Co-dominant removal and N and C fertilization experiment for moist meadow tundra, 2002 - 2018.

In 2002 seven experimental sites were set up in areas of moist meadow alpine tundra on Niwot Ridge. At each site, ten 1 m^2 plots were established where there was roughly even cover by two dominant plant species, Geum rossii (forb) and Deschampsia cespitosa (grass). In a factorial design, plots were assigned treatments of 1) removal of G. rossii, D. cespitosa, or control (no plant removal), and 2) nutrient addition of nitrogen (N), carbon (C), or control (no addition). A tenth plot was assigned a treatment of random biomass removal and no nutrient addition. Plots were visited annually to implement removal and fertilization treatments, and to measure plant species composition. Plant productivity was measured every other year and nematode communities once via 18S rRNA metabarcoding, together with soils. Carbon addition plots were dropped from the experiment in 2016.

2002年，研究人员在尼沃特岭（Niwot Ridge）的湿润草甸高山冻原区域设立7个试验位点。每个位点内设置10个1平方米的样方，这些样方内两种优势植物——高山水杨梅（Geum rossii，杂类草）与发草（Deschampsia cespitosa，禾本科草本）的盖度大致均等。本试验采用析因设计，将样方划分为两类处理因子：其一为植物移除处理，包含移除高山水杨梅、移除发草及对照（不进行任何植物移除）三个水平；其二为养分添加处理，包含添加氮（N）、添加碳（C）及对照（不添加养分）三个水平。另有1个样方接受随机移除生物量且不添加养分的处理。研究人员每年对样方进行回访，以执行植物移除与施肥处理，并测定植物物种组成。植物生产力每两年测定一次，线虫群落则仅通过18S核糖体RNA（18S rRNA）宏条形码技术，结合土壤样品完成了一次测定。2016年，本试验移除了所有碳添加处理的样方。