SEV-LTER Mean x Variance Experiment Desert Grassland Soil Moisture and Temperature

We designed novel field experimental infrastructure to resolve the relative importance of changes in the climate mean and variance in regulating the structure and function of dryland populations, communities, and ecosystem processes. The Mean x Variance Experiment (MVE) adds three novel elements to prior designs (Gherardi & Sala 2013) that have manipulated interannual variance in climate in the field by (i) determining interactive effects of mean and variance with a factorial design that crosses a drier mean with increased (more) variance, (ii) studying multiple dryland ecosystem types to compare their susceptibility to transition under interactive climate drivers, and (iii) adding stochasticity to our treatments to permit the antecedent effects that occur under natural climate variability. This new infrastructure enables direct experimental tests of the hypothesis that interactions between the mean and variance of precipitation will have larger ecological impacts than either the mean or variance in precipitation alone. A subset of plots have soil moisture and temperature sensors to evaluate treatment effectiveness by addressing, How do MVE manipulations alter the mean and variance in soil moisture and temperature? And, how does micro-environmental variation among plots influence how much MVE treatments alter soil moisture profiles over three soil depths? This data package includes soil moisture and temperature sensor data from the Mean x Variance Climate experiment in the Desert grassland ecosystem at the Sevilleta National Wildlife Refuge, Socorro, NM.

本研究搭建了新型野外实验平台，以厘清气候均值与方差变化在调控旱地种群、群落结构与功能以及生态系统过程中的相对重要性。均值×方差实验（Mean x Variance Experiment, MVE）在已有野外操控气候年际方差的实验设计（Gherardi & Sala 2013）基础上，新增三项创新设计：其一，采用析因设计探究气候均值与方差的交互效应，设置偏干旱均值与更高变幅两个梯度进行交叉组合；其二，选取多种旱地生态系统类型开展研究，对比不同生态系统在气候交互驱动下发生转变的易感性；其三，为实验处理引入随机性，以还原自然气候变率下的前置效应。该新型实验平台可直接验证以下假说：降水均值与方差的交互作用对生态系统的影响，相较于单独改变降水均值或方差的影响更为显著。本实验选取部分样地安装土壤湿度与温度传感器，用于评估处理效果，具体围绕两个科学问题展开：其一，MVE操控如何改变土壤湿度与温度的均值与变幅？其二，样地间的微环境差异会在多大程度上影响MVE处理对三层土壤剖面湿度的调控效应？本数据包包含美国新墨西哥州索科罗市塞维利塔国家野生动物保护区内荒漠草原生态系统的均值×方差气候实验中获取的土壤湿度与温度传感器监测数据。