EAGER: How genetic variation in riparian trees influences stream succession and ecosystem function

河流通常是非常古老的水道，数千年来一直在峡谷和山谷中雕刻。由于新的溪流和河流很少，人们对它们的形成知之甚少。我们可以了解这个过程的一个地方是在火山景观中。在灾难性的火山爆发后，泉水和融雪雕刻出新鲜的河道。树木排列在新形成的河流和小溪旁边，为这些水生系统提供树荫、庇护所和重要的树叶和营养物质。这些树木也有助于塑造河流本身，稳定银行，创造曲折，减缓侵蚀。这个项目研究了在圣海伦斯火山爆发后形成的沿着溪流定居的柳树。研究人员将研究这些树木的遗传变异对相关溪流群落的发展、生态系统结构和演替过程的影响。了解树木遗传学在河流系统发展中的影响，有可能改变我们对水生生态系统结构的理解。这项研究对于河流的管理和保护也很重要，因为它探讨了树木在河流系统形成中的关键作用。该项目还将开展外联活动，吸引公众和中学生参与，并促进女孩参与STEM。 这项研究探讨了新的作用，殖民树木的遗传学可能在构建流网络，扩展基因生态系统的研究进化地貌。使用已建立的共同花园和四个源头流在圣海伦斯山，本研究将探讨如何男性和女性杨柳树不同的凋落物质量，草食引起的叶片化学变化，以及随后的影响流凋落物依赖的微生物，大型无脊椎动物，和落叶分解。将使用确定杨柳基因型的既定引物对已标记为雄性或雌性的植物和克隆进行基因分型以确定遗传相关性。CHN成分和缩合单宁将被测量为每个杨柳基因型采样从共同的花园和垃圾袋将在溪流中孵化，以量化的遗传和化学差异对河流生物群落的影响。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

Rivers are generally very old waterways that have been carving through canyons and valleys for thousands of years. Because new streams and rivers are rare, little is known about how they form. One place we can learn about this process is within volcanic landscapes. After catastrophic volcanic eruptions, water from springs and snowmelt carve fresh stream channels. The trees that line the newly formed rivers and streams then provide shade, shelter, and crucial inputs of leaves and nutrients into these aquatic systems. These trees also help shape the rivers themselves by stabilizing banks, creating meanders, and slowing erosion. This project examines willows that have colonized along streams that formed after the eruption of Mount St. Helens. Researchers will study the influence of genetic variation in these trees on the development, ecosystem structure, and successional processes of the associated stream communities. Understanding the impact that the genetics of trees plays in the development of river systems has the potential to transform our understanding of how aquatic ecosystems are structured. This research is also important for the management and conservation of rivers because it explores the critical roles trees play in the formation of river systems following disturbances. This project will also provide outreach that engages the public and middle school students and promotes the participation of girls in STEM. This study explores the novel role the genetics of colonizing trees may play in structuring stream networks; extending genes-to-ecosystems research into evolutionary geomorphology. Using established common gardens and four headwater streams at Mount St. Helens, this study will examine how male and female willow trees differ in terms of litter quality, herbivory-induced leaf chemical changes, and their subsequent influence on in-stream litter-dependent microbes, macroinvertebrates, and leaf litter decomposition. Plants that have been tagged as male or female and clones will be genotyped to determine genetic relatedness, using established primers for determining willow genotypes. CHN composition and condensed tannins will be measured for each willow genotype sampled from the common gardens and litterbags will be incubated in the streams to quantify the impact of genetic and chemical differences on riverine biotic communities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.