Biodiversity adventures in wild Los Angeles: A comparative landscape genomic study of multiple species persistence across the urban-wildland interfaces

城市化相当于近乎永久地消灭当地占主导地位的自然生态系统。鉴于对全球城市化飞速发展的预测，维持和增强城市生物多样性要求我们不仅要了解物种的分布，还要了解城市化如何从机制上影响物种现在和未来的进化潜力。物种的持久性取决于繁殖个体在栖息地斑块之间移动的能力。由此产生的基因流使局部适应得以传播，它改善了小种群中近亲繁殖抑制的影响，并保持了健康的元种群动态。这里提出的研究旨在确定直接影响物种在大城市分布的关键驱动因素，为提高我们对基本城市进化生态学和保护原则的理解提供了一个无与伦比的机会。我围绕城市进化生态学中的四个关键问题组织我的研究，这些问题将通过利用大洛杉矶城市地区独特的许多城市-荒地界面来回答。通过为七对物种汇编一个前所未有的基因组数据集，每对物种由范围广泛和范围更窄的城市居民物种组成，我将量化基因流模式允许区分城市通才和城市专才物种的方式。让我提出这些问题的技术突破是使用数千个遗传标记，或单核苷酸多态性（snp），从每个物种的数百个个体中收集。由此产生的数据分辨率非常精细，能够以以前无法达到的分辨率识别基因流动的驱动因素。到目前为止，只有少数研究在同一景观中比较了两个以上的物种，而且没有一个研究集中在城市地区，或者利用大量的基因组水平的SNP数据进行基因组推断。我还将利用统计技术的最新进展，应用一种从未在城市环境中应用过的新型景观基因组优化程序。包括植物、无脊椎动物和脊椎动物物种，本提案建立在最新研究进展的基础上，强调了进化在维持城市生态过程中的作用。随着居住在城市的人口不断增加以及缓解当地气候变化的需要，城市生物多样性将在健康的城市生态系统服务方面发挥越来越重要的作用，包括其对人类福祉的影响。通过复制同一城市内多个物种的基因组方法，本研究将为充分理解城市景观增强或减少基因流动从而促进或抑制城市生物多样性的机制提供一个关键的、完全缺失的先决条件。

Urbanization is tantamount to a near-permanent elimination of the locally dominant natural ecosystem. In the light of predictions of soaring global urbanization, maintaining and enhancing biodiversity in cities requires that we understand not just the distribution of species, but mechanistically how urbanization impacts the evolutionary potential of species now and in the future. Species persistence depends on the ability of breeding individuals to move between habitat patches. The resulting gene flow allows local adaptations to spread, it ameliorates the effects of inbreeding depression in small populations, and it maintains healthy metapopulation dynamics. The research proposed here is designed to identify key drivers directly impacting the distribution of species across a megacity, providing an unparalleled opportunity to improve our understanding of fundamental urban evolutionary ecology and principles of conservation. I organize my research around four key questions in urban evolutionary ecology, which will be answered by making use of the many urban-wildland interfaces unique to the Greater Los Angeles urban region. By compiling an unprecedented genomic dataset for seven species pairs, each composed of a broadly and a more narrowly ranging urban resident species, I will quantify the ways in which patterns in gene flow allow differentiating urban generalist and urban specialist species. The technological breakthrough allowing me to ask these questions is using thousands of genetic markers, or single nucleotide polymorphisms (SNPs), collected from hundreds of individuals per species. The resulting data resolution is extremely fine-scaled, enabling the identification of drivers of gene flow at previously unattainable resolution. Thus far, only a handful of studies have compared more than two species within the same landscape and none have focused on urban areas or has made use of large, genome-level SNP data for genomic inferences. I will also make use of the latest advances in statistical techniques, applying a novel landscape genomic optimization procedure that has never been applied in an urban context. Including plant, invertebrate and vertebrate animal species, this proposal builds on latest research developments, emphasizing the role that evolution plays in the maintenance of urban ecological processes. With a growing human population living in cities and the need for local climate change mitigation, urban biodiversity will play an increasingly important role in healthy urban ecosystem services, including its well-documented impact on human well-being. By replicating genomic methodology for multiple species within the same city, this research will deliver a critical, and completely missing prerequisite for a full understanding of the mechanisms by which urban landscapes enhance or reduce gene flow and therefore promote or inhibit urban biodiversity.