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Blog Post 3: Ongoing Field Observations
I returned to my study site for the second time on July 12, 2019 at 19:00 h. The weather was overcast but not raining or windy. For my subject I have chosen to study a biological attribute of the area. I am interested in the change in species composition and species diversity along the elevation gradient of the slope. The response variable is the species diversity. One possible explanatory variable is the amount of sunlight which changes with rising elevation due to cedar hedges across the field from the slope causing shade. This data would be considered both categorical (presence or absence of certain species at specific elevations) and continuous (percent coverage of species at distinct elevations).
Location 1: The first location was at the base of the slope, 0 metres above the flat field. Ferns (Athyrium filix-femina), were the dominant species with approximately 80% coverage. These ferns were similar height, standing at 1 metre tall. These ferns were directly across the field from cedar hedges (Thuja occidentalis) that were around 5 metres tall. Other vegetation includes corn sow thistle, clover, and tall grasses. The clover looked desiccated despite frequent rainfall in the area.
Location 2: The second location was approximately 3 metres up the slope from the base. This area was dominated by Saskatoon berry bushes (Amelanchier alnifolia). There were also 2-3 developing birch (Betula) and maple (Acer). This was the only location where I noticed there was a species of bird present. The height of these plants was approximately the same as the opposing hedges.
Location 3: The final location 10 metres from the base of the slope. Fully developed pine and birch trees were the dominant species. There was a minimal number of ferns but they were shorter than the ferns found at the base of the slope.
In an area with no blockage by the cedar hedges, there were several fully developed pine trees at base level.
My hypothesis is as follows: Plants need sufficient access to resources including nutrients, water, and sunlight. In the absence of any of these resources, plants may not develop into complex organisms. Therefore, the change in species composition and diversity may be attributed to the lack of sunlight to base level plants due to the taller cedar hedge rows.
My prediction is as follows: If the cedar hedges are taller than the developing plants across the field, then they will not have sufficient access to sunlight and will not be as complex or tall as the plants found at higher elevations with greater access to the sunlight.
Hi,
I love the idea behind your study. The fact that the hill creates a gradient for sunlight exposition is pretty cool. I wonder if the elevation could also affect some of the other variables that you stated in your hypothesis (access to nutrients and water). If that is the case, I fear that those confounding variables could alter your data.
Your prediction is clear and relates well to your hypothesis. Though, I would have trouble falsifying it without knowing the height of the cedar edges and the angle of your hill. Maybe just add this data since all cedars and hills are not the same height and angle.
Cheers and good luck!
Shannon
Hello there,
Very interesting topic to take on! Great job in identifying the key resources that would affect the complexity of the plants- would you consider competition as another factor at play? Competition is linked to the resources you stated above in your hypothesis; however, I believe you could enhance your hypothesis by changing “In the absence of any of these resources” to “In the absence or scarcity of any of these resources”. This way your hypothesis does not disregard the possibility that plant development and complexity may change with just a shortage of these resources. I believe that if you changed up the wording the discussion part of your report may be easier to write. Considering competition as a factor may help rule out the cause of the relatively shorter fern bushes surrounding the fully developed birch and pine trees located 10 meters from the base of the slope.
Very strong hypothesis and prediction otherwise! I’m interested in reading your next few posts!
Emily