Some species are very efficient crop pollinators: Bombus, Osmia…. Native bees are adapted to local weather conditions Some species emerge in synchrony with specific crops to pollinate them exclusively Long term sustainability of pollination: $3 billion of fruit and vegetable pollination May be considered ‘pollination insurance’ Why consider native bees for crop pollination?
Pollinator diversity to ensure crop pollination 10 year blueberry yields – my fictional data!!
Unmanaged land generally benefits native bee communities Kremen et al. 2002, Greenleaf and Kremen 2006, Winfree 2007 Wild bees perform better in organic vs. conventionally managed crop landscapes. Gabriel and Tscharntke 2007, Holzuch et al. 2008 Bee communities are generally suppressed by insecticides –Fenitrothion application caused native bee declines Kevan 1997, Kevan and Plowright 1989 –Pesticide program less important than proximity to native landscape Kremen et al. 2002, 2004 Tillage reduces populations of ground-nesting bees. Schuler et al. 2006 Response of native bees to agricultural intensification
Increase native bees on farmland by providing… 1. Nectar and pollen –selective mowing of ditches and field borders. –combine flowering plant species to provide overlapping blooms. –insect conservation strips at edges of fields. –integrate woody and herbaceous plants for early and late-blooming flowers. 2. Nesting habitat –undisturbed open sandy soil –old trees, snags, woodland 3. Environment free of toxic insecticides - adopt IPM/organic practices - selective insecticides - use biological controls
Research questions 1.Which species of native bee are present in blueberry fields? 2.How do local habitat type and management intensity in and around blueberry fields influence native bees? 3.Do insecticides targeted at pests after bloom affect abundance of native bees during bloom the following year?
Which native bees are present during blueberry bloom? Sampled twice during bloom at 15 farms in 2004, 2005, 2006 digger bees
2.0 -1.5 1.5 Andrenid bees Halictid bees other native bees insecticide program soil cult. perimeter woods treeline ditches other fl crops adj. blueberry meadows floral abundance plant sp 2005 Native bee abundance is affected by farm management practices
sample time in relation to blueberry bloom Many native bee species are active through the year focus on blueberry visit different species’ flowers throughout spring and summer
Overlap between pollinator activity and pest activity AprilMayJuneJulyAugSept Osmia bees andrenid bees halictid bees Bombus queens Bombus workers = Blueberry bloom
Index of pesticide risk to bees Grower spray records obtained for each season prior to bee monitoring, starting in 2003. An insecticide program toxicity (IPT) score for each field each year was calculated: Determine relationship between native bee counts and insecticide intensity from the year prior to each sample during bloom.
Native bees declined with increasing IPT score this trend was seen in two of three sampling years 2004 data Pesticide toxicity (IPT) in previous year Number of bees Number of bee species
Summary Blueberry fields contain a diversity of native bee species during bloom, with variable nesting biology, timing, and specialization. The abundance and richness of native bees are affected by some in-field management practices, and by adjacent land use. Fields receiving pest control programs with higher pesticide toxicity have lower native bee abundance and richness.
Reducing toxicity of pest control practices will support greater bee abundance and richness. Foraging and nesting resources are needed throughout the season. Flower and nesting resources near to crop fields can help support the native bee community. Implications for bee conservation on farms
Midwest prairie plants most attractive to beneficial insects Benefits Enhance native biodiversity Restoration of imperiled habitats Less likely to be invasive Adapted to local climate Provide habitat permanency Potential negatives Multi-year establishment Availability Cost funded by
Bees: sweat bees, digger bees, cuckoo bees, small and large carpenter bees, and bumble bees Natural enemies: chalcid wasps, minute pirate bug, spiders Yellow coneflower (Ratibida pinnata) Bloom: late July - mid August
Bees: sweat bees, small carpenter bees, digger bees, bumble bees Natural enemies: minute pirate bug, predatory plant bug, Chalcid wasps, soldier beetle, spiders Boneset (Eupatorium perfoliatum) Bloom: August – early September www.nativeplants.msu.edu
Bloom phenology and relative attractiveness of native plants Fiedler et al. (2007) Also at: www.nativeplants.msu.edu
Enhancing pollinator conservation on farmland avoid bee toxic pesticides during bloom flowering perimeters flowering ground cover limited tillage nesting habitats clean water only use bee safe pesticides natural area refuges landscape management Research on crop-specific and regionally appropriate practices Cost : benefit analyses Financial incentives Demonstration programs Information delivery
Incentive payments for working lands Farm Bill conservation programs: EQIP, WHIP, GRP, WRP, CRP, CSP, etc. Many USDA-NRCS “conservation practices” can be used to provide habitat for pollinators An increasing number of sources to help fund pollinator conservation practices State Acres for Wildlife Grants (SAFE) Conservation Innovation Grants (CIG) now targeting pollinator projects (new in 2008) Conservation Security Program (CSP) has a specific nectar corridor enhancement The new Farm Bill?
Pollinator conservation information www.nativeplants.msu.edu More information at www.xerces.org and www.pollinator.org
Collaborators Anna Fiedler Doug Landis John Ascher, AMNH Mace Vaughn, Xerces Soc. Research assistants Steve Van Timmeren Jack Langdon Matthew Tuell Casey McLean Jessie Siemen Grower Cooperators Larry Bodtke Randy Bowerman Bob Carini Joe DeGranchamp Beverly DeJonge Karlis Galens R.J. Rant Dave Stansby Terry Tiles Doug Wassink Jan Woods Thanks! Funding
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