Promoting Native Bumblebees in Agricultural systems for conservation and ecosystem service

View the project final report

• 2009 annual report
• 2010 annual report

Commodities

• Animals: bees

Practices

• Education and Training: on-farm/ranch research, workshop
• Farm Business Management: whole farm planning
• Natural Resources/Environment: biodiversity, hedgerows

Pollinators, as vectors of plant reproduction, are an exceptionally important part of natural and human-dominated communities. They are believed to pollinate 75% of the world’s crops, providing up to 35% of global crop production. The rapid decline of European honeybee (Apis mellifera) colonies from colony collapse disorder threatens to drastically impact food production and has intensified the need to seek alternate pollinators such as native bees. Like most native pollinators, Bombus (bumblebees) can play an important role in providing pollination services to native plants and crops and insure against continual honeybee losses. Specifically, they provide pollination services to a wide variety of crops with relatively high efficiency and can pollinate some crops, such as tomatoes, that honey bees cannot. However, native pollinators are also in decline from habitat degradation, invasive species, disease, loss of native flora and climate change. Bumble bee species may be particularly sensitive to these effects. In California and southern Oregon, two bumble bee species are believed to be extinct, and at least two more are in decline. Despite these documented or purported declines, little is known about the natural history of most pollinators, which makes conservation efforts difficult. My project will focus on two sympatric species of bumble bee in California, Bombus californicus and B. vosnesenski. Both of these species occur in many agricultural areas and are known to visit a wide array of agricultural plants. I will identify and quantify the floral use of these bumble bee species in grasslands, an ecosystem that is frequently converted to agricultural use, throughout the year to identify floral availability and use prior to the land use change. I will investigate both early pollen resources that are critical for colony establishment and late season resources that are important for the creation of reproductives. Although pollen quality and availability limit colony success, this has received little attention. I plan to use the information learned in natural ecosystems about floral use and preference to improve hedgerows by tailoring them to include the suite of plants known to be heavily used and preferred by local bumble bees, particularly during these critical temporal windows. This will help increase bumble bee populations in agricultural systems, which will benefit both conservation efforts and the ecosystem services provided to crops.

1. The primary objectives are to: Quantify the available pollen resources in grassland sites. Identify pollen sources chosen by bumble bees. Evaluate the characteristics of the plants chosen by bumble bees. Identify native plants that are essential to bumble bees throughout their life cycle. Quantify changes in bumble bee abundance after improving hedgerows. Provide information to farmers, researchers and societies to improve conservation, pollination and restoration efforts, especially oriented toward these important agricultural pollinators, bumble bees.