1. Prairie Restorations Impact on Biodiversity: Understanding Restoration Impacts on Flowering Plant Frequency and Insect Pollinator Abundance
Alyssa Ayen (Lawrence University), Jackson Yow (University of South Carolina), Monica Zakariya (Northeastern Illinois University)
BACKGROUND
METHODS
RESULTS
RESULTS
Within the past few centuries tall grass prairies have been undergoing expansive declines as urbanization expands and reduces ecological processes. In Illinois alone, it’s found that only about 1/100th of 1 percent of high quality remnant prairies remain (Heslinga, 2010). In response to this reduction, more areas are being restored within the Chicago region to increase the amount of natural spaces, with hopes of providing the ecological and social benefits observed at remnant sites. However, habitat fragmentation is a concern that can lead to isolated endemic species and threaten herbivorous insects and their host plants (Kluger et al., 2011).
Our team surveyed a total of six sites of various ages to conduct observational fieldwork on pollinator counts, flowering plant quantities, blooming plant frequency and milkweed density. The intermediate age sites are found in various areas within the Burnham Wildlife Corridor, encompassing Caracol, La Ronda Parakata , and Sankofa for the Earth. The intermediate sites have ages ranging from 4-7 years since restoration occurred. Older restoration sites (10+ years) consist of 41st Street Bioretention Site, Burnham Nature Sanctuary, and McCormick Place Bird Sanctuary.
This bar graph represents the variables related to our first hypothesis that flowering plant frequency would increase with age of restoration. The older sites were found to have a higher average flowering plant frequency (1.18 +/ ) than the intermediate sites (1.48 +/ ). Yet the difference was not statistically significant, as evident by a chi-square test on these data that resulted in a P-value of
This bar graph illustrates the breakdown of the amount of insect pollinators at each individual site. Intermediate age sites are shown on the left and older sites on the right. 100 subplots were sampled at each site. Pollinators were identified across five insect orders and are represented by different colors within bars. The total about of pollinators from different orders varied between the intermediate and older sites. Overall, there were higher amounts of hymenoptera and diptera observed at the older sites compared to the intermediate sites, which illustrate increased amounts of orthoptera.
Figure 1: Bar graph +/- 1 showing the relationship between age of restoration site and average frequency of flowering plants. Intermediate and older ages consist of 3 sites each. N=100 quadrats per site. Average flowering plant frequency calculated by average of first subplot that a flowering plant was observed in (A=3, B=2, C=1, none=0) at each site and then within each group.  
Through the establishment of the Burnham Wildlife Corridor, urban natural areas are undergoing rehabilitation under the supervision of collaborators such as The Field Museum, Chicago Park District and myriad local partnerships (Friedberg, 2017). This allows reintegration of once lost portions of a local ecosystem to be revived (Clewell & Aronson, 2006). This 100 acre corridor is an experiential laboratory for restorative prairie sites, stretching from McCormick Place to East 47th Street.
Figure 4: Pollinator abundance broken down between individual sites. Pollinators identified by order (N=5) and represented by color within each bar. Intermediate aged restoration sites shown on the left and older aged restoration sites are shown on the right. N=100 quadrats per site.
This scatter plot shows the relationship between flowering plant frequency and pollinator abundance. Flowering plant frequency ranged from 0.67 (Sankofa) to 2.31 (Bioretention site). Pollinator abundance is the sum of all pollinators observed in all quadrats (N=100) within each site, of which 6 were studied. These values range from 298 (La Ronda) to 563 (McCormick). A linear regression yielded an R2 value of
CONCLUSIONS
Through past research on remnant sites, it was expected to find similar interactions occurring between age of restoration, flowering plant frequency and pollinator abundance. For both hypotheses, there was no statistical significance observed between age and flowering plant frequency, as well as insect abundance and flowering plant frequency. Additionally, our research expanded to understanding the relationship between age of restoration and the average pollinator abundance, finding the occurrence of a direct correlation. This observed phenomena could be due to the recruitment of insect pollinators, allowing formation of non-migratory communities at these natural sites.
The continuation of this data collection is necessary to develop an understanding of the health and function of restored sites within the Burnham Wildlife Corridor in comparison to remnant tall grass prairies in the Midwest. Based off the results of Vickery’s study, understanding when prescribed burnings occurred would be relevant information to help examine possible correlations between disturbances and insect pollinator abundance. Furthermore, collecting primary data on restored prairie within the Chicago Park District can be used in a comparison study to remnant sites.
A random number generator was used to set the locations of where the transects would be placed, extending up to 100 meters. A meter squared frame was laid every five meters on both sides of the transect at each inquiry point. Subplots within these quadrats were divided into sections A, B, and C in order to identify measures of frequency and abundance. A represented high frequency with visibility within the first 25% of a quadrat pair, B represented 50% and C was the entirety of the third quadrat or 50%-100% frequency. Average flowering plant frequency was calculated by assigning number values to these subplots as follows: A=3, B=2, C=1, none=0. A hundred subplots per site were used, equating to six hundred total across the six sites of study. One and a half minutes after placing the quadrats down, insect abundance were identified to the order level. This wait time was observed in accordance with a widely used, standardized pollinator monitoring methodology in order to minimize the effect of disturbance.
It holds prime importance in restoring native ecosystems, but has potential differences from traditional remnant prairies. Research on restored prairie sites is a growing, but limited area, causing uncertainty in what interactions are occurring between plants and pollinators, as well as many other biotic and abiotic features. Therefore, to access the health and function of restored sites, insect pollinator and flowering plant frequency were examined further.
Figure 2: Scatter plot showing relationship between flowering plant frequency and abundance of insect pollinators with linear regression results and R2 value (0.035).
This bar graph shows the relationship between age of restoration site and average abundance of pollinators between the 3 sites that make up each age group.  The average pollinator abundance at intermediate age sites was found to be 380 individuals and at the older sites it was found to be individuals. A strong positive correlation between age of site and abundance of pollinators was found (p<0.001, df=1).
OBJECTIVE
To assess the health and function of restored sites, insect pollinator and flowering plant frequency were examined further. These two hypotheses were generated:
As restoration age increases, flowering plant frequency will increase
As flowering plant frequency increases, insect pollinator abundance will increase
The data was compiled and organized through the use of excel. The various data found was then analyzed and illustrated using excel and PAST. The chi- squared values, p values, and linear equations, inducing an r-squared value were calculated. These are originally represented through bar and linear regression graphs.
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Alyssa Ayen
Figure 3: Bar graph +/- 1. showing relationship between age of restoration site and average insect pollinator abundance between older and newer sites. Each age consists of 3 sites each. N=100 quadrats per site. p<0.001.