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).

本数据集旨在验证竞争与植物性状相关理论，于2014年9月14日、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Stong Pond东侧草原（地理坐标：43°46'15.5"N 79°30'26.2"W）开展野外采样，记录了遮阴程度、植物密度以及3种植物的株高。该草原中观测到的植物物种包括：加拿大一枝黄花（Solidago canadensis）、欧洲白菀（Aster ericoides）、折茎菀（Aster prenanthoides）、矛叶蓟（Cirsium vulgare）、野胡萝卜（Queen Anne's lace，Daucus carota）、普通蒲公英（Taraxacum officinale）以及禾本科草本（Graminoids, grasses）。本数据集使用的采样工具为样带（belt transect）与样带卷尺（measure transect tape）。本次共计采集60个样方（记为"重复样方（replicates）"），其中前30个重复样方采自草原内部（记为"I"组），后30个采自草原外部（记为"O"组）。9月14日采样流程：当日设置的样带沿遮阴至向阳的环境梯度铺设，从草原中部的随机起点朝向最近的单株树木或树丛延伸。沿样带每5米设置一个样方，单个样方的区域为以样带上该采样点为中心、向四周各步行两步所覆盖的范围。每条样带共计采集10个样方，当日在草原内部共完成3条遵循相同流程的样带采样。9月21日采样流程：当日设置的样带从草原边缘的随机起点朝向边界上的另一随机点延伸。沿样带每5米重复上述采样流程。当日在草原外部共完成3条样带采样，每条样带采集10个样方。变量定义：1. 遮阴程度（shadiness）：指样方内的遮阴覆盖率，通过目视从上方观察地面进行评估，将每个样方划分为三类："L"=高遮阴、"S"=部分遮阴、"N"=无遮阴。2. 植物密度（又称拥挤度（crowdedness））：通过目视评估每个样方内的植物拥挤情况，记录目标物种所在斑块的拥挤等级：0=开阔无遮挡，1=附近存在少量植株，2=附近存在相当数量的植株，3=50厘米范围内存在极为密集的植物群。3. 株高：使用样带卷尺测量每个样方内目标物种个体的株高（单位：米），具体测量指标包括加拿大一枝黄花（Solidago canadensis）株高、矛叶蓟（Cirsium vulgare）株高以及折茎菀（Aster prenanthoides）株高，测量起点为地面，终点为植株的最高处。数据集可视化与统计检验：本数据集通过两类图表进行可视化展示：其一为分组条形图，包含3个分组（无遮阴、部分遮阴、高遮阴），每个分组内包含3个条形，分别对应3种目标物种；其二为以拥挤度为横轴、株高为纵轴的散点图，用于展示株高与拥挤度的关联关系。本数据集采用两类统计检验方法：一是显著性水平α=0.05的单因素方差分析（Analysis of Variance, ANOVA），用于检验不同组间物种株高与遮阴程度的显著性差异；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。