Collaborative Research: Exploring the Functional Role of Antarctic Plants during Terrestrial Succession

南极半岛在20世纪后期迅速变暖，比全球平均速度快得多，预计这种变暖将在21世纪剩余时间内恢复并继续。这种快速变暖的一个后果是冰川融化和随后的退缩，导致半岛上以前被冰覆盖的新暴露的土地增加。一旦新的地形暴露出来，生态演替的过程就开始了，早期定居的植物，如苔藓和地衣，以及土壤生物的到来——这一过程通常被称为南极洲的“绿化”。演替的早期阶段将成为南极半岛日益普遍的特征，但它们在南极大陆发生的机制尚未得到很好的了解。一旦植物在新暴露的土壤上建立起来，它们可以改变许多重要的性质，如水动力学、养分循环、土壤发育和微生物栖息地，这些将最终决定未来生态系统的结构和功能。植被、土壤和相关微生物之间的这些关系，被称为“植物-土壤”相互作用，是我们几乎一无所知的。这个项目将是第一个全面研究殖民植物的类型，以及这些植物因气候变化而扩张，将如何影响南极洲陆地生态系统的项目。了解这些过程对于了解南极洲的绿化是如何发生的以及这些不断扩大的植物群落如何影响土壤群落和过程至关重要。通过这项工作，研究团队还将集中培训本科生和研究生，包括培训来自代表性不足群体的学生，以及合作培训来自智利和美国的学生。此外，研究小组将继续把重点放在与K-12学校和公众的科学宣传上，以扩大对南极洲气候变化影响的认识。在本研究中，研究人员将通过对南极半岛和斯科舍弧演替点的调查，以及在冰川演替点的操作现场实验，来测试物种特异性植物功能性状如何影响绿化南极洲的土壤性质和相关的微生物和无脊椎动物群落。在此过程中，他们将追求三个综合目标，以了解冰川退缩后演替过程中南极植物功能特征如何改变其土壤环境和土壤群落。AIM 1)在不同的南极洲植物区系中描述六个基本的植物功能特征（热导率、持水量、反照率、可分解性、组织养分含量和二次化学）；目的2)测量南极冰川演替梯度上植物基本功能性状对土壤物理性质和土壤生物地球化学的相对影响；3)测量南极冰川演替梯度上植物基本功能性状对土壤微生物和无脊椎动物群落的相对影响。他们将探索早期殖民植物，特别是苔藓和地衣，如何改变土壤物理，生物地球化学和生物成分，潜在地影响后来的演替模式。研究人员将在演替地点对植物-土壤相互作用进行深入调查，并在南极洲的南设得兰群岛进行操纵移植实验，以实现他们的目标。研究人员将收集植物功能性状及其对土壤物理性质、生物地球化学、生物丰度和微生物宏基因组学的影响的数据。收集到的数据将是第一个全面衡量南极气候变化导致的冰川退缩和植被扩张期间植物功能类型相对重要性的方法，有助于我们了解在南极洲绿化过程中植物功能群的多样性和丰度是如何变化的。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Part I: Non-technical summaryThe Antarctic Peninsula warmed very rapidly in the late part of the 20th century, much faster than the global average, and this warming is predicted to resume and continue over the rest of the 21st century. One consequence of this rapid warming is the melting and subsequent retreat of glaciers, leading to an increase in newly-exposed land on the Peninsula that was previously covered with ice. Once new terrain is exposed, the process of ecological succession begins, with the arrival of early-colonizing plants, such as moss and lichens, and soil organisms - a process commonly referred to as the “greening” of Antarctica. Early stages of succession will be an increasingly common feature on the Antarctic Peninsula, but the mechanisms by which they occur on the Antarctic continent is not well understood. Once the plants have established on the newly-exposed soil, they can change many important properties, such as water dynamics, nutrient recycling, soil development, and habitat for microscopic organisms, which will ultimately determine the structure and functioning of the future ecosystem as it develops. These relationships between vegetation, soil, and the associated microorganisms, referred to as “plant-soil” interactions, are something we know virtually nothing about. This project will be the first to make a comprehensive study of how the type of colonizing plant, and the expansion of those plants from climate change, will influence terrestrial ecosystems in Antarctica. Understanding these processes is critical to understanding how the greening Antarctica is occurring and how soil communities and processes are influenced by these expanding plant communities. Through this work the research team, will also be intensively training undergraduate and graduate students, including training of students from underrepresented groups and collaborative training of students from Chile and the US. Additionally, the research groups will continue their focus on scientific outreach with K-12 schools and the general public to expand awareness of the effects of climate change in Antarctica.Part II: Technical summaryIn this study, the researchers will use surveys across succession sites along the Antarctic Peninsula and Scotia Arc as well as a manipulative field experiment at glacier succession sites to test how species-specific plant functional traits impact soil properties and associated microbial and invertebrate communities in a greening Antarctica. In doing so, they will pursue three integrated aims to understand how Antarctic plant functional traits alter their soil environment and soil communities during succession after glacial retreat. AIM 1) Characterize six fundamental plant functional traits (thermal conductivity, water holding capacity, albedo, decomposability, tissue nutrient content, and secondary chemistry) among diverse Antarctica flora; AIM 2) Measure the relative effects of fundamental plant functional traits on soil physical properties and soil biogeochemistry across glacial succession gradients in Antarctica; and AIM 3) Measure the relative effects of fundamental plant functional traits on soil microbial and invertebrate communities across glacial succession gradients in Antarctica. They will explore how early-colonizing plants, especially mosses and lichens, alter soil physical, biogeochemical, and biological components, potentially impacting later patterns of succession. The researhcers will use intensive surveys of plant-soil interactions across succession sites and a manipulative transplant experiment in the South Shetland Islands, Antarctica to address their aims. The investigators will collect data on plant functional traits and their effects on soil physical properties, biogeochemistry, biotic abundance, and microbial metagenomics. The data collected will be the first comprehensive measures of the relative importance of plant functional types during glacial retreat and vegetative expansion from climate change in Antarctica, aiding our understanding of how plant functional group diversity and abundance are changing in a greening Antarctica.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.