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Wild bees are dying off and need to be protected — but not for the reasons you think

The western bumble bee, Bombus occidentalis, has one of the highest economic values to agriculture in the United States of any wild bee species. REUTERS/Stephen Ausmus/USDA/Handout via Reuters
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Few species have attracted as much nation-wide concern in recent years as the honeybee. A critical pollinator of the crops humans depend on for survival, honeybees — a non-native species commercially managed by humans in North America for the purpose of harvesting their honey — have been devastated over the past few decades by colony collapse disorder, a mysterious phenomenon that causes bees to suddenly abandon their hives. It’s thought to be brought on by a complex set of factors, including pesticides, parasites and other environmental influences, and has helped account for a 40 percent decline in commercial honeybee colonies in the past year.

With all the hubbub over commercial honeybees and how vital they are to pollinating crops, it’s easy to forget about their wild cousins — the hundreds of un-managed bee species that still buzz all over the world. Many of these species are either endangered or significantly declining, but until now it’s been a little unclear how important they are to agriculture. Now, a new study reveals just how big a role wild bees also play in pollinating crops, and offers some surprising insight into the arguments conservationists should and should not use when advocating for their protection.

In a paper published last week in the journal Nature Communications, researchers used data from 90 studies to examine the impact of 785 different bee species on crops across five continents. The scientists revealed that wild bees contribute $3,251 per hectare to the production of crops through their pollination — giving them essentially the same economic value as commercial honeybees. But there’s an important catch: Out of the hundreds of wild bee species flitting around the country, only two percent of them account for 80 percent of all crop visits. In other words, just a few species do almost all the pollinating that wild bees are responsible for and account for almost all of their economic value.

“That, to me, was a surprise — how few do so much of the work,” says co-author Taylor Ricketts, director of the Gund Institute for Ecological Economics at the University of Vermont. The news underscores the idea that wild bees may deserve just as much attention as honeybees when it comes to their impact on agriculture. But there’s another important underlying message to this revelation.

Conservationists often use the concept of “ecosystem services” to justify the protection of wild plants, animals and habitats. This is the idea that wild things can provide important services to humans that are often economically beneficial, and honeybees are often used as a prime example: By pollinating crops, honeybees make agriculture more profitable and help feed humans.

But this study shows that using this argument as a justification for expanded conservation measures doesn’t apply to most wild bees, since so few species are responsible for the crop pollination that benefits human agriculture. And if we only focus on this reasoning too much, Ricketts says, we run the risk of neglecting the needs of species that haven’t shown themselves to be economically important.

To complicate matters, the wild bees most in need of protection are generally species that don’t account for much crop pollination. This means conservationists need to come up with other ways of convincing policymakers that protecting wild bees — all of them — is the right thing to do.

“There’s more than just economic reasons to protect nature and the species in it,” Ricketts says. For one thing, species that aren’t pollinating crops are still pollinating other wild plants, which may be important to the larger ecosystem, creating food and habitat for other wild species.

In addition, there’s no guarantee that the species providing agricultural benefits now will be the same species providing them in the future. Different bee species may respond differently to environmental changes in the future, such as climate change, and some of the species that play an important agricultural role now may start to decline in the future, Ricketts says. Protecting all wild bee species now is a kind of economic investment: If some species start to die off, others will still be around to step in and take their place as key pollinators.

In some ways, wild pollinators have already made it to the national stage, Ricketts says.  Last month, the White House released its National Strategy to Promote the Health of Honeybees and Other Pollinators, which outlines strategies for conserving and protecting pollinators around the nation. While the document has a particular focus on honeybees and monarch butterflies, Ricketts says its suggestions — which include stricter regulations on pesticides and better natural habitats for insects — can be helpful to many species that don’t have a significant impact on agriculture. The same pesticides that are harmful to honeybees may be harmful to wild bees too, he says, and expanding gardens and wild spaces will only benefit all wild pollinators.

In the end, Ricketts argues, it’s important to address conservation issues from a variety of angles. Using only an economic-based argument for conservation may exclude many species, but using only moral arguments — the idea that we should protect wildlife simply because it’s the right thing to do — may not always hit home with policymakers. Presenting multiple reasons at the same time for protecting related species is, according to Ricketts, “a powerful way to make sure [the argument] connects to multiple interest groups and audiences.”