User: | Open Learning Faculty Member:
3 areas which are 10m x 10m in size were chosen at Papago Park around a man-made oasis. Area 1 was 5 meters south of the oasis. Area 2 was 20 meters south of the oasis. Area 3 was 50m south of the oasis. These 3 sites were chosen in a southern direction because south had the most unimpeded land (either by road or rock). The three sites were arranged in a line and did not veer substantially to the south-east or south-west. Each area was divided into grids of 25 subplots each measuring 2m x 2m. Each grid was assigned coordinates of x and y values. To pick the initial subplot in each area, the google number generator with n = 5 was rolled. I rolled it twice, with the first number acting as the x coordinate and the second number acting as the y coordinate. From there I used a systematic sampling method where each individual individual Larrea tridentata was counted and measured. From the first subplot, I would increase and decrease the x value until I have x = 1, 2, 3, 4 ,5. Y-values were y and y-1 (where y – 1 = 0, would wrap around back to around to y = 5).
5 subplots were selected in each of the three areas for a total of 15 replicates. The total time for the sampling and recording of data took approximately 1 hour and 35 minutes. Distance between each individual in the each chosen subplot to its closest neighbour was recorded, as well as the number of Larrea tridentata individuals and each plants height. There were few difficulties with this method of sampling. The only issue was that the number of individuals in area 1 was quite low and 2 of the chosen subplots ended up being empty which may skew the estimates of the height as empty plots had to be disregarded.
I noticed that the total number of plants (of any species) increased dramatically in area 1 relative to the other 2 areas. However, the number of creosote bushes dropped substantially which was against my set out hypothesis. There was no ancillary pattern in the distribution of individuals but in terms of height, creosote closer the water were larger than those further away.
