Pollinators in Peril

An Interview with a Crusading Entomologist

Pollination is the simple act of transferring pollen from one flower to another. And 90 percent of flowering plants in the world depend on insects or animals - like hummingbirds, bees, bats and flies - to facilitate this transfer. Without pollinators, these plants can't reproduce.

For three decades Buchmann has been studying pollinators, especially bees. In recent years he has become more than a scientist; he has become a leading advocate for the conservation of bees, butterflies, bats and other animals that help plants reproduce. In 1997, he co-wrote the book The Forgotten Pollinators and co-founded The Forgotten Pollinators Campaign with Gary Nabhan. Recently, he has founded a company called The Bee Works and is working closely with a new national pollinator conservation and education coalition called the National Pollinator Protection Campaign.

Recently, I talked with him about the scientific evidence pointing to a decline in pollinators and how home gardeners can help reverse the trend. Here is an edited transcript of that interview.

GSC: Are pollinators in decline?
Buchmann: I believe that they are. We have limited evidence in the U.S., because there's almost no baseline data. So we can study an area and find out how many and what kinds of bees and other insects are there, but we don’t know what was there 20, 40 or 100 years ago.

We do have good data on pollinator declines in other parts of the world. For example, bee losses have been documented in Europe; several bumblebee species have gone extinct in Britain and others are in decline. Britain is a nation of naturalists and gardeners and they do huge surveys (of animals, plants, insects etc.) and enlist the help of students and gardeners. So we know a lot about what has happened over the years and especially in the past decade.

In the late 1960's there were 5.9 million colonies of managed honey bees in the U.S., according to a Cornell University study. In 1995, there were 2.5 million colonies. Today, we likely have fewer than 2 million. This decline is due to two parasitic mites and the huge number of people who have left the beekeeping business.

There are incredible gaps in our knowledge of pollinators, especially in the tropics. But we’re learning more all the time. For example, Dr. David Roubik of the Smithsonian has been learning that Africanized honey bees and stingless bees (of the genera Melipona and Trigona) are really effective and important pollinators of coffee in Panama. And coffee is the second most valuable commodity in the world.

GSC: What is the difference between honeybees and native bees?
Buchmann: Honeybees were introduced to the U.S. during colonial times. They are important pollinators for many crops, but not for all.

Honeybees don't do a very good job with cucurbits (squash, pumpkins, etc.). They are also very ineffective with blueberries, cranberries, eggplant, tomato and kiwi. These plants require something called buzz pollination. This is when a bee turns into a little tuning fork and vibrates. These vibrations cause pollen to blast out of tiny holes in the flowers’ anthers. Honey bees can’t perform these floral buzzings, and other bees, like bumblebees, have to take up the slack.

There are about 21,000 to 25,000 known species of bees in the world. My guess is that there are really 30,000 to 35,000 species globally. Just in the U.S. there are 4,000 species. Some of these bees are generalists and go to a wide variety of species, others are very specialized.

Agricultural crops and wild plants depend on a wide variety of these native bees. For example, a couple of years ago in New York a lot of the pumpkin crop failed due to temporary population crashes of squash and gourd bees.

GSC: What are researchers doing to learn more about pollinator populations?
Buchmann: A lot of groups are trying to do specific site surveys to gather good baseline data so we can come back and see what happens in the future. Plus these researchers are finding new species all the time.

And we're still learning what pollinates different plants. In Arizona, I've published some of the only information on what pollinates the giant saguaro cactus and mesquite trees. If we don’t know about the pollination biology of our state flower or many widespread perennial plants, well then gosh we certainly don't know much at all about what's pollinating native wildflowers and other plants.

GSC: If pollinator populations continue to decline, how will that impact the average U.S. citizen?
Buchmann: We can thank a pollinator for every third bite of food we eat. All of the really fun stuff to eat, the spices and great flavors come from things pollinated by animals, especially by bees: including fruit drinks, coffee, vanilla, spices, a lot of fruit and vegetables, even some medicines.

Without pollinators we wouldn't be here. Pollinators are the ecological glue that keep our ecosystem running. Take them out of the picture and everything tends to fall apart.

GSC: What can home gardeners do to help?
Buchmann: Each of us can take small but positive steps that will make a difference. Planting the right plants will have an effect. In many hybrid plants the nectar and pollen has been selected out, so they have big, ruffly flowers with hundreds of petals, but the pollinators show up and ask where’s the nectar?

If you have large enough property, leaving dead trees or the odd dead branch is extremely important. Some species of bees like leafcutters and mason bees use holes left by wood boring beetles as nests. If you have any ditch banks or a few small areas of open ground, leave it open for native bees to nest in. These bees are safe pollinators, not prone to sting.

Also be safe and sane when using pesticides. This is vital. All pollinators are super sensitive to insecticides and some to herbicides. So be very careful if you use pesticides.

Also, bee condos (nesting blocks or straws) are an important way to get a viable population of bees in your yard. They're safe. Yes females can sting but only if you pinch them and grab them. Plus you can watch them coming and going with mud and leaves and making nectar or pollen foraging trips.

If you have any questions or comments, please e-mail: info@gardeners.com

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