Competitive responses of eight old-field plant species in four environments

Variation in relative competitive abilities among environments has been proposed to control the species composition of plant communities. We tested whether the competitive responses of eight species varied with fertility and disturbance in an old field. We also tested whether the competitive effects of vegetation varied with fertility and disturbance in an old field. We also tested whether the competitive effects of vegetation varied with fertility and disturbance. Plots received one of four combinations of nitrogen (added or not) and disturbance (tilled or not) in each of five years. There were 10 replicates of each treatment. In the fifth summer, transplants of eight species comprising annual and perennial forbs and grasses were grown in all four combinations of the N and disturbance treatments. Transplants were grown in subplots with all neighbors, with only roots of neighbors, or with no neighbors. Transplant roots and shoots were harvested after one summer and individual growth rat...

学界已提出，不同环境下相对竞争能力的差异可调控植物群落的物种组成。本研究在一处弃耕地中开展实验，首先检验8个物种的竞争响应是否随土壤肥力与干扰程度发生变化；此外还验证了植被的竞争效应是否同样随土壤肥力与干扰程度产生变化。实验设置了氮素（添加/不添加）与干扰（翻耕/不翻耕）的4种组合，连续处理5年，每个处理包含10个重复样地。在第5个夏季，我们将包含一年生、多年生非禾本科草本与禾本科草本在内的8个物种的移栽幼苗，种植于上述4种氮素-干扰组合的样地中。移栽幼苗被分别定植于3类亚样地：保留全部邻株、仅保留邻株根系、无任何邻株。经过一个生长季后，收获移栽幼苗的地上与地下部分，并测定其个体生长速率（原文后续内容未完整呈现）