Native Bee Habitat Rehabilitation; Encouraging greater adoption of sustainable pollination practices – part III

Final Report for ONE11-150

Project Type: Partnership
Funds awarded in 2011: $14,934.00
Projected End Date: 12/31/2011
Region: Northeast
State: Pennsylvania
Project Leader:
Alexandru Surcica
Penn State Cooperative Extension
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Project Information

Summary:

A third of the human diet relies directly or indirectly on biotic pollination. Pollinators contribute 9.5% to the global agricultural output, or about $153 billion. In the U.S., the value of pollination services has been estimated at $18.9 billion for honeybees and $3 billion for native bees. Without bees, the flowers of bee pollinated crops will abort or will set small, misshaped, flavorless and quickly perishable fruit. In addition, many wind pollinated crops have better yields when bees augment the pollination process. Currently, honeybees are decimated by a combination of pests, pathogens, and stresses as result of poor management and overexploitation. However, wild bees can successfully pollinate commercial crops by themselves if some farm land is managed as bee habitat with an abundance of floral and nesting resources. Wild bees not only provide free pollination but are active in inclement weather and are more effective in vectoring pollen between flowers than honeybees.

This is the third phase in a three-year project that deals with the monitoring of the bee population on two farms on which were installed plots with abundant floral provisioning. The overall goal of this project was to determine the change in the diversity and density of native bees when plots with floral provisioning are installed. With the knowledge of how to conserve and restore the native bee habitat and the costs needed to do so, farmers will be better equipped in avoiding the lack of or expensive pollination triggered by the ongoing honeybee crisis. Besides a ready supply of on-farm pollination services, by actively managing a population of plants rewarding to native pollinators throughout the year, growers will have a healthy and diverse population of pest predators, reduced farm soil erosion, irrigation water loss and fertilizer runoff, as well as more windbreaks, weed suppression, etc.

Introduction:

Numerous organizations throughout North America are working on conserving and encouraging pollinators, with great emphasis on honeybees. Valuable research is being done on bee biology, habitat restoration, pollinator plants, plant pollinator interactions, bee diversity, bee pests and diseases, synergistic and sublethal pesticide effects on bees, etc. However, despite the significance of the subject matter and the information available, the Northeast and Mid-Atlantic regions have no programs investigating the effects on the native bee populations as result of installing floral provisioning plots on farms. Moreover, the farmers in these regions need to have demonstration farms that will be how-to guides for providing forage and nesting resources for the native bee population. These types of projects can incorporate all the available data and give a full perspective to the farmer on the volume of work and financial investment needed for accomplishing pollination sustainability.

This project represented the third phase in a three-year project and it dealt with managing and monitoring the research plots. The desired goal of this research project is to assess if there is a change in the diversity and density of the bee population on farms as a result of installing floral provisioning plots. For a better understanding of the environmental impact of the floral provisioning, the bee population was monitored bi-weekly. For achieving consistent and nonbiased results, only the pan trapping method was used.
In 2009, at Dickinson College Farm and Penn State Southeast Agriculture Research and Extension Center were installed two 25’ by 100’ plots with floral provisioning. Although the later site was not specified in the 2009 NESARE contract, this was possible due to significant educational discounts on plant materials and some in-house funds. In 2010, the goal was to maintain the research plots and continue to monitor the general trend in the diversity and density of the bee population.

To ascertain the costs and benefits of installing floral provisioning on farms, we will be factoring in the time and funds invested in the initial installation and yearly maintenance. The returns will be determined by the rate of which the diversity and density of the population of native bees is changing.

Project Objectives:

Besides maintaining the research plots weed free on an as-needed basis, the objective in 2011 was to assess the change in the density and diversity of the bee population at Dickinson College Farm in Boiling Spring, PA, and at the Penn State Southeast Research Center in Manheim, PA.

A second goal of this project for 2011 was to establish watermelon plots on which farm and quantify the yield differences between plots close to the floral provisioning and plots away from floral provisioning. Watermelon crop was chosen because of its high value and its high requirement for pollination services. According to the literature, the watermelon flowers are visited by several dozen species of bees. Hence a diverse population of bees should have a positive effect on the quality and quantity of the yields.

Cooperators

Click linked name(s) to expand
  • Dr. Alyssa Collins
  • Jennifer Halpin

Research

Materials and methods:

On both farms, every two weeks— and sometimes weekly—from 7:00 am to 5:00 pm, the bee population was monitored. The monitoring process consisted in deploying brightly colored (white, yellow, and blue), 3.25 ounce bowls. The bowls were filled with soapy water, which has minimum surface tension. A number of twenty bowls were used on each farm, with 10 bowls being placed adjacent to the floral provisioning plot and other 10 bowls placed 300 meters away and towards the middle of the agricultural field. On each transect the bowls were placed 5 meters apart, ensuring that their colors alternated.
At the end of the day or the very next morning, the bee specimens trapped in the soapy water were collected and placed in vials with 70% alcohol. At the end of the season the specimens were washed, dried, pinned, and labeled. Easy-to-identify species were identified in-house, while harder-to-identify ones were taken to Sam Droege, biologist at USGS Patuxent Wildlife Research Center, for expert identification.

Once all bee specimens were identified, an Excel database was generated. The results were analyzed to determine the trend in the density and diversity of the bee population on each farm. For a complete list of all bee species collected in 2009, 2010, and 2011 see Excel file # 1.

Unfortunately, in 2011 only on one farm was possible to install watermelon plots. Because of a colder- and wetter-than-normal Spring, Penn State Research and Education Center in Manheim could not cultivate watermelon in a timely fashion. Therefore, watermelon plots were installed only at the Boling Spring farm. The watermelon variety selected for growing was Crimson Sweet. Two 100-foot long installed, plot I 170 feet away from the floral provisioning plot, and the other one 600 feet away from the floral provisioning plot and towards the center of the agricultural field. Both watermelon plots were started at the same time and were managed identically. Fruit was harvested throughout the month of August. Only marketable fruits were harvested and recorded. For a full database on the watermelon yields and the harvest dates, see attachment # 7.

Research results and discussion:

Based on the number of samples collected, the following are the results regarding the trend in the density and diversity for the bee population for each of the farms involved in this study:

Density
Boiling Springs, PA
– Compared to 2010, the overall number of bee specimens captured in 2011 increased with 87% for plot I (floral provisioning), 6% for plot II (300 meters away from floral provisioning plot and towards the center of the agricultural field), and 42% for the overall—see Excel file # 2 for more info;
– Compared to 2009, the overall number of bee specimens captured in 2011 increased with 260% for plot I (floral provisioning), 181% for plot II (300 meters away from floral provisioning plot and towards the center of the agricultural field), and 222% for the overall—see Excel file # 2 for more info;

– Compared to 2010, the average number of bee specimens captured per each collection event in 2011 decreased with 20%—see Excel file # 4 for more info;
– Compared to 2009, the average number of bee specimens captured per each collection event in 2011 increased with 79%—see Excel file # 4 for more info;
However, one can see in the capture list that the capture for Calliopsis andreniformis is an outlier, making up a considerable amount of specimens for the farm located in Manheim, PA. This might be because this farm has a high percentage of agronomic crops, including soybeans. Calliopsis sp. are known to use pollen from species in legume family. Therefore, it is possible that the population of Calliopsis was influenced by the rotation of soybeans and not necessarily by the floral provisioning plot. When controlling for this by eliminating the capture records for this species at both farms, the following are the results for the density:

– Compared to 2010, the overall number of bee specimens captured in 2011 increased with 41% for plot I (floral provisioning), 9% for plot II (300 meters away from floral provisioning plot and towards the center of the agricultural field), and 23% for the overall—see Excel file # 3 for more info;

– Compared to 2009, the overall number of bee specimens captured in 2011 increased with 207% for plot I (floral provisioning), 250% for plot II (300 meters away from floral provisioning plot and towards the center of the agricultural field), and 226% for the overall—see Excel file # 3 for more info;

– Compared to 2010, the average number of bee specimens captured per each collection event in 2011 decreased with 31%—see Excel file # 5 for more info;
– Compared to 2009, the average number of bee specimens captured per each collection event in 2011 increased with 81%—see Excel file # 5 for more info;

Manheim, PA
– Compared to 2010, the overall number of bee specimens captured in 2011 increased with 316% for plot I (floral provisioning), 88% for plot II (300 meters away from floral provisioning plot and towards the center of the agricultural field), and 154% for the overall—see Excel file # 2 for more info;

– Compared to 2009, the overall number of bee specimens captured in 2011 increased with 808% for plot I (floral provisioning), 733% for plot II (300 meters away from floral provisioning plot and towards the center of the agricultural field), and 767% for the overall—see Excel file # 2 for more info;

– Compared to 2010, the average number of bee specimens captured per each collection event in 2011 increased with 112%—see Excel file # 4 for more info;

– Compared to 2009, the average number of bee specimens captured per each collection event in 2011 increased with 433%—see Excel file # 4 for more info;

However, one can see that the capture for Calliopsis andreniformis is an outlier, making up a considerable amount of specimens for Penn State SEAREC. This might be because this farm has a high percentage of agronomic crops, including soybeans. Calliopsis sp. are known to use pollen from species in legume family. Therefore, it is possible that the population of Calliopsis was influenced by the rotation of soybeans and not necessarily by the floral provisioning plot. When controlling for this by eliminating the capture records for this species at both farms, the following are the results for the density:

– Compared to 2010, the overall number of bee specimens captured in 2011 increased with 57% for plot I (floral provisioning), decreased with 28% for plot II (300 meters away from floral provisioning plot and towards the center of the agricultural field), and decreased with 2% for the overall—see Excel file # 3 for more info;
– Compared to 2009, the overall number of bee specimens captured in 2011 increased with 242% for plot I (floral provisioning), 197% for plot II (300 meters away from floral provisioning plot and towards the center of the agricultural field), and 218% for the overall—see Excel file # 3 for more info;

– Compared to 2010, the average number of bee specimens captured per each collection event in 2011decreased with 11%—see Excel file # 5 for more info;
– Compared to 2009, the average number of bee specimens captured per each collection event in 2011 increased with 133%—see Excel file # 5 for more info;

Diversity
Boiling Springs, PA
– Compared to 2010, the overall number of bee species captured in 2011 increased with 0%—see Excel file # 6 for more info;
– Compared to 2009, the overall number of bee species captured in 2011 increased with 169%—see Excel file # 6 for more info;

– Compared to 2010, the species richness in 2011 increased with 35%—see Excel file # 6 for more info;
– Compared to 2009, the species richness in 2011 increased with 457%—see Excel file # 6 for more info;

Manheim, PA
– Compared to 2010, the overall number of bee species captured in 2011 increased with 37%—see Excel file # 6 for more info;
– Compared to 2010, the species richness in 2011 increased with 236%—see Excel file # 6 for more info;

– Compared to 2010, the species richness in 2011 increased with 69%—see Excel file # 6 for more info;
– Compared to 2009, the species richness in 2011 increased with 761%—see Excel file # 6 for more info;

Based on the watermelon yields data, the field closer to the floral provision (1700 feet) registered almost three times more marketable fruit than the field that was 600 feet away from the floral provisioning plot. Not only that, but more than half of the marketable fruits in plot I was almost a week earlier ready for harvest than the earliest marketable fruit from the plot II. For more information, please see attachment # 7.

Research conclusions:

Compared to 2010, both farms registered a decrease in the overall number of bee specimens captured or the average number of bee specimens captured per each collection event. This might be related to an unusual wet and cold 2011 spring, followed by a very dry summer. In addition to this, in August both farms experienced heavy and prolong rain events, with a big part of the Manheim farm being flooded for several days.

However, based on the actual number of bee species captured, as well as on the interpolated data, the bee diversity (species richness) increased on both farms.

Based on the data obtained from the watermelon yields, the floral provisioning plot had a major impact on the yields of the watermelon plot located in close proximity. Compared to the watermelon plot installed 600 feet away, the watermelon plot installed only 170 feet ways yielded almost three times more marketable fruits. Not only that, but the fruits were also produced significantly earlier in the watermelon plot closer to the floral provisioning plot. This earliness could provide a significant boost to the farmer’s net returns.

While this is encouraging news, it is important to note that this project has monitored the bee population only for three years and only at two sites and has collected information the watermelon yields only for one growing season. This, unfortunately, did not capture sufficient data, for providing a conclusive and statistically sound inference. To obtain that, more sites need to be established and the monitoring needs to be performed over many more years.

Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary

Education/outreach description:

The Principal Investigator of this project presented some of the preliminary results at the following events:
1) 2011 Pennsylvania Association for Sustainable Agriculture Conference – approx. 55 growers;
2) 2011 Summer Garden Experience – approx. 35 MGs and landscapers;
3) 2011 Discovery Day @ Penn State Southeast Research Center – approx. 60 legislators and aids;
4) 2011 PVGA Growers Meeting – approx. 50 growers;
5) 2011 various farm visits – approx. 10 farmers;
6) 2012 Mid-Atlantic Horticulture Short Course – approx. 200 participants;
7) 2012 Berks County Vegetable Growers meeting – approx. 70 participants.

Project Outcomes

Project outcomes:

In 2011, the research plot at Manheim needed very little weed suppression. This was a direct result of a successful establishment of the floral provisioning. Being in their third year, the plants had matured and filled in, crowding out the weed species.
Unfortunately, this was not the case with the plot at Boiling Springs. Virtually, one third of the plot was overtaken by weeds. This is partly due to adverse environmental conditions and the inability to use a pre-emergent herbicide at planting.

In the end, despite the deep plugs’ higher rate of successfully establishing in the field, the cost of the deep plugs is the single most important disadvantage. Establishing large floral provisioning plots from seed is more feasible, especially when the weed pressure is controlled through pre-emergent and post-emergent chemical applications.

The following represent the costs incurred for establishing in 2009 one 100 ft x 25 ft floral provisioning plot:
1) Mechanized labor for tilling and leveling the ground 2 hours @ $25 per hour $50
2) Manual labor for installing the deep plugs 40 hours @ $10 per hour $400
3) Manual labor for maintaining in the growing season 40 hours @ $10 per hour $400
4) 4-inch deep plug perennials $.80 each x 50 pcs x 23 $920
5) Approximately $150 per year for the second and third year for manual weed control.
Total: $2,520

According to economic analysis for the watermelon production published by Penn State University, the average net return a farmer can expect for an acre of watermelon is $712.06. Assuming that the increase in the yield experienced by the Boiling Springs farm for the watermelon plot that was in the close proximity of the floral provisioning plot is due to a higher diversity and density of the bee population, we can conclude that a farmer can nearly triple the net returns when establishing floral provisioning between agricultural fields. At this rate, the costs for establishing such floral provisioning plots will be offset in less than two years.
However, at each farm, for establishing and maintaining the 25’ by 100’ floral provisioning plot was necessary an investment of approximately $2,500. With this investment, a famer could establish and maintain a considerable larger floral provisioning plot when using seed mixtures.

Based on the data collected through the monitoring of the bee population, providing floral provisioning is a major step towards achieving sustainable pollination services. However, this needs to be done along with managing the nesting habitat and a reduce use of pesticide use or the use of softer pesticides during the crops’ bloom period.

Farmer Adoption

The mangers of the Boiling Springs farm are very interested in maintaining and expanding the floral provisioning plot. Similarly, many other farmers are very interested in installing floral provisioning plots. However, the costs of establishing such plots from deep plugs are still very high. On the other hand, establishing them from seeds results in less consistent results, mainly due to an increase in the weed pressure. Currently, Penn State in collaboration with NRCS is looking into what are the best practices for establishing floral provisioning plots on farms.

Assessment of Project Approach and Areas of Further Study:

Areas needing additional study

More information is needed regarding what are the most important pollinator species for each crop grown in the Northeastern U.S. The phenology of these pollinators needs to be studied in detail. For each commercially important pollinator species is necessary to determine what non-crop floral resources are visited. This information can be used for better determining what non-crop flowering plants need to be established on a given farm.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.