Pollinators & the City

image: Samantha Gallagher via Bee Safe Alexandria

image: Samantha Gallagher via Bee Safe Alexandria

Saving Native Bees to Save Diversity

Bees are one of nature’s biggest celebrities. They have been on the cover of Time magazine, written about in The New York Times, and featured in multiple documentaries with various celebrities. And there is good reason for it. Bees are responsible for the pollination of the majority of foods, including almonds, blueberries, avocados, and watermelons, as well as the pollination of many flowering landscape plants. Bees are a keystone species, and we need to rehabilitate their populations or face a serious change in the composition of our landscape and meals…which is not something I take lightly. Take away blueberries and avocados and I would have an anxiety attack. But my work is about much more than just saving the bees. It’s about biological design as everyday practice. It’s about changing policy and education to support the creation of living landscapes and not monocultures. It’s about diversity on all scales of life because diversity attracts diversity. And it all starts with bees.

In the United States, the non-native honey bee is most relied upon for pollination, especially for crops, but honey bees have encountered many setbacks. According to a 2007 report published by the National Research Council’s Committee on the Status of Pollinators in North America, “Over the past 58 years, domesticated honey bee stocks have declined by 58% in the United States.” The lack of diversity in pollinators makes it easier for our agricultural and landscape systems to fail.

Relying upon on one main pollinator is comparable to our reliance upon one major energy source. Lose the main player and many related systems fail along with it. Luckily, the future of US food and plant supplies do not have to rely solely on honey bees. There are thousands of other bee species in the US that can fill the pollination gaps left by dwindling non-native honey bee stocks. These bees are broadly referred to as native bees.

Native bees of Eastern North America image: © Clay Bolt | claybolt.com | beautifulbees.org

Native bees of Eastern North America
image: © Clay Bolt | claybolt.com | beautifulbees.org

There are about 4,000 native bee species in the United States, each with different pollination methods and plant specializations. There is only one species of European honey bee and it is limited in its plant interactions. Michael Warriner notes that “In some cases, just over 200 native bees can do the same level of pollination as a hive of honey bees containing over 10,000 workers,” (Warriner, 2012). Native bees are more efficient pollinators than honey bees, too: “Many native bee species are more effective than honey bees at pollinating flowers on a bee-for-bee basis,” (Mader et al 2010). Honey bees operate at 72% efficiency, while native bees operate at 91% efficiency (Winfree et al, 2007). Also, native bees are active for more hours in the day and more days in the year than honey bees (Winfree et al, 2007).

Not only are native bees great for pollination, but they are safer around humans, too. Honey bees are social and live in a colony. Their life is dedicated to the hive and they will do anything to protect it, which is why they sting. In the United States, 75-90% of native bee species are solitary, not social, nesters (Shepherd, 2003). Solitary nesters are much less likely to sting, and only female native bees have stingers. Solitary bees do not live in hives, either. They live in bare ground patches and soft wood burrows.

Unfortunately, these solitary bees do not produce honey, but their value as pollinators is undeniable. If native bees are so great, why aren’t they being used for pollination efforts on a large scale already? The edge that honey bees have over native bees is that we can attach a dollar amount to honey bees’ ecosystem services for both honey and pollination. Having a hive makes them portable and quantifiable. Apiarists can charge a flat rate per hive and know how much area a hive can pollinate and roughly how much honey that will result in. Native bees are not as portable because they live “randomly” in the ground or in wood, but that also means you will have pollinators available all year long instead of only when a hive is rented.

Native bees have simple needs: they require food year-round and bare ground or a soft wood patch to live in. Honey bees require transport, which uses fossil fuels and weakens their immune systems. They also require regular maintenance of their hives. It has even been said that since native bees are not treated with chemicals like honey bees are for the very destructive varroa mite, their populations are much more stable because all the susceptible populations have died off. Chemicals have kept susceptible honey bee populations alive and reproducing. On a surface level, honey bees make sense in the context of a capitalistic society, but the fact is, native bees cost next to nothing, are better pollinators, and have more stable populations. It is time to shift our mindset from short-term to long-term solutions, from linear measures to closed loop systems.

Overall analysis image: Danielle Bilot

Overall analysis
image: Danielle Bilot

The biggest physical barrier to increasing native bee populations is the paucity of suitable habitat that meets the life cycle needs for bees. I assessed the life history of native bees and identified two scales of interventions necessary to sustain their populations: a planning scale that supplies a sufficient distribution and proximity of habitats and a site scale that provides the necessary plant composition and ratio of nesting to foraging elements within identified habitats.

Without proper habitat dispersal, we will create populations sinks. The problem is not ‘If you build it, will they come?’, it is rather ‘If you build it, can they leave?’. We have focused on site scale interventions when we should be concerned about dispersal of adequate habitat. In the end, I developed a transferable framework that provides a set of performance-based guidelines for planners to select, prioritize, and design (urban) sites to support a wide range of native bees and other pollinators as well.

Flight categorizations image: Danielle Bilot

Flight categorizations
image: Danielle Bilot

I focused on creating native bee habitat within urban areas because cities possess less barriers than rural agricultural lands. The main life cycle needs of native bees cannot be met within our current agricultural context, especially because of the high use of pesticides/insecticides. The framework I created can be easily applied to a variety of situations, but we need to save the bees now and cannot wait for an overhaul of our agricultural system.

Urban areas have their own challenges in creating integrative biological solutions, but cities are in a unique position to create a safe haven for pollinators because of the quantity and dispersal of underused land use types. Roadside strips, medians, surface parking lots, etc. all possess great potential to contribute positively toward natural ecosystems, but currently most hold very little ecological value. We have forgone diversity in the urban landscape for ease of permitting/maintenance, mass plant production techniques, and over-manicured aesthetics.

Distribution circles for Houston, TX image: Danielle Bilot

Distribution circles for Houston, TX
image: Danielle Bilot

Currently, I am working on the education, policy, and implementation aspects of my thesis while also working at a private design firm. I am lucky to be at a firm that supports my work. I had a meeting with the Mayor’s Office in Houston and they have agreed to issue an executive order on pollinators and the use of pesticides and insecticides in the city. I will also be working with the planning department to change the list of allowable parking lot and median plants to include beneficial plants to pollinators.

Since I have focused on distribution strategies, I’ve begun to take connectivity to a national scale by being part of an advisory committee that is providing legislative recommendations to the federal government for the creation and maintenance of pollinator habitat. Our solutions have to be transferable and account for many things, including time, money, and safety. Policy is an outlet where we can create wide-spread change by requiring land owners to take ecological responsibility instead of only suggesting it. It is a very different realm of practice that I am excited to have an impact on.

Existing vs. proposed parking lot image: Danielle Bilot

Existing vs. proposed parking lot
image: Danielle Bilot

Mahatma Gandhi said, “Be the change that you wish to see in the world.” My pollinator designs largely represent what I want to see change in the world: a greater focus on native and local, ecological and political support for diversity on all scales of life, and promotion of activity instead of passivity. It’s time for change and if not you, then who?


Mader, E., Vaughan, M., Shepherd, M. and Black, S. (2010). Alternative Pollinators: Native Bees. ATTRA – National Sustainable Agriculture Information Service. Accessed from January-June 2012.

Shepherd, M., Buchmann, S., Vaughn, M., Black, S. (2003). Pollinator Conservation Handbook. Portland, Oregon: Island Press.

Warriner, Michael D. (2012). New Bumble ID Graphic and Upcoming Article. Retrieved from Texas Bumblebees.

Winfree, R., Williams, N., Dushoff, J., Kremen, C. (2007). “Native Bees Provide Insurance Against Ongoing Honey Bee Losses.” Ecology Letters, 10, 1105-1113.

by Danielle Bilot, Associate ASLA

11 Responses to “Pollinators & the City”

  1. Suzan Hampton Says:

    This is both fascinating and encouraging: a great go-to to justify beneficials as valid plant choices for urban sites. Comment: I wonder about the population stability of native bees over the past 58 years. Since they’re still around, it would appear they’ve developed resistance to many commercial ag pesticides. If that’s true, a rural as well as an urban case could be made to nurture their populations’ health. Question: as the population of non-native honeybees has declined, has the population of native bees risen? In other words, if the efforts to “save” the non-native honeybee are effective, will they crowd out some species of native bees to extinction? Idea: your point about the ability to quantify the cost/benefit of fostering honeybee productivity is spot-on. If we can measure it and make money at it AND it’s good for the environment, it’s a win/win/win. Is there any possible way to do that with one of these native bee species? That species could then be a “poster child” to get people to pay attention to all the native bee populations. GREAT article!

  2. Lisa Cowan, PLA, ASLA Says:

    Danielle, Excellent article and thank you for posting! Great insights that landscape architects should be aware of as we engage in discussions on creating and supporting habitats for a diversity of pollinators!

  3. Matthew Shepherd Says:

    This is a great article and an excellent project! Urban areas have a lot to offer bees and other pollinating insects, From community gardens in New York to suburban greenways in Oregon, patches of vegetation and flowers can support a surprising diversity of bees. If you are looking for more information, the Pollinator Conservation Handbook mentioned as a reference is a good start. That book is still available used but there is a new and better book — also from the Xerces Society — that is widely available: Attracting Native Pollinators (Storey Publishing, 2011).

    Suzan Hampton asks about competition between honey bees and native bees. Whether one is pushing out another is something that will be debated. The reality is that any action taken to support bees will help all bees. The honey bee will remain a key part of our farming systems, so ensuring healthy hives is important. Native bees will supplement managed honey bees as crop pollinators and are essential for our natural areas. Creating more habitat, whether at ground level or twenty stories up on a green roof, will provide more foraging resources for our bees, whether native or managed.

  4. brvogt Says:

    Freaking fantastic piece. Finally, someone puts it all together in a lean yet powerful appeal. Thank you.

  5. Pollinator Says:

    Glad to see this, especially in contrast to the article about too many honey bees in the city. Many people think, erroneously, that honey bees are the entire answer to pollination problems.

  6. Elke Says:

    Thank you Danielle for posting an inspiring article. As a landscape architect, arborist, beekeeper and native bee hive breeder in Australia, this is a very pertinent article about ensuring we include a wide variety of beneficial and pollinator plants for a wide range of insects as our street tree plantings.
    The details for Australian plants and Australian native bees are different, but your U.S strategy is largely the same and will include our local councils to get on board.

  7. Polly Furr Says:

    Thank you, Danielle, for your fine work, and for letting us know about it. I am glad to be corrected in my limited thinking about the demise of the non-native honey bee. And Matthew Shepherd, I will be look up the book you mentioned, to ensure that we are doing everything we can in our landscape architecture office to take provisions for native pollinators into account in our design work.

  8. Phyllis Stiles Says:

    Wonderful article! Many thanks for articulating the reason we launched Bee City USA in 2012. To date, 5 cities have been designated: Asheville, Carrboro and Matthews, NC, and Talent and Ashland, Oregon. Our mission is creating pollinator awareness and enhancing healthy, native floral rich habitat as free of pesticides as possible. Each designated city brings the passion of its citizenry to the cause which has been sanctioned by city leaders and staff through the Bee City USA application process. Our goal is growing this network so that we can teach each other about “bringing nature home” as Doug Tallamy says. The application process is explained at http://www.beecityusa.org.

  9. Creating a Native Bee Apartment | EARTHeim Landscape Design Studio Says:

    […] Pollinators in the City- by the American Society of Landscape Architects […]

  10. Joe Fowler Says:

    Tell me about Bee City USA. We are in the beginning stages of planting utility right of way for pollinators.

    • Phyllis Stiles Says:

      Thanks for your interest Joe! We are now up to 19 certified Bee City USA communities and 12 Bee Campus USA institutions. With our help, Toronto started Bee City Canada in April. So the movement is definitely catching on. We would love to hear more about your utility ROW work. What an opportunity for pollinator habitat across the country.

      You can read all about our certification process here: http://www.beecityusa.org/heres-how.html. We think the most impactful part of the program is that each city/county must reapply for certification each year and report on what they did the previous year to make their community safer/friendlier for pollinators. Last year’s reports are posted at http://www.beecityusa.org/certified-cities.html#/news/. Our goal is to foster a network of cities that teach each other how to transform our communities to be more PC–pollinator conscious. In fact, we have monthly conference calls with city representatives for sharing.

      Each city starts at a different place, but each brings its own resources to bear. Most importantly, they are making a long-term commitment to changing their landscaping paradigms from both the policy and practice levels, and addressing both public and private land.

      Our mission is to make considering the pollinators in landscaping decisions the norm rather than the exception. It will take transforming how every cog in the process works (which we already see happening)–what nurseries are growing (more natives!) and how they are using pesticides (or not); what retail nurseries are offering customers and telling customers (they probably have more influence over plant selection decisions than anyone else); how our land grant universities are educating horticulturists and the message their cooperative extension agents are giving their communities about pesticides and plant selection; the recommended species lists cities give to developers…

      Utility rights of ways and roadsides offer millions of acres of potential life-giving and important highly visible demonstration pollinator habitat. Kudos on your work. You can reach us at beecityusa@gmail.com if you’d like to talk further.

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