Is urban streams are eco-evolutionary drivers of freshwater fish invasion?

自工业时期开始以来，生物多样性，特别是淡水生境的生物多样性严重枯竭。栖息地退化和入侵物种被认为是造成这种下降的两个主要原因，但它们的影响取决于背景。一些地区是入侵的热点，入侵物种不成比例地丰富。建议入侵热点更多地出现在受干扰的生境中，特别是城市和郊区环境。虽然入侵生物学认识到，入侵物种可以从城市环境中受益于最初的引入、建立和二次扩散，但这种促进机制仍有待更好地描述。在生态学上，提出了两种不同的假设，一种是不耐受干扰的物种减少竞争，另一种是城市耐受入侵物种增加对受干扰生境中生态机会(如食物资源、栖息地)的依赖。从进化的角度来看，越来越多的证据表明，在上述生态相互作用的推动下，城市诱导的进化是入侵的推动者。然而，所有城市入侵物种进化的例子都是在植物、哺乳动物或鸟类模式物种中发展出来的；鱼类在这一领域仍然很少见。因此，确定城市流是否以及如何成为入侵的热点，以及它们是否作为入侵的进化驱动因素，对于更好地了解入侵动态，减少入侵潜力和改进城市规划至关重要。在这个为期五年的研究计划中，我的目标是评估在城市化日益加剧的梯度下导致入侵鱼类流行的生态机制，分析受干扰社区的生态位(例如营养和热量)和生命速率(例如生长速率和条件)的种内和种间响应的方向和幅度随环境的变化，并寻找城市诱导适应受干扰栖息地的生理特征(代谢率)进化的证据。通过应用综合生态学框架，该框架将结合群落生态学、生物地球化学(稳定同位素分析)和基于田间的呼吸测量，我们将深入了解生物入侵的基本机制，以及城市的适应性管理如何减少入侵机会。确定城市组成部分(如河岸植被、水管理、土地利用)如何增加城市溪流中入侵物种的流行，将指导管理者在提供有价值的生态系统服务的被忽视的生境促进生物多样性保护。

Biodiversity, especially in freshwater habitats, has suffered severe depletion since the onset of the industrial period. Habitat degradation and invasive species are identified as the two main causes for this decline, but their effects are context-dependent. Some regions act as invasion hotspots, where invasive species are disproportionately abundant. Invasion hotspots are suggested to be more prevalent in disturbed habitats, notably urban and suburban environments. Whereas invasion biology recognizes that invasive species could benefit from urban environments for the initial introduction, establishment and secondary dispersal, mechanisms of this facilitation remain to be better described. Ecologically, two alternative hypotheses are suggested, where either decrease of competition by disturbance-intolerant species or increase of reliance on ecological opportunities (e.g. food resources, habitats) in disturbed habitats by urban-tolerant invasive species. From an evolutionary point of view, growing evidence is pointing toward urban-induced evolution, fueled by said ecological interactions, as a promoter of invasion. All examples of urban evolution of invasive species, however, have been developed in plants, mammals or avian model species; fishes remain uncommon in this field. Hence, establishing if and how urban streams are hotspots of invasion and if they act as an evolutionary driver for invasion is crucial to better understand invasion dynamics, decrease invasion potential and improve cities planning. In this 5-years research program, I will aim to assess the ecological mechanisms resulting in invasive fish prevalence in an increasing gradient of urbanization, to analyze the context-dependent variability of direction and magnitude of the intra- and inter-specific responses of the ecological niche (e.g. trophic and thermal) and vital rates (e.g. growth rates and condition) in communities subjected to disturbance and to find evidence of urban-induced evolution of physiological traits (metabolic rates) adapted to disturbed habitats. By applying an integrative ecology framework, which will combine community ecology, biogeochemistry (stable isotopes analysis) and field-based respirometry we will provide insights into fundamental mechanisms at play in biological invasion and how adaptive management of cities could mitigate invasion opportunities. Identification of how cities' components (e.g. riverbank vegetation, water management, land-uses) increase the prevalence of invasive species in an urban stream will guide managers for promotion of biodiversity conservation in overlooked habitats providing valuable ecosystem services.