Courant Julien, Vogt Solveig, Marques Raquel, Measey John, Secondi Jean, Rebelo Rui, De Villiers André, Ihlow Flora, De Busschere Charlotte, Backeljau Thierry, Rödder Dennis, Herrel Anthony
UMR 7179, Département d'Ecologie et de Gestion de la Biodiversité, Centre National de la Recherche Scientifique, Paris, France.
Herpetology Section, Zoologisches Forschungsmuseum Alexander Koenig, Bonn, Germany.
PeerJ. 2017 May 16;5:e3250. doi: 10.7717/peerj.3250. eCollection 2017.
Invasive species are among the most significant threats to biodiversity. The diet of invasive animal populations is a crucial factor that must be considered in the context of biological invasions. A broad dietary spectrum is a frequently cited characteristic of invasive species, allowing them to thrive in a wide range of environments. Therefore, empirical studies comparing diet in invasive and native populations are necessary to understand dietary requirements, dietary flexibility, and the associated impacts of invasive species.
In this study, we compared the diet of populations of the African clawed frog, in its native range, with several areas where it has become invasive. Each prey category detected in stomach contents was assigned to an ecological category, allowing a comparison of the diversity of ecological traits among the prey items in the diet of native and introduced populations. The comparison of diets was also performed using evenness as a niche breadth index on all sampled populations, and electivity as a prey selection index for three out of the six sampled populations.
Our results showed that diet breadth could be either narrow or broad in invasive populations. According to diet and prey availability, zooplankton was strongly preferred in most cases. In lotic environments, zooplankton was replaced by benthic preys, such as ephemeropteran larvae.
The relative proportions of prey with different ecological traits, and dietary variability within and between areas of occurrence, suggest that is a generalist predator in both native and invasive populations. Shifts in the realized trophic niche are observed, and appear related to resource availability. may strongly impact aquatic ecosystems because of its near complete aquatic lifestyle and its significant consumption of key taxa for the trophic relationships in ponds.
入侵物种是生物多样性面临的最重大威胁之一。入侵动物种群的饮食是生物入侵背景下必须考虑的关键因素。广泛的饮食谱是入侵物种经常被提及的特征，这使它们能够在广泛的环境中繁衍生息。因此，有必要进行实证研究，比较入侵种群和本地种群的饮食，以了解饮食需求、饮食灵活性以及入侵物种的相关影响。
在本研究中，我们将非洲爪蟾在其原生范围内的种群饮食与它已成为入侵物种的几个地区的种群饮食进行了比较。在胃内容物中检测到的每个猎物类别都被归入一个生态类别，从而能够比较本地种群和引入种群饮食中猎物项目的生态特征多样性。还使用均匀度作为所有采样种群的生态位宽度指数，并使用选择性作为六个采样种群中三个种群的猎物选择指数，对饮食进行了比较。
我们的结果表明，入侵种群的饮食广度可能窄也可能宽。根据饮食和猎物可获得性，浮游动物在大多数情况下是强烈偏好的猎物。在流水环境中，浮游动物被底栖猎物取代，如蜉蝣幼虫。
具有不同生态特征的猎物的相对比例，以及不同发生区域内和区域间的饮食变异性，表明非洲爪蟾在本地和入侵种群中都是广食性捕食者。观察到实际营养生态位的变化，并且似乎与资源可获得性有关。非洲爪蟾可能会对水生生态系统产生强烈影响，因为它几乎完全水生的生活方式以及对池塘营养关系中关键类群的大量消耗。
