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

该项目旨在解决一个科学问题：早期人类殖民者的系统性燃烧是否足以改变澳大利亚的植被，从而对气候和生物群产生明显的非线性破坏？研究人员将使用一系列可测试的预测来解决这个问题，以评估使用可追溯地质档案中的示踪剂的假设。研究小组将整合实地和分析数据，提供环境情景，可以用中尺度气候模型进行测试，以评估假设的人类引起的植被变化对季风降雨的影响。在过去的6万年里，现代人类已经从他们祖先的非洲家园分支到许多土地上殖民。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使用大型，不会飞的鸟类蛋壳中的地球化学示踪剂，记录了巨型动物的灭绝和人类殖民时期植被的不可逆转的损失。一个新出现的情况是，在人类殖民之前，干旱地带的植被包括各种各样的草和耐旱树木和灌木，支持大型有袋类食草动物（大多数现已灭绝）和有袋类和爬行类食肉动物。当全球条件有利于强季风降雨时，澳大利亚夏季季风经常深入澳大利亚内陆。然而，巨型动物在人类殖民之后灭绝，当时植被多样性大大减少，季风降雨未能实现，即使全球强迫很强，其他季风系统重新活跃。教育部分将与卡内基研究所科学教育学院合作进行。几名本科生和一名博士后学者将支持这项研究。CASE将测试各种学习模块，最好的模块将通过该小组的网站提供给更广泛的受众。计划开展三项活动：1）一项使用地理信息系统（GIS）软件的活动，该软件是为教授GIS原理以及澳大利亚生态系统变化科学的学生编写的; 2）关于澳大利亚气候、动物群和植物群的教育部分将放在该项目的网站上，以加强GIS活动; 3）将华盛顿特区的学校与澳大利亚的一所姐妹学校联系起来。

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.