In this paper, we estimated how far the bees we collected from our Garden Pollinators Study could move between gardens and pollination-dependent cropland. We found that when pollination-dependent crops (commercial-scale or residential-scale) are nearby, 30–50% of the garden bee community could potentially provide pollination services to adjacent crops.
But, we currently know so little about bee movements in complex landscapes ~ if and how bees move across roads or through gardens embedded in housing developments. This question will be a focus of our future work.
Over the past year, I have have given many presentations that highlighted the high bee activity at ‘site 51’; a garden that is fairly small (0.1 acre) and in a heavily developed area of East Portland. Despite its size and location, ‘site 51’ had the second highest number of bees from our 2017 collections. I suspect bee diversity will also be high at site 51.
This garden is managed by someone who is an avid Xerces Society member. He gardens specifically for pollinators, and it shows! His garden is a true testament to the idea that ‘if you plant it, they will come’.
So what plants are in this garden? Our preliminary plant list (from a brief 2017 survey) can be found below. I will add Latin names, when I have a moment. For now, I hope that the common name list might introduce you to a new plant or two that might work well in your own garden.
All bees have been pinned, labelled, and data-based. Now we’re (and when I say ‘we’re’, I’m mostly referring to Lucas and Isabella) are going through the painstaking process of photographing all specimens: head on, from the top, and from each side. We’ll then start sorting them by morphotype (how they look), and working to identify them. Some of the bees are very common, and fairly easy to identify (like Anthidum manicatum, Bombus vosnesenskii, Apis meliifera). Others will take a bit more time and expertise to get to species.
You can take a look at the entire album, representing about 150 of the nearly 700 collected bees. We’ll be adding the rest of the bees, as we can.
We collect and pin the bees, because most are difficult to identify, without getting them under a microscope, and without the help of a museum-level bee specialist. For those bees that are easy to identify by site (such as the ones listed above), we only collect one per garden (so that we have a record of its presence). We don’t collect multiple specimens of the same species, if we can identify it in the field. And, we don’t collect obvious queens (larger, reproductive bees).
We collect using a combination of water pan traps and hand collection. For hand collection, we use a pooter (an insect aspirator) for the smaller bees and baby food jars for the larger bees.
This is such an exciting part of the research for me. I find myself obsessing over the photos, trying to organize them in my mind, and to at least get them to genus. Grouping them by genus makes it easier for an expert to sort through and identify them. And, I’m so grateful for their assistance, that I want to make it as easy as possible for them!
We’ve collected bees from gardens near Forest Park, in Portland’s city center, and in outlying suburbs. We’ll analyze the data to see if there are any patterns associated with garden location (forest, city, suburbs), or to see if there are specific bees that are only found in forest gardens, for example.
The post below comes from Aaron Anderson, a M.S. student in the OSU Department of Horticulture, and a member of the Garden Ecology Lab.
This past summer, we conducted the first field season of a study screening native plants for their attractiveness to pollinators and natural enemies. We selected 23 native Willamette Valley wildflower species based on drought tolerance, as well as four exotic garden species known to be attractive to bees: Nepeta cataria ‘Catnip’; Salvia elegans ‘Pineapple Sage’; Origanum vulgare ‘Italian’; Lavandula intermedia ‘Grosso’.
Table 1. Native plants selected for this study.
Giant blue eyed Mary
Baby blue eyes
Acmispon (Lotus) parviflorus
Western red columbine
We planted them in meter squared plots at OSU’s North Willamette Research Center. Between April and October, we monitored floral visitation, sampled visiting insects using an “insect vacuum”, and tracked floral bloom.
With one season in the books, we have some purely anecdotal impressions of which wildflower species are the most attractive to bees. Goldenrod (Solidago canadensis) and Douglas aster (Symphyotrichum subspicatum) were both highly attractive to a wide diversity of native bees, as well as to a variety of beetles, bugs, and syrphid flies. As an added bonus, both these species had long bloom durations, providing habitat and colorful displays for significant portions of the summer. Annual flowers Clarkia amoena and Gilia capitata attracted a range of native bees; Clarkia was also visited by leafcutter bees for a different purpose – cutting circular petal slices to build nest cells with.
Results from this year need to be analyzed, and further research is needed to account for seasonal variability and to gather more data on floral visitors.
Additionally, w e will ask the public to rate the attractiveness of each of our study flower species in an effort to determine the best candidates for garden use. After a few more field seasons (and sorting lots of frozen insect samples!), the result of this study will be a pollinator planting list for home gardeners, as well as a pollinator and natural enemy friendly plant list for agricultural areas. These will help inform deliberate plantings that increase the habitat value of planted areas.