Functional-phylogenetic diversity in European and African freshwater systems

人口增长和气候变化严重威胁着全球淡水系统的完整性，降低了淡水系统提供生态系统服务和支持生物多样性的能力。淡水系统是地球上生物多样性最集中的地区——它们只占地球表面的不到1%，但却拥有大约10%的已描述物种，其中至少60%是水生昆虫。然而，对于导致这种显著多样性和塑造当代淡水物种分布的过程，人们几乎一无所知。我们之前发现，热适应和物种适应静水或流水的生态差异塑造了温带地区昆虫物种的分布，但它们的广泛分布尚不清楚，这些特征是否对淡水昆虫的多样化也很重要尚不清楚。在我们提出的项目中，我们将以非洲和欧洲蜻蜓（Odonata）为模型系统，了解几种潜在的热适应和扩散能力与淡水昆虫多样化历史和当代分布的关系。我们的框架结合了世界上几乎完整的蜻蜓系统发育，以及大约900种非洲和欧洲蜻蜓物种的分布、功能和系统发育差异的数据——整个昆虫序列的多样性跨越了完整的纬度梯度。这将使我们能够解决(1)温度与蜻蜓物种的身体颜色（亮度）和身体大小的变化之间的联系是否对它们的分布具有普遍的（机械的）重要性，(2)与物种栖息地稳定性相关的翅膀形态适应的重要性，以促进蜻蜓谱系之间的多样化和范围大小变化，以及(3)大多数蜻蜓谱系是否保留了它们最初的，热带生态位（系统发育生态位保守性）。我们的方法结合了广泛的最先进的方法，包括计算机辅助数字图像分析，锚定杂交富集测序，结构方程模型和功能-系统发育多样性的零模型。这些方法将使我们对形成蜻蜓和其他淡水生物分布的基本生态和进化过程有前所未有的了解。有了这项研究的结果，我们将能够评估蜻蜓物种对气候变化的敏感性及其相应的分散能力。

Human population growth and climate change severely threaten the integrity of freshwater systems globally, reducing their ability to provide ecosystem services and to support biodiversity. Freshwater systems contain the highest concentrations of biodiversity on Earth - they occupy less than 1% of the Earth's surface but harbour approximately 10% of all described species, of which at least 60% are aquatic insects. Yet almost nothing is known about the processes that led to this remarkable diversity and shaped the contemporary distributions of freshwater species. We previously found that thermal adaptations and differences in the ecology of species adapted to standing or running waters have shaped the distribution of insect species in temperate regions, but their broad-scale distribution is unknown and whether these traits are also important for the diversification of freshwater insects remains unclear. In our proposed project, we will use African and European dragonflies (Odonata) as a model system to understand the association of several potential thermal adaptations and proxies of dispersal ability with the diversification history and contemporary distribution of freshwater insects. Our framework combines a near-complete phylogeny of the dragonflies of the world with data on the distribution as well as functional and phylogenetic differences of approximately 900 African and European dragonfly species - the diversity of an entire insect order across a complete latitudinal gradient. This will allow us to address (1) whether the association of temperature with the variation in body colour (lightness) and body size of dragonfly species is of general (mechanistic) importance for their distribution, (2) the importance of adaptations in wing morphology that are associated with the stability of the species habitats for the diversification of and range size variation among Odonata lineages, and (3) whether the majority of Odonata lineages have retained their initial, tropical niche (phylogenetic niche conservatism). Our approach combines a wide spectrum of state-of-the-art methods, including computer-assisted digital image analysis, Anchored Hybrid Enrichment sequencing, structural equation models and null models of functional-phylogenetic diversity. These methods will allow unprecedented insights into the fundamental ecological and evolutionary processes that shaped the distributions of dragonflies and other freshwater organisms. With the results of this research we will be able to assess the sensitivity of dragonfly species to climate changes and their ability to disperse accordingly.