An Evaluation of Dispersal Distances of Two Treeline-Forming Species

随着时间的推移，环境发生了变化，植被必须适应、迁移或死亡。植物的迁移能力是生物地理学和生态学中最为棘手和悬而未决的问题之一。遗传学的最新进展使以前无法评估的植物迁移潜力得以分析。在气候变化的条件下，植被带可能发生变化。这些变化的幅度以及变化发生的速度可以由气候变化的速度和植被群落元素能够对这些变化作出反应的速度来决定。植物传播种子的能力以及这些种子在气候变化下生根发芽的能力尚不为人所知。这项研究将对不同植被类型之间的过渡带（过渡带）的文献做出重要贡献，最终回答了一个问题，即在一个广泛的植被过渡带（高山树线）上的新个体是来自当地环境还是来自长途旅行。确定树线扩散距离的程序也可推广到其他过渡带或生态系统。本研究将通过使用基因组DNA的微卫星（短序列）分析来确定阿拉斯加中南部的白云杉和山铁杉的遗传亚种群，从而检验上述核心问题。这些种群将被用来确定进入树线的新种群与近种群还是远种群的关系更密切，从而确定长距离还是短距离扩散的流行程度。还将进行亲缘关系分析，以估计实际的扩散距离和方向。这项研究将有助于培养研究生和本科生，并加强美国和德国科学家之间的联系。将努力在研究中招募代表性不足的学生群体。此外，通过与美国国家公园管理局（NPS）和美国鱼类和野生动物管理局已经建立并将进一步加强的联系，将促进与公众的互动。教育推广机会将包括向国家自然资源管理局工作人员进行公开演讲，以及向前往基奈峡湾国家公园、基奈国家野生动物保护区和德克萨斯州当地学校的游客传播主要发现。

As environments change over time, vegetation must adapt, migrate or die. The ability of plants to migrate is one of the more intractable and unanswered problems in both biogeography and ecology. Recent advances in genetics allow analysis of plant migration potential that previously had been impossible to assess. Under a changing climate, vegetation zones may shift. The magnitude of those shifts as well as the speed at which those shifts occur can be determined by both the rate of climate change and the rate at which elements of vegetation communities are able to respond to those changes. The ability of plants to disperse their seeds and for those seeds to become established under climate change is not well known. This research will make a vital contribution to the literature on transition zones (ecotones) among different vegetation types by finally answering the question whether new individuals at one wide-spread vegetation transition (the alpine treeline) are derived from the local environment versus if they are traveling long distances. The procedures developed to determine dispersal distances at treeline could also be extended to other ecotones or ecosystems.This study will examine the central questions above by employing microsatellite (short sequence) analysis of genomic DNA to identify the genetic sub-populations of both white spruce and mountain hemlock in southcentral Alaska. These populations will be used to determine if recruits to the treeline are more closely related to near or far populations, thereby determining the prevalence of long versus short distance dispersal. A parentage analysis will also be conducted to estimate actual dispersal distances and directions. This research will aid in the training of both graduate and undergraduate students and strengthen ties between scientists in the US and Germany. Efforts will be made to recruit under-represented groups of students in the study. Furthermore, interaction with the general public will be facilitated through the connections that have been made and will be further strengthened with the US National Park Service (NPS) and the US Fish and Wildlife Service. Educational outreach opportunities will include public presentations to NPS personnel as well as dissemination of key findings to visitors to the Kenai Fjords National Park, the Kenai National Wildlife Refuge, and to local schools in Texas.