Does pollinator diversity loss affect pollination services: a test with the California poppy and tarweed

Many plant species depend on insect pollination for successful reproduction. Bees play key roles as pollinators, and both bee abundance and species richness can be negatively affected by human disturbances. Surprisingly, the relationship between pollinator diversity loss and the reproductive success of plant species that rely on insect pollination has not been well documented, especially in natural ecosystems. In this study, I propose to experimentally test how empirically documented declines in bee diversity affect the reproductive success of Eschscholzia californica (California poppy) and tarweed in coastal sage scrub ecosystems of San Diego County, California. Our lab has documented that the bee faunas of fragmented coastal sage scrub ecosystems exhibit reduced diversity compared to natural reserve sites. I hypothesize that poppy and tarweed reproductive success will be positively related to the diversity of visiting pollinators.