Date of Award:

8-2022

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Committee Chair(s)

Edward W. Evans

Committee

Edward W. Evans

Committee

Terry L. Griswold

Committee

Shannon Wing Belmont

Abstract

Bees are considered to be the most important animal pollinator, providing billions of dollars in pollination services each year. Despite their importance in both natural and agricultural settings, the status of most native bees is unknown. Native bees are subject to a variety of threats including habitat loss, pesticide use, and climate change. Yet, monitoring programs have been implemented in few natural areas. Pinnacles National Park, PNP, in California is one of the only natural areas to have a large historical dataset on bees across decades with surveys conducted in 1996, 1997, 1998, 1999, 2002, 2011, and 2012. These surveys have found PNP to house an exceptionally diverse community of bees. To determine how the bee community at PNP has changed over time we returned to survey bees in 2020 and compare the current collection to historical collections. We found that overall diversity levels remained at similar levels across years, but community composition changed among years, suggesting that the bee community experiences species turnover, but has not experienced over diversity losses. Using our bee survey as a framework, we discuss some issues with current bee monitoring practices and recommend creative solutions. To provide better techniques for site selection or monitoring monolectic species habitat we used Ceratina sequoiae Michener abundance at PNP, as a framework to model suitable habitat using citizen science records. We selected six topographic factors to model in conjunction with the required floral and nesting resources of C. sequoiae. The suitability modeling indicated that considering elevation in addition to the required floral and nesting resources could better predict C. sequoiae abundance. Throughout the duration of our bee survey at PNP, we also observed a novel foraging behavior. We discovered tens of bees feeding on aphid-produced pine honeydew, a seemingly rare behavior among native bees. The culmination of our findings highlight the importance of long term pollinator monitoring studies, not only to detect diversity shifts over time, but also to determine the diversity of behaviors exhibited by bees.

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