DISSERTATION RESEARCH : Species pool influences on the structure and function of fungal symbiont communities

为了解释当地生态系统的多样性和物种组成，有必要考虑到物种在更大范围内的分布。在广泛的时空尺度上发生的过程，如地理隔离和物种进化，驱动了这些区域模式，并决定了可能占据一个位置的区域物种库或物种群。该项目将通过实验来确定当地群落或来自大区域的物种是否解释了与植物及其根相关的真菌的数量和种类。由于这些真菌无处不在，它们是全球营养循环和生态系统生产力的重要驱动力。通过支持博士生的教育和培训以及来自代表性不足群体的本科生的参与，将加强科学工作队伍。该项目将有助于改善园艺和保护环境。区域物种池会以多种方式影响当地群落的聚集。这个问题将解决真菌共生体的根与一种特有的夏威夷植物，calycinum。利用植物-真菌微生物，将实验共生体物种池引入无菌幼苗，根据最初分离共生体的地点的平均年龄和环境异质性，改变真菌物种的数量。高通量分子方法将与物理测量和分析化学相结合，评估根系内已实现的本地共生体群落组成。本文将验证三个假设：(1)更古老或环境异质性更强的区域将导致区域物种库中更大的功能多样性；(2)相对于区域物种库的规模，来自更古老或环境异质性更强的地区的物种库将导致更大的本地实现多样性；(3)区域物种库的丰富度和功能多样性将是共生功能的主要驱动力，以寄主植物的生物量和养分积累为衡量标准。一个地区的地质年龄和环境异质性将通过区域物种库的组成与当地群落的组合和功能联系起来。

In order to explain the diversity and species composition of local ecosystems it is necessary to account for species distributions across larger areas. Processes occurring over broad spatial and temporal scales, such as geographic isolation and species evolution, drive these regional patterns and determine the regional species pool, or group of species that could potentially occupy a location. This project will use experiments to determine whether local communities or species from large regional areas explain the number and kinds of fungi associated with plants and their roots. Because these fungi are ubiquitous, they are globally important drivers of nutrient cycling and ecosystem productivity. The scientific workforce will be strengthened through support for the education and training of a doctoral student and participation of undergraduates from underrepresented groups. The project will contribute to improved horticulture and conservation.The regional species pool will affect local community assembly in multiple ways. This problem will be addressed for fungal symbionts associated with the roots of an endemic Hawaiian plant, Vaccinium calycinum. Using plant-fungal microcosms, experimental symbiont species pools will be introduced to sterile seedlings, varying the number of fungal species along with the mean age and environmental heterogeneity of the sites from which the symbionts were initially isolated. High-throughput molecular methods will be used in combination with physical measurements and analytical chemistry to assess the realized local symbiont community composition within roots. Three hypotheses will be tested: (1) older or more environmentally heterogeneous regions will result in greater functional diversity in the regional species pool; (2) species pools from older or more environmentally heterogeneous regions will result in greater realized local diversity relative to the size of the regional species pool; (3) the richness and functional diversity of the regional species pool will be the primary driver of symbiotic function, measured as the host plant's biomass and nutrient accumulation. The geologic age and environmental heterogeneity of a region will be linked to local community assembly and function via the composition of the regional species pool.