Collaborative Research: Identifying the Footprints of Human Colonization on Australian Ecosystems and Climate

该项目试图解决一个科学问题：早期人类殖民者的系统性焚烧是否足以改变澳大利亚的植被，从而对气候和生物群造成明显的非线性破坏？研究人员将通过一系列可检验的预测来解决这个问题，以使用可测年地质档案中的示踪剂来评估这一假说。研究小组将整合现场和分析数据，提供可以用中尺度气候模型测试的环境情景，以评估假设的人类诱导的植被变化对季风雨的影响。在过去的6万年里，现代人已经从他们的非洲祖先的家园分裂出来，殖民了许多土地。澳大利亚与世界其他地区隔绝了5000万年，为评估人类活动的足迹提供了独特的环境。美国和澳大利亚的一个联合研究小组重建了澳大利亚半干旱地区的生态系统和气候变化。该团队最近的努力集中在大型不会飞的鸟类的蛋壳中使用生物地球化学示踪剂，这些示踪剂记录了大型动物的灭绝和人类殖民时期植被的不可逆转的丧失。一种新的情况是，在人类殖民之前，干旱地区的植被包括各种草本植物和耐旱乔灌木，支持大型有袋食草动物(大多数现已灭绝)以及有袋类和爬行动物食肉动物。当全球条件有利于强季风降雨时，澳大利亚夏季风经常深入澳大利亚内陆。然而，大型动物在人类殖民后灭绝，当时植被多样性大大减少，季风雨未能出现，即使在全球强迫很强，其他季风系统重新焕发活力的情况下。教育部分将与卡内基学院的科学教育学院(CASE)合作开展。几名本科生和一名博士后学者将得到这项研究的支持。CASE将测试各种学习模块，最好的模块将通过该组织的网站向更广泛的受众提供。计划开展三项活动：1)利用地理信息系统软件为学生编写活动，讲授地理信息系统原理以及澳大利亚的生态系统变化科学；2)在项目网站上开设关于澳大利亚气候、动植物的教育板块，以加强地理信息系统的活动；3)将华盛顿特区的学校与澳大利亚的姊妹学校(S)连接起来。

The project seeks to address the scientific question: Did systematic burning by early human colonizers sufficiently alter Australian vegetation to produce a distinctly non-linear disruption of climate and biota? The researchers will address this question using a series of testable predictions to evaluate the hypothesis using tracers in dateable geological archives. The research team will integrate field and analytical data to provide environmental scenarios that can be tested with mesoscale climate models to evaluate the impact of hypothesized human-induced vegetation change on monsoon rainfall.Over the past 60,000 years, modern humans have branched out of their ancestral African home to colonize many lands. Australia, isolated from the rest of the world for 50 million years, provides a unique setting to evaluate the footprint of human activity. A joint US-Australian team has reconstructed ecosystem and climate change across portions of semi-arid Australia. Recent efforts by this team have centered on using biogeochemical tracers in eggshells of large, flightless birds that document the extinction of megafauna and an irreversible loss of vegetation at the time of human colonization. An emerging scenario is that prior to human colonization, arid-zone vegetation included a diverse mixture of grasses and drought-tolerant trees and shrubs, supporting large marsupial herbivores (most now extinct) and marsupial and reptilian carnivores. When global conditions favored strong monsoonal rainfall, the Australian summer monsoon regularly penetrated well into the interior of Australia. However, megafauna became extinct following human colonization when vegetation diversity was much reduced and monsoon rains failed to materialize, even when global forcing was strong and other monsoon systems were reinvigorated. The education component will be undertaken in collaboration with the Carnegie Institution's Academy of Science Education (CASE). Several undergraduate students and a postdoctoral scholar will be supported with the research. CASE will test various learning modules and the best will be made available to a wider audience through the group's website. Three activities are planned: 1) an activity using geographic information systems (GIS) software written for students teaching the principles of GIS as well as the science of ecosystem change in terms of Australia; 2) Educational sections on Australia's climate, fauna, and flora will be on the project's website to augment the GIS activities; and 3) Connecting schools in Washington DC with a sister school(s) in Australia.