Rödder Dennis, Ihlow Flora, Courant Julien, Secondi Jean, Herrel Anthony, Rebelo Rui, Measey G J, Lillo Francesco, De Villiers F A, De Busschere Charlotte, Backeljau Thierry
Herpetology Section Zoologisches Forschungsmuseum Alexander Koenig (ZFMK) Bonn Germany.
UMR7 179 CNRS/MNHN Paris France.
Ecol Evol. 2017 May 10;7(11):4044-4058. doi: 10.1002/ece3.3010. eCollection 2017 Jun.
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 , 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 -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.
尽管对于入侵生物学和气候变化影响评估至关重要，但物种如何应对和适应超出其当前实际气候生态位（即现有种群所暴露的气候条件）的环境状况，仍然广为人知。原产于非洲南部的非洲爪蟾在多个大陆建立了众多入侵种群，使其成为研究环境生态位动态的相关模式生物。在本研究中，我们评估欧洲、南美洲和北美洲入侵种群的实际生态位是否代表该物种在其原生分布范围内实际生态位的子集，或者生态位转移是否可追溯。如果转移是可追溯的，我们会问入侵种群的实际生态位是否仍然包含源种群生态位的特征，这可能表明局部适应。对原生范围和入侵范围生物气候条件的单变量比较显示，入侵种群嵌套在原生种群的可变范围内。然而，与此同时，通过多维超体积量化，入侵种群在多维生态位空间中差异明显。最偏离的入侵种群来自欧洲。我们的结果表明存在不同程度的实际生态位转移，主要由温度相关变量驱动。在入侵范围内训练的超体积的交叉投影显示，西南开普地区可能是所有入侵种群的起源地，这在很大程度上与DNA序列数据一致，并表明入侵种群在逐步探索新的气候空间。
