Ongoing Field Observations at Turner’s Bog
Gorse (Ulex europaeus) is extremely competitive and displaces native plants, often creating a shrub layer where none existed previously. Established patches of gorse can produce a large amount of acidic litter that inhibits the germination and growth of many native types of grass and other plants.
- Most of the gorse is located on the NE end of Turner’s bog facing Westshore Pkwy on an elevated gradient. Is this species thrive with a favourable sun aspect?
- Gorse fixes atmospheric nitrogen, creating soil conditions that favour other non-native species. The aforementioned location of Gorse at this site holds a strong presence of Himalayan blackberry (another invasive) contributing to about 40% shrub cover in the B layer.
- Hypothesis: Is dispersion of gorse have any relation to aspect and abundance?
- Prediction: Growth of gorse dramatically increases with favourable sun and nitrogen fixated soil
- Response variable: Himalayan blackberry
- Explanatory variable: Consistency of sunlight
Hi there, it’s nice to see another from Vancouver Island taking this course!
I am replying to this post as part of Module 4 criteria.
I think you have an interesting field of study and an intriguing initial hypothesis/prediction. You’ve clearly stated some observations and patterns you observed leading to a solid hypothesis. I think your response and predictor variables are well stated and make sense. Here are a few comments I have as an outsider to your project. You probably have simple answers to these questions but maybe they will be involving something you haven’t considered or maybe you have answered these questions in a future post.
I am mainly interested in your response and predictor variables.
1. How do you plan to measure your response variable? I am assuming since this is a competitive species it will be quite dense. Maybe you can simply measure the presence and absence of these at varying sun exposures. Maybe you could use a distance based approach using a point that is centered at high sun exposure and one that is completely covered?
2. How are you going to designate the predictor variable will it be categorical or continuous?
3. Have you considered if they grow towards any resources such as water or sunlight and thrive around regions of high resource? Would the elevated gradient have easier access to rain water or worse?
Thank you for taking time to read. I hope that these questions make sense/help you and I hope your project and data analysis goes smoothly.
Best,
Noah
Thanks for sharing your research. I think you have a solid starting point but I wanted to mention a few things:
With regards to your hypothesis, you are forming it as a question rather than a statement. A hypothesis is a statement about something you predict will happen. The way you have written your hypothesis, it is as if you are asking yourself a question that you are unsure of. The question that you have is great but it should be used to formulate a strong hypothesis that specifically states something for example the sunlight exposure at at Turners bog positively impacts the growth patterns of gorse. Then you could go further to say as hours of daily sunlight to a given area increases, the growth of gorse increases based on surface area covered. The null hypothesis being that sun exposure has no impact on the growth pattern of gorse at Turners Bog.
How do you independently test the two predictor variables you have mentioned: Sunlight and nitrogen fixation? For sunlight you could record how much sun a sample site is exposed to but how are you testing nitrogen fixation? Also how do you know if one or another is causing the growth patterns you are seeing or if its both equally that impact your response variable.
Also when you say that the response variable is Himalayan Blackberry do you mean simply the presence of it at a specific location? Since you will have different amounts of sunlight at different areas perhaps you might look at the size of a given plant. For areas most exposed to sunlight the plants will be larger than compared to plants in areas exposed to less sunlight. I feel as though the way you have simply stated response variable : Himalayan Blackberry is too vague and that if you spend a little more time refining your hypothesis everything else will become more well defined and easier to measure. I hope that makes sense!
Also I know that you could very well be completed this course already but I am simply responding as part of the course requirements. Either way I hope that everything turns out successful for you!