Dissertation Research: Investigating the Role of a Cryptic Life Stage in Fern Evolution and Community Assembly

蕨类植物代表了一个成功的和多样化的血统，由一个独特的生命周期，已经持续了数亿年的统一。与蕨类植物或种子植物不同，蕨类植物的单倍体配子体和二倍体孢子体能够在很大程度上彼此独立地发生，因此代表了不同的生态实体。目前蕨类植物生态学的知识几乎完全基于较大的，容易观察到的孢子体阶段;相反，蕨类植物配子体由于其较小的尺寸（通常为1厘米）和缺乏可靠的物种鉴定的形态特征，大多被生态学家忽视。然而，配子体代表了负责繁殖的有性阶段，因此对理解蕨类植物生态学至关重要。DNA条形码技术的最新进展使蕨类植物配子体的鉴定成为可能，并为这一被忽视的植物生物学领域的研究开辟了新的途径。这项研究将利用广泛的DNA条形码库的蕨类植物的莫雷阿，法属波利尼西亚，以确定现场收集的配子体和比较的分布和生态适应的蕨类植物配子体和孢子体在广泛的进化背景。该项目将为多个群体提供福利，包括莫雷阿当地社区和美国的大学生，这对蕨类植物的保护具有重要意义。计划在莫雷阿岛的阿蒂蒂亚社区中心开展外联活动，包括在博物馆举办一次关于蕨类植物生物多样性的多语种展览。此外，本研究的部分数据将由哈佛大学培训的本科生生成。将通过增加博物馆藏品和描述新物种来增加对生物多样性的了解。最后，对物种进行调查。配子体分布将揭示分布模式，这在设计濒危蕨类植物物种保护计划时非常重要。

Ferns represent a successful and diverse lineage, unified by a unique life cycle that has persisted for hundreds of millions of years. Unlike bryophytes or seed plants, the haploid gametophyte and diploid sporophyte of ferns are capable of occurring largely independent of one another, and thus represent distinct ecological entities. Current knowledge of fern ecology is based almost exclusively on the larger, easily observable sporophyte stage; fern gametophytes in contrast have been mostly ignored by ecologists due to their small size (typically 1 cm) and lack of morphological characters for reliable species identification. The gametophyte represents the sexual phase responsible for reproduction, however, and is thus critically important to understanding fern ecology. Recent advances in DNA barcoding methods now allow for the reliable identification of fern gametophytes, and have opened new avenues for research into this neglected area of plant biology. This study will leverage an extensive DNA barcode library of the ferns of Moorea, French Polynesia to identify field-collected gametophytes and compare the distribution and ecological adaptations of fern gametophytes and sporophytes in a broad evolutionary context. This project will provide benefits to multiple groups including both the local community on Moorea and university students in the U.S., and will have important implications for fern conservation. Outreach activities including a multilingual museum display on fern biodiversity are planned for the Atitia community center on Moorea. In addition, data for this research will be partially generated by undergraduates trained at Harvard University. Knowledge of biodiversity will be increased by adding to museum holdings and describing new species. Finally, investigations into species? gametophyte distribution will reveal distribution patterns that will be important to consider when designing conservation programs for endangered fern species.