MBI 115 Section AI
16 October 2018
Lab 3: Biodiversity Challenge
Over the course of two weeks, students observed and identified a variety of invertebrates in two different areas, mulched and non-mulched, to see how invertebrate biodiversity and environmental factors/abiotic conditions differed between those two areas (BIO/ MBI 115 Laboratory Experiences, 2018 p. 31). During Lab 4, students were able to test the hypothesis which states, in the areas were mulch is present, there will be more invertebrates found than in the non-mulched areas.
For this lab, a variety of data was collected and then was used to calculate certain values to show the diversity in both areas. Each group, while at their study areas, took the measurements for moisture content and temperature in both the mulched and non-mulched areas. As shown in Figure 1, the average temperature in both the mulched and non-mulched areas were very similar; the values ranged from 24.4°C to 22.95°C. Along with the temperature, moisture content was measured and showed that, just like the temperature, mulched and non-mulched areas were very similar and had values 2.5 and 4 (Figure 2). Both of these figures, present how the measurements/readings differ between the two study areas.
Along with these measurements, students found that there was a higher number of individuals (N) and species richness (S) in the mulched areas. This also showed that the calculations for Shannons Diversity Measure (H), evenness (E), and Simpsons Index of Diversity (D) were also higher in the mulched samples compared to the non-mulched samples. (Table 3-7)
These results from this lab show that the data does, in fact, support the hypothesis that in the areas were mulch is present, there are more invertebrates found in comparison to non-mulched areas. This diversity in the mulch area is due to many factors. As shown from other collected data, the reason invertebrates are more prevalent in mulch areas is most likely due to the fact that mulch increases health and fertility of the soil which causes invertebrates to be more drawn to it (BIO/ MBI 115 Laboratory Experiences, 2018 p. 29). Going along with this, if the moisture content in higher in an area, which is most common in mulch areas, then invertebrates are more likely to be present. The mulch will have a higher diversity, in comparison to non-mulched areas because mulch provides a protective layer from the sunlight and it make the soil stay moist longer and is a more complex habitat (K. Farleigh, personal communications, October 2, 2018). Since the mulch area for lab was in close proximity to the water, it also contributed to the higher diversity because of the prevalence of a water source.
In the case of this lab, moisture content and temperature for the mulched and non-mulched areas were similar (Figure 1 and Figure 2). This is led to the closeness of calculated values and number of species present in the two-different type of sample areas (Table 3-7). Although the moisture and temperature readings along with similar calculation results, the mulch still has a more diversity. The mulch area had a higher Shannons Diversity Measure meaning that there was higher diversity and lower predictability compared to the non-mulched samples. Along with this, the higher evenness and since this value was closer to one, it shows that in the mulched areas there are more evenness in abundance for all the species present. The Simpsons Index of Diversity, which measures diversity, was also greater in and closest to one in the mulched areas meaning that as evenness and species richness become or are greater, so is the diversity. These measurements and calculations support the hypothesis that the mulched areas are more diverse than non-mulched.
Before samples and readings were taken for this lab, a mass amount of precipitation occurred in the study area. This rain diluted the concentration of nutrients causing the individual invertebrates to move into the non-mulched area since the moisture content was similar to that of the mulched (Figure 1). The rain pushed the insects out of the sample site leading to a lower number of morphotypes present (K. Farleigh, personal communications, October 2, 2018). Despite the closeness of the calculations and recordings, the values of the mulch areas still supported that there was more diversity than in the non-mulched area, ultimately supporting the hypothesis.