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DISSERTATION RESEARCH: Biotic interactions and the geographic range limit of Clarkia xantiana across a complex environmental gradient

论文研究：复杂环境梯度下的生物相互作用和 Clarkia xantiana 的地理范围限制

基本信息

批准号：
1701072
负责人：
David Moeller
金额：
$ 1.99万
依托单位：
University of Minnesota-Twin Cities
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-05-15 至 2019-04-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1701072&HistoricalAwards=false
关键词：
DISSERTATION RESEARCH Biotic interactions geographic

项目摘要

It is a longstanding question why some species are found across vast portions of the earth (e.g., dandelions), and some species only occur in small patches of habitat. Similarly, the fact that some species are expanding their ranges rapidly (e.g., invasive species) while many are not remains difficult to explain. Figuring out what enables, or prevents, plants from growing in certain areas has far reaching consequences for management of invasive species, continued productivity of crops in variable environments, and protection of threatened organisms. This project uses a Californian plant species, (Clarkia xantiana), restricted to a small area of Southern California to explore the environmental factors limiting species distributions. Studies often only consider climatic factors, such as temperature and precipitation, as drivers of these distributions. But researchers are increasingly realizing the role microorganisms play in affecting plant growth and distribution. This project will characterize soil microbial communities within and outside C. xantiana's native range, and use a novel field experiment to test how microbes and rainfall may interact to limit C. xantiana's range. The researchers will also conduct a series of educational field trips with a local middle school to teach students about hypothesis testing, scientific experiments, and the natural history of Southern California. This project uses next generation sequencing and a manipulative field experiment to explore interactions between soil microbial communities, precipitation, and plant traits, and how these factors influence the geographic distribution of Clarkia xantiana ssp. xantiana in the foothills of the Southern Sierra Nevada. Multivariate statistical analyses will be used to examine patterns of community shifts across geographic space, focusing on those microbial taxa differentiating sites within and outside C. xantiana's distributional limit. An in situ soil microbial transplant experiment, paired with a rainfall manipulation treatment, will quantify the main and interactive effects of these factors on fitness outside the range. PVC growth cores installed in the ground at sites outside the range edge will be used to manipulate local soil microbial environments surrounding individual xantiana plants via inoculation with microbial communities from inside the range. This is paired with a rainfall manipulation treatment in a split-plot design, where half of the plots will receive 50% rainfall addition. The effects of site, rainfall treatment, inoculum, and all two-way interactions on components of lifetime fitness and phenology will be analyzed using ANOVA.

这是一个长期存在的问题，为什么有些物种在地球的大部分地区被发现（例如，蒲公英），有些物种只出现在小块的栖息地。同样，一些物种正在迅速扩大它们的分布范围（例如，入侵物种），而许多不是仍然很难解释。弄清楚是什么使植物能够或阻止植物在某些地区生长，对于入侵物种的管理，作物在可变环境中的持续生产力以及受威胁生物的保护具有深远的影响。本计画以加州一种仅限于南加州一小块地区的植物Clarkia xantiana为研究对象，探讨限制物种分布的环境因子。研究往往只考虑气候因素，如温度和降水，作为这些分布的驱动因素。但研究人员越来越认识到微生物在影响植物生长和分布方面的作用。该项目将描述C. xantiana的原生范围，并使用一种新的实地实验来测试微生物和降雨如何相互作用，以限制C。Xantiana的范围。研究人员还将与当地一所中学进行一系列教育实地考察，向学生讲授假设检验、科学实验和南加州的自然历史。该项目使用下一代测序和操作性田间实验来探索土壤微生物群落，降水和植物性状之间的相互作用，以及这些因素如何影响Clarkia xantiana ssp的地理分布。位于内华达州南部山脉的山麓丘陵中的桑蒂亚纳。多变量统计分析将被用来检查跨地理空间的社区转移的模式，重点是那些微生物类群区分内和外的C。Xantiana的分布极限原位土壤微生物移植实验，配以降雨处理，将量化这些因素对健身范围外的主要和相互作用的影响。PVC生长芯安装在范围边缘以外的场地的地面上，将用于通过接种范围内的微生物群落来操纵单个xantiana植物周围的当地土壤微生物环境。这与裂区设计中的降雨操纵处理配对，其中一半的地块将获得50%的降雨量。将使用ANOVA分析场地、降雨处理、接种物和所有双向相互作用对终生适应性和物候组成部分的影响。