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，正在越来越多地影响地球环境和生态系统。由于碳和养分在生物圈中循环，而植物物种的特征不同，会影响这些元素的循环速度，因此物种的丰富性和多样性必然会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和生态系统对扰动的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能在多大程度上相互替代？决定一种植物物种对营养循环的影响是否可以被其他物种取代的关键特征是什么？阿拉斯加草袜冻土带的一项田间实验将通过移除在有无施肥的情况下不同植物物种的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养分在施肥下的重新分配，因为在这个高度养分有限的生态系统中，养分是控制碳储存的主要因素。他们还将跟踪潜在的新物种的引入，因为植物群落组成因移除或受精而发生变化。这一结果将有助于揭示人类引起的环境扰动如何改变生态系统碳储存以及植物物种丰富度和多样性的控制机制。这是与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)