TECO: Collaborative Research: The Jasper Ridge Global Change Experiment: Ecosystem-scale Responses to Elevated CO2 Warming, Nutrient Deposition, and Increased Moisture Inputs

未来几十年的全球变化几乎肯定是多因素的，包括大气二氧化碳、温度、氮沉降和降水水平的改变。到目前为止，还没有实验研究解决这一领域的全套相互作用的全球变化。尽管对这些因素之间相互作用的性质严重缺乏共识，但解释和预测的基础主要建立在对自然模式的观察和单因素实验的数据上。虽然这些可以，至少在原则上，获得全套潜在的重要机制，单因素实验和沿着自然梯度的观察并不能提供一个背景来评估我们预测几个同时运行的机制的后果的能力。为了解决这一信息不足的问题，该项目将利用改变CO2、温度、水输入和氮输入的因子组合进行实地试验。本研究着眼于四个综合响应变量——初级产量、土壤碳储量、土壤养分有效性和物种或功能群组成——将检验对变暖和二氧化碳浓度升高的响应本质上是相加的零假设，即对单个因素的响应的总和。实验将采用mini-FACE和红外加热技术，在加利福尼亚一年生草地上进行，在那里可以执行结合几代优势生物，一系列处理和合理复制的设计。为了便于与模型输出进行比较，将使用三种CO2水平和三种温度水平的实验。

Mooney 9727060 Global changes over the coming decades are almost certain to be multi-factorial, with altered levels of atmospheric CO2, temperature, nitrogen deposition, and precipitation. To date, no experimental studies address this full suite of interacting global changes in the field. Despite a profound lack of consensus on the nature of the interactions among these factors, the foundation for interpretation and prediction is built largely from observations on natural patterns and data from single-factor experiments. While these can, at least in principle, yield access to the full suite of potentially important mechanisms, single-factor experiments and observations along natural gradients do not provide a context for evaluating our ability to predict the consequences of several, simultaneously operating mechanisms. To address this lack of information, this project will use field experiments with a factorial combination of altered CO2, temperature, water inputs, and nitrogen inputs. Focusing on four integrated response variables - primary production, soil carbon storage, soil nutrient availability, and species or functional group composition - this research will test the null hypothesis that responses to warming and elevated CO2 in combination are essentially additive, the sum of the responses to the individual factors. The experiments will employ mini-FACE and infrared heater technology in a California annual grassland, where it is feasible to execute a design combining several generations of the dominant organisms, a range of treatments, and reasonable replication. To facilitate the comparison with model output, experiments with three levels of CO2 and three levels of temperature will be used.