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January 20, 2021

12:00pm Zoom Webinar

Lauren Ponisio
Institute of Ecology and Evolution, Data Science Initiative, University of Oregon

" Wild and Managed Bee Health in CA Industrial Agriculture "


Managed and wild bee populations contribute over $15 billion in pollination services to US agriculture, yet both are declining or becoming increasingly vulnerable to disease. Many economically important crops (e.g., nut, fruit, and oilseed) are today grown in monoculture which blooms in synchrony. This pulse of floral resources can provide pollen, nectar, and temporary habitat for wildlife such as wild pollinator populations. In monoculture farms, the vast spatial scale and short duration of bloom (for example,>1.5 million acreage of almond will bloom in the Central Valley of California within 3 weeks) necessitate the importation of managed honey bees (Apis mellifera) for adequate pollination. However, honey bees and wild bees are susceptible to numerous parasites. Several studies have identified the role of flowers in the transmission of parasites but it unknown how mass-flowering monoculture crops influence rates of parasitism in wild and managed bees. We examine whether mass-flowering monoculture agriculture amplifies disease in wild and managed bees, and whether on-farm, non-crop habitat can mitigate that effect.   We found wild bee abundance amplified parasitism in wild bees and diluted parasitism in honey bees. Encouragingly, parasitism in wild bees was mitigated by on-farm habitat.  Our results corroborate the results of other studies suggesting that monoculture crops alone cannot support healthy bees.


Next, to better understand what might incentivize growers to adopt bee-friendly practices such as the on-farm habitat that we found diluted disease transmission, we conducted a survey of California almond growers, whose orchards are entirely dependent on bee pollination and draw nearly 88% of US bee colonies each February to pollinate almond bloom. We asked 329 respondents across all major almond growing regions of CA about their adoption rate and incentives for planting cover crops, pollinator habitat, as well as their interest in bee-friendly certification programs. Using a model selection framework, we evaluated which geographic, social, operational and pollination-service related factors were predictive of bee-friendly practice adoption. We found that no single factor was a statistically significant predictor of adoption across all models, suggesting there is no silver bullet determining bee-friendly practice adoption. However, we discovered that region and concerns about future pollination services consistently emerged as important factors related to all of the practices we investigated. These findings suggest that a regionally flexible pollinator conservation strategy focused on supporting honey bee colonies might have the highest likelihood of grower participation and adoption.

Host: Morgan Tingley