Since the 1890s, Americans have responded to economic declines by transforming urban vacant land for agricultural production. Similar trends continue today and urban agriculture is revitalizing post-industrial cities, like Cleveland, OH where economic recession has resulted in the formation of over 22,000 vacant lots. Currently, Cleveland hosts an estimated 235 urban farms and this proliferation reflects worldwide interest in urban agriculture initiatives. However, as our world’s 800 million urban farmers try to address food insecurity and support growing human populations, they are faced with land use legacies including soil compaction, contamination, and high degrees of impervious surface—factors which challenge urban pollinators and influence availability of floral and nesting resources. Since research shows that urban bees are critical to urban crop quality and quantity, the sustainability of urban agriculture relies on urban pollinator populations. Therefore, we propose to identify the flowering plants that sustain wild bee populations critical for urban farm pollination in Cleveland, OH. Our project aims to utilize next generation sequencing tools to: 1) determine the crop and non-crop floral resources found within an urban farm that are important for bee larvae and 2) evaluate if the establishment of “pocket prairies”, or vacant lots seeded with native prairie vegetation, alter bee foraging and improve reproductive success. Through these two objectives, we will identify which cavity nesting bees pollinate urban crops, assess the potential contributions of these solitary bees to urban farm pollination, and make recommendations for on-farm flower plantings that will encourage bees to nest and reproduce near urban farms. In the short term, our project will contribute to important research on how to analyze pollen more effectively and conserve urban pollinators. Long term, our project will inform urban farmers about pollinator resources (both nesting and foraging) and encourage them to improve farming practices to benefit pollinator communities and the services they provide. As economic success is integrally tied to ecological success, our work will support healthier urban environments and more productive urban agriculture.
Our research’s long-term goals are to demonstrate the value of cavity nesting bees for urban crop pollination, and examine how to manage urban habitats to support productive bee communities. We will progress towards these general long term goals through two learning outcomes and one action outcome. By the end of our project, we will help 60-100 urban farmers and gardeners learn (1) what crop and non-crop floral resources bees are using on urban farms and (2) if planting prairie plants near nesting sites improves bee reproductive success. Likewise, we will encourage these urban farmers to take action and modify their farm management practices to incorporate pollinator habitat on their farms (Action Outcome).
In order to achieve our learning and action outcomes we will conduct pollinator workshops, field days in urban farms and pocket prairies, extension factsheets, scientific publications, and partner with a farming advisory committee of six Cleveland urban farmers, who will be compensated for their time and participation. Educating our advisory committee and other urban farmers about pollinator communities within urban agroecosystems will provide these growers with the information they need to make sustainable decisions.
- We established trap nests at nine urban farms and nine pocket prairies in Cleveland, OH on April 5, 2017.
- Trap nests consisted of a PVC pipe filled with thirty cardboard nesting straws (15 cm long) at three diameters (4,6,8 mm) and provided supplementary bee nesting cavities.
- Throughout the 2017 and 2018 summers (April- July), we visited each nest biweekly, removed all occupied straws, and replaced them with new straws.
- We also completed a floral inventory and measured bloom abundance and area along four 10 m transects, arraying out from each nest in cardinal directions.
- Removed straws were then X-rayed to confirm nesting, and the pollen was dissected from the straws for further molecular analysis.
- We have extracted the DNA from all of our pollen samples and are currently working on preparing this DNA for sequencing.
- We use a multi-locus, consensus based approach to our pollen metabarcoding– this means we are amplifying our pollen DNA at three molecular markers (ITS2, trnl, rbcl) and we can confirm if a plant is present in the pollen sample by locating its DNA multiple times.
- For each sample, we are conducting 9 PCR reactions (we use a three step process for each molecular marker). We are currently working on the last PCR step for all three of our markers, so we’re 2/3 of the way done!
- We collected 111 bee nests from 6 urban farms and 8 urban prairies in Cleveland, OH.
- All bee nests were X-rayed and then pollen/bees were dissected
- A total of 559 larvae were counted from our collected nests.
- DNA extraction is underway.
- Bee nesting abundances were pretty poor in 2018, but we still collected an additional 36 nests containing 180 bee larvae.
- (That’s a 68% decrease in nest abundances although there were still 5 bees per nest, on average.)
- We pooled pollen from each nest and have completed DNA extraction for all of our 2017-18 samples.
- We are 2/3 of the way through our sequencing preparation and are hoping to send our samples out this Spring!
Educational & Outreach Activities
2017: In conjunction with the Cleveland Botanical Garden’s Green Corps and the Ohio Ecological Food and Farming Association, Katie and her mentored undergraduate co-presented to an estimated 100-115 urban residents about their research on urban farms and its potential to influence urban pollinators.
Rodney and Katie also co-conducted two separate field days with 47 youth who were employed as urban farmers through Green Corps. On these field days they broadly taught youth farmers about insects, and then familiarized them with urban pollinators and their role in pollinating crops.
Katie also traveled to Uppsala, Sweden and presented her research (to-date) to a collaborator’s group at the Swedish University of Agricultural Sciences (SLU).
2018: We continued our collaboration with Cleveland’s Green Corps of youth urban farmers this year. We developed and ran a workshop about urban biodiversity on the farm. As part of workshop, we taught this year’s cohort of youth farmers about insect taxonomy, convinced them to try both insect catching and pinning, and facilitated a scavenger hunt about common plants and insects that occur on urban farms. Involved in this outreach event were Denisha Parker (another NCR SARE recipient) and our two mentored undergraduates, who helped design our workshop stations.
Both Rodney and Katie presented about their research at the annual Entomological Society of America’s meeting in Vancouver, BC, Canada in November 2018. Katie also has submitted a talk for the Ecological Society of America’s meeting in Louisville, KY in August of 2019 where she will talk about urban bee nesting in Cleveland and what we’ve learned so far.
Moreover, Rodney successfully defended his dissertation in December and has now accepted a Post-Doc position at York University in Toronto, Canada!
We are currently investigating the knowledge gained by participating with our research through a Project Assessment and are waiting to hear back from our partnering farmers.