Dissertation Research: Why Plant Communities Shift After Changes in Nitrogen Availability: The Organic Connection

论文研究：为什么植物群落在氮可用性变化后发生变化：有机联系

• 批准号: 0508571
• 负责人: David Tilman
• 金额: --
• 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: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0508571&HistoricalAwards=false
• 关键词: Dissertation; Research; Why; Plant; Communities

Nitrogen is often considered the most important element structuring terrestrial ecosystems. Human activities now add more inorganic nitrogen (IN) to ecosystems than all natural processes combined, resulting in losses of biodiversity, increased pollution of groundwater, and often leading to weedy invasive species displacing natives. However, the mechanisms behind these community shifts remain unexplained. New studies exploring the importance of organic nitrogen (ON) to plants offer exciting and novel hypotheses. Recent research suggests that many temperate grassland communities are comprised of species adapted to nutrient poor environments, with few species able to capitalize on the relatively rare condition of abundant IN. Consequently, when IN becomes readily available, either through experimental addition or through deposition from human activities, most species present are unable to utilize this resource and are rapidly displaced by opportunistic weeds. My research will investigate drivers of biodiversity loss following IN addition by exploring how species differ in their abilities to use IN versus ON, as well as predict communities that are particularly sensitive to N deposition. I am currently involved in mentoring several undergraduate students from underrepresented groups who are conducting ecological research and by developing teaching modules on biodiversity for the Sunrise Park Middle School, and by working on similar collaborative projects with researchers from the United States and Europe.

氮通常被认为是构成陆地生态系统的最重要的元素。人类活动现在向生态系统中添加的无机氮(IN)比所有自然过程的总和还要多，导致生物多样性丧失，地下水污染加剧，并经常导致杂草入侵物种取代原住民。然而，这些社区转变背后的机制仍然没有得到解释。探索有机氮(ON)对植物重要性的新研究提供了令人兴奋的新颖假说。最近的研究表明，许多温带草原群落是由适应营养不良环境的物种组成的，很少有物种能够利用相对罕见的丰富IN条件。因此，当IN变得容易获得时，无论是通过试验性添加还是通过人类活动的沉积，现有的大多数物种都无法利用这种资源，并迅速被机会性杂草取代。此外，我的研究还将通过探索物种利用IN和ON的能力的不同，以及预测对N沉积特别敏感的群落，来调查生物多样性丧失的驱动因素。目前，我正在参与指导几名来自代表不足群体的本科生，他们正在进行生态学研究，为日出公园中学开发生物多样性教学模块，并与美国和欧洲的研究人员合作开展类似的合作项目。