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

这一博士论文研究项目调查了高山林线交错带种子传播的重要性。一般来说，在对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，这一问题对于我们理解这种过渡带可能会随着时间的推移而变化至关重要。如果种子只在短距离内传播，植物只能缓慢地适应环境条件的变化。然而，如果种子在长距离传播，植被带可能能够更近距离地跟踪快速变化的环境。以前，由于在整个土地上追踪种子的挑战，很难确定有效的传播距离。利用分子遗传学技术，可以对树线上已建立的个体植物的起源进行评估，以确定种子生产在多大程度上是局部过程或长距离传播的结果。这一点尤其重要，因为预计未来气候的变化速度将比过去快得多，研究人员了解物种的迁徙潜力以预测未来的生态系统可能是什么样子是很重要的。这项研究将调查遗传信息在区域和地方尺度上的传播和流动。这项研究将结合地理和遗传学技术来检验两个假设：1)长距离扩散发生在树线上，2)克隆繁殖不是树线种群的主要繁殖模式。更好地理解远距离种子传播的重要性和克隆繁殖的相对丰富性将广泛地转移到其他交错带的研究中。此外，将遗传分析纳入空间生态学的背景下，将有助于在未来进行更多的此类研究。这项研究是一项新颖的地理学和遗传学的结合，旨在回答一系列相关问题，从而更深入地了解树线在气候变化下可能会如何迁移。此外，这项研究的结果将有助于更好地理解种子传播对树线动态的影响。产生的扩散数据将有助于改进厚尾扩散曲线的参数化，这些曲线可用于未来的研究，以模拟气候变化情景下的迁移。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应对不断变化的生态系统的能力的重要性有关的其他假设。研究小组将在基奈国家野生动物保护区和基奈峡湾国家公园向研究和管理人员以及公众展示这项研究的结果。该团队将通过Refuge Notebook专栏为半岛克拉里昂撰写一篇文章，并将在被引用的期刊上发表文章，以进一步传播他们的发现。调查结果还将在会议上和通过在线数据共享进行传播。该项目将促进德克萨斯农工大学本科生在野外和实验室工作方面的科学教育和培训。本科生的参与将着眼于纳入代表性不足的群体。作为博士论文研究改进奖，该项目将为有前途的学生建立独立的研究生涯提供支持。

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.