I have changed my field site from Finnerty Gardens to Mount Douglas in Victoria BC.
Date: August 15, 2024. 2:00 PM – 4:00 PM
Weather: Cloudy, 18 degrees celsius, humidity 78%, 7 km/h winds.
I am studying how soil moisture changes along an elevation gradient, and how this may affect plant species diversity and density. I will also be looking at soil pH, however, I hypothesize that it will remain relatively constant at the different elevations. I’ve chose 3 elevation levels, low elevation 0-10 meters, 100-110 meters, and 200-210 meters (the highest point of the mountain). I have only made visual observations, and plan to return back to site to measure soil pH and moisture levels.
At the lowest elevation, plant diversity seems to be high with a mix of herbaceous plants, shrubs, and large trees. Vegetation also seems to be quite dense. At mid elevation, plant diversity seems to still be high, however there is somewhat of a transition from large trees to more shrubbery. Vegetation is still dense. At the highest elevation, the plant diversity was definitely lower. There were no large trees and shrubs and herbaceous plants were more sparse, with more bare ground and exposed bedrock.
Hypothesis: As elevation increases on Mount Douglas soil moisture will decrease and will affect the plant diversity and density.
Prediction: If soil moisture decrease with elevation, at a high elevation (200-210 m), there will be lower plant diversity, with higher abundance of species that can tolerate drier conditions. Plant density will also be lower.
A response variable is the plant diversity, measured as species richness and the Shannon-Wiener Index. This is a continuous variable.
A predictor variable is soil moisture, measured using a moisture meter that uses a relative scale of 1-10. This is a continuous variable.
Hi, make sure to review the hypothesis tutorial on how to word hypothesis and predictions for this course. Your hypothesis will be about your piece and your pattern and your prediction will be more specific about what you think will happen.
One big issue here is you have to be careful as you can’t say for certain that soil moisture is associated with the changes in plant diversity since elevation is also changing and there could be other factors. You can keep your hypothesis as soil moisture influences plant diversity but you need to be very careful in your interpretation of your results. Another option is to make a hypothesis about the combination of elevation and soil moisture.
Remember to include more details on your moisture meter. What is a 1 and what is a 10. Ones designed for house plants may not work as soil moisture measurements outside might not be on the same scale.
Hi Robyn,
Thanks for your feedback. Would it be more practical to only focus on elevation?
And use other scientific literature to discuss why this may be? Thanks!