Don’t Forget Butterflies! Our Pollination Crisis Is About More Than Honeybees
When President Obama signed an order last week creating a task force that will seek to promote pollinator health, honeybees grabbed the headlines.
“Obama announces plan to save honeybees,” CNN proclaimed. “White House creates new honeybee task force,” the Wire echoed. “White House task force charged with saving bees from mysterious decline,” the Guardian added, referencing the colony collapse disorder that contributed to the death of 23 percent of managed honeybees last winter.
But those headlines overlooked the most important part of the presidential order: it encompassed all pollinators, including birds, bats, native bees, and butterflies — not just honeybees. The memorandum will spur the creation, within the next 180 days, of a National Pollinator Health Strategy that will lay out ways for the U.S. to better study and better tackle the problems facing pollinators, both wild and managed. While the plight of bees has gotten deserved attention of late, many species of pollinators face the same threats: habitat destruction, climate-induced changes in flowering and weather patterns, and in some cases, pesticides.
Wayne Esaias, director of NASA’s HoneyBee Net, said that while his work involves using honeybee hives to track changes in nectar flow over time to see how climate change is impacting honeybees, the problems wild pollinators face worry him more than the plight of managed honeybees.
“Our natural ecosystems depend not on the honeybee for pollination, but on our native bees and native pollinators,” Esaias said. “And we hardly know all their names.”
Esaias’ assessment that the full spectrum of pollinating insects hasn’t even been identified is one part of a major weakness in the study of insect pollinators in the U.S., especially native bees. There are about 4,000 species of bees in North America, and about 400 haven’t been identified yet. That’s because there are only “a handful” of people who are familiar enough with bees to tell one species from another, said Sam Droege, biologist at the USGS’s Patuxent Wildlife Research Center and expert on wild bees.
“You can’t identify them on the wing like a butterfly,” he said. “A bee on the wing is a little black dot, and they move really fast, and a lot of those little black dots look essentially the same until you get them under a 60 power microscope.”
With managed honeybees, it’s easy to figure out how populations are doing. Honeybees — which didn’t exist in North America before settlers brought hives over from Europe — live in hives and are managed by beekeepers, so determining the percentage of bee losses that have occurred over the course of a year or a decade involves surveying those beekeepers.
Determining the status of thousands of species of native bees, on the other hand, is more complicated. Droege is trying to complete a survey of wild bees throughout the U.S., using biologists and citizen volunteers who put out red party cups full of propelyne glycol. The bees are attracted to the color of the cups and end up falling in and being preserved by the propelyne glycol. The volunteers then send the bees into the lab for Droege to identify. But being one of the only people qualified for this task makes the process of identifying the bees slow and creates a bottleneck in the research, Droege said.
CREDIT: Oregon Zoo/ Michael Durham
Another thing that makes identifying and tracking bees difficult is the lack of citizen engagement. There are four or five times as many native bee species in the U.S. as there are bird species, but bees lack that contingent of people who are passionate about going out into the woods, looking for bees and noting which ones they see. Essentially, there aren’t enough bee enthusiasts: the U.S. has a vast network of birders, but far fewer bee-ers.
“We know relatively little about bees compared to birds, where you have an amateur group who’s going out all the time and they’re eBirding and that type of thing,” Droege said. “There’s just no real amateurs group [for bees] because you have to identify them under a microscope and they have to be dead. So the biggest problem is that we don’t have that kind of boots on the ground look at where things are and where they’re not.”
But so far, Droege said, his survey trials have given him a good hold on the basics: what sorts of bees are present in the environment, which species are common and which are rare. But since the study is so new — and because there’s little previous data to compare findings to — he has no idea how these creatures are doing over time, and won’t until he’s able to collect about 10 years of data. That’s a problem, because unless a huge crash in a certain species happens one year, there’s no way to tell if of the species, particularly the ones that are already rare, are steadily declining.
A few years ago, Droege published a paper that conducted a survey of bee practitioners east of the Mississippi River to see what sorts of bees they had been seeing over the last few decades. In general, he said, it didn’t look like there was any sort of species disappearance or collapse. But the base information that came from the survey would be “unconscionable” if it had been used in a case for conservation for any other animal, meaning it wouldn’t work in a plea for bee conservation either.
“That’s the sort of primitive state where we can say common species are still around. Rare species, we don’t know,” Droege said. “We’re looking to gather more information of course, but the state of understanding is extremely poor.”
Bees, Butterflies, And Birds
There’s more known about certain species of bees than others, however. There are 46 species of bumblebees in North America and some are used in conjunction with commercial honeybees to pollinate crops. Scott Black, executive director of the Xerces Society, a group focused on invertebrate conservation, said one-third of the bumblebee species in the U.S. are at risk of extinction. Black said that the relatively low number of bumblebee species in the U.S. and their importance to crop pollination means there’s generally more data on them than there is for other kinds of bees.
And some of that data is troubling. A study last year found that three species of bumblebees have shown a “rapid and recent population collapse” from 1872 to 2011. Another study, from 2011, found that four bumblebee species have “declined substantially” over the last 20 to 30 years in the U.S. The suspected reasons for this decline have included parasites and shrinking habitat, as well as disease, which studies have shown can move from managed honeybees to native bees.
One species, the rusty patched bumblebee, is threatened with extinction. According to the Xerces Society, diseases from commercial bumblebees — part of a bumblebee industry that the group maintains is not sufficiently regulated — as well as other diseases, climate change, pesticides and habitat destruction have fueled declines in rusty patched bumblebee populations to the point where remaining populations are “small and isolated.”
Black said it’s important to understand the problems facing wild bees because, as honeybee populations struggle, the U.S. will be forced to look to alternatives for pollination. Bumblebees already pollinate blueberries, tomatoes and watermelon, and could possibly be used in conjunction with honeybees to pollinate more crops. But if bumblebees fall victim to the same diseases as honeybees, using them to boost honeybee efficiency won’t work.
But bees — or even invertebrates — aren’t the only pollinators that have seen some of their species decline.
Changes in weather have led to changes in butterflies’ flight seasons, which, depending on the species, begin either when butterflies emerge from hibernation in the spring or when the first butterflies of the season break out of their chrysalises. One study found that, with each degree Celsius rise in temperature, butterfly flight seasons start an average of 2.4 days earlier. In a warming world, this could have major implications.
“If they emerge too early, they could encounter frost and die,” said Heather Kharouba, lead author of the study. “Or they might emerge before the food plants they rely on appear and starve.”
Monarchs, whose larvae feed exclusively on milkweed, declined by 90 percent over the last two decades, from populations of more than 1 billion in 1997 to 33 million this year. Deforestation, removal of milkweed and changing weather patterns have all factored in to the butterfly’s decline.
Black said that among North American conservationists, the prevailing view is that many common butterfly species are in decline — but as with bees, lack of data is a problem when it comes to verifying that view.
“These are butterflies that people didn’t really think about because they saw them every day, and there were lots of them,” he said. “We don’t have clear data on this, but many many of the scientists I work with are very concerned that these broadly distributed, common butterflies are in decline.”
Broad-tailed hummingbirds, another pollinator, are facing similar problems. As springs come earlier, flowers are blooming earlier, too. One study found that glacier lilies, a main food source for hummingbirds, are blooming 17 days earlier than they did in the 1970s. That means that once the hummingbirds arrive in the Rockies after migrating from Central America, they sometimes miss the blooming of the lilies, which means there’s less food for them.
A Pro-Pollinators Future
But while honeybees — rather than bumblebees — may be grabbing headlines, Scott Black with the Xerces Society said overall, he isn’t as worried now about the public’s awareness on the importance of pollinators than he has been in the past. The plight of the honeybee is doing a lot to raise awareness of the importance for native pollinators, and is helping people clue into the fact that native pollinators might be facing similar problems to honey bees.
“I think in some ways, the honey bee decline, although terrible … has had a silver lining,” Black said. “If you had talked to people eight years ago, most of them would have had no idea how important a pollinator is. Honeybees have introduced people into the idea that pollinators are important, and the idea that pollinators are in decline.”
CREDIT: Sam Droege/Flickr
This momentum around pollinator health is something the Xerces Society is trying to take advantage of. In 2008, the group lobbied successfully to make pollinators a priority concern in the Farm Bill. The Farm Bill had already set aside money for farmers to engage in conservation projects; now, it provides an incentive for farmers to do things like add flowering landscapes next to and within their farms, to break up the monoculture and provide pollinators with fields in which to forage — fields that are disappearing largely due to agriculture and development.
So far, Black said, farmers have completed 120,000 acres of pro-pollinator habitat projects, and the pollinator clause made it in to the 2013 farm bill, too. Obama’s pollinator memorandum also singles out improving and enhancing pollinator habitat as a key area of focus, ordering agencies to, among other things, factor in pollinator habitat to restoration work and mandating that the Environmental Protection Agency “assess the effect of pesticides” on pollinators.
The Xerces Society also works to get certain insects on the endangered species list. Right now, they’re pushing for the Leona’s little blue, a butterfly that’s thought to have just a single population of 1,000-2,000 individuals in Oregon’s Antelope Desert, and the island marble butterfly. The organization has been successful in the past in creating conservation strategies for insects but, as always, the lack of information about many of these creatures is a stumbling block.
“There’s a lot more information about mammals and birds, and even in most cases about lizards and amphibians, than there are about many insects,” Black said. “So that’s number one — we’re starting with a deficit of information.”
The good thing about pollinator conservation, according to Black, is that while it’s going to take a lot more research and a lot of political will to protect the habitats pollinators depend on and to curb the climate change that’s impacting all creatures, people can help pollinators very easily themselves — and not just by sending a check to a pollinator-friendly organization. Planting flowering plants (ideally organic, so that the seeds haven’t been exposed to pesticides that can harm pollinators) and using natural forms of pest control in a garden (by doing things like attracting aphid-eating ladybugs to a vegetable garden) can help pollinators find safe food sources, which can help populations overall.
“It does not matter if you’re a farmer, whether you manage a park or wildlife area, or whether you have a tiny backyard, you can do something for pollinators,” Black said. “This is all around us and we can all take action.”
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