Effect of plant height and plant crowding on insect abundance in York University's Danby Grasslands

Group 4. Group members: Nassar Khan, Alex Qiu, Kristine Del Rosario and Michael Angelini. Site/Field Location: York University Danby grasslands.Grasslands heavily covered in grasses with some trees. Group 4 measured insect abundance in relation to plant crowding and plant height. The potential hypothesis is higher severity of plant crowding along with taller plant height will result in a great insect abundance. Sampling took place on 2 days, October 21st and 28th 2015 at approximately 3:00PM Eastern Standard Time. On each day, 40 samples were taken. The sampling procedure consisted of distributing 8 white plastic bowls labelled from 1 to 40 to each group member. Each member then randomly places bowls right side up on the grassland ground. If spaces between bowls were not at least 1 meter apart, one of the bowls were randomly placed elsewhere. Each bowl was filled halfway with soap water provided by the teaching assistant, creating a pan trap. Bowls were left untouched for 2 hours before data collection. After the waiting period, sampling took place. A sample consisted of placing a 1 meter by 1 meter metal quadrat around 1 of the 40 bowls, ensuring the the bowl was centered inside the quadrat. Plant crowding was determined by looking at the quadrat area and using a scale of 1 to 4 of crowdedness. 1 meaning very few plants within quadrat but soil/dirt on ground is very visble, 2 meaning several plants but soil/dirt on ground is moderately visible, 3 meaning many plants but soil/dirt on ground is slightly visible, and 4 meaning plants covering entire quadrat. Plant height was measured by determining the area within quadrat of most crowding, and measuring the rough median plant height within that group of plants. This was done my looking at measuring tape along the length of platns within the quadrat. Lastly, the insect abundance was measured by picking up each bowl and counting each individual insect using the observer's eyes.

第4组。小组成员包括纳萨尔·汗（Nassar Khan）、亚历克斯·邱（Alex Qiu）、克里斯汀·德尔·罗萨里奥（Kristine Del Rosario）与迈克尔·安杰利尼（Michael Angelini）。实验场地为约克大学丹比草原（York University Danby grasslands），该区域以草本植被为主体，点缀少量乔木。第4组本次实验旨在探究昆虫丰度与植物拥挤度、植物株高的相关性，预设假设为：植物拥挤程度越高、株高越高，则昆虫丰度也随之提升。采样工作于2015年10月21日及28日开展，每日采样时间约为东部标准时间下午3:00。每日共采集40份样本。具体采样流程如下：为每位小组成员分发8个编号1至40的白色塑料碗，各成员将碗口朝上随机放置于草原地面；若碗间距不足1米，则随机调整其中一只碗的摆放位置。每个碗内注入由助教提供的肥皂水至半满，制成盘式诱捕器（pan trap）。放置完毕后需静置2小时再进行数据采集。静置结束后启动采样：将1米×1米的金属样方框（quadrat）罩于40个碗具中的任意一个上方，确保碗具位于样方框的中心位置。植物拥挤度通过观察样方框内的植被情况，采用1至4级评分法评定：1级代表样方框内植物极少，地表土壤清晰可见；2级代表样方框内有若干植株，地表土壤可见度中等；3级代表样方框内植株众多，地表土壤仅略微可见；4级代表样方框完全被植被覆盖。植物株高的测量步骤为：选取样方框内植被最密集的区域，测量该区域内植物的近似中位株高，具体操作是通过卷尺沿样方框内植物的生长方向进行测量。最后，昆虫丰度通过拾取每个碗具，以目视计数的方式统计其中的昆虫个体数量。