Doctoral Dissertation Research: A Genetic Approach to Dispersal at the Alpine Treeline Ecotone

本博士论文研究项目探讨种子传播在高寒乔木线交错带的重要性。总的来说，在植被过渡带的研究中，种子是在当地传播还是从遥远的种群到达的问题对于我们理解这种过渡带如何随时间变化至关重要。如果种子只传播很短的距离，植被只能缓慢地适应环境条件的变化。然而，如果种子长距离传播，植被区可能能够更密切地跟踪快速变化的环境。以前，由于在整个景观中跟踪种子的挑战，很难确定有效的传播距离。利用分子遗传学技术，可以评估树线上已建立的单株植物的起源，以确定种子生产在多大程度上是局部过程还是长距离传播的结果。当未来的气候变化预计将比过去快得多时，这一点尤为重要，研究人员了解物种的迁移潜力，以预测未来的生态系统可能是什么样子，这一点也很重要。本研究将调查遗传信息在区域和局部尺度上的传播和流动。该研究将结合地理和遗传学技术来验证两个假设：1)远距离扩散正在树线发生；2)无性系繁殖不是树线种群繁殖的主要模式。对种子长距离传播的重要性和克隆繁殖的相对丰度的进一步了解将广泛地转移到其他过渡带研究中。此外，将遗传分析纳入空间生态学背景将促进未来此类研究的进一步开展。这项研究将地理学和遗传学结合起来，回答了一系列相关的问题，从而更深入地了解了气候变化下树木线是如何迁移的。此外，本研究的结果将有助于更深入地了解种子传播对树线动态的影响。生成的扩散数据将有助于改进肥尾扩散曲线的参数化，可用于未来气候变化情景下的迁移模型研究。该项目还将用于产生与扩散、基因流动以及景观配置和地理对植物响应不断变化的生态系统能力的重要性有关的其他假设。该小组将编写一份研究结果的报告，向基奈国家野生动物保护区和基奈峡湾国家公园的研究和管理人员以及公众展示。该团队将通过避难所笔记本专栏为半岛号角写一篇文章，并将在评审期刊上发表，以进一步传播他们的发现。调查结果也将通过会议和在线数据共享传播。该项目将在野外和实验室工作中促进德克萨斯农工大学本科生的科学教育和培训。本科生参与的目标是纳入代表性不足的群体。作为博士论文研究进步奖，该项目将提供支持，使有前途的学生建立一个独立的研究生涯。

This doctoral dissertation research project investigates the importance of seed dispersal at the alpine treeline ecotone. In general, in studies of vegetation transition zones, the question of whether seeds are dispersed locally or arrive from distant populations is critical to our understanding of how such transition zones may change over time. If seeds are only traveling short distances, vegetation can only adapt slowly to changes in environmental conditions. If, however, seeds are traveling long distances, vegetation zones may be able to track a rapidly changing environment more closely. Previously, it has been difficult to determine effective dispersal distances due to challenges in tracking seeds across the landscape. Using molecular genetics techniques, the origin of established individual plants at treeline can be assessed to determine to what degree seed production is a local process or the result of long distance dispersal. This is particularly important when future climates are expected to change much more rapidly than they have in the past, and it is important that researchers understand migration potential of species to predict what future ecosystems may look like. This study will investigate dispersal and flow of genetic information both regional and local scales. The research will integrate a combination of geographic and genetics techniques to test two hypotheses 1) long distance dispersal is occurring at treelines, and 2) clonal reproduction is not the dominant mode of reproduction at treeline populations. Improved understanding of the importance of long distance seed dispersal and the relative abundance of clonal reproduction will be broadly transferrable to other ecotone studies. Furthermore, the incorporation of genetic analyses into a spatial-ecology context will facilitate additional research of this kind in the future.This study is a novel integration of geography and genetics to answer a pertinent set of questions allowing for a deeper understanding of how treelines may migrate under altered climate. Additionally, the results from this study will contribute to a stronger understanding of the influence of seed dispersal on treeline dynamics in general. The dispersal data generated will contribute to improved parameterization of fat tailed dispersal curves that can be used in future research to model migration under changing climate scenarios. The project will also be used to generate additional hypotheses related to dispersal, gene flow, and the importance of landscape configuration and geography on the ability of plants to respond to changing ecosystems. The team will develop a presentation of the study's findings to present to research and management staff and to the general public at the Kenai National Wildlife Refuge and Kenai Fjords National Park. The team will write an article for the Peninsula Clarion, via the Refuge Notebook column, and will publish in refereed journals to further disseminate their findings. Findings will also be disseminated at conferences and through online data sharing. The project will foster science education and training to an undergraduate at Texas A&M University in both field and laboratory work. Undergraduate involvement will target inclusion of underrepresented groups. As a Doctoral Dissertation Research Improvement award, this project will provide support to enable a promising student to establish an independent research career.