Operation Pollinator Michigan: Phase IA

Transcription

1 Year 1 Summary Report, 2010 Rufus Isaacs, Julianna Tuell, and Keith Mason Department of Entomology, Michigan State University, 202 CIPS Bldg., East Lansing, MI Contact: isaacsr@msu.edu Sponsors: Page 1

2 Background and Purpose of this Study To meet the needs of an ever growing human population, agriculture faces several important challenges related to finite resources. One of these finite resources is arable land. Some of this land is being lost through conversion to other land uses. Some land has been degraded through unsustainable agricultural practices, resulting in loss of top soil and/or loss of ecosystem function. Some landscapes that would otherwise provide resources for wildlife such as pollinators and predators of crop pests have become devoid of these habitats or have become fragmented such that these ecosystem services have become degraded. The current model in conventional agriculture is high yields through planting large acreages of monoculture crops managed using synthetic fertilizers, pesticides, and cultural practices (e.g. tilling) implemented to reduce pest and disease pressure. This includes removal or suppression of plants that might provide habitat for beneficial wildlife in field borders. For crops that require animal-mediated pollination, this system of agriculture places a heavy burden on a single pollinator: the European honey bee. However, in North America there are more than 4000 different non-honey making, mostly solitary bee species that could provide pollination services if given the resources that they need to thrive. These bees require nesting materials or undisturbed nesting areas, such as ground that is minimally or only shallowly tilled, field borders containing bunch grasses, and nesting boxes or blocks. They also require access to flowering plants for nectar and pollen in field margins when the focal crop is not in bloom. There are several examples of systems in which native or other non-apis bees already contribute a significant proportion of crop pollination (e.g. native bees in melon fields in Pennsylvania and New Jersey; squash bees on Cucurbita spp. along the mid-atlantic states; Andrena spp. in lowbush blueberry in Maine and Nova Scotia). What these crops all have in common is that they are grown in relatively small patches surrounded by heterogeneous landscapes that apparently contain sufficient resources to maintain populations. Operation Pollinator is a spin-off of a project begun in the UK called the The Buzz Project and later called Operation Bumble Bee in which flowering plants are added back into intensive agricultural landscapes with the goal of increasing wild bee abundance and the valuable ecosystem services they provide. The project was begun in 2010 in Michigan, Florida, and California. The aim of Phase IA of Operation Pollinator was to test different regionally adapted flowering native plant mixes, to assess the cost and ease of establishment, and their attractiveness to wild pollinators. This study was conducted in collaboration with Jamie Ellis lab at the University of Florida and Neal William s lab at UC Davis, who will be submitting separate reports. Page 2

3 Michigan has a diverse agricultural sector, with farms across the state that include many valuable pollination-dependent crops such as blueberry, apple, cherry, pickling cucumbers, etc. worth over $500 million in Michigan is one of the leading producers of fruit and vegetable crops. Much of the pollination of these crops is done by managed honey bees. Native bees have the potential to make an important contribution to pollination of these crops. Operation Pollinator is a natural fit to expand the knowledge of bee conservation efforts among growers and decision-makers in Michigan agriculture. Prior to and independent of this project, the Michigan team has been involved with several pollinator conservation projects. The native bees associated with highbush blueberry in Michigan have been identified. Forty-three different native perennials have been tested for their attractiveness to pollinators and use in pollinator conservation plantings. Resource plantings are currently being tested next to blueberry and apple orchards. The native plant study and our experiences with conservation plantings in Michigan have greatly influenced our selection of the plants used in the perennial mixes for this study in Michigan. An active extension-outreach program to engage growers in the concept of conservation plantings for pollinators is already underway. Aims and Objectives Phase I is the Field Research Phase of Operation Pollinator in North America. The main objective of Phase I is to evaluate a variety of seed mixes to enhance native bee populations on field margins and determine which seed choices are the most viable/preferred for native bee pollinators in Michigan. For Phase IA, our main objective is to develop region-specific activities for establishing and managing pollinator habitat, so that during Phase IB we will be able to test and verify the results on commercial production farms. This report describes the 2010 results from Phase IA Operation Pollinator studies in Michigan. Page 3

4 Sites selected for Phase IA in Michigan Initially, four sites were selected, all fruit research stations belonging to the Michigan Agricultural Experiment Station of Michigan State University: the Northwest Michigan Horticultural Research Station (NWMHRS), the Clarksville Horticulture and Extension Station (CHES), the Trevor Nichols Research Complex (TNRC), and the Southwest Michigan Research and Extension Center (SWMREC) (Figure 1). After it became evident that there was poor stand establishment, the SWMREC site was dropped. NWMHRS NWMHRS CHES CHES TNRC SWMREC SWMREC TNRC Figure 1. Locations and aerial photos of sites selected for Phase IA in Michigan. Table 1. Descriptive characteristics of the three sites sampled in Site Location Elevation Nearest town Soil series name NWMHRS N 791 Traverse City, MI Emmet-Leelanau Complex W CHES N W 872 Clarksville, MI Lapeer Sandy Loam/ Dryden Sandy Loam TNRC N W 675 Fennville, MI Brookston Loam Page 4

5 Experimental Design At each site, six different treatment plots were randomly distributed and seeded in the spring of The treatments consist of a control plot, a basic annual mix, a diverse annual mix, a basic perennial mix, a diverse perennial mix, and a plot planted on one half with the basic annual mix and on the other with the basic perennial mix. In addition, on one end of each set of plots, one plot of flowering buckwheat was planted for comparison. Table 2 contains the species and quantities (pounds per acre) that were used. Table 2. Native seed mixes tested in Phase IA. Treatment No. Seed Mix Rate (lbs/acre) 1 Weedy control n/a 2 Annual Basic Triodanis perfoliata (Venus looking glass) Linum sulcatum (grooved yellow flax) Lobelia inflata (Indian tobacco) Coreopsis tinctoria (plains coreopsis) Cassia fasciculata (partridge pea) Total Annual Diverse Triodanis perfoliata (Venus looking glass) Linum sulcatum (grooved yellow flax) Lobelia inflata (Indian tobacco) Coreopsis tinctoria (plains coreopsis) Cassia fasciculata (partridge pea) Cleome serrulata (rocky mountain bee plant) Froelichia floridana (cottonweed) Agalinis tenuifolia (slender gerardia) Total Perennial Basic (80/20 Perennial/Clover) Rudbeckia hirta (black-eyed Susan) Lupinus perennis (wild lupine) Monarda fistulosa (wild bergamot) Solidago speciosa (showy goldenrod) Dalea purpurea (purple prairie clover) Total Perennial Diverse (80/20 Perennial/Clover) Rudbeckia hirta (black-eyed Susan) Lupinus perennis (wild lupine) Monarda fistulosa (wild bergamot) Solidago speciosa (showy goldenrod) Asclepias syriaca (common milkweed) Ratibida pinnata (yellow coneflower) Silphium perfoliatum (cup plant) Symphyotrichum novae-angliae (New England aster) Symphyotrichum leave (smooth aster) Dalea purpurea (purple prairie clover) Total Annual/Perennial/Clover (50/40/10) Triodanis perfoliata (Venus looking glass) Linum sulcatum (grooved yellow flax) Lobelia inflata (Indian tobacco) Coreopsis tinctoria (plains coreopsis) Cassia fasciculata (partridge pea) Rudbeckia hirta (black-eyed Susan) Lupinus perennis (wild lupine) Monarda fistulosa (wild bergamot) Solidago speciosa (showy goldenrod) Dalea purpurea (purple prairie clover) Total Buckwheat control Page 5

6 Perennial species were selected based on the Michigan team s prior experience with the perennials in earlier studies. The annual species were selected based on availability and likelihood of attracting bees, and on the soil moisture requirements specified in seed catalogs. The rates used were calculations based on a desired number of seeds per square foot, which were between seeds per square foot, with the exception of the buckwheat which was planted according to the book Managing Cover Crops Profitably. Flowering buckwheat is known to attract bees and is an inexpensive non-native, commonly used cover crop. A number of the annual species required a cold treatment prior to seeding if seeding in the spring, which they were given using refrigeration. However, nearly all of the species that were given a cold treatment failed to emerge in the plots after seeding. Therefore, it is recommended that during Phase IB that plots be seeded in the fall so that seeds can be naturally cold stratified. Plot Set-up and Maintenance Notes At all sites in the fall prior to planting, soil samples were collected from each plot and each received an application of Round-up (glyphosate) for weed suppression. Plots were then rotovated in the late fall. In the following spring, all plots except the control plots were treated with Touchdown Total (glyphosate) two weeks prior to planting. On the day of planting, excess dead vegetation was removed from plots by hand with rakes. As Leelanau County is a historically dry area, an overhead mister irrigation system was installed at the NWMHRS site to foster plant establishment. Hand weeding was performed in plots as needed to prevent weed species from setting seed. Additionally, all perennial plots at the CHES site were mowed to suppress weeds in mid-july. Perennial grasses were particularly difficult to control with hand weeding, so Fusilade DX (Fluazifop-P-butyl) was applied in late July to all plots at CHES and TNRC, excluding the control plots. Plots at NWMHRS were not treated because grass was not a problem at that site. The next few pages contain images of each of the sites and plots at peak bloom. Page 6

7 Northwest Michigan Horticultural Research Station (NWMHRS) Page 7

8 Clarksville Horticultural Experiment Station (CHES) Page 8

9 Trevor Nichols Research Complex (TNRC) Page 9

10 Sampling Methods Floral Density Sampling In association with each bee sampling day (see below), each plot was sampled for floral density, either on the same day as the bee sampling, or within one day of bee sampling. Sampling was conducted using standard quadrats. Ten 0.5 by 1 m quadrats were randomly distributed throughout the plot. The only exception to this was in the Annual/Perennial plot in which five quadrats were randomly distributed down the Annual side of the plot, and five quadrats were randomly distributed down the Perennial side of the plot. Also, at the TNRC site, only half of the Annual Basic plot was successful in establishing, so only five quadrats were used to assess floral density in this plot. Results were adjusted accordingly. Within each quadrat, each kind of flowering plant was identified using the Peterson Field Guide to Wildflowers (Northeastern/North-central North America). The number of flowers per kind of plant was counted. The proportion of the quadrat occupied by the plant in bloom was estimated. At the first instance of a plant flowering, a sample was taken to verify its identity and to measure the diameter of individual flowers so that floral area could be calculated. Sampling was only conducted in plots in which desired plants were in bloom. Other than in the control plot where everything that bloomed was counted, only the plant species that were intentionally planted were counted when they were in bloom. Floral Density Sampling Dates in 2010 Site NWMHRS 28 June 20 July 5 Aug 19 Aug 3 Sept 20 Sept CHES 29 June 22 July 4 Aug 18 Aug 1 Sept 30 Sept TNRC 29 June 21 July 4 Aug 18 Aug 13 Sept 1 Oct Page 10

11 Flower Visitor Observations This sampling was conducted only when plots were in bloom and when the following weather conditions were met: sky clear to mostly sunny, temperature greater than 16C (60.8F) (or if overcast, temp > 21C (69.8F)), and wind speed less than 4.5 m/s (10 mph). A pocket weather meter (Kestrel 2500, Nielsen-Kellerman, Boothwyn, PA) was set up at shoulder height, out of direct sunlight, to record temperature and maximum wind speed. Each plot was sampled between 9:00 and 16:00, for two 10 minute periods, for a total of 20 minutes, or when only half the plot was in bloom, for one 10 minute period. Observations were conducted by walking slowly around each plot, stopping every few feet to watch denser patches of flowers for up to 1 minute then moving on again. The shadow of the observer was kept from overlapping areas that were yet to be observed so as not to disturb potential flower visitors. All bees, butterflies, and hover flies (syrphids) observed alighting on or moving between flowers were recorded. Butterflies were identified by color patterns, bees were identified by description of color and size, or by genus and species when possible. Page 11

12 Vacuum Sampling On a day when both weather conditions and flower abundance were optimal, immediately following the end of observations, each plot was vacuum sampled using a leaf blower modified into a vacuum (Stihl BG55, Norfolk, VA) with a fine mesh bag (Kaplan Simon Co., Braintree, MA) placed over the intake to capture the sample. All the vegetation in the plots was sampled or for up to 5 total minutes of sampling. Samples were kept on ice then stored in a freezer until they could be sorted. To sort the samples, all arthropods were sorted from plant material which was discarded. Arthropods were then counted and identified to groups of interest (see list below of categories used). Identification is still underway and so the results are not able to be reported here. Category Coleoptera - Chrysomellidae Coleoptera - other Coleoptera - weevils Diptera - other Diptera - syrphids Hemiptera - aphids & hoppers Hemiptera - other bugs Hemiptera - tarnished plant bug Hymenoptera - ants Hymenoptera - other wasps Hymenoptera - parasitic wasps Hymenoptera - bees (and then to genus/species) Lepidoptera - brushfooted butterflies Lepidoptera - caterpillars Lepidoptera - moths Lepidoptera - white & sulphur butterflies Spiders Page 12

13 Results Which native species bloomed in the first year? ANNUALS: Of the species planted in the annual plots, there were two that did very well: Coreopsis tinctoria (on the left below) and Cassia fasciculata (in the middle below). In the annual diverse plots, Cleome serrulata (on the right below) and Lobelia inflata (not pictured) also bloomed. Triodanis perfoliata, Linum sulcatum, Froelichia floridana, and Agalinis tenuifolia failed to bloom in the annual plots. PERENNIALS: Of the species planted in the perennial plots, only the Rudbeckia hirta (on the left below) and Symphyotrichum novae-angliae (on the right below) bloomed, but Lupinus perennis, Monarda fistulosa, Solidago speciosa, Asclepias syriaca, Ratibida pinnata, and Dalea purpurea were detected and are expected to bloom in the second year. Silphium perfoliatum and Symphyotrichum leave were not detected or could not be distinguished in the first year. Page 13

14 Floral Density Below are graphs depicting floral density as it progressed throughout the season at each plot and site. Buckwheat plots bloomed first and then tapered off as the annual plots began to bloom. The perennial plots were the last to come into bloom and had the lowest overall floral density, which is expected in the first year of perennials planted from seed NWMHRS Control Annual Basic Annual Diverse Perennial Basic Perennial Diverse Annual/Perennial Buckwheat Flo ral de nsit y (cm 2 ) per 5 m CHES TNRC Sample Round Page 14

15 Below is the average bloom density across the three sites. Average floral density (cm 2 ) per 5 m Control Annual Basic Annual Diverse Perennial Basic Perennial Diverse Annual/Perennial Buckwheat Sample Round Plots in peak bloom at NWMHRS: Native annuals Native perennials Buckwheat Control Page 15

16 Flower Visitors Timed observations at each plot at each site during 2010, revealed strong preferences in some groups of flower visitors compared with others. Hover flies were least abundant in the control plots and perennial basic plots and most abundant in the annual plots. Butterflies, in particular the Pearl Crescent butterfly, were more abundant in the perennial diverse, and annual/perennial plots than in the other plots. Non-Apis bees (i.e. bees other than honey bees) were distributed relatively evenly among the plots, except that they were somewhat lower in the control plots. When observed in the annual plots, bees in the sweat bee family (Halictidae) preferred the Coreopsis tinctoria. Bumble bees showed a preference for Cassia fasciculata and Cleome serrulata (when present) in the annual plots. These patterns may also be a response to the higher flower density in the annual plots. Honey bees were more likely to be found in control plots than in any of the native plant plots, which may not be surprising since they appeared to be more attracted to flowers originally native to Europe and either naturalized (in the case of the control plots) or planted (as in the case of the buckwheat plots). In particular, honey bees preferred the buckwheat plot when it was in bloom over the other plots. Avg. no. of individuals per 10 min honey bees non-apis bees butterflies hover flies Page 16

17 The abundance of hover flies, butterflies, non-apis bees, and honey bees observed in each plot per 10 minutes observation are shown below Hover flies Butterflies Avg. no. of indi vid uals per 10 min Non-Apis bees Honey bees Page 17

18 Conclusions In this first year of Operation Pollinator in Michigan, we have planted and evaluated four mixes and a combination of native seeds for their ability to support pollinators. At the start of the season, Michigan experienced very cold and late freeze conditions that delayed planting, followed by unseasonably hot conditions in May. These combined to make spring plot establishment and maintenance challenging. In addition, there was high weed pressure due to the presence of weedy grasses in two of the three sites, although these were controlled with selective herbicides. Hand weeding was used in these plots and this would not be practical for larger scale plots. We therefore emphasize the need to integrate effective weed control plans into establishment of such plots, ideally with one year pre-plant weed control to minimize the competition present in pollinator plantings. All plots had some flowering of the planted mix species, although this was also variable among sites. In the annual mix, Coreopsis tinctoria and Cassia fasciculata were most successful in establishing, and in the diverse annual mix we also saw Cleome serrulata establish well. In the perennial plots, Rudbeckia hirta and Symphyotrichum novae-angliae bloomed in the first year, and other species were detected. We expect much higher abundance and diversity in these plots in The mixes tested provided bloom from mid-summer to late-summer in this first growing season, but we expect a much greater spread of bloom times in 2011 after annual seeds experience normal overwintering conditions and perennials have a full year of growth. Floral visitor observations at these plots through the summer revealed strong preferences in some groups of insects. Non-Apis bees were distributed relatively evenly among the plots, except that they were somewhat higher in the plots seeded with native plants. When observed in the annual plots, halictid bees preferred the Coreopsis tinctoria, while bumble bees showed a preference for Cassia fasciculata and Cleome serrulata. Honey bees were more likely to be found in control plots than in any of the native plant plots. This suggests a preference for nonnative plants by this non-native insect. Hover flies were most attracted to annual plants, whereas butterflies were more abundant in the perennial diverse plot and the annual/perennial plots. Plots of buckwheat established next to the native plant plots, bloomed in high abundance and attracted honey bees and butterflies, but were no more attractive across the whole season to the hover flies and non-apis bees. Page 18

19 Lessons Learned The combination of late frost followed by unseasonably warm temperatures made spring plot establishment and maintenance challenging in This suggests that a thorough fall site preparation followed by a frost-seeding is the best method for establishing these kinds of plots in this region. This will provide the added benefit of improved seed stratification. Only three of the annual species germinated and flowered in the plots. The species that were not successful required a cold treatment. Although an artificial treatment was applied prior to seeding, we expect that fall seeding would provide these conditions more appropriately. High weed pressure from perennial grasses was experienced at two of the four sites in 2010, necessitating the use of selective herbicides and hand weeding. Hand weeding would be impractical in Phase IB and would be cost-prohibitive for growers. In 2011, we will pay closer attention to grass weed development and be prepared with a selective grass herbicide if needed. Flowers that were dominant in the perennial plots seemed to establish well and be attractive to bees during the first season. These early-bloomers should be included in mixes to provide Year 1 show that will keep growers interest in maintaining the planting, rather than having only vegetative growth in Year 1. Sampling multiple farms in different part of the state with the unpredictability of Midwest summer weather is challenging. Closer geographic location of plots would help make this project more efficient and improve data quality. Relevant Outreach Activities Tuell, J. (Dec 2010) Farm Management Strategies for Encouraging Vine Crop Pollinators. Great Lakes Fruit, Vegetable and Farm Market Expo, Grand Rapids, MI (30 minute talk, 100 growers) Presented two meetings (September 2, 2010 in Traverse City area and September 9, 2010 in Fennville area) on Conserving Beneficial Insects for Crop Pollination and Pest Suppression. These meetings were designed to help growers learn to identify native bees and natural enemies, establish and maintain wildflower plantings, update on current MSU-SARE research, and inform on cost sharing opportunities that exist to help establish habitats for beneficial insects. Attendees at both meetings included fruit growers, crop consultants, USDA-NRCS and USDA-FSA staff, MSU Extension staff, and members of our Operation Pollinator Team. Page 19

20 Acknowledgements We thank Beth Ansaldi, Alyson Rich, and Brett Blaauw for assistance with data collection, and the staff of the research stations for plot maintenance assistance. Thanks also to the many undergraduate students in our lab for field assistance. We also thank Operation Pollinator for the support of this research project. Page 20