LTREB: The Population and Community Dynamics of Desert Winter Annuals

0212782这项LTREB提案旨在扩展美国亚利桑那州图森市附近沙漠实验室的索诺兰沙漠遗址上沙漠冬季一年生植物种群和群落动态的连续记录。它将澄清和扩大对人口统计差异和协变及其在人口和社区进程中的作用的理解。将对10至19年前在灌木树冠下和该野外站露天建立的长期地块持续监测沙漠一年生植物的萌发、存活和繁殖。发芽延迟和种子年际交接被认为对沙漠一年生植物的持久性很重要，因此将监测土壤种子储量的大小，并确定灌木下和开阔地带每种植物每年发芽的比例。种子将从标准化的土壤样本中分离出来，并进行生活力测试。这项研究的结果将与天气数据一起分析，以确定气候变化如何决定这些一年生植物物种的种群变化。然后，研究人员将构建这个沙漠年度系统的种群和群落模型。这些模型将被用来探索土壤种子库在面对环境变化时缓冲种群的作用。它们还将被用来研究物种之间的生活史差异如何促进它们的共存和物种多样性。沙漠一年生植物作为模式生物，在我们理解生物如何适应多变和不可预测的环境方面发挥了重要作用。它们还被用来举例说明在可变环境中的非平衡群落动态。然而，它们的动态在经验上并不为人所熟知，尤其是种子的行为。这个项目将为评估这些想法提供最好的长期数据。已经在该系统的进化生态学、种群生态学和群落生态学方面进行了大量的理论和实验工作。这种理论和实验工作与长期观察的结合被证明是在植物生态学中产生新见解和新合成的强有力的方法。这项研究将通过发生在一所主要研究型大学的学术环境中，进一步实现研究和教育相结合的目标。研究生和本科生将参与培养实践培训和研究经验的能力，这是对正规课程的补充。博士、硕士和本科生荣誉项目将作为这项研究的一部分或分支得到促进。相关的本科项目将寻求REU的支持。在这项研究的第一阶段，该项目的本科生和研究生参与者中有一半以上是妇女，并将努力在拟议的研究中纳入较高比例的妇女。该协会将致力于将少数族裔和文化群体纳入这项研究，方法是与校园内的少数族裔访问项目合作。

0212782VenableThis LTREB proposal is to extend the continuous record of population and community dynamicsof desert winter annual plants on permanent plots at a Sonoran Desert site at the DesertLaboratory near Tucson, AZ, USA. It will clarify and extend the understanding of demographicvariation and covariation and its role in population and community processes. Data ongermination, survival and reproduction of desert annual plants will be continuously monitored onlong-term plots established from 10 to 19 years ago at locations both under shrub canopies and inthe open at this field station. Delayed germination and between year seed carry over are thoughtto be important for the persistence of desert annuals, so the magnitude of the soil seed reserveswill be monitored and determine what fraction germinate in each year for each species undershrubs and in the open. Seeds will be separated from standardized soil samples and tested forviability. The results of this research will be analyzed together with weather data to determinehow climatic variation determines population variation for these annual plant species. Theinvestigators will then construct population and community models of this desert annual system.These models will be used to explore the role of soil seed banks in buffering populations in theface of environmental variation. They will also be used to investigate how life historydifferences among species promote their coexistence and species diversity.Desert annual plants have played an important role as model organisms in the development of ourunderstanding of how organisms adapt to variable and unpredictable environments. They havealso been used to exemplify ideas about non-equilibrium community dynamics in variableenvironments. Yet their dynamics are not well known empirically, especially the behavior ofseeds. This project will provide the best available long-term data for evaluating these ideas.There has been considerable theoretical and experimental work carried out on the evolutionaryecology, population ecology and community ecology of this system. Such combinations oftheoretical and experimental work with long-term observations are proving to be a powerfulapproach to yield new insights and syntheses in plant ecology.This research will further the goal of combining research and education by virtue of occurring inthe academic environment of a major research university. Graduate and undergraduate studentswill be involved in capacities that fosters hands-on training and research experience thatcomplements formal coursework. Ph.D., Masters, and undergraduate honors projects will befacilitated as part of or offshoots of this research. REU support will be sought for relatedundergraduate projects. In the first phase of this research more than half of the undergraduateand graduate participants in this project were women and an attempt will be made to include ahigh percentage of women in the proposed research. The PI will endeavor to includeunderrepresented ethnic and cultural groups in this research by working with minority accessprograms on campus.