My field research was done at a local park every day for approximately a month. This was a large time commitment but made easier as I have to enter the park multiple times a day on my route to school or work. This part of the project was well planned out as it was convenient for me to frequent my sampling area as often as needed.
This project has shown me how time-consuming and how many more variables there seems to be in ecology research compared to the laboratory experiments that I am used to. Out in the field, it is very difficult to make controls like you can in the lab, therefore, it seems that many many more replicates need to be done to ensure accurate data.
I feel that my experiment worked well for the resources and time commitment I had available but if I was to have access to more I would design one in a rural setting where the results could have larger implications to ecological topics. This would have been a far too large and engaging experiment for a few short weeks though.
Article:
Comeau, P.G., and Heineman, J.L. 2003. Predicting understory light microclimate from stand parameters in young paper birch (Betula papyrifera Marsh.) stands. Forest Ecology and Management 180(1–3): 303–315. Elsevier BV. doi:10.1016/s0378-1127(02)00581-9.
This article is: Academic, peer-reviewed research material.
It is academic:
The lead author (Comeau) is associated with the department of Earth Sciences at the University of Alberta so can be considered an expert.
There are in-text citations.
The article contains a bibliography.
It is peer reviewed:
The journal is Forest Ecology and Management which states that it uses: “A peer-review process ensures the quality and international interest of the manuscripts accepted for publication.”
The article also notes when it was received and received again in revised form, indicating that it had been reviewed and re-submitted after revision.
For my research data, I decided to analyze it using the Kruskal-Wallis statistic test. This allows me to compare the median of my response variable to multiple intervals of my predictor variable. I used Minitab 18 to coordinate the data and calculate the medians, means and standard deviations which I then used to for the graph below.
Fig.1. Average squirrel abundance measured at View Royal Park in relation to the number of domestic dogs present.
The average amount of squirrels was calculated within each interval and plotted here with error bars that were calculated using the individual standard deviation. There is an inverse relationship between the number of dogs present and the number of squirrels observed. The statistical test used to analyze this data was the Kruskal-Wallis test. The P-value was found to be P<0.05, therefore, we can reject the null hypothesis and all the means are different.
The study area is approximately 15 acres of crown land behind my house located approximately 10 km south of Smithers, B.C. It is on the slope of a hillside facing east to slightly north of east. The slope ranges from 0% grade at the bottom to approximately 30% grade at the upper end of the study area. It is a wooded area of mostly deciduous with a minor amount of coniferous tree species. There is no evidence of anthropogenic disturbances such as logging or road building. Up-slope and higher in elevation from the site is a dominantly pine forest.
Study Area
The most recent site visit was on March 21st, 2019 around 1500 hours. The weather was sunny, warm (10 degrees centigrade), with snow cover on the ground and no wind. The tree types I observed in the forest includes paper birch, cottonwood at the base of the slope, aspen, spruce, and pine. I plan on more thoroughly identifying the species later on in the study. I roughly estimate the forest composition to be approximately 60% poplar, 25% birch, and 15% coniferous. The undergrowth includes willows, devils club, and thimbleberry. There is abundant ungulate (moose) sign throughout the area including tracks, beds, and droppings.
Moose bed, tracks, and droppings
Typical forest mid slope
This site is interesting because there seems to be (through my own other observations and talking with other locals) an abundance of birch on this site compared to other sites around the Bulkley Valley. It is also a widely spaced deciduous forest in an area where much of the forests are primarily coniferous. This leads me to believe that there may have been a disturbance, perhaps fire, that lead to the deciduous community coming up in succession. Questions I have about this site are:
Is this a site of a natural disturbance?
Are the majority of tree species in this forest typical to disturbance-succession environments?
Is the distribution and abundance of birch trees at this site consistent with other sites around the Bulkley Valley region?
I’ve decided to study Typha latifolia or Broad Leaf Cattail. The cattails are seen along the river’s edge and only seem to be found in marsh areas or in lower areas of the landscape. I will observe the cattail where the lake enters the river, along the river (further downstream) and off shore away from the river and lake.
Hypothesis: Broad Leaf Cattail will only be found in marsh areas (river or lake side) and lowers areas in the landscape because they require moisture to survive.
Prediction: the lower the landscape and the closer to water, the greater abundance of Broad Leaf Cattail.
I tried to incorporate as many of the sampling strategies of the virtual forest tutorial as possible. However, due to the nature of my study some do not fit into the context of my investigation. Collecting data along the study transect is a systematic sampling. I collected data at all of the stations along the transect and could now apply a random aspect to the study by querying random samples from the complete data set. At each interval, I conducted an Area-sampling by analyzing data from a square metre sample. I am not concerned with specific species so the dispersion, succession and diversity sampling is not relevant. There are topographical and edaphic factors which undoubtedly impact the ecology of the area but they are outside the scope of my study.
I’ve decided to examine the abundance and distribution of English Ivy in Colliery Dam Park. The ivy is seen throughout the park on a variety of trees, ferns, and shrubbery. Community groups have conducted pulls to remove the invasive species. Some trees are still covered in the dead ivy and you can see where they have been clipping from the roots at the base of the trees. The paths and trails fragment the parkland.
Hypothesis: That paths and trails have a negative impact on English Ivy dispersal because of fragmentation of habitat.
A potential response variable is the presence or absence of English Ivy on trees. This response variable would be categorical. A predictor variable is that fragmentation between the strata has effects on the dispersal of ivy.
English Ivy on tree.
Partial map of Colliery Dam Park showing fragmentation from the trails.
For my field study, I am going to examine whether there is a correlation between available light in a forest and the amount of ground cover in continuously disturbed areas.
Since the vegetation along the footpath in the study area undergoes continual but somewhat random disturbance from pedestrian traffic I am wondering if the amount of available light is the key resource that determines whether the forest floor revegetates after it is trampled by humans and pets.
My field observations consist of light meter readings at each interval and photographs of ground cover along a gradient extending perpendicular to the footpath. The photographs will be digitally process to determine the percentage of ground cover at each interval.
Therefore, my null hypothesis is:
There is no connection between available light levels in the forest and the percentage of forest floor covered by plant leaves.
I predict that there will be a correlation between available light and ground cover.
My explanatory variable is Light level (measured in Lux) and my response variable will be the percentage of ground cover in each delineated area (measured in percentage).
The resource Climate is a stronger driver of tree and forest growth rates than soil and disturbance (https://www.jstor.org/stable/41058855) is a peer-reviewed report published in the British Journal of Ecology. It is co-authored by eleven ecology academics from organizations with excellent credentials. Since this was a study conducted by numerous professionals, published in a leading journal, peer-reviewed, and based on extensive primary research, I found that this resource to be a top-quality and reliable scientific source. Its conclusions are important in the age of climate change. The one possible drawback of this paper is that it was published in 2011 and while still presenting valid conclusions, there may be newer resources incorporating more recent data.
The collection of data for my project proved to have some challenges. Due to the timeframe of my sampling, the dirt samples were hard to collect with the years first real snow dump falling down. The two plots I was sampling also proved to be quite rocky, so it took some time to find spots I could dig to an acceptable depth as to have a soil core that would be indicative of the actual soil pH. When I was preparing the samples for testing with a pH meter I had to pick out as much of the organic matter and gravel as possible which also proved challenging. Once the samples were separated down to just dirt, I used the pH meter get some actual numbers, but the pH read was rather uniform in its distribution across the samples, hovering at around 6 pH. Even the control sample of just distilled water read a surprisingly low pH level of 5.75. I definitely need to re-approach how I’m going to gather my data; however, I’m relatively sure that the results are due to my methods used rather than the actual samples. I found online that most studies use a salt dilution to help the sensor pick up the pH, as in distilled water there may be too few ions for the sensor to properly pick up the change in pH from one sample to the next. The other solution is to use a more even distribution as some researchers just use a 1:1 ratio for water to soil mix it up and give it 5 minutes to settle. I also plan on acquiring a sieve to help remove the remaining organic matter that I couldn’t grab and double check the results of the pH meter with pH strips. I think with the sieve and using a closer ratio of dirt to water the actual pH should be easier to pick up, and the pH strips will allow me to double check my results.
