The Pollinator Quandary
Image © © Russ Ottens, bugwood.org
We couldn’t enjoy foods such as broccoli (pictured here) without the help of pollinators.
by Ron Skleney, Naturalist
Imagine preparing a grocery list that included apples, carrots, honeydew melons, eggplant, peaches, cauliflower, broccoli and raspberries. Then, imagine that your favorite store didn’t carry any foods pollinated by bees. You’d have quite a short shopping trip. In fact when one grocery store in Rhode Island removed (temporarily) all of its bee-dependent produce, the shelves of 237 of its 453 fruits and vegetables stood empty.
Bees, birds, bats, butterflies, flies, hummingbirds and some beetles are all considered pollinators. They fertilize plants by transferring pollen from one plant to another so new plants can develop, many that produce important sources of food for humans and animals. But drops in pollinator populations, bees in particular, are causing worldwide concerns. In the U.S. alone, bee populations have dropped by 25 percent since 1990.
“More than 85 percent of Earth’s plant species — many of which compose some of the most nutritional parts of our diet — require pollinators to exist. Yet we continue to see alarming declines in bee numbers," says Eric Mader, the assistant pollinator conservation director at The Xerces Society.
Aside from the effect they have on food supplies, bees also play an important role in the economy. According to a recent Natural Resources Defense Council report, “More than $15 billion a year in U.S. crops are pollinated by bees, including apples, berries, cantaloupes, cucumbers, alfalfa and almonds. U.S. honey bees also produce about $150 million in honey annually. … But fewer bees mean the economy takes a hit: The global economic cost of bee decline, including lower crop yields and increased production costs, has been estimated at as high as $5.7 billion per year.”
Bees face threats such as habitat loss, climate change and competition from nonnative species, but some researchers are particularly concerned about a new class of insecticides called “neonicotinoids” or “neonics.”
Neonics are long-lasting compounds absorbed by the vascular systems of plants. Farmers can spray them on crops, but today, most corn and soybean crops in the U.S. are grown from neonic-treated seeds, which means the insecticide is present throughout the plant, including the pollen and nectar.
If neonics do not kill bees outright they do so over time by impairing the insects’ ability to navigate to pollen sources and efficiently return to the hive. This means that the bees use more energy looking for pollen but ultimately find less.
Another problem with neonics is that they don’t stay where they belong. According to a July 2014 U.S. Geological Survey study of the Mississippi and Missouri rivers and seven other rivers and streams that receive runoff from most of Iowa and parts of Minnesota, Montana, Nebraska, North Dakota, South Dakota and Wisconsin — states with the highest uses of neonics in the nation — neonics were present in all nine waterways.
Neonics may also be affecting farmland bird populations. The American Bird Conservancy reports a decline in swallows, swifts, martins, flycatchers and other insectivores, which catch prey as they fly. Habitat loss, intensive agricultural practices and other human activities are definite causes, but the widespread use of insecticides that indiscriminately target the insects these birds rely on for food also play a part.
The European Union has placed a two-year moratorium on three of the most popular neonics, but in the U.S. parties on different sides are at the beginning of the debate. In the meantime, the National Wildlife Federation and the Xerces Society offer some steps that we all can take to create favorable conditions for bees right in our own backyards.
Provide pollen and nectar.
Active from early spring through late fall, bumblebees need access to a variety of nectar- and pollen-producing flowers so food is available during all stages of the insects’ life cycle. Native plants are best because they have coevolved with indigenous bumblebees.
Provide nesting sites.
Most bumblebees nest underground in holes made by larger animals; others nest in abandoned bird nests, grass tussocks or hollow logs or under rocks. They may use compost piles or unoccupied birdhouses.
Protect hibernation habitat.
Because most queen bees overwinter in small holes on or just below the ground’s surface, avoid raking, tilling or mowing your yard until April or May. If you do need to mow, do so with the blade set at the highest safe level.
Avoid using insecticides and herbicides. In particular, steer clear of systemic pesticides such as neonicotinoids, which are taken up by the vascular systems of plants. See more information about neonics.
Courtesy of Whole Foods Market