Pollination by Native Bee Communities in Berkeley, California

Abstract

Pollination by Native Bee Communities in Berkeley, California Kevin Welzel Environmental Sciences, College of Letters and Sciences University of California, Berkeley Department of Environmental Science Policy and Management Keywords: Bees, native bees, honey bees, food, crops, sustainability, urban agriculture, Ecosystem services, Berkeley B S J Abstract Urban agriculture is on the rise in many areas throughout California. Native bees are a viable option to satisfy the growing demand for sustainable pollination services. Nevertheless, little is known about native bee ecology. This study examines native bee pollination in two urban agricultural sites that differ in their proximity to natural habitat. Squash, tomato, strawberry and sunflower plants were observed at the Oxford track and Berkeley Youth Alternative garden in Berkeley, California. Data collected from both sites include; distance from natural habitat, diversity of native bee pollinators and their visitation rates. I hypothesized that the Oxford Tract would have higher native bee diversity and visitation rates than Introduction Urban agriculture utilizes sustainable agricultural techniques in order to produce food for inner city communities which often lack access to healthy foods and local retailers (McClintock 2008). Urban agriculture has been on the rise in many urban areas including Oakland, California, where the city council has mandated that thirty percent of all food in Oakland must come from a local source such as urban agriculture by 2015 (Green 2007). As agriculture becomes more prominent in urban settings, the demand for pollination services also increases (Green 2007). One way to meet the pollination demand is to utilize existing native bee populations. Incorporating resources for native bees into urban agriculture will promote urban ecosystem health by providing viable seeds and fruits for insects, birds, and other wildlife (Delaplane & Mayer 2000) in addition to providing urban neighborhoods with sustainable produce. 1 • B erkeley S cientific J ournal • A ccidents • V olume 14 • I ssue 2 the Berkeley Youth Alternative garden, because the Oxford Tract was closer to native bee habitat. The community statistics gave mixed results for genus richness and evenness. The t-test indicated no significance of visitation rates for each plant type between each site. Results indicated that close proximity to natural habitat had no effect on native bee visitation rates to crops. The factors expected to contribute to a healthy native bee population are: common floral resources between native and non-native habitats, habitat fragmentation and age variability of gardens. City planners and conservationists should be cognizant of these factors when developing an urban agricultural site that can provide food and sustain biodiversity. Little is known about native bee ecology as new studies are only beginning to surface (Hernandez et al. 2009). Current studies show that native bees are a rich natural resource in urban California gardens (Frankie et al. 2009a), have preferences for certain plants (Frankie et al 2005), and are found in small residential gardens (Frankie et al. 2009b). Furthermore, native bees are generally more numerous and diverse near natural habitats where they provide pollination services to various crops (Kremen et al. 2002, Klein et al. 2003, Ricketts et al. 2004). Native bees are just as effective at large scale-pollination as commercial honey bees and thus gaining more popularity amongst researchers and the agricultural industry (Kremen et al. 2004, Kremen et al. 2007, Williams & Kremen 2007). Studies in agricultural landscapes have shown For questions, contact Kevin Welzel. Phone number: (909) 653-9237 E-mail: kwelzel@cal.berkeley.edu