Week 4. Sweep Net

This experiment was done on October 03, 2014 in the woodland near Danby woods of York University, keel campus. Other members in the group are: Anees, Jamal, and Tarafdar. Collecting data was started at about 3 pm. It had been raining slightly (Less than 1 mm) for about an hour, so the condition of the field was wet and muddy. The temperature was at 18c; it was cloudy and slightly windy; and it continued raining for the duration of data collection. This experiment used a transect sampling method. Also, the location of transect used a non-probability sampling method since it was chosen to lay the transects along tall grass and vegetation. The transect was set to 10 meters and placed on the ground. The experimenter walked along the transect for 3 minutes while slowly sweeping the net from left to right. The sweep net was held close to the ground and made contact with grass or any vegetation. This motion was continued, and the experimenter walked along the transect 6 times in the 3 minutes trial duration. At the end, the number of insects in the sweep net was counted, and the different number of rtus (recognizable taxonomic units) was observed and recorded. After emptying the contents of the net, the transect was moved to a new location and the process repeated. The new location chosen was at least 2 meter away from any of the previous locations to avoid any overlap. This was done for 10 trials, and the process took about 50 minutes to complete.

本实验于2014年10月3日在约克大学基尔校区丹比林周边林地开展。团队其余成员包括Anees、Jamal及Tarafdar。数据采集工作于当日约下午3时启动。此前已持续小雨约1小时（降雨量不足1毫米），致使野外地表湿滑泥泞。实验期间气温为18摄氏度，天气多云且伴有微风，且数据采集全程持续降雨。本实验采用样带采样法（transect sampling method）。由于样带沿高大草本与植被区域布设，因此样带点位选取采用非概率抽样法（non-probability sampling method）。单条样带长度设定为10米并铺设于地面。实验者沿样带行走，耗时3分钟，同时缓慢地从左至右挥扫扫网（sweep net），扫网贴近地面并与草本或其他植被接触。在3分钟的采样时长内，实验者需沿样带重复该扫网动作6次。采样结束后，计数扫网内的昆虫数量，并观察、记录不同可识别分类单元（recognizable taxonomic units，RTUs）的数量。清空扫网内的采集物后，将样带转移至至少距此前所有采样点位2米的新位置，重复上述采样流程。本次实验共完成10组采样，全程耗时约50分钟。