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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.

为什么有些物种遍布地球的大部分地区（例如蒲公英），而有些物种仅出现在小片栖息地中，这是一个长期存在的问题。同样，一些物种正在迅速扩大其活动范围（例如入侵物种），而许多物种却没有迅速扩大，这一事实仍然很难解释。弄清楚是什么使植物能够在某些地区生长或阻止植物在某些地区生长，对于入侵物种的管理、作物在多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。该项目使用仅限于南加州一小片地区的加州植物物种（Clarkia xantiana）来探索限制物种分布的环境因素。研究通常只考虑气候因素，例如温度和降水，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所发挥的作用。该项目将描述 C. xantiana 原生范围内和之外的土壤微生物群落特征，并使用新颖的田间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，向学生传授假设检验、科学实验和南加州的自然历史。该项目利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。 xantiana 位于内华达山脉南部的山麓。多元统计分析将用于检查跨地理空间的群落变化模式，重点关注 C. xantiana 分布范围内外的微生物类群区分位点。原位土壤微生物移植实验与降雨操纵处理相结合，将量化这些因素对范围外适应性的主要影响和相互作用。安装在范围边缘之外的地下的 PVC 生长芯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控制处理相结合，其中一半的地块将获得 50% 的降雨量增加。将使用方差分析分析场地、降雨处理、接种物以及所有双向相互作用对终生健康和物候学组成部分的影响。