What we did this summer: bee surveys!

by Avalon Carthew

The green roof at Daniels Spectrum is covered in sedum, and we have worked hard to cultivate a portion of it. While we only have 6 inches of soil, we have grown okra, beans, borage, and more. These plants attract a variety of different insects such as butterflies, hover flies, and bees. Did you know that Toronto has over 350 species of bees?

This pollen covered bumble bee was at one of our school gardens.

This summer, GTGK wanted to determine how many native bees and honey bees visited our rooftop garden. So, we set out on conducting a pollinator survey. Insects play many different roles in the ecosystem, and bees are pollinators. If we discovered that our roof wasn’t attracting enough bees, perhaps it would be ideal to get hives of honey bees to ensure adequate pollination.

What is a pollinator survey, anyway? Well, it doesn’t consist of asking insects questions, as fun as that would be. I found a couple of different pollinator survey protocols, and determined that the Xerces Society’s ‘Streamlined Bee Monitoring Protocol’ would work best for our needs. While the protocol is designed to be done twice over the course of the summer, I decided it would be best if we did it once a week in July and August. I wanted to ensure that everyone would have a chance to participate and learn how to conduct the survey.

In order to conduct the survey, the roof had to be split into sections called transects. Luckily, Becca already had a map of our garden and its measurements. This allowed me to split the garden into 6 transects. It would take 4 minutes to complete each transect.

During each survey, we looked to see if bees were present on the reproductive parts of flowers. If a bee was on a leaf or petal, it didn’t count. Then, it was time to determine whether a bee was a honey bee or a native bee. Honey bees are originally from Europe, and compete with native bees for resources. Did you know that blueberry bees are capable of buzz pollination, or sonication, which is required to get pollen from blueberry flowers? Honey bees don’t do this, and so they aren’t capable of pollinating blueberries and tomatoes.

This bee is pollinating a scarlet runner bean flower on our green roof.

Altogether, we conducted 7 surveys and saw a total of 174 native bees and 42 honey bees. I don’t think we’ll need bee hives anytime soon!