Doctoral Dissertation Research: Investigating the Influence of Biotic and Abiotic Factors on Grasslands in the Great Plains Region of the U.S.

地理空间科学（GSS）项目本博士论文研究项目将评估生物和非生物因素对草原组成的影响，通过花粉组合表现出来。 这项研究将为湖泊沉积物岩心的花粉解释提供新的见解，揭示植被随时间的变化，并提供有关花粉生产力和天然草原环境组成年际变化的重要信息。 虽然是在当代背景下进行的，但该项目将通过帮助量化花粉（作为植被代理）与火、食草动物和地形等关键驱动因素之间的关系，帮助回答古生态学研究中的重要问题。 该项目将提高长期数据集的价值，该数据集是北美草原花粉组成的最长年度记录。 该博士生将与一所为代表性不足的人口服务的高中合作，将基于研究的模块整合到他们的科学课程中。 此外，该项目还将产生新的信息和见解，以更有效地完善健康和医疗领域的过敏评估。 作为博士论文研究改进奖，该奖项将提供支持，使有前途的学生能够建立强大的独立研究事业。北美草原出现在大约2500万年前，尽管气候和动物群发生了巨大变化，但一直存在。 随着时间的推移，特别是在整个全新世时期，物种组成和生物群落的范围发生了变化，但影响这些变化的生物和非生物因素的作用仍然未知。 这位博士生将在堪萨斯州的高草草原上开展该项目。 研究区域是多样的，具有可变的地形，并包括网站，经历了一系列不同的燃烧和放牧处理。 研究将侧重于量化草原花粉组合与影响该地区的生物和非生物变量之间的关系。 这将通过在整个研究过程中从多个陷阱中识别花粉来完成，以产生一组多年的现代花粉数据。 博士生将量化这些数据，以便通过多元统计分析评估草原花粉的年际变化。 这项研究的结果将能够更好地解释过去的植被覆盖，并促进更好地预测草原对人类引起的火灾和草食动物制度的变化在一系列当前和未来可能的气候条件。

NATIONAL SCIENCE FOUNDATIONGEOGRAPHY SPATIAL SCIENCES (GSS) PROGRAMABSTRACTThis doctoral dissertation research project will evaluate the influence of biotic and abiotic factors on grassland composition as exhibited through pollen assemblages. The research will provide new insights into interpretations of pollen from lake sediment cores that reveal changes in vegetation over time and contribute important information about interannual variation in pollen productivity and composition of a natural grassland environment. Although conducted in a contemporary context, the project will help answer important questions in paleoecological research by helping quantify the relationships between pollen (as a vegetation proxy) and key drivers like fire, herbivory, and topography. The project will enhance the value of a long-term dataset that is the longest-running annual record of North American grassland pollen composition. The doctoral student will work with a high school serving underrepresented populations to integrate a research-based module into their science curriculum. In addition, the project also will yield new information and insights to more effectively refine allergy assessments in the health and medical fields. As a Doctoral Dissertation Research Improvement award, this award will provide support to enable a promising student to establish a strong independent research career.North American grasslands emerged about 25 million years ago and have persisted despite dramatic changes in climate and fauna. Over time, and especially throughout the Holocene Epoch, the species composition and the extent of the biome has changed, but the role of the biotic and abiotic factors influencing those changes remain unknown. The doctoral student will conduct this project in a tallgrass prairie in Kansas. The study area is diverse, with variable topography, and includes sites that have experienced a range of different burning and grazing treatments. The research will focus on quantifying the relationships between grassland pollen assemblages and the biotic and abiotic variables influencing the region. This will be accomplished by identifying pollen from multiple traps throughout the study to produce a multi-year set of modern pollen data. The doctoral student will quantify these data in order to assess interannual variations in grassland pollen through multivariate statistical analyses. Outcomes from this research will enable better interpretation of past vegetation cover and facilitate better predictions of grassland response to human-induced shifts in fire and herbivory regimes during a range of current and possible future climatic conditions.