The Negative Effects of Increasing Canopy Coverage on Plants

VariablesCensus - the week number the data was collected.Calendar Date - the month and day the data was collected.Campus - the university where the data was collected.Group_ID - a group specific identification tag that is used to represent which group collected the data.Lat - the latitude of the forest where the data was collected. The measurement was provided by the teaching assistant (TA) Jenna Braun and the forest is the one located on York University with the closest intersections being Keele St. and The Chimneystack Rd.Long - the longitude of the forest where the data was collected. The measurement was provided by the TA Jenna Braun and the forest is the one located on York University with the closest intersections being Keele St. and The Chimneystack Rd.Elevation - the elevation of the forest where the data was collected. The measurement was provided by the TA Jenna Braun and the forest is the one located on York University with the closest intersections being Keele St. and The Chimneystack Rd.Rep - the data collection number. This is reset to 1 for each different dataset. abundance.native.plants - the number of native plants, determined with the help of the TA. A plant was classified as native if it originated from its respective habitat. This is a discrete variable.<br> <br> abundance.exotic.plants - the number of exotic plants, determined with the help of the TA. A plant was classified as exotic if it originated outside of its respective habitat. This is discrete variable.<br> <br> total.number.flowers(quadrats) - the number of flowers. This was measured using a quadrat that was 1m by 1m encompassing a 1m² area. Flowers who had roots outside the quadrat were not counted: only flowers with roots inside were. This is a discrete variable. abundance.woody.plants - the number of woody plants (e.g., trees). A tree was defined to have a height of 1.5m or more. This is a discrete variable. canopy.cover - the percentage of the sky that is covered by tree canopy. This is an approximation determined by the amount of light exposure that can be seen through tree branches and leaves. This is a continuous variable.<br> <br> ground.cover - the percentage of the ground that is covered by vegetation. This is an approximation determined by the amount of soil that can be seen. This is a continuous variable.<br> <br> total.flower.numbers(transect) - the number of flowers. This was measured using a two transects that spanned a total distance of 50m. This is a discrete variable. <br> <br> abundance.vertebrate - the number of vertebrates, where a vertebrate is defined as an animal with a structural backbone. This is a discrete variable<br> <br> vertebrate.species - the number of species of vertebrates, where species was distinguished based on morphological traits. This is discrete variable.<br> <br> abundance.human - the number of humans observed in the forest located on York University near Keele St. and The Chimneystack Rd. This is discrete variable.<br> <br> abundance.invertebrates.observed - the number of invertebrates, where an invertebrate is defined as an animal lacking a structural backbone. This is discrete variable.abundance.invertebrates.pantraps - the number of invertebrates that were captured in pantraps. An invertebrate was counted for as long as it was on some part of the pantrap (e.g., in the liquid, on the side or on the bottom). The pantraps consisted of colours blue, white and yellow. This is a discrete variable. <br> <br> abundance.invertebrates.sweep - the number of invertebrates that were captured using sweep nets. An invertebrate was defined as an animal lacking a structural backbone. This is a discrete variable.<br>Methods<br> <br> Data was collected by four observers in BIOL2050. Each student worked on a separate dataset and later compiled their data into a single digital document. The data was collected approximately from 15:00 to 17:00 on October 24^th, 2016. The habitat that was under study is the forest located at the Keele campus of York University, with the major intersections being Keele St. and The Chimneystack Rd. The forest was on the outskirts of the campus and it was dominated by the <i>buckthorn</i> tree. The forest was dry and the ground was covered with maple leaves and broken tree branches. Litter (e.g., pop cans) could be seen every 10m. The forest was comprised of multiple dead trees or fallen trees and saplings that were less than 1m in height. The weather was around 5°C: it was cloudy with strong wind and partial sun. Each dataset was completed once with its specific repetitions as outlined in the BIOL2050 lab manual found at practicalecology.org. To begin the datasets, two transects were placed from the edge of the forest to the inner parts of the forest totaling a distance of 50m. This served as the reference point for each dataset. An observer set up six pantraps along the start of the transect in alternating colours of blue, white, and yellow. Each pantrap were 3m apart. Another observer poured soap water into each pantrap until they were 1/3rd full. The pantraps were laid out at 14:55 and collected at 15:41. During collection, the number of invertebrates in each pantrap was recorded. As long as the invertebrate touched the pantrap, it was counted for. Afterwards, the observer completed a total of 10 sweep nets along the transect: 5 on each side. At the end of each sweep, the abundance of invertebrates was recorded. A second observer would begin to place a quadrat along the transect alternating from left and right. He did this 25 times with each quadrat distanced 2m apart from the last. During each repetition, the abundance of native and exotic plants and the number of flower heads were counted for.<br> <br> At the same time, the third observer would walk along the transect and collect data every 2m. An approximation of tree and flower abundance; and canopy and vegetative ground coverage were recorded. To estimate canopy coverage, the observer would look up and within a 1m² view, the observer would see how much light seeped through the tree branches and leaves. For example, if there was a vast amount of sunlight that could be seen, then canopy coverage would be a smaller percentage versus if there was a smaller amount of sunlight. To estimate ground coverage, the observer would look down and compare the amount of vegetation with the amount of soil that could be seen. If soil could not be seen then vegetation was said to be 100% coverage. <br> <br> The last observer completed two point surveys: the first point survey consisted of a 50m radius and the second a 5m radius. For the first point survey, the observer used a cell phone to set an alarm for 15 minutes. During that time, the observer would walk around the transect and visualized a 50m radius using the transect as a reference. Abundance of vertebrates, vertebrate species and the abundance of humans were recorded. If a vertebrate was not in the forest (e.g., a bird above the forest) then it was not recorded: only vertebrates inside or flying through the forest were counted for. For the second point survey, the observer reset the alarm for another 15 minutes. This time, a 5m radius was covered: 5 giant steps was used as a reference. Again, the observer walked around the transect and recorded the number of invertebrates. Invertebrates were only counted if they were within view and did not take longer than 1 minute to notice (e.g., an ant on the floor covered in leaves would take longer than 1 minute to notice) <br> Hypothesis:As canopy coverage increases, more plants become negatively affected due to competition for the limited sun exposure.<br>Prediction: 1. If canopy coverage increases, then ground coverage decreases2. If canopy coverage increases, then the abundance of woody plants increases