In an experiment to determine the effect of light availabili…
Questions
In аn experiment tо determine the effect оf light аvаilability оn species richness in an environment, a grassland was divided into 26 plots that were assigned to one of two treatment groups: 1. Clipped – plots were mowed to simulate the grazing of herbivores that maintain the low height of grasses. 2. Enclosure – plots were enclosed in fences, and grasses were allowed to grow undisturbed to their maximum height. After eight years, data was collected on the amount of light penetration to the soil (bottom light density) and the number of species in the two treatment groups. Figure 1 shows the averaged light penetration measurements, and Figure 2 shows the averaged number of species per plot type. The horizontal axis is labeled Treatment, and the two bars indicated along it are labeled Enclosed and Clipped respectively. An error range is given for each bar. The vertical axis is labeled Bottom Light Density, in watts per meter squared, and the numbers 0 through 600, in increments of 200, are indicated. Each bar is described as follows. Note that all values are approximate. Enclosed. 500, plus or minus 25. Clipped. 170, plus or minus 25. Figure 1. Average bottom light intensity in clipped plots versus enclosed plots The horizontal axis is labeled Treatment, and the two bars indicated along it are labeled Enclosed and Clipped respectively. An error range is given for each bar. The vertical axis is labeled Average Number of Species per Plot, and the numbers 0 through 20, in increments of 2, are indicated. Each bar is described as follows. Note that all values are approximate. Enclosed. 11.6, plus or minus 0.3. Clipped. 17, plus or minus 1. Figure 2. Richness comparison of two treatments Which of the following statements is consistent with the data shown in the figures?