Heterogeneity of patterns and processes along biological invasion successions

已经证明，生物入侵会造成重大的生态影响，在某些情况下会导致重大的经济损失。确定入侵的内在生物驱动因素是了解当前和预测未来入侵模式的关键一步。入侵是一个复杂的多阶段过程，包括引进、建立和传播非土著物种，直到它对土著社区有害，因此在某些情况下成为有害生物。传统的方法是确定支撑物种入侵能力的相关生物学特征。然而，最近的研究表明，在入侵开始时有益的特征(即有利于新栖息地的殖民)可能不同于入侵后期喜欢的特征。因此，在入侵演替过程中观察到的性状的这种变异在表型和基因组水平上都应该是可见的。例如，在入侵的前沿，个体可能拥有更好的捕食者识别技能和/或更有效的免疫系统来抵御新的病原体。同样，在种群一级，较高的分散率和/或较高的繁殖率可能被证明是入侵早期阶段的决定因素。因此，对于个体来说，在关键阶段(例如，建立、传播)表现出特定的特征对于成功的入侵发生至关重要。然而，目前我们不知道这些性状变异是否有遗传基础，或者它们是否直接来自表型可塑性。此外，个体表型对特定侵袭阶段的贡献仍有待证实。在这个项目中，我们建议描述入侵演替中这些特征变异的模式，并测试这些变异(即遗传和表型)在入侵的不同阶段的重要性。通过实地调查和大规模半自然实验，我们的目标是确定入侵种群沿入侵生境的年龄梯度的遗传和表型异质性是如何表现出来的。为了推广这些发现，我们将使用对一系列生态系统服务具有明显生态和社会经济影响的陆地和淡水模式生物。这些生物已经得到了非常好的研究，整个欧洲的入侵历史的详细特征已经存在(即入侵以来的时间)，并有大量的空间标本收集来支持我们的项目。基于这些经验证据，我们将建立一个抽样策略，以收集关于几个表型特征(形态、生理、行为)的额外信息，以及入侵不同阶段种群的生物和非生物数据。我们还将估计生殖率和传播率，以及遗传中性和非中性多样性，以了解随着种群年龄的变化的起源和后果。其次，我们将在创新和现实的大规模实验设置中创建不同组成(表型特征、生活史特征和关联性)的种群，以测量扩散、殖民和对生态系统的影响。实地调查和实验的结果将被用来校准以个人为基础的模型，旨在推广我们的结果，并为利益攸关方提供一个有效的工具。这类工具将有助于管理者优先考虑和预测限制非本地物种传播的行动。

Biological invasions have been shown to drive significant ecological impacts that in some cases lead to substantial economic losses. Characterizing intrinsic biological drivers of invasions is a crucial step to understand current, and predict future patterns of invasion. Invasion is a complex, multi-stage process including introduction, establishment and spread of the non-native species until it becomes harmful for native communities and therefore a pest in some cases. The traditional approach is to identify relevant biological traits that underpin a species ability to invade. However, recent studies suggest that traits beneficial at the start of an invasion (i.e. favouring the colonization of novel habitats) might be different from traits being favoured at later stages of invasion. Such variation in observed traits along the invasion succession should therefore be visible at both the phenotypic and genomic level. For example, at the front of invasion, individuals may have better predator recognition skills and/or a more efficient immune system to endure novel pathogens. Similarly, at the population level higher dispersal rates and/or higher reproductive rates may prove to be determinant during the early stage of invasion. Therefore it seems crucial for an individual to express a specific trait at key stages (e.g. establishment, spread) for a successful invasion to occur. However, currently we do not know whether there is a genetic underpinning to these traits variations or if they arise directly from phenotypic plasticity. In addition, the contribution of individual phenotypes to specific invasion stages remains to be shown. In this project, we propose to characterize these patterns of trait variations within an invasion succession and test for the significance of these variations (i.e. genetic and phenotypic) at different stages of the invasion. Using field surveys and large-scale semi-natural experiments, we aim to determine how the genetic and phenotypic heterogeneity of invasive populations along an age-gradient of invaded habitats is expressed. In order to generalize findings, we will use both terrestrial and freshwater model organisms that have clear ecological and socio-economic impact on a range of ecosystems services. These organisms have been extremely well studied and detailed characterization of invasion history across Europe already exist (i.e. time since invasion), with large spatial collection of specimens in support of our project. Based on these empirical evidences, we will establish a sampling strategy to collect additional information on several phenotypic traits (morphology physiology, behaviour) along with biotic and abiotic data for populations at different stages of the invasion. We will also estimate reproductive and dispersal rates, as well as genetic neutral and non-neutral diversity to understand the origin and consequences of variation with population age. Second, we will create populations of different composition (phenotypic traits, life history traits, and relatedness) in innovative and realistic large-scale experimental set-ups allowing measuring dispersal, colonization and impact on ecosystems. Outputs from the field survey and the experiments will be used to calibrate individual-based models aiming at generalizing our results, and at providing an effective tool for stakeholders. Such tool will be useful to managers for prioritizing and anticipating actions limiting the spread of non-native species.