Figure 3 

Figure 3 Legend

Peach Tree vs Tomato Plant Soil Shannon Diversity Index, Richness, and Evenness 

We measured the soil richness, Shannon diversity, and evenness levels of our two conditions. We obtained our data by culturing bacteria from our soil samples and running them through an ecoplate. Figures 3A-3C show our averages (means) and standard deviations of our two conditions for Shannon Diversity (S) measurements, Richness (H) measurements, and evenness (E) measurements respectively. Figure 3D shows the organic molecule relative utilization efficiency of each of our conditions. The average Shannon diversity index, richness, and evenness of our peach soil were 3A) 3.33, 3B) 29.125, and 3C) 0.985 respectively.  The average values for our tomato soil were 3A) 3.32, 3B) 29, and 3C) 0.007, respectively. The standard deviations for peach soil were 3A) 0.06, 3B) 0.06, and 3C) 0.008, respectively. The standard deviations for the tomato soil were 3A) 0.06, 3B) 1.51, and 3C) 0.007. We conducted an unpaired t-test, assuming unequal variance, to compare our data. 

Functional Biodiversity Method

Before we were able to culture our bacteria, we had to dilute a soil sample containing the bacteria. we started this by taking two small scoops of the soil and putting the soil sample into a vial with 9 mL of sterile water.  We mixed it well and, from there diluted it through a 1:10 method (9 parts sterile water, 1 part soil solution). From there, we put it into an Eco Plate and filled two sides with our two conditions. After they were incubated for 7 days, each group sent their data to Meredith, who sent out all of the group's data. We used Excel to find the average, standard deviation, create graphs, and calculate the p-value.

Functional Biodiversity Results

For Figure 3A, there is a difference of means of just .125 and a p-value of 0.8764 from an unpaired t-test assuming unequal variance. For Figure 3B, there is a difference of means of just .005 and a p-value of 0.8699 from an unpaired t-test assuming unequal variance. For Figure 3C, there is a difference of means of just .00125 and a p-value of 0.7438 from an unpaired t-test assuming unequal variance. Because all of our p values are greater than .05, there is not a significant difference in soil biodiversity between our two conditions. Figure 3D shows similar proportions of molecule makeup for each sample. 

Based on our data, we conclude that each condition, the peach tree soil and the tomato plant soil, are fairly equal in terms of functional biodiversity. Neither had particularly unique values for their Shannon biodiversity indexes (p-value = .87 > 0.05), Richness values (p-value 0.88 > 0.05), or evenness values (p-value = 0.74 > 0.05). Each p-value is greater than 0.05, which is the maximum cut-off for our unique values between data sets. For Figure 3D, when examining the graph, the peach soil and tomato soil data sets have marginal differences in the percentages of the relative utilization efficiencies of each different type of molecule. The minimal differences in data sets are apparent in both our visual data (figures 3A-3D) and in our p-values, which are all well above our maximum cutoff of 0.05, so we are 95% confident in our conclusions and statements that the data sets do not provide unique values.

According to Biodiversity and Conservation, biodiversity in residential and urban gardens can be promoted significantly by non-native plants in the area (Delahay et al.). Our two conditions were soil from peach trees and tomato plants. Tomato plants are originally from South America but have now become a known global crop, cultivated in many parts of the world (University of Illinois). Similarly, peach trees originated in China, but when the New World was being colonized, peach trees began to spread abundantly throughout the colonies (Peaches). This leads our group to conclude that these two conditions may not provide significantly unique values partially due to their long-lasting status as common crops in most of the world, including Indiana and their proximity in the urban garden where we harvested samples. We took the samples from the same urban garden. The garden is not large, so the samples were inevitably taken from a similar area of soil with similar soil properties. Biodiversity in the garden soil could be increased by introducing more uncommonly cultivated and non-native plants to Indiana.