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Before Two Degrees: Diagnosing the Pollinator Problem

By Savannah Miller, GWC guest blogger

Imagine the Rocky Mountains as you would the human body. Think of the organs as the slopes, meadows, valleys, and forests, and the heart as the snow-packed peaks, feeding the landscape with snowmelt through its arteries—the Rio Grande, Yellowstone and Saskatchewan. But it’s our necessary warriors, the pollinators, that act as capillaries in every vein. They are responsible for assisting between 75 percent to 95 percent of all flowering plants on Earth. This includes 75 percent of our entire food supply. Despite their ecological significance, mobile nature and resiliency, bee populations are dwindling. And fast.

A Black-tailed bumble bee, (Bombus melanopygus) flies in front of the Golden Gate Bridge.

A Black-tailed Bumble Bee (Bombus melanopygus) flies in front of the Golden Gate Bridge. (Photo by Clay Bolt)

Bee populations are faced with the growing impacts of climate change, which exacerbates present threats of pesticide usage, land-use change, and emerging parasites and pathogens. The dramatic decline of wild bees’ species richness over the last 50 years, as well as their steady population decline, has catalyzed much-needed research in the field. Most critically, researchers are trying to understand how climate change influences the behaviors and habitats of pollinators—and those effects on the plants they pollinate, many of which humans depend on. The most-feared scenario, where plants and pollinators find themselves in the “wrong place” at the “wrong time” due to changing temperatures, would pose severe repercussions for biodiversity and food security. Avoiding this scenario is a must.

Does The Early Flower Get the Bee?

At the Rocky Mountain Biological Lab, Rebecca Irwin of North Carolina State University, Zak Gezon of Disney’s Animal Programs, and David Inouye of University of Maryland have spent the last eight years collaborating to understand the bees this Colorado region and, more recently, how bees and their flowering plants respond to climate change. In Colorado, recent warming trends have caused plants to repeatedly flower earlier than normal.

“We’re talking about something that’s a plant, an autotroph; and a bee, a heterotroph,” Irwin says. “The question is: will these two different things respond to climate change in the same way? Are they using the same cue to emerge? If so, are they responding at different rates?”

Gezon and Irwin’s research used two different experiments to alter the blooming patterns of the Rocky Mountains native spring herb Claytonia lanceolata. In one experiment, they induced flowering in a greenhouse at different times before returning plants outside in experimental arrays.

A female leafcutter bee (Megachile subgenus Megachiloides sp), returns to her nest with a small circular piece of leaf which she'll use to line the nest of her young. Pickens, South Carolina.

A female Leafcutter Bee (Megachile subgenus Megachiloides sp) returns to her nest with a small circular piece of leaf which she’ll use to line the nest of her young. (Photo by Clay Bolt)

Irwin and Gezon found some surprising results in their recent experiments pushing plants to flower early: “We do see that bees are there, ready and waiting, and so I think there is an opportunity for some pollination mutualisms to withstand earlier flowering times as long as climate change is not that severe in the short term.”

Timing, however, isn’t everything. Even though pollinators appeared during early conditions, the bees may remain victim to more frequent extreme weather events, also associated with climate change.

A central bumble bee (Bombus centralis) pollinates wildflowers in the Bridger Range, Bozeman, Montana.

A Central Bumble Bee (Bombus centralis) pollinates wildflowers in the Bridger Range, Bozeman, Montana. (Photo by Clay Bolt)

Gezon and Irwin’s research also found early bloomers to be increasingly more vulnerable to severe frost events, resulting in fewer flowers. The wicked problem is this: fewer flowers due to extreme weather means less food for the bees, and less food means less bees, and less bees mean less pollination for surviving plant species.

And the cycle continues.

So, even if a “forced spring” may not be a major issue right now, Gezon and Irwin found that the abundance of floral resources did drop dramatically after frost events.

Gezon compares the current situation to Jenga. “You can lose a few more bricks, and the structure will remain standing. But it doesn’t take a lot to knock those bricks down.”

The Gaps That Remain

Researcher Hollis Woodard of the University of California, Riverside now finds herself working in one of the frontiers of bee research, the Arctic region of the upper Fairbanks. She found an incredible lack of data about the prevalence of bees in the area, especially related to the bumble bee Bombus polaris. According to Woodard, researchers have much to learn about both the extent and consequences of pollinator declines, especially as our ecosystems continue to change so dramatically.

Bee on chives. (Photo by Allan Harris via Flickr Creative Commons)

“There is growing evidence that global warming is leading to a phenology mismatch,” Woodard said. “But to really understand flower phenology within the Arctic, you need multiple years of data collection to see how things are shifting. Ultimately, it will take many years to do that.”

Woodard stresses how much remains unknown, and the need for a balancing act between research and action. Researchers are still grappling to understand how temperature changes will impact not only bumble bees’ ability to pollinate, but also their complex social structure, their biology, and individual behaviors. And despite bumble bees’ big personalities, they represent a small fraction of the world’s 25,000 bee species in need of extensive research.

Metallic Green Bee (Augochloropsis metallica) collecting nectar and pollen from a Black-eyed Susan. (Photo by Clay Bolt)

“We need to collect more and more information,” Woodard says. “But that doesn’t mean we can’t also act now. People need to continue studying how climate change, pesticide usage, etc., is impacting the bees. That doesn’t mean individuals can’t also make decisions now on how to limit their own use of pesticides. This middle ground is necessary because the clock is ticking.”

The Power in Your Hands (And Backyard)

No matter the uncertainties, there is consensus that wild bees are subject to multiple interacting stressors driving their decline. President Obama responded to growing concerns by implementing the Federal Pollinator Health Task Force in June 2014. However, wild bee populations won’t rebound in the White House. Real solutions are found in our own communities, backyards and balconies.

Photo by Tim Berberic via Flickr Creative Commons

“It’s important to focus on the everyday things that everyday people can do to conserve pollinators,” Irwin says. “For example: ‘once a week I’m going to bike to work or use public transit as an effort to reduce fossil fuels use,’ or ‘I will continue to plant native wildflowers.’ If everyone tries to do something, this combined effort will make a big difference.”

Here are a few more at-home suggestions for pollinator progress:

  • Reduce cosmetic use of agrochemicals in your yard. It’s critical to limit or eliminate your use of agro-chemical pesticides. When stressing this tip, researcher Berry Brosi reminded me of the 2.5 million honey bees recently killed in South Carolina due to pesticide spraying.
  • Honey bees are important pollinators for many agricultural crops and for the production of honey. However, honey bees are non-native species, and Irwin emphasizes that people should consider strategies such as pollinator-friendly gardens to promote native been conservation.
  • Plant native wildflowers sourced from local nurseries. Many bee species are specialists and this is one of the best ways to ensure food for a variety of bees.
  • Don’t fret over the grass! Provide a yard with some bare patches so ground-nesting bees can easily excavate holes.
  • And lastly, support with your fork! Brosi noted how beneficial local farming plots are to wild bee nests and nutrition, and that choosing local, organic staples also means prioritizing our pollinators.

Through the developing research of Gezon, Irwin and Woodard, and so many others, we find that our bees are often resilient to an earlier spring season. However, this is one piece of the puzzle. As we find with our own health, any strain can have its repercussions. For the bees, this can include more frequent frosts, floral die-offs, glacial melt or heat waves. The doctor is in, thanks to an impeccable team of researchers, but the full diagnosis remains unresolved.

Top photo: Fuzzy-legged Leafcutter Bee. (Photo by Clay Bolt)

Before Two Degrees
The Before Two Degrees is a series by environmental advocate Savannah Miller and GWC associate director of communications Lindsay Renick Mayer that examines the inextricable link between climate change and wildlife extinction through the stories of those most at risk. Read the series introduction and first installment about how climate change is exacerbating threats to amphibians in the Neotropics.

About the Author

Savannah Miller

Savannah Miller

Savannah Miller is an environmental advocate looking to make a difference through communication, collaboration and policy. As founder of the web domain www.sustainable-directions.com, Savannah intends to engage her generation in climate change science through what she calls the “millennial environmental literacy project.” Her content is largely pulled from her fieldwork in Sub-Saharan Africa, Peruvian Amazon and, most recently, Antarctica with the 2041 Foundation. In addition, Savannah is currently pursuing her Masters in Public Administration within environmental sciences and policy at Columbia University’s School of International and Public Affairs and The Earth Institute. Savannah holds a dual degree in environmental sciences and creative writing from Emory University.

Comments

  • Nick Howe

    Hi Savannah,

    Very nice article. I was curious though where you got the “75% of our entire food supply” statistic from? Certainly a lot of food we grow is dependent on pollinators, but the majority of our food supply comes from staples such as wheat and rice which are wind pollinated. 35% from Klein et al., 2007 http://rspb.royalsocietypublishing.org/content/274/1608/303, is the estimate I normally use.

    The article addresses some important things about phenological mismatch. The research you talk about only really considers things from the plant side, climate change will likely have an impact on pollinator’s overwintering, for more info: http://jeb.biologists.org/content/213/6/980.short. In bumblebees we’ve seen as well that they sometimes don’t overwinter http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0009559, which could negatively effect them as they may not be able to survive winter http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0080061.

    Thanks again for a good article!

    • From Savannah Miller: Thank you for this commentary. I’d like to first address the question regarding 75%. I sourced my number from the 2016 assessment of a two-year study conducted by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), and my miscommunication may lie in the IPBES’ determination that 75% of the world’s food crops depend at least in part on pollination. I apologize if this aspect was not fully clarified in the article. Secondly, thank you for your comments on phenological mismatch. Yes, this piece focuses largely on pollinators’ response to plant repercussions due to climate change, but it by no means limits concern to this aspect alone. Bee behavior is incredibly nuanced and complex, only re-emphasizing the urgency to research bee populations to better understand how these species will be personally impacted by climatic changes. Thank you again for your questions and comments!

  • Lindsay Renick Mayer

    From Savannah Miller: Thank you for this commentary. I’d like to first address the question
    regarding 75%. I sourced my number from the 2016 assessment of a
    two-year study conducted by the Intergovernmental Science-Policy
    Platform on Biodiversity and Ecosystem Services (IPBES), and my
    miscommunication may lie in the IPBES’ determination that 75% of the
    world’s food crops depend at least in part on pollination. I
    apologize if this aspect was not fully clarified in the article.
    Secondly, thank you for your comments on phenological mismatch. Yes,
    this piece focuses largely on pollinators’ response to plant
    repercussions due to climate change, but it by no means limits concern
    to this aspect alone. Bee behavior is incredibly nuanced and complex,
    only re-emphasizing the urgency to research bee populations to better
    understand how these species will be personally impacted by climatic
    changes. Thank you again for your questions and comments!