphosis in Xenopus laevis (Amphibia: Anura)

“…Since the African clawed frog (Xenopus laevis), which comes from South Africa, has created numerous invasive populations on several continents, it has become a convenient model organism for the study of environmental issues (Rödder et al 2017). The African amphibian Xenopus laevis is generally considered to be an invasive species which constitutes a threat not only to local fauna but also to biodiversity the world over, as it has a strong invasive potential (Tinsley et al 2015).…”