Local plant diversity and soybean biological control 2011 Harvest Measures:Biodiversity II: Effects of Plant Biodiversity on Population and Ecosystem Processes

Biodiversity II (E120) is designed to determine how the number of plant species affects the dynamics of ecological processes at the population, community, and ecosystem levels. By experimentally manipulating the number of species and the kinds of species, the amount of plant growth and the change from year to year, that result can be examined. Plots are large (9m x 9m actively maintained) and well-replicated, allowing responses of plant pathogens, insect herbivores, seed predators, soil parameters, invasive plant species and other variables to also be studied. Plots were seeded in May 1994 to have 1, 2, 4, 8, or 16 species, with roughly 30 replicates of each diversity level. The species composition of each plot was chosen by random draw from a pool of 18 grassland perennials that included four warm-season (C4) grasses, four cool-season (C3) grasses, four legumes, four non-legume forbs, and two woody species. All species occur in monoculture allowing comparison of responses of each species in monoculture to combinations of these same species. The experiment was established in 1994 by the lead investigators David Tilman, Peter Reich, Johannes Knops, and David Wedin. Experiment 120 is similar to Experiment 123, but it uses larger plots to provide a large capacity for long-term subexperiments.

Biodiversity II (E120) 旨在探究植物物种数量如何影响种群、群落与生态系统层面的生态过程动态。本实验通过实验操控植物物种的数量与种类、植物生长量及其年际变化，即可对相关结果进行考察。实验采用的样地规模较大（9米×9米，需定期维护）且重复设置充分，可同时开展植物病原菌、昆虫植食者、种子捕食者、土壤参数、入侵植物物种及其他变量的响应研究。1994年5月，各实验样地被播种有1、2、4、8或16个物种，每个多样性梯度约设置30个重复样地。每个样地的物种组成均从包含18种草原多年生植物的物种库中随机抽取得到，该物种库涵盖4种暖季型（C4）禾草、4种冷季型（C3）禾草、4种豆科植物、4种非豆科杂类草以及2种木本植物。所有物种均可进行单作栽培，便于对比单作栽培下各物种与这些物种组合的响应差异。本实验由核心研究者David Tilman、Peter Reich、Johannes Knops及David Wedin于1994年建立。E120实验与E123实验设计相似，但E120采用了更大规模的样地，可为长期子实验提供充足的实验容量。