Collaborative Research on the Effects of Plant Species and Functional Types on Diversity, Ecosystem Function, and Ecosystem Response to Perturbation in Arctic Tundra

人类活动不仅通过对气候和元素循环的直接影响，而且通过加快物种引进和灭绝的速度，对地球环境和生态系统的影响越来越大。由于碳和营养物质在生物圈中循环，而植物物种的不同特性会影响这些元素的循环速率，因此物种的丰度和多样性必然影响生态系统的功能。然而，单个植物物种对生态系统功能的影响程度以及物种多样性与生态系统对扰动响应之间的关系在很大程度上仍然是未知的。植物物种在生态系统功能上的相互替代在多大程度上？哪些关键性状决定了一个植物物种对养分循环的影响是否可以被其他物种所取代？在阿拉斯加的草丛苔原上进行的一项野外实验将通过在有无施肥的情况下去除不同的植物物种组合来检验这些问题。研究人员将详细了解植物物种之间的相互作用如何控制施肥下营养物质的重新分配，因为在这个营养高度有限的生态系统中，营养物质是碳储存的主要控制因素。他们还将跟踪随着植物群落组成因清除或施肥而发生变化而可能引入的新物种。这些结果将有助于揭示人类引起的环境扰动如何改变控制生态系统碳储量和植物物种丰度和多样性的机制。这是一个与Michelle Mack （DEB-0212749）合作的项目

Human activities are increasingly affecting earth's environment and ecosystems not only through direct impacts on climate and element cycling, but also by increasing the pace of introductions and extinctions of species. Because carbon and nutrients are cycled through the biosphere and plant species differ in traits that affect the rates of cycling of these elements, the abundance and diversity of species must affect ecosystem function. However, the extent to which individual plant species affect ecosystem function and the relationship between species diversity and ecosystem response to perturbation are still largely unknown. To what extent can plant species substitute for each other in ecosystem function? What key traits determine whether a plant species' effect on nutrient cycling can be substituted by other species? A field experiment in Alaskan tussock tundra will examine these questions by removing different combinations of plant species in the presence and absence of fertilization. The investigators will obtain a detailed picture of how interactions between plant species control how nutrients are redistributed under fertilization, because nutrients are a primary control over carbon storage in this highly nutrient-limited ecosystem. They will also track potential introductions of new species as plant community composition shifts because of the removals or fertilization. The results will help reveal how human-induced environmental perturbations may change the mechanisms controlling ecosystem carbon storage and plant species abundance and diversity.This is a collaborative project with Michelle Mack (DEB-0212749)