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

氮通常被认为是构成陆地生态系统最重要的元素。现在，人类活动向生态系统中添加的无机氮（IN）比所有自然过程加起来还要多，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本地物种。然而，这些社区转变背后的机制仍然无法解释。新的研究探索有机氮（ON）对植物的重要性提供了令人兴奋和新颖的假设。最近的研究表明，许多温带草地群落由适应营养贫乏环境的物种组成，很少有物种能够利用相对罕见的丰富IN条件。因此，当氮变得容易获得时，无论是通过实验添加还是通过人类活动的沉积，大多数物种都无法利用这一资源，并迅速被机会主义杂草取代。我的研究将调查生物多样性丧失的驱动因素，此外，通过探索物种在利用氮和氮的能力方面的差异，以及预测对氮沉积特别敏感的群落。我目前正在指导几名本科生，他们来自代表性不足的群体，正在进行生态研究，并为日出公园中学开发生物多样性教学模块，并与来自美国和欧洲的研究人员开展类似的合作项目。

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.