Bees

---

Pollination Nation: Effects of Urbanization and Flower Number on Pollinators Naiem Habib, Victoria Von Ancken, Monia Begum, Bryan Flores, Jennifer Rojas, Karen Salatandre, Dominique Santiago, Aleksandra Serafin Text

ABSTRACT

In Prospect Park, there is a marginally significant difference in average pollinator visits between urban and naturalized plots (p-value = 0.069). In the Bronx Zoo there was no significant difference (p-value = 0.82) (Figure 1). In Prospect Park and Bronx Zoo there was no significant difference for pollinator diversity. (Prospect Park; p-value = 0.5438, Bronx Zoo; p-value = 0.3438) (Figure 2). In Prospect Park there was a significant difference between average pollinator time spent in quadrat in urban and naturalized plots. (p-value = 0.02881). In the Bronx Zoo there was no significant difference (p-value = 0.393) (Figure 3)! 16!

7!

Pollinator Diversity!

14! 12! 10! 8! URBAN!

6!

NATURAL!

4! 2! 0! PP!

6! 5! 4! 3!

URBAN! NATURAL!

2! 1! 0!

BXZ!

PP!

Sites!

500! 400! URBAN!

300!

NATURAL!

200! 100! 0! PP!

BXZ!

BXZ!

Sites!

Figure 3: Time in quadrat!

20! 15! 10! 5!

0!

10!

20!

30!

40!

0.7! 0.6! 0.5! 0.4! 0.3! 0.2! 0.1! 0! 0!

50!

y = 0.1872x + 1.4811!

0!

10!

20!

30!

40!

30!

40!

50!

Figure 5: Average pollinator diversity v. flower number (Prospect Park)! ! Average Pollinator Diversity!

Average Pollinator Visits!

Figure 4: Average pollinator visits v. flower number (Prospect Park)! 18! 16! 14! 12! 10! 8! 6! 4! 2! 0!

20!

Flower Number (wild bergamot) !

Flower Number (wild bergamot)!

INTRODUCTION

10!

1800! 1600! 1400! 1200! 1000! 800! 600! 400! 200! 0! -200! 0!

50!

60!

Flower Number (black-eyed Susan)!

0.8! 0.7! 0.6! 0.5! 0.4! 0.3! 0.2! 0.1! 0!

y = 0.003x + 0.3591!

0!

10!

20!

30!

40!

50!

60!

Flower Number (black-eyed Susan)!

Figure 8: Average pollinator diversity v. flower number (Bronx Zoo)!

Figure 7: Average pollinator visits v. flower number (Bronx Zoo)!

y = 21.562x - 97.87!

Figure 13: Carpenter bee! 10!

20!

30!

40!

50!

400! 350! 300! 250! 200! 150! 100! 50! 0!

y = 2.8491x + 64.545!

Figure 15: Hummingbird moth! 0!

10!

20!

30!

40!

50!

60!

Flower Number (black-eyed Susan)!

Figure 9:Average pollinator time in quadrat (Bronx Zoo)!

In the Bronx Zoo, there is a significant relationship between pollinator visits and canopy coverage (p=0.0046, rho=-0.61). In both sites, there is a significant relationship between canopy coverage and average pollinator time spent in quadrat (p=0.015, rho=-0.54 for Bronx Zoo) (p=0.021, rho=-0.52 for Prospect Park)!

We surveyed 20 quadrats 0.5-m2 each in two sites (Prospect Park/Bronx Zoo) for number of pollinator visits and pollinator diversity. Within each site we had an urban and a naturalized plot and we observed 10 quadrats in each. We used a hand tally to count the flower number of our study species; wild bergamot at Prospect Park and black eyed Susan at the Bronx Zoo. In addition, we counted total flowers for our species and any other miscellaneous species present in the quadrat. For 10 minutes per quadrat, we observed the number of pollinators, their morphospecies and the time they spent pollinating. We also took note of the time, surroundings, canopy cover, temperature, and weather in each quadrat. The statistical analyses used in this study were the nonparametric Wilcoxon Rank-Sum Test, and the nonparametric Spearman’s Rank Correlation Test.

Figure 14: Milkweed beetle!

Flower Number (wild bergamot) !

!

METHODS AND STUDY SITE

We hypothesized that there would be fewer pollinator visits, less pollinator time spent in quadrat, and less pollinator diversity in an urban plot. We found that the effects of urbanization varied between different sites and variables. Multiple trends may be attributed to our two different study species. Examining canopy coverage may explain why some measures of pollinator activity varied among sites. Canopy coverage had a significant correlation with pollinator visits at the Bronx Zoo as well as pollinator time spent in quadrat at Prospect Park and the Bronx Zoo. As such, increased canopy coverage may decrease the number of pollinators present. We also hypothesized that a greater number of flowers would increase the amount of pollinator visits, pollinator diversity, and pollinator time spent in a quadrat. Flower number is an important determinant in pollinator variables in both sites: Prospect Park and Bronx Zoo. In both Prospect Park and Bronx Zoo there is a significant relationship between flower number and average time pollinators spent in a quadrat (Figure 6, 9), average pollinator visits ( Figure 4, 7), and average pollinator diversity (Figure 5, 8). As flower number increases the amount of pollinator visits, pollinator diversity, and pollinator time spent in a quadrat will also tend to increase. This is relevant because flower number may be decreasing due to herbivory, which is ultimately increased by urbanization (Christie).

Figure 6:Average pollinator time in quadrat (Prospect Park)! Average Pollinator Time in Quadrat (sec)!

25!

y = 0.0048x + 0.4335!

0.8!

Average Pollinator Time in Quadrat (sec)!

y = 0.3678x + 2.0342!

0!

Honeybees are considered to be the most economically valuable pollinators for crops worldwide (Klein). However, pollinators have recently declined in diversity and abundance due to habitat fragmentation that is associated with urbanization (Ahrné). As buildings and roads disrupt greenspace, pollinators have fewer areas to live (Klein). For this study, we examined the effect of urbanization and flower number on pollinator visits and pollinator diversity. Studying pollinators in urban and naturalized areas allow us to compare and study this relationship. Fewer flowers may dissatisfy pollinators, while more flowers may attract a greater amount. With our studies, we have gained understanding of the relationship between plant fitness, urbanization, pollinator visits and pollinator diversity.

600!

Figure 2: Pollinator diversity!

Average Pollinator Diversity!

We hypothesized that urban plots will have a decrease in pollinator visits, diversity and time spent in a quadrat 0.5-m2 compared to naturalized plots. We hypothesized that a greater number of flowers will increase the amount of pollinator visits, pollinator diversity, pollinator time spent in a 0.5-m2 quadrat

700!

In both sites, there is a significant relationship between flower number and average pollinator visits (p=.0002, rho=0.74 for Prospect Park, Figure 4) (p=0.002, rho=0.64 for Bronx Zoo, Figure 7). In both sites, there is a significant relationship between flower number and average pollinator diversity (p=0.45, rho=0.18 for Prospect Park, Figure 5) (p=0.15, rho=0.33 for Bronx Zoo, Figure 8). In both sites, there is a significant relationship between flower number and average time pollinators spent in a quadrat (p=9.07e-06, rho=0.82 for Prospect Park, Figure 6) (p=0.01, rho=0.54 for Bronx Zoo, Figure 9).!

Average Pollinator Visits!

●  How does urbanization affect pollinator visits, pollinator diversity, and pollinator time spent in quadrat? ●  How does flower number relate to pollinator visits, pollinator diversity, and pollinator time spent in quadrat ?

800!

Sites!

Figure 1: Pollinator visits !

QUESTION AND HYPOTHESIS

Average Pollinator Time in Quadrat (sec)!

! Pollinator Visits !

Increased urbanization may have impacts on pollinator abundance, diversity, and time spent pollinating. To assess the effect of urbanization on pollinators, we conducted an observational study of urban and naturalized plots in two sites. At the Bronx Zoo we studied black-eyed Susans and in Prospect Park we studied wild bergamot. Results varied among site and study species. At the Bronx Zoo, we found that as canopy coverage increased, pollinator visitations decreased. As such, canopy coverage may also be a factor for our varied data. In addition, we examined the relationship between the amount of flowers of our study species and various pollinator variables. In both the Bronx Zoo and Prospect Park the average pollinators visits, pollinator diversity, and average pollinator time spent in quadrat increased as flower number increased for urban and naturalized plots. This is important because an increase in urbanization may reduce plant fitness which consequently may reduce their attractiveness to pollinators.!

DISCUSSION

RESULTS

Figure 16: Eastern Yellow Swallowtail!

LITERATURE CITED Ahrné K, Bengtsson J, Elmqvist T (2009) Bumble Bees (Bombus spp) along a Gradient of Increasing Urbanization. PLoS ONE 4(5): e5574. doi:10.1371/ journal.pone.0005574 Alexandra-Maria Klein, et. The Importance of Pollinators in changing landscapes of World Crops. February 2007. Volume 274 Issue: 1608.

Average Canopy Cover!

80!

Christie, Fiona J., and Dieter F. Hochuli. "Elevated levels of herbivory in urban landscapes: are declines in tree health more than an edge effect." Ecology and Society 10.10 (2005).

70! 60! 50! 40!

Urban ! Natural!

30! 20!

ACKNOWLEDGEMENTS

10!

This research is funded by the National Science Foundation as a part of Project TRUE (Teens Researching Urban Ecology)—a partnership between Fordham University and the Wildlife Conservation Society.

0! PP!

Sites!

BXZ!

Figure 10: Average Canopy Cover! Figure 11: Prospect Park naturalized site!

Figure 12: Prospect Park naturalized site!

Prospect Park Alliance