Assessing the threats of climate change to the distribution and functional diversity of a continental freshwater fish assemblage

全球气候变化被认为是生物多样性的主要威胁。淡水生态系统预计将非常容易受到气候变暖和降水模式变化以及多种人为压力的影响。由于淡水生态系统的大小差异很大，因此它们在地理上高度不均匀，但往往高度集中，物种丰富度特别容易受到全球变化的影响：虽然淡水生态系统覆盖不到地球表面的1%，但它们包含了所有描述的物种的约10%。此外，淡水生态系统是支离破碎的栖息地，特别是多种压力因素的结合，成为居住在这些独特热点的物种高度脆弱性的驱动因素。因此，确定最多样化和最易受影响的淡水物种的空间保护优先位置是高度优先事项。结合特征信息，组合的功能多样性可以量化，物种的独特性明确包括在保护的优先次序，拟议的项目旨在进行这样的评估，解决气候变化影响的背景下，整个大陆淡水组合，北美鱼类动物的生物多样性的多个层面。该地区有1050种物种，具有高度多样性，而且具有非常强大的数据情况。这将使我能够首先使用最先进的贝叶斯空间建模方法和新开发的表征河流条件的高分辨率环境层，建立一个可靠的基线预测和对当今鱼类分布的理解。这些预测与气候变化预测相结合，缩放到流水平将使我能够详细评估当前与未来的丰富中心和物种地理范围的潜在变化。通过扩展现有的特征数据集，并将其与空间物种预测，我将解决有关北美鱼类区系的基本地理问题，并具体评估物种丰富度和功能多样性模式之间的潜在差异。最后，我将评估潜在的变化和损失的不同生物多样性方面的预测范围的变化与物种的功能独特性在气候变化的scenaries.The拟议的工作将提供一个大陆规模的地理和明确的空间气候变化评估的一个重要群体的淡水生物。通过应用最新的空间和环境建模技术并将辅助物种信息联系起来，它有可能奠定有用的方法基础，并解决几个普遍关心的问题。众所周知，淡水物种的研究仍然不足，这项工作可能会为其他地区（例如欧洲鱼类）或分类群提供有用的蓝图或比较点。

Global climate change is considered a major threat for biodiversity. Freshwater ecosystems are expected to be highly vulnerable to warming climates and changing precipitation patterns, accompanied by multiple anthropogenic stressors. Due to their substantial variation in size freshwater ecosystems harbour geographically highly uneven yet often highly concentrated species richness that is exceptionally susceptible to global change: while freshwater ecosystems cover less than 1% of the Earth's surface, they contain approximately 10% of all described species. Moreover, freshwater ecosystems are fragmented habitats, and especially the combination of multiple stressors acts as a driver for a high vulnerability of species inhabiting these unique hotspots. Identifying the most diverse and susceptible locations for freshwater species for spatial conservation prioritisation is thus of high priority. Combined with trait information, the functional diversity of assemblages can be quantified and species distinctness explicitly included for conservation prioritization.The proposed project aims to undertake such an assessment addressing multiple dimensions of biodiversity in the context of climate-change impacts for a whole continental freshwater assemblage, the fish fauna of North America. With 1050 species the region is highly diverse and moreover has an exceptionally strong data situation. This will allow me to first build a solid baseline prediction and understanding of current-day fish distributions using state-of-the-art Bayesian spatial modelling approaches and newly developed high-resolution environmental layers characterizing stream conditions. These predictions combined with climate change projections scaled to the stream level will allow me to assess in detail current day vs. future centres of richness and potential changes to species geographic ranges. By extending existing trait datasets and linking it to spatial species predictions I will address basic biogeographic questions about the North American fish fauna and specifically assess the potential discrepancy between patterns of species richness and functional diversity. Finally, I will evaluate the potential changes and loss of different biodiversity facets by relating projected range changes to species functional distinctness under climate change scenarios.The proposed work will provide a first continental-scale biogeographic and explicitly spatial climate-change assessment of an important group of freshwater organisms. By applying latest spatial and environmental modelling techniques and linking in ancillary species information, it has the potential to lay a useful methodological groundwork and address several questions of general interest. Freshwater species remain notoriously understudied, and the work may offer a useful blueprint or point of comparison for other regions (e.g. European fish) or taxa.