Elliott Chaparral Reserve

05 Mar, 11 PM - 30 Jun, 12 PM

Rationale: Recent declines in European honeybee (Apis mellifera) populations have raised global alarm, especially in the agricultural sector. Equally importantly, studies also suggest global declines in the population of native bees, which are indispensable pollinators of a large fraction of terrestrial flowering plants. Ecologists and conservationists are still investigating the mechanisms that drive the complex responses of native bees to the biggest causes of their declines?habitat loss and fragmentation. In my dissertation research, I aim to compile an updated record of native bee species occurring in the coastal sage scrub (?CSS?) habitats of San Diego County (which has received insufficient attention from taxonomists), as well as investigate how ornamental plants grown in urban areas contribute to the diet of native bees (i.e. nectar and pollen) persisting in natural habitats fragmented by urbanization. The surveys proposed below will document and compare the distribution patterns of native bee species in large, relatively intact natural reserves versus fragments of CSS embedded in the urban matrix. Methods: Bowl trap: Each bowl trap consists of a fluorescently painted souffl? cup approximately 7cm in diameter, containing a 100ml mixture of tap water, salt, and household dishwashing detergent. Bowl traps will be placed, on bare ground or on elevated stands, in 5m intervals in linear transects within each study plot. During each sampling period, bowl traps will be deployed between 7h00 and 9h00, and harvested between 15h00 and 17h00 on the same day. Manual aerial netting: Bees flying near flowers and over bare ground will be captured via aerial netting. At each site, netting will be performed for one hour between 9h00 and 12h00 and one hour between 12h00 and 15h00 (totaling 120min of netting within each study plot). Sampling will be conducted by myself and up to two assistants. Trap-nests: Each trap-nest unit consists of 30 cardboard tubes of various internal diameters (3-7mm) housed in a PVC pipe section. Each tube is colonized by a single female bee. Six trap-nest units will be installed (via tying to thick-stemmed shrubs such as Laurel Sumac) in each study plot at 5, 20, and 35m from the edge of the plot. A subset of colonized tubes from each trap-nest unit will be collected to harvest pollen samples.

Visit #28040 @Elliott Chaparral Reserve

Approved

Under Project # 24765 | Research

The influence of urban food resources on the persistence and composition of native bee assemblages in San Diego's Mediterranean scrub habitats

graduate_student - University of California, San Diego

Reservation Members(s)

Keng-Lou Hung Mar 5 - Jun 30, 2012 (118 days)
Keng-Lou Hung Mar 5 - Jun 30, 2012 (118 days)

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