BIOL 2050 - Lab 3: Sweep nets and transect tape

The objective was to use a distance based sampling method to determine the abundance and richness of insects inhabiting a given area. Using a combination of the sweep net method and transect method we were able to actively collect walking and flying insects. The dataset for this experiment was collected on Thursday, October 1 2015 between 3 and 4:00 pm within the grasslands of York University's Keele Campus. This region is isolated from human acitivity. The weather was sunny with a temperature of 15 degrees celsius. The direct sunlight allowed for clear visualization of organisms captured by the sweep net. The materials included in the study were: a stop watch to record time, notebook and pen to record data, transect tape for distance measurement and sweep net for gathering insects. The approach taken was carefully selected prior to the execution of this method. The grasslands were divided into 2 regions, mowed and non-mowed. This study had a total of 10 trials (n=10), 5 trials involved the mowed land and 5 trials involved the non-mowed land. This study involved the participation of all 4 group members (Adilah Ismail, Amrutha Balamurugan, Harshvir Hehar and Olivia Kazmierczak). Harshvir Hehar was responsible for laying out the transect tape to a distance of 20 m. All 10 placements of the transect tape were made cautiously to prevent abstraction of organisms from the same region. Adilah Ismail was responsible for gathering the insects using a sweep net. The sweep net was forcefully moved back and forth in a figure eight motion to extract as many insects as possible. The sweeping motion was kept consistent amongst both the mowed and non-mowed regions. High rising plants were not given any mercy. After sweeping, the net was flipped over so that the open portion of the net was facing the sky and then it was closed off using Adilah's hand to prevent insects from escaping. At this point the abundance and RTUs were counted. Amrutha Balamurugan recorded the time with a stopwatch. The time spent sampling was slightly different for each replicate (with an average time of 23.6 seconds). Olivia Kazmierczak recorded all the data in her notebook. After each trial all organisms captured were released to prevent recounting and restore them into their natural habitat. Overall this sampling method was slightly destructive. There were high concerns of reducing population. It did however, reveal a correlation between the region (mowed vs non-mowed) and abundance of a certain species.