Over the course of a seven-month study in the Presidio, researchers led by Dr. John Hafernik of San Francisco State University observed 57 species of bees representing 23 genera. Within the umbrella order Hymenoptera, rare species were observed from bee families including Anthrophoridae (cuckoo and carpenter bees), Megachilidae (leaf-cutting bees), Colletidae (plasterer bees), and Halictidae (sweet bees).

Though bee abundance and diversity varied at each study site, the researchers were impressed by the overall diversity of bees in the park. Corresponding with peak blooming periods, bees were most abundant in the park during the spring. The highest number of rare species was observed in the remnant native habitats of the park, suggesting that insect diversity can be a benchmark of the long-term success of natural restoration projects.