Around the world, the animals that pollinate our food crops — over 20,000 species of bees, butterflies, bats and many others — are the subject of growing attention. An increasing number of pollinator species are thought to be in decline, threatened by a variety of mostly human pressures, and their struggles could pose significant risks for global food security and public health.
Until now, most assessments of pollinator health have been conducted on a regional basis, focusing on certain countries or parts of the world. But this week, a United Nations organization has released the first-ever global assessment of pollinators, highlighting their importance for worldwide food and nutrition, describing the threats they currently face and outlining strategies to protect them.
The report, which was released Friday by the U.N.’s Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), has been in the works since the summer of 2014. The research team consisted of more than 70 experts, who drew on the most up-to-date global pollinator science, as well as local and indigenous knowledge, to complete the assessment.
The report includes four overarching findings, said Simon Potts, deputy director of the Center for Agri-Environmental Research at Reading University, during a Friday press briefing. First, there are well-documented declines in pollinators, both wild and managed, throughout the world. Second, these pollinators provide society with a wide range of benefits. Third, they are threatened by a variety of factors. And fourth — and most importantly — there are still opportunities to protect them.
The importance of pollinators
The health of pollinator populations is intrinsically tied up with global food security, the IPBES assessment notes. Altogether, nearly 90 percent of all flowering plants on Earth depend on animal pollination, and that includes about 75 percent of the world’s food crops.
Keeping agricultural production high enough to feed the world’s ballooning human populations will depend in a big way on the insects and other animals that help them reproduce. The assessment reports that in the past 50 years alone, the volume of agricultural production that depends on animal pollination has increased by about 300 percent.
“Our nutritional security is intimately linked to pollinators, with many of our vitamins derived from pollinated crops,” Potts said. “So there is this kind of link between pollinators, crops and human diets and ultimately health.” Some of the most widely enjoyed crops that heavily depend on animal pollination include apples, cocoa beans, coffee and almonds.
And pollinators’ importance to agriculture means there’s a big economic factor to consider there as well. “The global market value linked to pollinators is huge,” Potts noted. The assessment finds that anywhere from $235 billion to $577 billion worth of global food production every year relies on animal pollination.
Additionally, many pollinator species have immense social and cultural value, Vera Imperatriz-Fonseca, co-chair of the assessment and an ecology professor at the University of Sao Paulo in Brazil, said at the briefing. She pointed out that many are “a source of inspiration for all of us in art, music, literature, religion and technology.”
So there are clear reasons to care about the fate of the world’s pollinators. The problem is that in many places, they aren’t doing so well.
Using data from the International Union for Conservation of Nature’s Red List of Threatened Species, the IPBES assessment points out that more than 16 percent of vertebrate pollinators on Earth — that’s mainly bats and birds — are threatened with extinction. Insects are a little harder to assess because there tends to be less global data about them. But regional studies have shown widespread declines throughout many parts of the world, especially among bees and butterflies.
“Using internationally accepted IUCN assessment criteria, there are some national red lists for bees which often have more than 40 percent of the species listed as threatened,” Potts said. He also added that there’s been only one continental assessment conducted, which studied bees and butterflies in Europe and found that 9 percent were threatened. Even this number is likely an underestimate, he added, given that approximately half the bee species on the continent could not be assessed due to a lack of data.
The declines are a concern for both wild pollinators and managed ones, which are kept by humans, the researchers are careful to note. Honeybees are the most common managed pollinators. And while overall the number of honeybee hives throughout the world has doubled in the last 50 years, certain regions — most notably Europe and North America — have experienced significant declines as a result of colony collapse disorder.
What’s threatening the pollinators — and how can we help them?
According to the assessment, there are a wide variety of factors affecting pollinators throughout the world, and it would be difficult to pinpoint one primary source of all the trouble.
Habitat destruction and degradation is one important source. Some species of pollinators can visit just about any type of plant they want — but others are much more specialized, and only feed on certain species. So having a high diversity of plants in any given area is important for attracting many different types of pollinators. Developing the land and cutting down on the natural plant diversity in an area can be a big problem.
Intensive agriculture, which focuses on only a few crops at a time, can be a contributor to this issue. And the use of pesticides has demonstrated harmful effects as well — an issue that’s recently come to the forefront of national attention in the United States. The Obama administration’s National Strategy to Promote the Health of Honey Bees and Other Pollinators, released by the White House last year, called for better scrutiny of the effects of pesticides on pollinating insects. And last month, the Environmental Protection Agencyreleased the first in a series of preliminary risk assessments of insecticides thought to be harmful to bees.
The U.N.’s assessment notes that the effects of pesticides depend on the type of chemical being used, the amount in which it’s applied and the type of pollinator that’s been exposed. However, the assessment does report that research has found a variety of lethal and nonlethal (but still negative) consequences of pesticide exposure in insect pollinators, mainly bees.
During Friday’s press briefing, the authors were quick to clarify that the report is not meant to be taken as a blanket condemnation of pesticide use. “We don’t provide recommendations,” Potts said. “Just really high-quality evidence based on what the available data says.”
Other factors thought to be affecting pollinators include disease and the influence of invasive species, which can compete with native species for resources. And climate change is becoming a growing concern, as well.
Many species have already been affected by the changing climate, said Jeremy Kerr, a biology professor at the University of Ottawa, who was not an author on the new assessment. Last year, Kerr was the lead author on a study published in Science which found that bumblebees in both North America and Europe have been shifting their ranges in response to climate change.
This kind of reaction is a concern because there’s a possibility that, over time, pollinators could shift their ranges out of reach of the plants they usually pollinate. And this is just one effect we’ll likely continue to see in the future.
“One of the other things that’s certainly an issue here in terms of individual species and the direct effect of climate on species … is the timing they have, or the phenology of these species — when they come out, when they do the things that they do,” Kerr said. Climate change can cause some species to emerge at different times of the year than they used to, for instance, or reproduce at different times. These kinds of changes could disrupt their seasonal interactions with the plants they pollinate.
With so many factors threatening the world’s pollinators, the looming question is whether anything can be done to save them. According to the new assessment, there are actually a lot of opportunities on this front.
Protecting natural areas and diversifying the landscape are obvious steps. The assessment suggests restoring native vegetation, planting flower corridors and trying to keep natural areas connected to one another as much as possible.
“Hospitable landscapes are ones where there are suitable nesting habitats for diverse pollinator species, and where consistent forage resources are accessible (within the flight range) of the bees throughout their flight seasons,” Neal Williams, an entomologist at the University of California Davis (who was also not an author on the new assessment), said by email.
The assessment also recommends more diverse and sustainable forms of agriculture — for example, utilizing organic farming practices, conducting crop rotations and allowing diverse communities of plants to grow alongside traditional farmland in order to attract and maintain pollinator populations.
More in-depth research will be necessary for a better understanding of the specific effects of individual pesticides, and governments may also consider coming up with strategies to reduce their pesticide use and develop more diverse pest management techniques, the assessment suggests.
And taking steps to minimize the introduction of invasive species, combat the spread of disease among pollinators and mitigate climate change are all crucial, as well. The biggest takeaway is that there are a huge variety of threats facing the world’s pollinators, and so proportional action must be taken to address each of them as soon as possible.
“The question for us as a society really, not just a science community, is can we walk and chew gum at the same time in terms of dealing with conservation solutions,” said Kerr. “Are we really only capable of doing one thing at a time, or can we manage habitats better than we do now, can we control our pesticide use so we’re just a little more careful than we are now?”
The answer remains to be seen, and will likely depend on the coordinated actions of individual governments. But there’s much to be optimistic about, according to the assessment’s authors. The report was agreed upon by the more than 100 countries belonging to IPBES, which demonstrates an international concern for the issue, they pointed out at Friday’s briefing. The role of IPBES, and its report, is to strengthen the dialogue between the scientific community and policymakers, said IPBES chair Zakri Abdul Hamid.
“We wanted the government to be moved to take action, and that’s what it’s all about,” he said.
Maj Rundlöf, a project coordinator from Lund University, summarizes the results from the field study focusing on the influence of the neonicotinoid clothianidin on several species of bees. (Johan Nyman/Lund University)
