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The organism that I would like to study is the Wolf Willow (Elaeagnus commutata). I chose three areas that are along the Bow River in the southwest of Calgary, Alberta that have a large population of E. commutata. The first area (1) was between two pathways, and a medium distance from the river; the second area (2) was at a much higher elevation than the river, close to the river; and the third area (3) was at a higher elevation than the river and far away from the river.
The plants that were closer to the river in area 1 appeared to be taller, and still had some berries present on the tallest branches. I didn’t bring a measuring tape but the plants here are taller than I am, so they are at least 6’ tall. The plants in area 2 were around 4’ tall, and much more abundant than either of the other areas. Only a few scattered berries were present, again on the tallest branches. In area 3, the furthest from the river, the plants were quite short – only around 2’ – and there were no berries present.
It’s unusual to see berries on plants during winter, but the wolf-willow’s berries seem to remain throughout the winter and into the spring. They are a pale silver colour.
From these observations I hypothesize that the growth of E. commutatais heavily reliant on a nearby water source. I predict that the tallest E. commutataplants will be in close proximity to the river. The responding variable would be the average height of the plants, which is a continuous variable. The explanatory variable would be the adequate water present in the form of the Bow River.
Hello,
I really enjoyed reading your blog post, you have a very clear set of observations which are followed by a clear, falsifiable, prediction. It is interesting that you have chosen a single species to observe at different levels of elevation and water availability.
Perhaps a confounding variable that might affect your hypothesis of the Wolf Willow relying heavily on a water source is the gradual increase in elevation, which could maybe also have a potential impact on Wolf Willow size (perhaps from a gradual temperature shift or soil quality?).
Another possible confounding variable could maybe be the presence of a groundwater source, with the Wolf Willow’s long and dense root hairs potentially using this water source. However, this could be checked for using a groundwater map.
Your post additionally mentions the explanatory variable of adequate water present (in the form of the Bow River). Would this be the distance of a Wolf Willow plant from the river? Maybe it would also be interesting to additionally measure soil moisture levels at each plant sample, that way any other (unknown) water sources could be possibly accounted for.
I also really enjoyed reading your field journal entry in the first blog post, it provided a clear and beautiful visual of the observations made of the Wolf Willow plant and surrounding area!
After reading your blog, I do think this is an study that would be very clear and easily measurable. I think you have chosen 3 good locations that will give you some clear variety within the E. commutatais species and it shall allow you to really differentiate the results. You have stated a clear hypothesis and prediction which I think is very reasonable and most likely the case of this phenomenon. You stated that the berries in this specific plant species usually aren’t present during the winter, however you noted the berries in the taller plants that were closer to the water source and not present in the smaller species that were further from the water source. Would you suspect that this is only due to the species being close/far away from the water source? Or maybe could it also be becasue the smaller E. commutatais are closer to the ground where the berries are more accessible to wildlife, whereas the taller E. commutatais are higher from the ground making them hard for the wildlife to get at. The only other thing I am curious about is the actual distance the these species are from the water source at all 3 locations? You did mention you hadn’t brought a measuring tape, but maybe the next time you return, that will be another thing you take into account to really give a clear visual. Overall, I think this is going to be a great study that you will be able to conduct without much difficulty since you have chosen such good responding variables and continuous variables.
Keep up the good work and good luck with your studies!