Effects of Sunlight Coverage and Soil Moisture Levels on Abundance of Plant Species

The purpose of the experiment was to determine the amount of plant species within each quadrat that was placed within grassland and relate them to the amount of sunlight and soil quality via moisture level. The data was collected on Monday October 19th 2015 from 3:00pm to 5:00pm at York Universities Danby Woodlot grassland (behind the forested part) located at 4700 Keele St in Toronto Ontario. It was 14 degrees outside and Sunny, the sun varied in position due to timing of experiment because it started to set off into the west. 2 quadrats were used to conduct the experiment; a quadrat is a tool used to calculate local abundance of individuals in a given area and works very well for stationary individuals such as plants. The quadrat was a 1 metre by 1 metre measurement of area. 120 quadrat replicates were used. The individuals that conducted the experiment were Sumera, Mustafa, Krystal and Savannah (me). Mustafa and I took one quadrat and conducted 60 replicates, 30 in open grassland near no trees and 30 on the edge of the grassland where trees were present. Sumera and Krystal took the other quadrat and did the same procedure. 6 steps were taken between each quadrat as per what the random number generator produced. A table was set up in a notebook with columns labelled # of Quadrat Replicates, Number of Plant Species, Soil Moisture Level, and Sunlight Coverage. This table was then transferred and duplicated into excel after the experiment was complete. All the variables used in table were Numerical, discrete. Number of plant species was interpreted through observation, a new species is determined if it looks nothing like the last species found within the quadrat, as in it had different colour or/and leaf shape or size. Only the number of recognizable taxonomic units was noted, not the actual names of each species of plant or number of how many individuals of that species were present. A scale was used to determine sunlight levels for the plants within each quadrat, 0 = 0%, 1 = 25%, 2 = 50%, 3 = 75%, and 4 = 100% coverage within the quadrat. This variable depended on the time of day, weather, and where the quadrat was situated in the grassland (by trees vs. in open). Estimations were given in this case to the quadrats that would normally get full sunlight, such as those found in the middle with no trees around them but because of the time of day (4pm sun is starting to set) was not getting as much as usual. Soil moisture levels were also determined by a scale, 0 equals completely dry, 1 is semi-dry, 2 is semi-wet and 3 is moist. The soil moisture level depended on rain and sunlight coverage. It had rained 24 hours before the data was collected and it was a sunny and fairly warm day. To determine what number on the scale each quadrat sample should be given, a sample of the soil was tested with our hands from the both the edges of the quadrat and the middle for consistency. This same procedure and definition of variables was used for all 120 quadrat replicates and data was noted in the table.

本实验旨在测定放置于草原样方（quadrat）内的植物物种数量，并将其与光照量及以湿度水平表征的土壤质量建立关联。实验数据采集于2015年10月19日周一下午3:00至5:00，地点位于加拿大安大略省多伦多市基尔街4700号约克大学丹比林地草原（林地区域后方）。当日室外气温为14摄氏度，天气晴朗；由于实验开展时段太阳开始西沉，太阳位置随实验进程发生变化。本次实验共使用2个样方（quadrat）：样方是用于计算给定区域内个体本地丰度的工具，对植物等固着个体尤为适用，本次使用的样方面积为1米×1米。实验共设置120个样方重复。参与实验的人员包括Sumera、Mustafa、Krystal与Savannah（即笔者本人）。其中Mustafa与笔者共用一个样方，完成60次重复采样：30次在无树木的开阔草原区域，30次在有树木分布的草原边缘地带；Sumera与Krystal使用另一个样方，执行完全相同的实验流程。每次样方采样之间，需按照随机数生成器的结果移动6步。实验记录采用笔记本制表，列标题依次为“样方重复编号”“植物物种数量”“土壤湿度水平”与“光照覆盖度”。实验结束后，该表格被复制并录入Excel软件。表格中所有变量均为数值型离散变量。植物物种数量通过目视观察判定：若某物种外观与样方内已记录的物种完全不同，即具有不同的颜色、叶形或叶大小，则判定为新物种。本次仅记录可识别的分类单元（taxonomic unit）数量，不记录具体植物物种名称，也不统计每一物种的个体数量。光照水平采用分级量表测定：0代表0%覆盖度，1代表25%覆盖度，2代表50%覆盖度，3代表75%覆盖度，4代表100%覆盖度。该变量受当日时段、天气状况以及样方在草原中的位置（靠近树木 vs 开阔区域）影响。针对本应获得全日照的样方（如位于无树木环绕的草原中部的样方），由于实验时段为下午4点，太阳已开始西沉，实际光照量低于常规水平，因此需进行估算修正。土壤湿度水平同样采用分级量表测定：0代表完全干燥，1代表半干燥，2代表半湿润，3代表湿润。土壤湿度水平受降雨量与光照覆盖度影响。数据采集前24小时曾有降雨，当日天气晴朗且气温较为温暖。为确定每个样方的土壤湿度分级，需从样方边缘与中部采集土壤样本，用手触摸评估以保证结果一致性。上述实验流程与变量定义均应用于全部120个样方重复，相关数据均记录于表格中。