Effects of sunlight and plant density on plant height in Aster prenanthoides, Cirsium vulgare and Solidago canadensis.Datasheet.

To test the theory of competition and plant traits, both shadiness,plant density and the heights of three plant species were recorded in the grassland east of Stong Pond (43°46'15.5"N 79°30'26.2"W) located at York University (4700 Keele Street,Toronto, ON M3J 1P3, Canada) , on September 14th and 21st,2014 from 3:00 pm to 5:00 pm. Plant species observed in the grassland included the following : Canada Goldenrob (Solidago canadensis), white aster (Aster ericoides), zig-zag aster (Aster prenanthoides), spear thistle (Cirsium vulgare), Queen Anne's lace (Daucus carota), common dandelion (Taraxacum officinale), Graminoids ( grasses). The tools used in this dataset are : a belt transect and a measure transect tape. In total n=60 plots (denoted as “replicates”) are sampled : the firstn=30 replicates were sampled in the inner grassland (denoted as "I") and the second n=30 replicates were sampled in the outer grassland (denoted as "O"). On September 14th, the belt transect was set down on the ground along a gradient from shady to sunny. In order to do this, the belt transect departed from a random point in the middle of the grassland towards the closest tree or group of trees. From the start of the belt transect,a plot was sampled every 5 meters along the transect and the variables (listed below) were collected for each plot. The plot area to sample was defined by walking two steps in every direction from a point on the transect each 5 meters.In total, n= 10 plots were sampled along each belt transect and n=3 belt transects were performed with the same procedure in the inner grassland during the field sampling. On September 21st, the belt transect was set down on the ground departing from a random point located on the edge of the grassland towards another subsequent point on the border. The sampling procedure was repeated each 5 meters along the transect. In total, n=3 belt transects were performed in the outer grassland and n=10 plots were sampled along each belt transect. Shadiness is the shade coverage in the plot. It was visually observed looking from above to the ground. Every plot was then denoted either as "L"= lots of shade, "S"=some shade, "N"=no shade. Plant density (denoted as "crowdedness") was visually observed and estimated in each plot. It was recorded whether the target species in the plot were in a crowded patch (0 = open, 1 = some plants nearby, 2 = quite a few plants nearby, 3 = very crowded bunch of plants within 50 cm). Height is measured in meters for individuals of the target species in each plot : S.canadensis height (m) , C.vulgare height (m) , A.prenanthoides height (m) . Height was measured using a measure transect tape from the ground to the tallest point of the plant which we were sampling. The dataset is represented using a clustered bar graph with three groups (no shade,some,lots) of three bars (for each of the target species) and a scatter plot where height is dependant on crowdedness. The statistical tests run are an one-way ANOVA (Analysis of Variance) with alpha = 0.05 to test the significance between groups (species height vs. shadiness) and a correlation test to see if crowdedness has an effect/trade-off (species height vs. crowdedness).

为验证竞争理论与植物性状相关假说，研究团队于2014年9月14日及21日每日15:00至17:00，在加拿大约克大学（York University，4700 Keele Street, Toronto, ON M3J 1P3, Canada）的松塘东侧草原（Stong Pond，坐标43°46′15.5″N 79°30′26.2″W）开展野外采样，记录遮阴程度、植物密度及3种目标植物的株高。该草原中观测到的植物物种包括：加拿大一枝黄花（Solidago canadensis，原文记为Canada Goldenrob）、欧洲白紫菀（Aster ericoides，原文记为white aster）、折茎紫菀（Aster prenanthoides，原文记为zig-zag aster）、矛蓟（Cirsium vulgare，原文记为spear thistle）、野胡萝卜花（Daucus carota，原文记为Queen Anne's lace）、普通蒲公英（Taraxacum officinale，原文记为common dandelion）以及禾本科草本（Grasses，原文记为Graminoids）。本数据集采用的采样工具为：带状样带（belt transect）与测距卷尺（measure transect tape）。本次共设置60个样方（记为“重复单元”，n=60），其中30个设于草原内部（标记为“I”），剩余30个设于草原外围（标记为“O”）。2014年9月14日，研究人员在草原内部布设带状样带：从草原中部的随机点位出发，朝向最近的单株树木或树丛延伸样带。沿该带状样带每5米设置1个样方，样方的采样区域为以该样带点位为中心向四周各步行两步划定的范围。每条带状样带共布设10个样方，当日在草原内部共完成3条同流程的带状样带采样。2014年9月21日，研究人员在草原外围布设带状样带：从草原边缘的随机点位出发，朝向边界上的另一随机点延伸样带，同样沿样带每5米设置1个样方，采样流程与内部一致。当日在草原外围共完成3条带状样带，每条样带含10个样方。各项指标测定方法如下：1. 遮阴程度（Shadiness）：指样方内的遮阴覆盖率，通过俯视地面目视估算，将每个样方划分为“多遮阴（L）”“部分遮阴（S）”“无遮阴（N）”三类。2. 植物密度（又称crowdedness拥挤度）：通过目视估算每个样方内目标物种的聚集程度，记录等级为：0=开阔无植株邻近，1=周边有少量植株，2=周边有较多植株，3=50cm范围内植株极为密集。3. 株高：针对每个样方内的目标物种个体，使用测距卷尺测量从地面至植株最高点的高度，单位为米，目标物种分别为加拿大一枝黄花、矛蓟与折茎紫菀，对应记录其株高（单位：m）。本数据集的可视化形式包含两种：一是分组柱状图，包含3组（无遮阴、部分遮阴、多遮阴），每组内包含3个分别对应3种目标物种的柱形；二是散点图，以拥挤度为自变量、株高为因变量。统计分析采用两类方法：一是单因素方差分析（one-way ANOVA, Analysis of Variance），设定显著性水平α=0.05，检验不同组间（物种株高与遮阴程度）的差异显著性；二是相关性检验，用于分析拥挤度对物种株高的影响及权衡关系。