Garden Ecology Lab undergraduate, Isabella Messer, is featured on this week’s episode of the PolliNation podcast. Isabella joins the ‘research retinue’ group of undergraduates at Oregon State University, to discuss recent research papers:
Gail’s manuscript on bees in home and community gardens has been published in Acta Hort. Briefly, the results of this literature review are that: 213 species of bee have been collected from a garden habitat; gardens have fewer spring-flying and fewer ground-nesting bees, compared to non-garden sites; I suspect that over-mulching might be cutting out habitat for ground-nesting bees in gardens.
Aaron presented his first Extension talk to the Marion County Master Gardeners. This 90-minute talk was an overview of using native plants in home gardens.
Most of the bees that we collected await identification. We did find a moderate relationship between lot size and bee abundance: larger yards hosted more bees. But, we also found evidence that suggests that intentional design can influence bee abundance: one of our smallest gardens (site 56 = 0.1 acre), located in the Portland urban core (surrounded by lots of urban development) had the second largest number of bees (42), of the 24 gardens sampled. This garden was focused, first and foremost, on gardening for pollinators. The plant list for this garden (photos, below) includes: borage, big-leaf maple, anise hyssop, globe thistle, California poppy, nodding onion, yarrow, fescue, goldenrod, Phacelia, Douglas aster, lupine, mallow, columbine, meadow foam, yellow-eyed grass, blue-eyed grass, coreopsis, snowberry, Oregon grape, trillium, mock orange, pearly-everlasting, serviceberry, coneflower, blue elderberry, currant, milkweed, dogwood, shore pine, crabapple, cinquefoil.
Mykl’s Poster on Urban Soils: we sampled soils from 33 vegetable beds across Corvallis and in Portland (co-authored with Gail)
All gardens were tended by OSU Extension Master Gardeners.
Gardens were over-enriched in several soil nutrients. For example, the recommended range for Phosphorus (ppm in soil) is 20-100 ppm. Garden soils averaged 227 ppm. The recommended range for Calcium is 1,000-2,000 ppm, but the mean value for sampled beds was 4,344 ppm.
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.
This post is modified from a submission from Michael Nelson. It details lessons learned from his survey of garden soils, across Corvallis, Oregon, and the Portland Metropolitan area. In September 2017, Michael sampled soils from about 25 gardens. These gardens used raised beds and/or in ground gardens to grow a variety of vegetables, herbs, and fruits. We wanted to study urban garden soils ~ and soils in raised beds versus in ground beds ~ for a few reasons. Specifically, we wanted to look at a few different questions:
Do raised bed gardens offer greater protection from soil contaminants than in-ground gardens? In the Master Gardener Program, we recommend raised beds as a way to work around soils that may have heavy metal contaminants. However, heavy metals can become airborne, and deposited on soils from industrial emissions, traffic, and re-suspension of road dust. If this is the case, then gardening in raised beds might offer a false sense of comfort. We thus chose to sample gardens that are close to, versus further from, major roadways and traffic.
Are garden soils deficient in some nutrients (such as nitrogen), but over-enriched in others (such as phosphorus)? With enthusiasm surrounding organic gardening and composting, we are wondering if repeated applications of compost might be contributing to nitrogen deficiencies, phosphorus leaching, or other soil nutrient issues.
What is the general state of urban garden soils in Oregon? If we had to ‘grade’ soil health, by looking at soil structure, tilth, nutrients, and other biological, chemical, and physical characteristics of soils ~ what would that grade look like?
I asked Michael to write up a short report on his summer work. What did he observe in the gardens? What did he hear from gardeners? Are there initial findings or impressions he could share? His report is below.
We began this project to examine differences between raised and in-ground garden beds in urban areas. We conducted a short survey of each site, where we noted weed pressure, garden area (in meters squared), and crops grown. We also noted any concerns voiced by the gardeners, about their vegetable production site. We sampled garden beds and kept samples separate depending on the type of bed (in ground versus raised-bed). We are now processing the soil samples in the Central Analytical Laboratory of OSU, so that we can determine the chemical, physical, and biological characteristics of our garden soil samples.
A few initial observations:
The most common complaint we heard from gardeners was a lack of space to properly rotate their crops. For example, nearly every site had tomatoes, but many did not have the space to avoid planting in the same ground as the previous season.
In the lab, our initial findings are that garden soils do not fit well with traditional soil testing methods. The very high content of organic matter and low incidence of rocks brings immediate problems to the lab testing process. The first step taken when a lab receives a soil sample is to pass the sample media through a sieve. The larger pieces are lightly ground and sieved again. The aim is to isolate the soil from non-soil matter in order to restrict laboratory tests to just the soil content itself. The organic matter is often shredded by this process, which can alter the results of the laboratory tests. The primary problem here is that the organic material in our sampled garden soils is mostly forest by-products: timber waste. This material is generally inert in the garden setting and not accessible to plants. When this organic matter is included in a soils analysis, the organic matter compounds are incorporated into the test results and skew the report away from the actual state of the garden’s soil.
The next steps in understanding garden soils are in research and application. In research, soil testing should be reconsidered with gardens in mind. There may be alternative processing techniques to reduce variability between test results and garden soil content. Theoretical models may be able to produce a metric which could be used to adjust the results of a standard soil test to reflect garden conditions more accurately.
In application, greater precision of terminology would allow for a more refined view and management of garden systems. In particular, bed-types should be grouped by their method of establishment (i.e. was soil transported to the garden, or not), rather than the presence or lack of a garden border. Additionally, organic mulches and compost should be considered in finer detail. The source of the product is important to determine what chemical content is being applied to the soil top. The physical structure of the product is important to relay the extent to which the mulch content will likely be incorporated into the soil, itself.
We’re still actively working to process and test samples. We look forward to sharing more results, in the near future.
This post was written by Isabella Messer, an undergraduate working in the Garden Ecology Lab.
The Gray Hairstreak (Strymon melinus(Hübner, 1818)) is a common butterfly in the US. Its habitat spans most of the country with the exception of some states in the midwest (1). The Gray Hairstreak is most common in the southeast but can also be found along the west coast, including Oregon and possibly some of your gardens (1). These butterflies can be identified by their ash-gray color of their wings, their noticeable white-bordered black median line, and a two orange patches on the outer angle of their hindwing (2). Due to their coloring, Gray Hairstreaks can be mistaken for an Eastern Tailed-Blue butterfly which also have orange spots on their hindwing s(3). However, the Eastern Tailed-Blue does not live in Oregon (4). If you want to attract more Gray Hairstreaks to your garden, it would be beneficial to plant goldenrod, mint, milkweed and winter cress (5). Keep an eye out on a sunny day for these sweet little beauties!
This entry is from Isabella Messer an undergraduate horticulture major at Oregon State University. It highlights one of the most common pollinators that we see in Portland area gardens.
Out of the twenty four different garden sites we visit, each month in Portland, we can count on one bumble bee being present in almost all of the gardens. This ubiquitous bee is Bombus vosnesenskii, otherwise known as the yellow faced bumble bee. With increasing evidence that some bumble bee populations are declining, Bombus vosnesenskii populations remains stable (1).
B. vosnesenskii is a very common bumble bee of increasing abundance across the western United States, although it ceases to be very common east of the Sierra Cascade Crest in California(2). B. vosnesenskii is most easily identified by the yellow hairs on the top of the head, on its face, on top of its thorax (middle body part), and as a yellow band at the base of their abdomen (bottom and biggest body part) (2). In terms of the flowers and plants that B. vosnesenskii likes to visit, they are broad generalists (3). This means that they like to visit a broad variety of plants. They are considered ‘medium tongue’ bees, which means that they can drink nectar from a wide array of flowers, with floral morphologies ranging from zinnias, to coneflowers to rhododendrons. Keep an eye out for their yellow heads the next time you are out in the garden and it is very likely you will come across one.
Lozier, Jeffrey D., James P. Strange, Isaac J. Stewart, and Sydney A. Cameron. (2011). Patterns of range-wide genetic variation in six North American bumble bee (Apidae: Bombus) species. Molecular Ecology, volume 20(23), pp 4870-4888.
Koch, Jonathan, James Strange, and Paul Williams. Bumble Bees of the Western United States. US Forest Service and the Pollinator Partnership. PDF.
Tepedino, V.J., Laura C. Arneson, and Susan L. Durham. (2016). Pollen removal and deposition by pollen-and nectar collecting specialist and generalist bee visitors to iliamna bakeri(malvaceae). Journal of Pollination Ecology, volume 19(15). Pp 50-56.
#OverlyHonestMethods is a hashtag that is trending on Twitter. With this hashtag (which is simply an easy way to sort and find posts), scientists share the honest, ugly truth behind research. Some examples:
“Data was not recorded on Sundays because I didn’t feel like coming in, and not recorded on this day because spiders” #OverlyHonestMethods
“Got a random number by asking my mom for a 3 digit number b/c I was too lazy to use an actual random number generator” #overlyhonestmethods
“Only read the abstract of the paper cited because I don’t have any money to pay for the full paper.” #overlyhonestmethods
This past week, I felt like I was swimming in my own #OverlyHonestMethods research sorrow.
First, it takes me 6.5 hours to drive to all sites, in one day. This is without doing any of the actual research. I had originally planned to sample all gardens June 21-23 ~ but this plan was quickly scrapped when I realized that there would be no way that we could physically drive to all gardens, set traps, sample for 10 minutes, and then return to pick up all traps the next day.
Working dawn to dusk, we were only able to sample 13 of our 24 gardens, June 21-22. So, we pushed our second set of garden samples (the remaining 11 gardens) to June 29-30. Not ideal ~ but this is why we are replicating our study across three years, and will be sampling gardens once a month, for 3-5 months, within each year.
In less than one week, I’ll be welcoming nearly 1,300 Master Gardeners to Portland ~ for a conference that begins on July 9th (pre-tours), and ends on July 17th (post-tours). That means that my crew and I have been stuffing 1,300 envelopes and bags. We’ve printed and are putting 3,900 meal tickets into 1,300 badges. I can’t over-emphasize how much work this conference has been (and continues to be!). On the one hand, sampling pollinators just before this conference is the LAST thing I needed to do. On the other hand . . . after spending too many late nights in a hot room, filled with boxes and boxes of conference envelopes, sampling garden pollinators is exactly what I needed.
Of course, when it rains, it pours. Last week, we also had issues with our Native Plant study. On Tuesday, I get a call from Aaron, who tells me that: (1) someone trespassed onto our plots, and sprayed herbicide, and (2) someone pulled our plants up, by the roots, in one of our study blocks (replicates).
It’s a long (and enraging) story. But, long story short ~ we lost all of the plants in our fifth study block. We only have five blocks / replicates in this study (with 24 plant species ~ it is both expensive and expansive to include more blocks). So, in one sad, sad day ~ we lost 20% of our replication, which will have negative impacts on our statistical power.
How will we cope? We’ll regroup and replant. We were already planning on repeating this study in 2018. Now, it seems like we’ll have to repeat in 2018 AND 2019 ~ which is a bummer . . . because this will extend Aaron’s time in grad school, will cost me 50% more to get him through grad school, and generally makes a sad, sad day for all.
But, the silver linings are: I love working with Aaron, and don’t mind supporting him for an extra year, and Aaron had already mentioned that he might want to stay on for a Ph.D., which would necessarily lengthen and/or expand the scope of his study.
C’est la research. Perhaps in 2-3 years, we’ll all be able to have a good chuckle about this challenging month.
Now that our lab group is working on native plants and native bees, I thought it would be fun to do a ‘Plant of the Week’ and ‘Bee of the Week’ series. This second entry is from Lucas Costner, an undergraduate environmental science major at Oregon State University. It highlights one of the plants that Aaron Anderson is using in his research.
The showy milkweed (Asclepias speciosa) is a perennial forb, native to the western United States and Canada(3). It is hardy through USDA zones 3a to 9b (1). While the showy milkweed is listed as threatened in Iowa, it can become fairly weedy once introduced to gardens if left unmanaged, due to rhizomatous growth
(3). The plants do best in full-sun, and are an excellent choice for gardeners looking for a low-maintenance, native plant that is very attractive to pollinators (3). In particular, the showy milkweed is known for its attractiveness to the monarch butterfly (Danaus plexippus), which utilizes the plant for habitat, as well as a larval host plant and adult nectar source (1,2,3). The monarch butterfly is not alone in its use of the showy milkweed. Eleven other species of Lepidoptera are known to reproduce on milkweeds (2), and the flowers are frequented by many species of bees and hummingbirds (1). The flowers are an appealing addition to the garden from an aesthetic perspective as well, featuring large, dense umbels of pink star-shaped flowers from May through September (3). The stems can reach heights of up to five feet and
have oppositely spaced, elongate leaves that are gray-green in color and covered in small hairs (3). At the end of the season, the flowers form interestingly shaped fruit pods packed with seeds whose silky white hairs are specially adapted for wind dispersal.
1. ”Showy Milkweed for Western Monarchs.” Monarch Butterfly Garden. N.p., n.d. Web. 26 June 2017. <http://monarchbutterflygarden.net/milkweed-plant-seed-resources/asclepias-speciosa/>.
2. Tallamy, Douglas W. Bringing Nature Home: How You Can Sustain Wildlife with Native Plants. Portland: Timber Press, 2009. Print.
3. Young-Mathews, Annie, and Eric Eldregde. Plant fact sheet for showy milkweed (Asclepias speciosa). Corvallis: USDA- Natural Resources Conservation Service, Aug. 2012. PDF.