Project Overview
Commodities
- Fruits: berries (blueberries)
- Animals: bees
Practices
- Crop Production: beekeeping, crop improvement and selection, pollination, pollinator habitat, pollinator health
Abstract:
The chief pollinator of U.S agriculture, the honeybee, is under serious threat. Honeybees face significant colony losses from Colony Collapse Disorder and other factors. This has significantly increased the cost of renting honeybee hives, which has significantly added to the production costs for farmers and has even endangered the U.S. food supply from a lack of possible pollinators in the future.
The best alternative to honeybees is the wild bees (native bees) already present in the local environment [1, 10-11]. With nearly 3500 species in North America alone, the diversity of different forms, pollen-strategies, and behaviors of native bees provide a wide range of use for agricultural operations.
Thus, the answer to creating a secure and sustainable pollination system in U.S. agriculture is native bees. Past research suggests two main methods to boost native bees in agricultural areas: (a) by providing nesting habitats and (b) by providing additional floral resources (particularly during periods of low food availability). Food resources were targeted by this study, since in the Southeastern U.S. region, the most useful native bees are ground nesting bees that could also nest in the wildflower plots [5]. The targeted ground nesting native bees include mining bees (Genus Andrena), bumble bees (Genus Bombus), and sweat bees (Genera: Augochlorella, Halictus, Lasioglossum).
The main purpose of the proposed study is to assess the benefits of floral enhancements (wildflower plots) to boosting native bee and pollinators in blueberry farms. Studies have shown floral enhancements on the edges of orchards and farms have had a significant effect in recruiting or bringing in more native bees. Now, scientists need to explore what is really going on in the wildflower patches during each major period of the growing season. Specifically, we need to know what is going on during the (1) pre-bloom period, (2) bloom period of the target crop (blueberries), and the (3) post-bloom period/summer dearth period (period of few floral resources).
Past research on native bees in Georgia have focused on the northern apple producing areas of Georgia. This will be one of the first studies with native bees in central Georgia. Thus, the study’s results will also allow us to compare and contrast native bees’ seasonal diversity and abundance in Northern Georgia (clay soils) verses Central Georgia (sandy soils).
Each region of the U.S. varies in farming conditions, bloom times, and variety of native bee species that are available for pollination activities [12]. Regional studies such as the proposed study are essential in gathering accurate information on which wildflower species have the best native bee recruitment characteristics.
In the current study, we studied wildflower effectiveness in recruiting bees and surveyed native bee diversity and abundance in the poorly studied Coastal Plain of Central Georgia. Twenty-two different wildflower species were seeded in wildflower enrichment patches next to experimental plots of blueberry bushes. Wildflowers were observed for bee visitation. The wildflowers that recruited the most bees were Indian Blanket (Gaillardia aristata), Lanceleaf Tickseed (Coreopsis lanceolata), Red Clover (Trifolium pratense), and Cosmos Sensation (Cosmos bipinnatus). Bees were surveyed in 2022 and 2023 to determine the impact of the wildflower plots on bee abundance and diversity. In 2023, the assembly of bees on the farm significantly changed.
During the first year of the study (2022 control year), 590 bees were collected. Small sweat bees dominated the collection, making up 89% of the collection. During the second year of the study (2023 experimental year), 510 bees were collected. Small sweat bee abundance in the collection dropped to 58%. The wildflower plots significantly altered the bee diversity and abundance of major bee groups. Large size bees (bumble bee and carpenter bee) increased 10-fold from 4 to 47 bees collected, and medium- size bee (blueberry bees and mining bees) increased 10-fold from 24 to 76 bees collected in the bee sampling.
Plots with wildflowers attracted more than double the bees. Sampling of plots with wildflowers yielded 359 bees verses only 151 bees sampled in control (no wildflower added) plots.
The bee numbers did not increase from control year (2022) to experimental year (2023), but rather the makeup of the bee community changed. However, the small, rather insignificant, sweat bees were replaced by large and very efficient bumble bees, blue berry bees, and mining bees. Scientists have long questioned the impact of the “gnat-size” sweat bees in pollination effectiveness, while the large bumble bees, blue berry bees, and mining bees have been documented to be effective pollinators and to carry large pollen loads flower to flower.
Project objectives:
The project main objective was to measure the effect of adding wildflower plots in agricultural areas on native bee populations, we performed an on-farm field experiment. The experimental location for the on-farm research project was the Pinefield Eco Farm in Hephzibah, Georgia. On the farm, we created six plots of blueberry bushes (3 control and 3 experimental). Figure 1. is a diagram of the plot design at the farm.
Figure 1. A diagram of the plot design at the farm
Each experimental plot consisted of 4 rows of blueberry bushes and 1 row of wildflower plants. The wildflower row was roughly 200 ft2 (50 ft x 4 ft) and sat in the center, between the two rows of blueberry bushes surrounding it on either side. The control plots each had 4 rows of blueberry bushes. The control plots are located on the opposite side of the farm, in regards to the experimental plots.
Objective 1: Measure native bee abundance in experiment blueberry plots with wildflowers vs. control blueberry plots during each of the 3 major periods of the growing season.
To gather the data needed to test this objective, we used a range of sampling methods shown to accurately sample native bee abundance and diversity in North Georgia Apple Orchards, based on a modified Bee Inventory Plot Design [5].
Year 1 (2022) was the control year. Six blueberry plots (3 control and 3 experimental) were set-up on the farm. We performed eight monthly samples (March-September) in each plot. Year 2 (2023) was the experimental year. We performed twelve samples, during the bee season: Pre-Bloom Sampling (March), Blueberry Bloom (April), and Post-Bloom/Summer Floral Dearth (May - September).
All bee samples collected were stored in 95% ethanol and taken back to Georgia Gwinnett College. They were washed, sorted, pinned, and then identified to genus. Professor Schlueter led the team of GGC undergraduates on sorting the samples and identifying the bees.
Objective 2: Determine which target bee species is present in each of the major periods of the growing season.
There are three major periods of concern: Pre-bloom, Bloom, and Post-Bloom/Summer Dearth (Poor food availability in farms).
During each day of sampling, researchers staked out and observed each flowering wildflower species. Each bee that landed on a targeted wildflower was photographed and/or collected. The majority of the bees were photographed to reduce damage to the wildflowers. The collected bees were be taken back to GGC for identification.
Objective 3: Assess native bee pollination behaviors on wildflowers.
During each day of sampling, researchers staked out and observed each flowering wildflower species. Video cameras mounted on tripods were also used to measure native bee behaviors at wildflowers and at the blueberry flowers. Video cameras allow bees to act normally, without the presence of humans, and frees up students to perform other sampling. However, the high heat limited the video cameras use. Battery life was significantly reduced. Due to video camera limitations ( small field of view and limited battery life), human observation yielded the best data and results.
The three goals of this objective are to determine: (1) which bee species is visiting which flower species, (2) the length of time individual bees spend on each flower, and (3) the types of interactions that occurs (e.g. buzz pollination, full body submersion into flower, etc.).
Objective 4: Assess the effect native bee pollination has on boosting blueberry crop quality and overall yield.
Later in the season, several bushes in each of the plots (Control and Experimental) were assessed for their overall blueberry yield. We examined two factors: (1) overall fruit quality (based on average size (width) of the berry) and (2) the average amount of berries produced by each bush (numbers and weight).
The data gathered allowed us to make conclusions about which wildflowers have the best characteristics for recruiting native bees to agriculture areas. Conclusions on the benefits on native bee pollination and the use of wildflowers plots can also be made based on their overall impact in boosting crop quality and amount.