User: | Open Learning Faculty Member:
I had to change field experiments halfway through the project, which caused many problems. Originally, I was looking at the relationship between moss and cedar trees (Thuja plicata) but they didn’t have a strong enough correlation. This study would have been considering seedling establishment so I chose to go with a categorical response variable for the cedar trees, with the logic that if no seedlings establish, then there will be no trees on the site. When I changed the field experiment to the relationship between soil moisture and cedar trees, I already had the data on the cedar trees and didn’t have time to restart. If I were to do this project again, I would choose a continuous response variable, such as density or productivity (most likely density, as it is easier to measure). This change in design would improve the study by not having to use logistic regression and having more data to work with.
Another issue I had with the design was that I didn’t have the tools to dig as far down as I would have liked to get the soil samples. My small shovel wasn’t very good for getting past large rocks or in some cases, I barely could dig at all as the bedrock was so close to the surface. I had to change my design so that I only dug down 10 cm deep or until I hit bedrock. If I were to do this study again, I would get some tools to be able to take samples at 2 meters deep as well as at the surface, to account for the tree’s root system.
Engaging in ecology has certainly changed how I think about ecological theory and its development. There are so many variables that contribute to ecosystems, such as inter and intraspecific interactions, resource availability and disturbances. It is difficult to decide which factors are the most relevant for a study because one definitely does not have the time or resources to consider them all! Although developing theory is difficult in all sciences, I feel like these extra variables and the difficulties in an uncontrolled environment make developing theory in ecology even harder.
Sounds like you had a true field experiement experience!