DISSERTATION RESEARCH: The relative contribution of pollen vs. seed dispersal to gene flow in a fragmented Neotropical landscape

砍伐森林是对世界各地生物多样性的主要威胁之一。当大片森林被砍伐(通常是为了容纳人类)时，剩下的孤立碎片的动植物灭绝的可能性增加了。对于植物来说，花粉和种子的移动有可能将这些森林连接起来，并增加长期的种群健康。该项目将研究森林碎片之间的花粉和种子流动如何影响遗传连通性和多样性，从而将灭绝风险降至最低。这项研究位于厄瓜多尔西北部一个快速发展的地区，那里的当地社区生活着高度多样化的动植物。这项研究的结果将直接与当地森林碎片的所有者、当地学校和社区以及负责管理该地区森林的地区政府机构分享。作为该项目的一部分，将为当地社区举办讲习班，介绍森林碎片的生物学和重要性。美国本科生志愿者将被招募参与这项拟议的研究，并将接受现场和实验室技术方面的培训。这个项目将支持一名博士生的研究和培训。新热带棕榈树的不寻常之处在于，种子可以附着在已建立的幼苗上数年。这一特征使研究人员能够通过对种子和叶片进行基因分型，将花粉和种子在同一个体内传播的遗传贡献分开。将对另外5个森林碎片中的已建立的苗木进行种子和叶组织的采样。这些样本将与已经从12个碎片中收集的组织样本结合在一起。微卫星标记将被用来对这些组织进行基因分型，结果将被用来估计花粉传播或种子传播对有效的遗传多样性和遗传结构的贡献更大。同样的数据将用于识别碎片内和碎片之间的花粉和种子来源，以及比较碎片和连续森林之间的遗传结构。这项研究将通过明确确定花粉和种子传播对已实现的遗传变异模式的单独和联合贡献，改进目前研究碎片化植物种群基因流的方法。这项研究还得到了一个模拟模型的补充，该模型预测限制花粉和种子传播或同时限制花粉和种子传播将如何影响森林碎片中的遗传多样性和结构水平。

Deforestation is one of the leading threats to biodiversity around the world. When large areas of forests are cut down, often to accommodate humans, the chance of extinction increases for plants and animals that remain in isolated fragments. For plants, the movement of pollen and seeds has the potential to connect these pieces of forest and increase long-term population health. This project will examine how pollen and seed movement among forest fragments influences genetic connectivity and diversity, thereby minimizing risk of extinction. This study is located in a rapidly developing region in northwest Ecuador where the local communities live alongside a high diversity of plants and animals. The results of this study will be shared directly with local owners of forest fragments, local schools and communities, as well as regional government agencies in charge of managing forests in the area. As part of this project, workshops will be given to local communities describing the biology and importance of forest fragments. US undergraduate volunteers will be recruited to participate in the proposed research and will receive training in field and laboratory techniques. This project will support the research and training of a doctoral student.The Neotropical palm Oenocarpus bataua is unusual in that seeds stay attached to established seedlings for several years. This characteristic affords the investigators the ability to separate the genetic contributions of pollen and seed dispersal within the same individuals by genotyping both seeds and leaves. Established seedlings throughout 5 additional forest fragments will be sampled for seed and leaf tissue. These samples will be combined with tissue samples already collected from 12 fragments. Microsatellite markers will be used to genotype these tissues and results will be used to estimate whether pollen or seed dispersal is contributing more to effective genetic diversity and genetic structure. The same data will be used to identify pollen and seed sources within and across fragments, as well as to compare genetic structure between fragments and continuous forest. The research will improve upon current approaches for studying gene flow of fragmented plant populations by unambiguously determining the separate and joint contributions of pollen and seed dispersal to realized patterns of genetic variation. This research is complemented by a simulation model that generates predictions of how restricting either or both pollen and seed dispersal will affect levels of genetic diversity and structure among forest fragments.