A Story of Gophers & Great Camas

According to the staff at Oak Creek and many other gardeners and farmers I’ve had the opportunity to talk to, it appears that though 2020 was a difficult year for humans, it was truly a remarkable year for gophers and other rodents.

From left to right: wild type Great Camas, Camassia leichtlinii, the native cultivar ‘Sacajawea’, and the native cultivar ‘Caerulea Blue Heaven’.

Gophers & Camas

No matter how often a gopher was trapped and removed from Oak Creek last summer, the next week there would always be a mound of freshly turned soil on the grounds, indicating a new gopher had taken its place. While they seemed to enjoy popping up in some of the Organic Gardening Club’s beds, they had an extra fondness for my own experimental garden beds. Fresh gopher-turned soil was most commonly found in any plot growing our native Camassia leichtlinii (Great Camas) and the plots surrounding them.

Bulb size comparisons for the three varieties included in our study.

We planted our 15 camas plots in the fall of 2019. Five plots were planted with the wild type camas species, Camassia leichtlinii (Great Camas). Five more were planted with the C. leichtlinii cultivar ‘Caerulea Blue Heaven’, and the final five were planted with C. leichtlinii ‘Sacajawea’. By the spring of 2020, the camas plots were relatively untouched, aside from some minor grazing by deer on a handful of plots. In April our three camas varieties began blooming in sequence (the native first, followed by ‘Blue Heaven’ and ‘Sacajawea’, respectively), and by mid June they had all gone to seed. 

Deer browsing on early spring shoots of C. leichtlinii ‘Sacajawea’.

Though the gopher troubles seemed to really begin in June, there were signs of their activity that we did not heed. In spring of 2020 I was planting a Clarkia amoena cultivar plug. Upon removing some soil to make room for the plant, I found that the soil seemed to drop off into a massive hole beneath the plot I was planting. I shook some soil loose to fill the hole, planted my Clarkia, and moved on. Later in the season, a different Clarkia plant would be found dead, and upon its removal, another tunnel would be found beneath the top layer of soil.

By August, there had been so much gopher activity in our beds that I decided we needed to conduct a damage assessment. I asked Tyler to dig around in a Camas plot that seemed particularly ravaged by the gophers, to see if he could find any of the original 40 bulbs we had planted. His searching returned no bulbs.

Bulb Thieves

I immediately went through each of the 15 camas plots and rated them with a visual assessment of the gopher activity that we would use to determine how many bulbs likely remained in the plots. The levels we decided on were “low/no damage” “Low damage”, “Moderate Damage”, “High Damage” and “Extreme Damage”. Plots with no damage were expected to have all 40 original planted bulbs. On the other end of the spectrum, plots labeled “Extreme” were expected to have no remaining bulbs.

At the end of our field season, we dug out the bulbs from each of the camas plots so we could assess the actual damage, and so we could install fencing to keep all future gophers out. During the bulb dig, we recorded the total number of bulbs found in each plot. In the table below, I have shared the visual damage rating for each plot, the estimated number of bulbs expected to be in the plots, and the actual number of bulbs we found.

Rep #Bulb TypeVisual Damage RatingEstimated Remaining BulbsActual Remaining Bulbs
1Blue HeavenLow-no402
2Blue HeavenLow-no4066
3Blue HeavenHigh1053
4Blue HeavenHigh1066
5Blue HeavenHigh105
Totals110192
1NativeExtreme00
2NativeLow408
3NativeExtreme08
4NativeExtreme030
5NativeHigh103
Totals5049
1SacajaweaHigh100
2SacajaweaHigh100
3SacajaweaModerate200
4SacajaweaLow-no400
5SacajaweaModerate200
Totals1000
Table 1: Camas Plot Estimated and Observed Damage. Damage values are estimates of how many of the original 40 bulbs are likely to remain in each plot.

While our findings from this unexpected study of bulbs were unfortunate, they tell an interesting story. An important point to note is that many of the bulbs have divided since they were planted, which is why in a few cases we found more than the original 40 planted bulbs. Regardless, there is a clear preference for the native C. leichtlinii and native cultivar ‘Sacajawea’ bulbs over the ‘Blue Heaven’ cultivar. We also noticed that any bulbs that were planted more shallow than the recommended 2-3x the height of the bulb were missed by the gophers.

Finding the Gopher Stash

After the exploratory bulb digging, we excavated each of our camas plots to around 1 foot in depth to install fences to keep the gophers from returning to our plots. While digging out the excess soil, we would often find a bulb or two that weren’t located during the initial bulb removal (these numbers are not included in Table 1, as we did not record them). In one section where the three camas types were planted in a row, we excavated a huge section of the garden, and made an amazing discovery (extra Kudos to Tyler who did the bulk of the work on this section).

On one of the walls of the hole, we found a gopher food chamber with thick white roots sticking out of the bottom of it. We removed some soil from the entrance, and discovered a chamber filled with camas bulbs. We carefully removed them and found over 60 bulbs that had been stolen from our plots. 

The 3 excavated plots, the food chamber, and the pile of 66 bulbs removed from the burrow.

Some of the bulbs were clearly the wild type great camas, identified by their characteristic long neck. The others we suspect to be ‘Sacajawea’ bulbs, as the burrow was found in what used to be a ‘Sacajawea’ plot. Any unknown bulbs were brought to my home and planted in a planter box to be identified in the next couple of months. The ‘Sacajawea’ bulbs have variegated foliage, making them easy to pick out once their shoots appear above the soil. We won’t know if the remaining mystery bulbs are ‘Blue Heaven’ or large wild type bulbs until they bloom in the spring.

Moving Forward

On the left: Jen (me) building a gopher exclosure. On the right: Tyler finishing installing a gopher exclosure.

In November of 2020 we installed our fences, refilled the gaping holes with soil, and replanted all of the camas bulbs, including some supplemental purchased bulbs of each of the three varieties. The native Camas and ‘Blue Heaven’ were successfully replanted with 40 bulbs. We were only able to order enough ‘Sacajawea’ bulbs to achieve a density of 30 bulbs per plot, though they will receive additional geophytes if any of the mystery bulbs turn out to be variegated. The mystery bulbs have yet to push their shoots through the soil, but I will include an update on their identities when I have them. 

Thank you to Tyler, Izzy, Max, and my fiancé Elliot for helping out in this laborious process. I absolutely would not have been able to safeguard the new camas plantings without your efforts and support in this process.

Garden Ecology Lab Year in Review: COVID Edition

This past year presented challenge and change to the Garden Ecology Lab. COVID locked us out of the lab and out of the field for a period of time. We said goodbye to two lab members (Angelee graduated! Cliff decided to move on from graduate school), and said hello to new lab mates (Cara took over Cliff’s project; Gwynne started her post-doc; Tyler, Jay, and Max all joined the lab as undergraduate researchers and research assistants). In addition to COVID and personnel changes, I had orthopedic surgery that took me away from work for a little under a month.

But somehow, despite the challenges and changes, we managed to make progress on several research projects. Below, I present a partial reporting of the Garden Ecology Lab year in review for 2020. Besides each project heading is the name of the project lead(s).

1) Garden Bees of Portland (Gail & Isabella): Jason Gibbs’ group from the University of Manitoba provided final determinations for a particularly difficult group of bees to identify: the Lasioglossum sweat bees. In addition, Lincoln (Linc) Best provided determinations for garden bees collected in 2019. Isabella is entering in some of our last remaining specimens, and I am working through the database of over 2,700 collected specimens to ‘clean’ the data and double check data entry against specimens in hand. There are a few specimens that need to be re-examined by Linc, now that we have determinations from the University of Manitoba, the American Museum of Natural History (Sarah Kornbluth), and a graduate of Jim River’s lab (Gabe Foote).

Altogether, we collected between 76 and 84 species of bee across a combined acreage of 13.2 acres (sum total acreage of 25 gardens). The low end estimate conservatively assumes that each unique morphospecies (i.e. Sphecodes sp. 1 and Sphecodes sp. 2) are a single species, whereas the high end estimate assumes that each is a unique species. A few noteworthy specimens:

  • We collected one specimen of Pseudoanthidum nanum, which is a non-native species to our area, which seems to be establishing and spreading in Portland. Stefanie Steele from Portland State University is writing a note on this apparent introduction, and is using data associated with our single specimen in her paper.
  • We collected one specimen of Lasioglossum nr. cordleyi which might or might not be a new species. The notation nr. cordleyi means that this specimen looks similar to L. cordleyi, but that the morphology of this specimen is different enough than the normal ‘type’ for this species, that it catches your attention. Jason Gibbs’ group is retaining that specimen. Further study will be needed to determine if it is indeed a new species, or not.
  • Some of the species we collected (as well as their ecological characteristics) suggest that gardens might be healthy habitat for bees. For example, we collected 72 specimens of Panurginus atriceps, which is a ground-nesting, spring-flying bee. Previous studies of garden bee fauna found ground-nesting and spring-flying bees to be relatively rare. We found them to be surprisingly (but relatively) common in our collections. We also collected seven putative species and 23 specimens of Sphecodes bees. This type of bee is a social parasite that does not collect nectar or pollen or construct a nest for their brood. Instead, they take advantage of the hard work of other bee species, by laying their eggs in the nest of another female. Parasitic bees are often used as bioindicators of habitat health. They would not be present on a site, unless the site also supported their obligate hosts.
  • We collected two species of bee that are listed on the IUCN red list for threatened and endangered species: Bombus fervidus (18 specimens) and Bombus caliginosus (10 specimens). I am not yet sure if their presence in urban gardens suggests that these species are recovering, that these species might be urban-associates that would be expected to thrive in urban gardens, and/or if gardens might represent particularly good habitat for these species.

In 2021, I *hope* that I can complete gathering data for this study, so that I can begin to analyze data and write. I hope to make it out to every garden, one last time, to finalize garden maps that will be used to calculate the area allotted to ornamental plants, edible plants, hardscape, and unmanaged areas. Aaron has already mapped out the landscape surrounding each garden at radii of 500 and 1000 meters. Together, these data will be used to understand whether/how garden composition and the surrounding landscape interact to influence bee species richness.

2) Native Plants and Pollinators (Aaron Anderson): In February, Aaron successfully defended his dissertation proposal and passed his oral examination, and thus advanced to Ph.D. candidacy!! Since that time, he has been busy sorting, identifying, and counting three years’ of insect samples from his 140 study plots, representing five replicates plots of 23 native plants, four ornamental plants, and a control ~ a task that he finished two weeks ago! His bees have been identified to species by Linc. Aaron has identified the thousands of other insects in his samples to the taxonomic level of family. He is working through analysis of his massive data set, and is simultaneously working on two manuscripts: one focused on just the bees and the other covering all other insects. We plan to turn the key points of these two chapters into an infographic that can be used by gardeners and green industry professionals, to select native plants that support an abundant and diverse assemblage of beneficial insects.

Aaron recently submitted the first paper from his dissertation for publication consideration, to the journal HortTechnology ~ and it was accepted, pending revisions! This paper reports on his survey of gardeners’ impressions of the aesthetic value of his study plants, and includes five specific recommendations for native wildflowers that Pacific Northwest nurseries might consider growing and marketing as pollinator plants (e.g. Gilia capitata, Clarkia amoena, Eschscholzia californica, Madia elegans, and Sidalcea asprella virgata). These plants all fell within the ‘sweet spot’ of being attractive to both pollinators and to gardeners.

Aaron’s plots at the NWREC station remain in place. Although we are through collecting data for Aaron’s study, I am applying for grant funding to study how plant traits ~ both the reward that plants offer pollinators and the displays that they use to attract pollinators ~ change with plant breeding for specific aesthetic traits, and whether/how these changes affect pollinator visitation. We also hope to study how highly attractive pollinator plants function in mixed plantings and in garden settings.

3) Bees on Native Plants and Native Cultivars (Jen Hayes):

Jen successfully completed her first field season of research, which is a monumental accomplishment during this time of COVID restrictions on our work. In early 2020, Jen finalized her list of study plants, which included one native species and 1-2 hybrids or native cultivars. This, in and of itself, was a huge accomplishment. Although we started with a much broader list of potential study plants, so many native plants did not have native cultivars or appropriate hybrids available for sale.

Jen’s study plants, which include one native (top photo in each group) and 1-2 native cultivars or native hybrids.

Once Jen and her crew put the plants in the ground, a new set of challenges emerged. For example the native yarrow emerged with pink flowers, which was a clear signal that these plants were not true natives. In addition, the Sidalcea cultivars that Jen and her crew planted came up looking different than the Sidalcea native. This sent Jen on a journey to the OSU Herbarium, where she learned that the Willamette Valley’s native Sidalcea malviflora has been reclassified as Sidalcea asprella, and that the cultivars we purchased were hybrids of Sidalcea malviflora (native to SW Oregon and California). This all suggests a need to work with local nurseries and/or growers of native plants, to see whether or not there needs to be or can be standards for sale of native plants. Should native species and native cultivars be verified or share provenance? Should gardeners be asking for this information? I don’t know, but I think that they’re important questions to consider.

With one field season’s worth of data in hand, the native cultivars were more attractive to all bees (with overall patterns being driven by the abundance of the European honey bee) for all floral sets, except California poppy. When we excluded honey bees from the analysis, to look at (mostly) native bees, no clear pattern of visitation on native plants versus native cultivars emerged. Native California poppy was most attractive to native bees. But, native cultivars of Sidalcea were more attractive to native bees (keeping in mind that in 2020, our native cultivars were not cultivars of our regionally appropriate native plant). For all other plants, there was no difference. We look forward to collecting additional data in 2021 and 2022, to see if the lack of difference in bee visits to native plants versus native cultivars holds up. Particularly for the perennials, we are finding that bee visits change so much from year to year, as the plant becomes established.

4) Garden Microbes in Soil and on Skin (Dr. Gwynne Mhuireach): Dr. Mhuireach successfully recruited 40 gardeners to participate in this study: 20 from western Oregon and 20 from the high desert. She has received and processed all soil samples and all skin swab samples for PCR (genotyping), which will be used to infer the diversity and identity of the soil microbial community in garden soils and on gardeners’ skin. She has also received survey responses from all study participants, so that she can characterize gardeners’ crop types, time in the garden, and gardening practices (e.g. organic, conventional, or mixed).

Dr. Mhuireach then sent me the soil samples, so that I could process them for submission to OSU’s Soil Health Lab. The Soil Health Lab is currently performing the chemical and physical analyses on each soil sample, so that we can determine if there is any relationship between soil characteristics, gardening region (e.g. western Oregon or high desert), crop choices, management practices, and the microbes that can be found in garden soils and/or on gardeners’ skin. Gwynne just received the first data back from the PCR analyses ~ and we can’t wait to share some of the intriguing findings with you, after we’ve had some time to process and digest the data!

Because of COVID-19 lab closures, we are a bit behind where we had hoped to be at this point. We anticipate receiving all data from each service lab by the end of January or in early February. You can read more about Gwynne’s project, here.

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Beyond these four studies, Tyler started his BioResource Research project (costs and yield of container grown and intercropped tomotoes), and Isabella worked on her thesis (parasitoids in Portland area gardens). We also collaborated with OSU Computer Science students to turn a database of first frost / last freeze dates that Angelee compiled, into a web-based app (the app is still in beta-testing, but we hope to release it, soon!). I will detail those studies, in another post. But for now, I’m getting excited for the smell of carnitas that is filling the house, and that will go on top of the New Years’ nachos that will help us ring in 2021! I hope that you all have a very Happy New Year, and that 2021 brings health, and happiness, and joy to all.

Five Scientific Studies that Changed the Way I Think About Gardens: Part 2, Putting a Price on Nature

This is the second is a series of articles that I am writing for the Hardy Plant Society of Oregon Quarterly Magazine. I extend my thanks to the HPSO editorial team for improvements to my narrative.

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Humans benefit from the natural world in many ways. These benefits include the products (such as food, fiber, or timber) that we can harvest from nature, or the processes (such as pollination, biological control, or nutrient cycling) that make earth such a nice place to live. Whether people recognize the importance of these so-called “ecosystem services” to our health and well-being varies considerably as a function of education, past experiences with nature, and other socio-economic factors. In fact, some people find abundant ecosystem disservices in nature. For example, some people view natural areas as dangerous places that should be avoided.

A major focus of the Garden Ecology Lab research program is to discover which garden plants may help maximize the ecosystem services of pollination and biocontrol.

In an increasingly urbanized world, where many people lack meaningful interaction with the natural world, how can we help ensure that the importance of nature is recognized and valued? As Robert Michael Pyle wrote in his book The Thunder Tree: Lessons from an Urban Wildland (1998: Oregon State University Press), “What is the extinction of a condor to a child who has never seen a wren?”

One approach to helping society value the natural world is to put a dollar value on it, and that’s just what Robert Costanza and 12 colleagues did over the course of a five-day workshop hosted by the National Center for Ecological Analysis and Synthesis in 1996. A few months later, they published the second global accounting of the monetary value of the ecosystem goods and services of our planet1.

The authors found over 100 studies that valued one or more ecosystem services. They standardized the dollar value of each ecosystem service as the 1995 dollar value per hectare. They noted the location of each study and categorized the biome where the study occurred. They also generated novel estimates of the dollar value of various ecosystem services in various biomes by constructing what were essentially supply and demand curves. With these curves, they mathematically asked questions such as “How much more valuable would pollinators be, if they were endangered?” In this way, they were able to mathematically manipulate supply and demand curves and estimate what is known as the “marginal value” of each ecosystem service. In short, they used a lot of math. On a global map, they measured the area taken up by each biome. They multiplied the dollar value of each ecosystem service per unit area by the area taken up by each biome and developed a global map of sum-total value of ecosystem services.

The authors estimated that the value of the earth’s ecosystem services averaged $33 trillion dollars per year (1995 dollar value), which was 1.8 times the global gross national product. Nutrient cycling represented the highest valued ecosystem service, at $17 trillion per year. Coastal systems were identified as the most valuable biome, at $12 trillion per year.

Urban and suburban areas were included in the study. What struck me about this paper, however, was that the dollar value of ecosystem services of urban areas was not listed. Instead, the authors noted that ecosystem services in urban areas (like desert, rocks, tundra) “do not occur or are known to be negligible.”

When I read this paper as a young Ph.D. student in 1997, I was incensed. My family grew food and raised chickens and rabbits in the backyard of our Baltimore rowhouse (ecosystem service = food). As a child, I captured water striders, turtles, and tadpoles from urban streams (ecosystem service = habitat). As an undergraduate, I loved exploring the urban forests of Patapsco Valley State Park for exercise and stress management (ecosystem service = recreation). Did urban areas really deserve a zero? This paper made me want to study the ecosystem services of cities, just to prove the authors wrong!

Composting is an example of the ecosystem service of waste treatment.

In 2002 I started to study the ecology of urban areas, as an assistant professor of biology at Fordham University in New York City. I collaborated with doctoral student Kevin Matteson to study the value of urban gardens as wildlife habitat and pollinator conservatories. We found that 18 small gardens dotting one of the most urbanized landscapes on earth were used by a diversity of insects, including 24 species of butterfly and 54 species of bee. At this same time, others were also documenting the ecosystem services of urban areas. For example, The New School’s Timon McPhearson estimated that raised bed gardens in New York City annually helped to retain and manage 12 million gallons of stormwater from flooding city streets. Karin Burghardt, as a University of Delaware undergraduate studying with Doug Tallamy, showed how plant choices can increase bird abundance and diversity in suburban gardens in Pennsylvania.

Raised beds in urban areas retain rainwater and reduce run-off and storm system overflows. This is an example of the ecosystem service of disturbance regulation.

In fact, the early 2000s were a heyday for urban ecology research, due in large part to National Science Foundation funding of urban long-term ecological research efforts in Phoenix, Arizona, and Baltimore, Maryland. Whereas less than one-half of one percent of all papers published in nine leading ecological journals between 1995 and 2000 focused on urban systems or urban species (Collins et al. 2000), by 2016 over 1,000 articles, books, and book chapters have been published; and over 130 students have been trained in urban ecology by the Phoenix and Baltimore programs, alone (McPhearson et al. 2016). Despite these advances, the field of urban ecology is still relatively young, and much remains to be discovered.

In 2014, Costanza and colleagues published a new paper, with an updated estimate for the value of our globe’s ecosystem services.2 They estimated that natural systems annually provided $125 trillion (2011 US$ value) in ecosystem services to humanity. At least part of this increase is due to improved documentation of the portfolio of ecosystem services provided by different biomes (see table). And this time, ecosystem services provided by urban areas were valued at $2.3 trillion dollars, or $2.9 trillion in inflation-adjusted dollars for 2020.

”Hmph,” I thought. “At least it’s a start.”

1Robert Costanza et al. (1997): “The value of the world’s ecosystem services and natural capital.” Nature 387: 253-260.

2Costanza (2014): “Changes in the global value of ecosystem services.” Global Environmental Change 26: 152-158.

Table 1. The Value And Ecosystem Services Provided By Various Biomes On Earth. All dollar values have been inflation adjusted to 2020 dollar values, and are reported as TRILLIONS of dollars. Red Text: Identified as a service in Costanza et al., 1997, but not 2014; Green Text: Identified as a service in Costanza et al., 2014, but not 1997; Black Text: identified as a service across both papers.

BiomeValue from 1997 PaperValue from 2014 PaperEcosystem Services
Open Ocean$14.8$27.9Gas regulation, Cultural, Climate regulation, Genetic resources, Recreation, Nutrient cycling, Biocontrol, Food
Coastal$22.1$35.3Climate regulation, Erosion control, Genetic resources, Disturbance regulation, Nutrient cycling, Biocontrol, Waste treatment, Habitat, Food, Raw materials, Recreation, Cultural
Forest$8.3$20.7Gas regulation, Pollination, Habitat, Climate regulation, Disturbance regulation, Water regulation, Water supply, Erosion control, Soil formation, Nutrient cycling, Waste treatment, Biocontrol, Food, Raw materials, Genetic resources, Recreation, Cultural
Grassland$1.5$23.5Climate regulation, Water supply, Habitat, Raw materials, Genetic resources, Cultural, Gas regulation, Water regulation, Erosion control, Soil formation, Waste treatment, Pollination, Biocontrol, Food, Recreation
Wetlands$8.5$33.65Gas regulation, Climate regulation, Erosion control, Nutrient cycling, Biocontrol, Genetic resources, Disturbance regulation, Water regulation, Waste treatment, Habitat, Food, Raw materials, Recreation, Cultural
Lakes/Rivers$2.9$3.1Water regulation, Water supply, Waste treatment, Food, Recreation
Desert$0$0 
Tundra$0$0 
Ice/Rock$0$0 
Cropland$0.3$11.9Climate regulation, Water supply, Erosion control, Soil formation, Waste treatment, Raw materials, Genetic resources, Recreation, Pollination, Biocontrol, Food,
Urban$0$2.9Climate regulation, Water regulation, Recreation

Five Scientific Studies that Changed the Way I Think About Gardens: Part 1

[Preface: For the past few years, I have written a column for the Hardy Plant Society of Oregon’s (HPSO) Quarterly Magazine. It has been a wonderful experience, as the HPSO provides excellent editorial assistance. Below, I share my most recent article for the HPSO Quarterly, and thank Eloise Morgan and her team for helping to improve and elevate my writing.]

I spend my nights thinking about gardens: not about the plants that I want to purchase or the crops that I want to plant. Instead, I puzzle over how to study a system that is incredibly variable (from person to person, or even in the same person’s garden from year to year) and complex (with more plant species than just about any other system that has been studied). Gardens are both wild and managed, and unlike other systems I have worked, it is impossible to divorce human behavior from the ecology and evolution of the garden.

In this series, I wanted to share five scientific studies that have had a large role in shaping how I think about gardens. Because of space limitations, I will share the first study in this article. I will wrap up the remaining four studies, in subsequent issues. The five studies are:

Simberloff and Wilson (1969). This study commenced 54 years ago, and yet remains a ‘must read’ for any ecology student. In 1966, Dan Simberloff and Ed Wilson selected six small mangrove islands off the coast of Florida. The islands varied in distance from the mainland coast, from near to far (Figure 1a), as well as size, from small to large (Figure 1b)

Figure 1. In Simberloff and Wilson’s experiment, they selected mangrove islands that varied in their (a) distance from the mainland (the coastline of Florida) and (b) their size. Attribution: Hdelucalowell15 / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0)

Simberloff and Wilson constructed a scaffold that encircled the edge of each island, covered the scaffold with a tarp, and then proceeded to ‘defaunate’ each island with methyl bromide pesticide. In other words, they killed every arthropod on the islands. After removing their ‘death tents’, and over the course of the next year, they carefully monitored, cataloged, and counted every arthropod that arrived and survived on each island. What they discovered was formulated into the ‘Theory of Island Biogeography’, or a theory about how organisms colonize new habitat, and assemble into a biological community.

They found that islands that were closer to the mainland coast of Florida were colonized earlier, and accumulated species faster, compared to islands that were farther (Figure 2). They also found that species would accumulate on each island, over time, until a maximum peak is reached (not shown). Then, the number of species would begin to drop, as ecological interactions (such as competition for food) would allow some species to prosper, while others went locally extinct. They found that smaller islands were more prone to species extinctions, than larger islands (Figure 2).

Figure 2. Island size (small or large) and distance from the mainland coast (near or far) infuenced the dynamics of species colonization and extinctions on mangrove islands. Image Source: https://commons.wikimedia.org/wiki/File:Island-biogeography.jpg#file

Size, distance, age: those are the three things that Simberloff and Wilson predicted would govern the diversity and assembly of organisms within a habitat.

My first faculty position was at Fordham University in New York City, where I studied pollinators in 18 community gardens in Harlem and in the Bronx. During the course of this study, I was inspired by Simberloff and Wilson. I could not help but see the 600+ community gardens that dot the landscape of New York City as islands of green in a sea of concrete.

We expected that gardens that had been long-established would have more pollinator species than newer gardens. We expected that larger gardens would host more pollinator species than smaller gardens. And, we expected that gardens that were closer to ‘mainland’ sources of pollinators, such as Central Park or the New York Botanical Garden, would have more species of pollinator than those that were distant.

We were wrong on two out of three predictions (Matteson and Langellotto 2010). Larger gardens had more pollinator species than smaller gardens, but neither distance nor age had any impact. I was so disappointed that we did not find an effect of distance, or of garden age. I had visions of ‘revitalizing’ the Theory of Island Biogegraphy for urban landscapes, but it was not to be. If anything, our study suggested that the ‘sea of concrete’ was not exactly a wasteland, afterall. The street trees, potted plants, windowsill gardens, and patio gardens all provided resources for urban pollinators, even in one of the most densely populated and heavily developed cities in the world.

This study showed me that it will be much more difficult to track pollinator movements among urban gardens, than I had hoped. We tried to use a traditional mark-recpture approach (see Matteson and Langellotto 2012), but out of 476 marked butterflies we only found four in a garden other than which it was marked and released. We were searching for the ‘needle’ of small butterflies in the ‘haystack’ of the New York City landscape. My students tried to follow pollinators as they left our study gardens, and almost got hit by a car, as they were running across the street. We played around with the molecular markers of a few bumblebees (see Morath 2007), to see if there was evidence of genetic differentiation, but were stymied by a lack of reliable primers that could help us look for any genetic differences in bees from different gardens. And then I moved to the Willamette Valley, where gardens are islands of green in an ocean of green. Understanding what draws pollinators to particular gardens will be even more difficult in this landscape, where pollinators have so many other choices for finding nectar and pollen.

Based upon our initial results from our Portland Garden study (2017-2019), I think I have a new hypothesis as to what might draw pollinators to home and community gardens. Our second study year (2018) was characterized by a hot and dry summer. Our first sampling season was also dry, but the spring months were wet, and the summer was cooler. In 2018, we collected far more bees (abundance) and more types of bees (species) than we collected in 2017 or 2019. In 2018, the landscape of the Willamette Valley was toast! Almost all flowering plant materials seems to shut down photosynthesis, so that they could conserve pressure water that would otherwise escape through open stomates. In this type of situation, bees seemed to concentrate in home gardens, which seemed to be one of the few places where they could reliably find nectar and pollen.

If this is the case, gardens aren’t necessarily going to be an important source of floral resources across all years. In a good year, there should be other plants in bloom in the greater landscape that bees can use. But in a hot, dry year, gardens may become an even more important refuge for bees. Most gardeners provide irrigation, which extends the bloom season beyond what is natural in the valley. Or, gardeners select plants that can prosper and bloom without supplemental irrigation, such as goldenrod or Douglas aster. It’s important to note that, even in the hot, dry weather of 2018, we still collected more bees from gardens that used drip irrigation, rather than overhead sprinklers. I think that the overhead irrigation physically blocks bees from navigating through a garden, which lessens their abundance and diversity.

Ultimately, I hope that our studies can lead us to a more predictive model of the resource value of home gardens to pollinators. The goal isn’t necessarily to understand what gardeners should do to attract pollinators, but to describe the conditions where gardens become increasingly important to pollinator conservation. In addition, I’d love to describe the value of gardens, relative to other habitat types, to pollinators. And finally, I hope to better understand the direction and movement of pollinators between gardens and other habitat types.

 

Garden Ecology Lab Research Update

COVID-19 has impacted our research in many different ways, including making it more difficult to find time to provide research updates on a regular basis. Despite the long silence, we have many projects up and running this summer! In fact, we’re launching four new projects, finishing up three long-term projects, and writing up another two projects.

In this blog post, I give a brief overview of the four new Garden Ecology Lab projects that launched this summer.

Microbiome of Garden Soils and Gardeners: Dr. Gwynne Mhuireach’s project has been spotlighted in a recent blog post and webinar. She has selected the 40 gardeners that will be included in her study: 20 high desert and 20 Willamette Valley gardeners, half of whom are organic and half of whom are conventional gardeners. Soon, these gardeners will be sending in their soil and skin swab samples. And then, the long process of analysis will begin.

She’s studying the microbe community in garden soils, and how those might differ according to garden region (Willamette Valley or high desert) and gardening practices (organic versus conventional soil managmeent). She’s also studying whether garden soil microbes transfer to gardeners’ skin during the act of gardening, and if so, how long those microbes persist on the skin.

Pollinators on Native Plants and Native Cultivars: Jen Hayes is well into the data collection phase of her first field season. She is working with undrgraduates Jay Stiller, Tyler Spofford, and Isabella Messer to: track flowering phenology, measure floral traits, observe pollinator visits to study plots, and collect pollinators so that they can later be curated and identified to species. Jen has written about her research project, in a past blog post. I’ve also set up a Flickr album to host photos from her study.

Native plant and nativar study site, at the Oak Creek Center for Urban Horticulture. A yarrow cultivar, ‘Salmon Beauty’, can be seen in the foreground. Nemophila, Clarkia, and Escholzia cultivars can be seen in the background.

Jen’s field site is located at the Oak Creek Center for Urban Horticulture at OSU, which makes it so much easier for undergraduate student researchers to participate in this project. She samples pollinators on Tuesdays and Fridays. She takes 5-minute observations of pollinator visits on Mondays and Thursdays. In between, lots of time is spent weeding and watering plots, counting flowers, and measuring floral traits.

Cost / Benefit Analysis of Growing Edible Plants in Containers: Tyler Spofford is a new lab member, who is completing his undergraduate degree in the BioResource Research program at OSU. He is working to develop a ‘budget’ for growing food in low-cost containers. I’ve summarized this ‘budget’ data for growing food in standard vegetable gardens, but no data yet exists (that I can find) for containerized vegetable gardens. Tyler is growing 40 tomato plants across two sizes of containers (3 gallons and 5 gallons), as single plants and in combination with basil. He’s keeping track of all of the costs (both money and time spent to grow food). When he harvests food, he’ll weigh his harvest, and track the economic benefit of his efforts, and how container size and planting configuration (one or two crops per container) influences harvest. I’ve set up a Flickr album for his study, to host project photos.

Tyler’s project grew out of my concern that, even though 18,000+ people enrolled in a free, online vegetable gardening course (over 40,000, at last count) ~ that the people who might be most at risk for food insecurity may not be benefitting from Extension Master Gardener resources and information. Tyler’s project is one component of a larger effort to develop more support for renters who might want to grow their own food.

Bucket gardens, on the day that the tomatoes were planted into 5-gallon BiMart buckets. We tried to keep all materials and plants low cost and easily accessible. Photo Credit: Tyler Spofford.

Below is an excerpt from a concept paper I’m writing on the topic:

We know that the COVID-19 pandemic is exerting stress on multiple pressure points related to the economic and food security of U.S. households: more people are in need of food aid and more people are concerned about food access. The U.S. has a long history of gardening in times of national emergency (e.g. Victory Garden of WW I and WWI II, ‘recession gardens’ of 2008). The benefits of gardening as a tool of economic security and resilience are well-established. However, research suggests that these benefits are largely restricted to homeowners. Currently, most state and local laws afford no legal right to renters who want to grow their own food. Community gardens might offer renters opportunities to grow their own food, except that these gardens are often associated with gentrification. To promote public health in the face of economic and health risks of COVID-19 and future pandemics, it is critical to support the food gardening efforts of the most vulnerable. Those in rental housing have been found to be most vulnerable to food insecurity, as well as the food and economic insecurity associated with natural disasters.

Pollinators on Buddleja Cultivars: Cara Still is studying how breeding butterfly bush (Buddleja davidii cultivars) for sterilty impacts the pollinator community that visits Buddleja blossoms. Buddleja davidii and some fertile varieties of this plant are considered noxious weeds in Oregon, and many other places. Normally, noxious weed status would make it illegal to sell or trade butterfly bush in Oregon. However, the Oregon Department of Agriculture allows exceptions for non-sterile cultivars and interspecific hybrids.

Buddleja ‘Buzz Velvet’ (I suspect that plant breeders have a lot of fun, naming new cultivars)

Cara is studying whether or not the plants that are allowed for sale, under the exceptions, still pose a risk of invasion. Our group is working with Cara to document the abundance and diversity of pollinators that visit eight fertile Buddleja cultivars with 16 cultivars that have been bred for sterility.

When I was initially approached to participate in this project, I thought that it should be obvious that sterile cultivars would not attract pollinators. Afterall, sterile cultivars don’t produce pollen, or produce very little pollen. Without pollen, I doubted that bees would visit the plants. But, it is possible that sterile plants would still produce nectar. And, many pollinators ~ such as butterflies and moths ~ visit plants to consume nectar, rather than pollen.

The more I looked into the literature, I realized that no one has yet studied how breeding for sterility might affect a plant’s attractiveness to pollinators. Would sterile forms of butterfly bush no longer attract butterflies? Would sterile varieties attract syrphid flies that visit blossoms for nectar, and not pollen? We’ll let you know what we find, in about a two years. In the meantime, you may want to visit the Flickr album of photos I set up for Cara’s study.

Link to ‘Garden(er) Microbiome’ Webinar Recording

Thanks to all who signed up for the ‘Citizen Science in the Garden!: Studying the Garden(er) Microbiome’ webinar. The webinar recording can be found below, or via THIS LINK.

If you are interested in participating in this project, please leave your information in this short survey. We will work to get back to everyone who responds, within the next month. Depending upon the volume of interest that we receive, it may take a bit longer.

Thanks to all wanting to learn more about the microbiome of garden soils and gardeners!

Welcome Gwynne Mhuireach and the Garden(er) Microbiome Project

This post a from Gwynne Mhuireach, who will be studying the microbiome of garden soils . . . and gardeners!!

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A little about me…

Gwynne Mhuireach will be studying the microbiome of garden soils and gardeners!

I am a researcher, farmer, and mom to twin teenagers. My formal education is broadly cross-disciplinary, including degrees in biology, architecture, and landscape architecture. While I was working on my Masters, I began studying microbes inside buildings as a member of the Biology and Built Environment Center at the University of Oregon, where we discovered that our exposure to microorganisms indoors depends a great deal on what microorganisms are present in the immediate outdoors. This line of inquiry was so fascinating that I entered the PhD program in Landscape Architecture to investigate how urban green space might influence the airborne microbial communities that people are exposed to in their daily lives. Ultimately with my research, I aim to gain a deeper understanding of how human health and environmental health are connected through the microbes we share. 

In addition to my academic research, I also own and operate a small livestock farm with my two teenagers, Lyric and Cadence, and my partner, Tom. A native Oregonian, I was born and raised on a small farm near Klamath Falls, Oregon, where my family produced (and continues to produce) hay and cattle. Now I choose to continue the agricultural lifestyle that has been my family’s way of life for three generations. Producing food through hard work and stewarding a small piece of land to pass on to my children is very important to me. I believe that having a strong connection to the land is also part of what drives me to study microbes in the context of the outdoors, particularly how we interact intimately with them by getting our hands dirty in the soil.

The Garden(er) Microbiome Project

In partnership with Gail Langellotto, I am launching a new citizen science project called, “Microbes under your fingernails? An exploration of the garden microbiome and potential transferability to human skin.” While soil science is well-developed in terms of nutrients and organic matter needed to keep plants healthy, less is known about the diversity and composition of microbes present in agricultural soils, particularly in small-scale farms and gardens. Astonishingly, despite the likelihood of substantial exposure to soil microbes while gardening, yet we lack even the most basic understanding of how much microbial transfer from soil to skin occurs, what types of microorganisms are transferred, or how long they persist. Through this project, we seek to answer these questions with the help of volunteers—you!

Gardeners who volunteer to participate in this project will be asked to collect soil samples from several different beds in their gardens and from the surface of their hands and/or forearms. There will also be questionnaires that ask for information about garden management practices and daily skin care (use of anti-bacterial soap or lotion, etc.) during the sampling period, which will last 2 days. Volunteers will receive detailed results, including a comprehensive soil health assessment and skin/soil microbiome reports. We will also share our findings with other researchers, farmers/gardeners, and the broader public online and through the Master Gardener network. We anticipate that this citizen science project will not only answer our original research questions, but also shed light on how different management practices can impact garden soil health in different climate zones of Oregon.

If you are interested in participating in this project, I am hosting an informational webinar on Friday, June 5th (2020) at 10am. Registration is required to attend. The webinar will be recorded and posted.

If you are unable to attend, but are still interested in participating, please let us know a bit more about you and your garden by taking this short survey. Please note that for this particular project, we are specifically seeking gardens located in Oregon’s Willamette Valley or High Desert regions.

How COVID-19 Has Impacted the OSU Garden Ecology Lab

I asked our group if they would be willing to share how COVID-19 is impacting their science, their studies, and their life. Our collective reflections can be found, below.

Gail Langellotto, Professor and Statewide Master Gardener Coordinator: In early February, I woke up from a dream, sobbing. I had dreamt that my parents were sick in Baltimore, but that domestic air travel had been shut down. I am not an expert in the ecology of infectious disease, but I used to teach infectious disease models to pre-meds. And, there were several things that I saw in reports of this emerging disease that greatly troubled me. Unfortunately, my fears of large scale community spread have come true, and life has changed for us all. Luckily, my parents and sisters continue to be healthy, even though they live in a COVID-19 hotspot.

I teach two face-to-face entomology courses at OSU during the spring term: ENT 311 and ENT/HORT 444/544. I had exactly one week to pivot these classes to fully remote offerings. Instead of real time (and automated) assessment of learning using TopHat, I’m building quizzes and assignments into Canvas, where I am manually grading 210 quizzes and assignments per week. I’ve drastically cut down on course content, in part because I continue to try and focus on essential messaging, but also because I know that many of my students are under immense stress.

Spring term is when I normally move to having a lighter touch with the Master Gardener Program. New Master Gardener students are completing their coursework and exams. Long-time Master Gardeners move their attention to plant sales, garden fairs, and educational outreach. Not this year. Training classes had to move online or to Zoom. Plant sales, garden fairs, and other Master Gardener events were cancelled. Our working group started trading resources and ideas via weekly Zoom meetings. Each new dictate from the Governor or the University requires attention and consideration of how it applies to the Master Gardener Program. It’s been a challenge to stay on top of everything, and a challenge to keep a positive attitude.

In terms of science, there has been good and bad. The ‘bad’ is that, as an Associate Editor of the journal Urban Ecosystems, it has been difficult to find peer reviewers for scientific manuscripts. And, it feels ‘out of touch’ to prod folks to get their reviews in, when they may be sick, or they may be busy home-schooling kids or shopping for senior family members. Also in the ‘bad’, I generally have zero time or energy to work on my own scientific manuscripts. Exhaustion is a constant. The ‘good’ is that I can’t sleep at night. And, during these sleepless nights, I often think about next steps in our research, and plotting out key questions in urban ecology that remain unresolved, but could be addressed in garden systems.

Gail’s workstation at home. The photo of the bear and fish (to the right) is named ‘A meditation on perspective’. When working, I often stop to tell myself ‘be the bear, not the fish’.

Angelee Calder, senior year June 2020, Agricultural Science undergraduate: Covid has greatly impacted my plans and life!  As some of you may remember from my last blog post, I was expecting to spend my final term as a senior at Oregon State University doing an internship in Costa Rica! Twelve days before I was scheduled to leave, we entered a worldwide pandemic and all my plans where flipped and turned upside down! In preparation to leave for Costa Rica, I had put in my 30 day notice in on my apartment and my roommate found somewhere else to live. Last minute, I had to scramble to get my refunds, register for classes, and find somewhere to live. Since then, I have been struggling with homelessness.

Currently, I am living in the emergency housing at OSU provided by the Human Resources and Services Center. While I am extremely thankful to be here, I am only permitted to stay for less than a month. Which means my struggle with homelessness during my final term of school will continue to be an issue well into finals week. I started my first term at OSU homeless and I am finishing my final term homeless! While this is stressful and uncertain, I have managed to continue to kill this term academically. I am proud of myself for prevailing during these hard times to thrive under these heavy pressures and keep my eyes on the prize of my diploma that I have worked 5 long years to earn.

My passion for agriculture and my dedication to school go unwavered. This time has helped me to feel more secure in my chosen field as Agriculture than I ever have before. After seeing the bare shelves at the store and hundreds of thousands of Americans get laid off of their jobs, I realize agriculture is about as “essential” as you can get! My passions and education can not only create stable work for myself but also can help the rest of the world through these difficult times with stable sustainable food production.

Angelee’s workstation at the OSU Human Services Resource Center.

Mericos Rhodes, M.A. Student in Environmental Arts and Humanities. As a practitioner of ecological agriculture, this COVID era is one of the most interesting times of my life. Put simply, I have never witnessed such intense interest in what is, to me, the most interesting topic in the world: local ecological farming.

The farm that I help run, Spoon Full Farm, has completely sold out of CSA memberships and many other items. Our waitlist is growing. Here in Corvallis, the farmers markets are well-adjusted and well-attended. I can understand why: a shorter food chain means far fewer opportunities for food to be contaminated. Healthy nutrient-dense food is a cornerstone of resilient health. Small businesses such as local farms need our support now, more than ever.

In an exciting development, a friend and I are busy converting an old grassy field, across from the Corvallis Fairgrounds, into a small-scale community-based farm. We connected with the landowner after he put up a sign at the co-op seeking farmers! So, our restorative farming project has begun! It doesn’t look like much, but we have 7 chickens moving rapidly through the grass between our dug rows of mixed perennials (mostly currant bushes and thyme), fertilizing the ground to support annual vegetable beds. We plan to dig a little pond and use a heavy mulch of leaves and/or wood chips.

The Corvallis field that Mericos and his partner are converting into a farm.

How is this relevant to the garden ecology lab? In two ways:
First, I am planning my graduate project to be a narrative introduction to ecological farming (stories, characters, motives will be highlighted). This personal experience will be part of the story. Second, this project will put into place many practices suggested by Gail’s Insect Agroecology class (ENT 544), which I am currently taking, including creating diverse perennial habitat for insects, and not spraying pesticides or synthetic nitrogen. It will also be an experiment in “Dry-Farming,” which basically means zero irrigation – perhaps a critical farming technique here in the Northwest, where irrigation water may be in much shorter supply, in the decades to come.

I feel extremely grateful to be able to work outside, with living nature, during these times when so many are stuck in screen world, all day every day.

Aaron Anderson, PhD Candidate: During this uncertain time, I feel lucky to be able to be part of the Garden Ecology Lab and be able to continue my classes and work. As I am in my fourth year as a graduate student here at OSU, I have already collected all of my field data. This means that I am able to hunker down at my desk here at home, without having to worry about the logistics of conducting fieldwork during a pandemic. I’ve been busy taking two courses, and also plugging away on some data entry and statistical work.

Things can be undeniably stressful due to the background worries about COVID-19, but working from home has had some plus sides. The first is the ability to work with a cuddly cat on my lap. I’ve also been able to take breaks out in the yard, where we’ve been working on our garden bed and also seeded the side yard with several native plants from my study. We have Phacelia heterophyla just starting to germinate, and Clarkia amoena and Achillea millefolium are both beginning to bolt. Hopefully, some native bees will be visiting soon!

Aaron’s cat.
Aaron’s side garden.

Signe Danler, Instructor, online Master Gardener training course: As an instructor of an online course, most of my work was already done online via computer before the pandemic hit. I have also worked from home for many years in a variety of jobs, so I already had a full office set up at home, and did much of my OSU work at home already. In this regard, there was not much change – I grabbed a few things from my office at OSU so I would have them at home, and have not been on the campus since the stay-at-home order.

Nevertheless, life suddenly became much more stressful. For the first few weeks, the constant bombardment of new and conflicting information was terribly distracting, making it hard to be productive on any project requiring sustained effort. The cancellation of virtually all events I normally participate in has been saddening and frustrating. With two vulnerable family members at home, we have to exercise great caution in outside contacts. I not only have to do all grocery shopping, but do it in a way that takes much longer than usual, and is tiring and stressful. I’m keeping trips out very infrequent!

All in all, though, I feel we are very fortunate, since we are in a position to ride this situation out with minimal problems. To stay healthy and sane I’ve been taking more walks, which is easy since we live at the edge of town and crowds are non-existent. My large garden is getting more attention than usual, and I’m propagating more of my own plants to reduce nursery visits. As I have adjusted to the new normal, my ability to focus is getting back to normal too, and I am confident we’ll get through it just fine. 

Signe’s Plant starts.

Mykl Nelson, Instructor of Urban Agriculture: The first thing I noticed was how much remained the same. I was already fully remote and integrated with eCampus. I was lucky. I watched the flurry of emails, the hectic conference meetings, the string of popular articles. Everyone seemed to scramble as essentially the entire academic world pushed to move fully online and remote. I’m excited to see this push because I hope to see advancement in the teaching of remote teachers. When I first started trying to educate myself about educating others in agricultural topics in a remote classroom, I saw very little supporting material. I hope that changes now.

I’ve seen real changes in the community around me. Store shelves lay bare as a slow realization—the façade of abundance—spreads across stores. I know from my time as a grocery clerk that those shelves aren’t stocked that deep, and the “back stock” is kept as thin as possible. I’m watching my country get squeezed around me; the most vulnerable of my fellow citizens being forced to confront the more dire aspects of this pandemic. 

But in this panic, I feel safe. I get to add yet another scenario to the privileged category of my life. From my youth in a military family to my time now as university faculty, I am repeatedly shown the benefits of access to health care. When it comes to basic hygiene and global health, I want everyone to be able to wash their hands just as easily as they could access medicine. It only makes sense to extend such secure foundations to as many people as possible.

Mykl’s workstation in Central Oregon.

Happy 50th Anniversary of Earth Day

Today is the 50th anniversary of earth day. I am almost as old as earth day (I will turn 50, next February), and am finding myself in a reflective mood.

Ever since I was a child, I have been fascinated by and loved nature. I used to try and catch lightning bugs, and put them in a mason jar, hoping to catch so many that I could make a lantern. Today, when I visit my folks near my childhood home, nary a lightning bug can be found. Scientists suspect that increased landscape development has removed the open field habitats and forests that the lightning bugs depend upon to display their mating signals and to live. Light pollution likely also plays a role.

lightning bug 8758
Eastern Lightning Bug. Photo Credit: Terry Priest. https://www.flickr.com/photos/artfarmer/197649535

My time in college was my first real exposure to nature. I worked at Patuxent Wildlife Research Center, supporting the work of James Wagner when he was a graduate student at UMBC. He was studying wolf spiders, and I fell in love with these amazing creatures. Did you know that wolf spider mommas carry their young on their back ~ at least for the first few days of a baby spider’s life? Did you know that to collect wolf spiders, you go out at night with a flashlight . . . shining the flashlight into the forest floor litter, to find eight tiny glowing eyes staring back at you? Wolf spider eyes glow, as an adaptation to capture more light (enabling them to see better) when hunting at night. Like a cat’s eye, wolf spiders have a tapetum at the back of their eye . . . a mirror that re-reflects light back out, and lets the spider’s eyes have a second shot at capturing that light. My time working with James was magical. For the first time in my life, I gained the skills to identify trees, and wildflowers, and birds, and insects. I tell people that it was as if a scrim had been lifted from my eyes, and I saw the world in an entirely different light. I was forever changed, by this newfound knowledge that allowed me to ‘read’ the natural world in a different way.

Behind the rusty eyes
A wolf spider. Photo Credit: Jean and Fred. https://www.flickr.com/photos/jean_hort/4430861610

As a graduate student, I studied salt marsh insects on the New Jersey coastline. I had never been to a salt marsh before, despite living within an hour of the ribbon of salt marsh that hugs the eastern seaboard. I saw horseshoe crabs for the very first time. I saw the fishing spiders in the genus Dolomedes that I had read about in books. I went bird watching and butterfly hunting with scientists who were generous with their time and knowledge, most notably, my advisor, Robert Denno. Now, so much of that ribbon of coastline has been destroyed. What remains is at risk due to increased nutrient pollution from fertlizers and run-off.

Big cordgrass salt marsh
Tall grass in an eastern salt marsh. Photo Credit: Ecological Society of America. https://www.flickr.com/photos/ecologicalsocietyofamerica/25086412492

My post-doctoral work was spent in California on many projects, including studying the food webs of cotton fields that were using organic or conventional production practices. From talking to the farmers and stakeholders, I learned that there are not insurmountable impediments to growing organic cotton. The problem was that there was a limited market for organic cotton, grown in the United States. Growers who would plant organic cotton faced an uncertain market and reduced yields. Often, reduced yields might be compensated for with a premium price for organic products. But not in the case of US-grown organic cotton. This is when I first started to realize that science can not work in a silo, but that an understanding of economics and the social sciences is critical to promoting more sustainable solutions.

My first faculty position was at Fordham University in the Bronx. I had no idea what I would study, as an entomologist in the Bronx. Luckily, I had the great fortune of taking on Kevin Matteson as my first graduate student. Kevin had been studying the birds of New York City community gardens. I asked him if he might be willing to instead study insects. His work was ground-breaking and is heavily cited, showing the potential of small garden fragments in one of the most heavily populated cities in the world, to support a diverse and abundant assemblage of insects. He also showed that the strongest predictor of butterfly and bee diversity in gardens was floral cover. Through Kevin’s work, as well as associated work by Evelyn Fetridge, Peter Werrell, and others in our Fordham lab group, I became convinced that the decisions that we make in home and community gardens have the potential to make a real and positive difference in this world.

I came to OSU in 2007, for the opportunity to work with about 30 faculty and staff and between 3,000-4,000 volunteers who were dedicated to sustainable gardening. Coming from a teaching and research position to an Extension position was initially a challenge for me. I recognized importance of bringing good science to Extension and outreach work, but I didn’t know exactly how I would or could contribute. In 2016, I started the Garden Ecology Lab at OSU, mostly because I was more convinced than ever, that having good science to guide garden design and management decisions can truly make a positive difference in this world. I sometimes talk about ‘how gardening will save the world’, which is a lofty and aspirational goal. But, I truly believe (and science backs up this belief), that the decisions that we make on the small parcels of land that we might have access to in a community or home garden matter. These design and management decisions can either improve our environment (by provisioning habitat for pollinators and other wildlife) or harm our environment (by contributing to nutrient runoff in our waterways, or by wasting water when irrigation systems fall on the sidewalk more than on our plants).

This is one reason that I stand in awe of the Master Gardener Program. When I was purely a researcher, rarely interacting with the public, I doubt that many people were able to take our research findings and apply them in their own yard. When I was initially struggling with my new Extension position, I went to my former Department Head at the University of Maryland entomology deparment, Mike Raupp. Mike had a lot of experience with Extension and outreach, in addition to being a world-reknown researcher and a super-nice person. I remember him saying ‘Gail, when you publish a research paper, you’re lucky if 20 eggheads will read it. When you talk to the Master Gardeners, you have the opportunity to make real change in this world.’

And together with the Master Gardeners, I hope that is what we have done. I hope that is what we will continue to do. I hope that we find new and novel ways to discover how folks can manage pests without pesticides, to reduce water use in the home garden, and to build pollinator- and bird-friendly habitat. And then I hope that we will reach and teach our neigbhors and friends how to appreciate the biodiversity in their own back yard, and the small changes that they can make to improve the garden environment that they tend. I hope that we can instill a wonder for the natural world in the next generations, and to preserve or improve the natural world, so that our kids, and grandkids, and subsequent generations can hunt for lightning bugs, or spiders, or butterflies.

And I want to do it with you, dear gardeners. Together, we truly can make a difference.

Does Repeated, Lethal Sampling Contribute to Insect Declines?

Over the past few months, I have shared data on bees and other insects that we have collected from Portland-area gardens. For every garden insect we study (except for butterflies, which can be identified to species by sight), we use lethal collection methods. This is because most insects can only be identified to species after close examination under the microscope. In fact, some insects require dissection before we can get them to species.

Bombus sitkensis male, with abdomen dissected, in order to make a species-level identification.

It seems odd that we kill bees in order to help understand how we can build gardens that can help to conserve bees. By collecting and killing bees and other insects, what role were we playing in promoting insect decline? How do projects, such as our own as well as the Oregon Bee Atlas, factor into bee declines?

That’s an excellent question, and one that we often ask ourselves. When we collect bees, we work to make sure that we are not needlessly causing harm. For example, our pan traps are good for collecting small bees, but are not good at collecting larger bees, including reproductive queens. When we hand-collect bees, we avoid taking queen bees. In fact, of the 2,716 bees that we collected in 2017-2019, only three were queens. We limited our sampling frequency to three times per year, and limited our sampling effort to 10 minutes of hand-collecting time and six pan traps, per garden. Even with these precautions, we are still faced with the question: does our research, or the research of others who collect and kill insects, harm the very species we are trying to conserve?

Water pan traps, used to collect garden bees and other small, flying insects. Insects are attracted to the color. When they land in the soapy water, they break the surface tension, drown, and die.

To address this question, I turn to the scientific literature. Gezon and colleagues set up an experiment to see whether lethal sampling for bees using pan traps and netting (the same methods we use in our research) has negative effects on bee abundance or bee diversity. For five years, they sampled nine sites every two weeks during the flowering season. They compared bee abundance and bee diversity in these repeatedly-sampled sites, to metrics from 17 comparable sites that were only sampled once. They found no significant difference in bee capture rate, bee species richness, or bee abundance between sites that were sampled repeatedly versus those that were sampled once. When they partitioned bees according to nesting habit (e.g. cavity, soil, wood, etc.), social structure (e.g. eusocial or not), and body size (e.g. small, medium, and large bees) they also found no significant differences in bee capture rates of single-sample versus repeat-sampled sites. They did catch more pollen specialists in repeated-sample sites than in single sample sites. However, the magnitude of the effect was relatively small, and did not represent a large change in catch rate between single-sample versus repeat-sampled sites. I suspect that the authors caught more pollen specialists at their repeat-sampled sites, because pollen specialists are fairly rare in time and in space. They drastically increased their odds of intercepting a pollen specialist on their repeatedly-sampled sites.

Gezon and colleagues suggest a few hypotheses that could explain why increased sampling effort had no significant effect on bee abundance or diversity. First, they suggest that reducing bee populations by sampling could benefit the bees that remain, by reducing competition for limited resources. If this is the case, bee populations can compensate for some losses due to sampling, by increasing reproduction in the bees that remain behind. Second, they note that if bees were sampled after they have mated and laid eggs, the overall impact of removing a bee from via sampling will be fairly small. Finally, they note that most bees are solitary, and that most solitary bees have short flight seasons. In this case, sampling every two weeks may not result in bee declines, if researchers are effectively collecting a new species during each sampling event.

I can breathe a bit easier. The data suggests that our research is not immediately responsible for documented bee declines. Still, I know that I can personally do more to help protect bees in my own garden. Even though our lab group studies native plants, I have not yet planted Aster subspicatus (Douglas’ Aster) in my own garden. This will be my mission for 2020: to find and plant this gorgeous perennial at home. In 2018 and 2019, it bloomed from mid June through mid November at our study plots in Aurora, OR, with peak bloom (75% or more of the plant in bloom) lasting one month! And, from 2017-2019, it was always a top five plant for native bee abundance. I give this Pacific Northwest native plant my highest recommendation for home gardens! There are plants that attract more native bees, such as Phacelia heterophylla. But, no other plant that we studied offers the triple threat of beauty, bees, and longevity.

Douglas’ aster (Aster subspicatus) is currently my favorite garden plant for bees.