Relationship between Pebble Size and Invertebrate Abundance within the Longfellow Creek
This research was driven by an experience in a past field experience class where invertebrates were collected from a stream. From this field experience and the last visit from Duwamish field, an observation was made that many invertebrates live under the pebbles and rocks in the area. This study makes a hypothesis that the size of the pebble affects the number of invertebrates living under them. Consequently, the methodology used was quantitative with quadrants used to sample the different pebbles. The results were also analyzed using linear regression and subjected to tests of significance. Finally, the results indicate a relationship between the size of the pebble and the number of invertebrates living under these structures.
Introduction/Background
Organisms in the wild are dependent on their habitats for shelter, protection and other resources such as food. During one of the class field experience, one of the activities carried out was the collection of invertebrates from a stream. Different experiences influenced the decision to carry out this research. The research was also meant to add to the existing studies. During this visits, it was noted that invertebrates in the stream and the creek lived under the pebbles and rocks. The idea for this study came from the observation of crabs living under the rocks. The relationship between the pebble size and the invertebrates under them was interesting. Consequently, the study hypothesizes that the size of a pebble affects the number of invertebrates living under these pebbles in the Longfellow Creek.
Methods
The methods chosen for the current study were quantitative in nature. The location chosen for this study was the Greg Davis Park in West Seattle that conveniently harbors a large population of the invertebrates. In addition, this park was chosen based on its proximity to the school. The data utilized in the study was collected within the Longfellow Creek where the initial observations occurred (Stage 2: Fieldwork. n.d). Sampling preceded the study where an appropriate method was selected. The sampling method employed is the random sampling technique. In addition, the study area was divided into one-square meter quadrants that were used to determine the pebbles to be collected. After subdividing the study area, the selected quadrants were assessed, and the pebbles within these quadrants collected for further evaluation. Next, the pebbles were put into a counter for further examination. The counter and a magnifier were used to check and count the number of the invertebrates under these pebbles. Additionally, the pebbles were divided into three different size groups, which are Small, Medium, and Large. The size of these pebbles was determined by the sum of the three short, middle and long axes (Stage 2: Fieldwork. n.d.). Fifteen pebbles were collected for each of the different size groups. The pebble sizes are described in the discussion part.
Discussion
The study proves the hypothesis that the number of invertebrates living under a pebble at Longfellow Creek is proportional to the size of the pebbles. The research finds that …
