Habitat Loss and Pesticides

Karen Edmundson Bean is a nationally published freelance journalist specializing in science and the environment. She is also an award-winning producer/writer/cinematographer of natural history and backcountry videos (www.walking-wild.com) and one of the few women to hold director of photography status in the International Cinematographers Guild. Her farm in Maple Falls is home to her cashmere goats, Shetland sheep and, of course, honeybees.

Part 2

It’s ironic that the worldwide decline of pollinators is, in part, due to the actions of people who most understand the value of bees: farmers and agricultural corporations. Honeybees are big business. They transport the pollen that fertilizes the crops that are sold for money — lots of money. In the United States, the value of food crops that depend on honeybee pollination was estimated to be over $14.5 billion in 2000. That was up from $10 billion just six years earlier.

Farmers know they need pollinators, and they pay for them. Plum growers paid almost $6.5 million in 1999 for the rental of bees. In 2006, California almond growers paid over $140 for each of the approximately one million hives that were placed in their groves. For these growers pollination is not an option, it is a necessity.

California’s almonds are a $1.2 billion crop, comprising nearly half of all the almonds in the world. Without pollination, however, an almond tree is simply a shade tree — no nuts. There are over half a million acres of almonds planted in California. If all the bees in that state were put to work in the groves, there would not be enough bees to pollinate all the trees. The need for pollinators and the price paid for hives brings beekeepers from all over the United States to California’s almond groves each year.

Migratory beekeepers follow the flower bloom for orchards and fields throughout North America. The almond bloom of February starts the year for many beekeepers. Some then travel north to Washington state for pollination contracts in the apple, pear and cherry orchards. Over a quarter-million hives are needed to pollinate fruit trees in the Pacific Northwest. Others head for other orchards or fields of vegetables, clover and alfalfa.

Pollination contracts are now the primary moneymaker for commercial beekeepers. “It used to be that beekeepers used pollination to offset expenses and their money was from honey,” explains Dr. Steve Sheppard, who holds the Thurber Chair of Apiculture, Department of Entomology, Washington State University, Pullman “[Beekeepers] made probably 40 percent of their income from pollination and 60 percent from honey. Now it’s more like 70 percent pollination to 30 percent honey.”

The majority of pollinating bees are honeybees. Native bees pollinate some commercial crops, but in most cases these natives are managed by beekeepers. Native beekeeping is a growing business in the United States.

The native orchard mason bee and the bumblebees are suited for managed, commercial pollination. Orchard mason bees are increasingly used for orchard crops and in home gardens. Bumblebees are able to pollinate a wide variety of crops from sunflowers to cucumbers.

Tomatoes are particularly dependant on bumblebees for pollination. Tomato flowers need a little motion to be pollinated correctly. Bumblebees know how to shake it. They vibrate their thorax as they grasp the tomato flowers and this releases the pollen. Honeybees just don’t vibrate. Regardless of the type of native bee used in large-scale, commercial pollination, all are currently under the care of beekeepers.

On some smaller farms, the natives need only a little help from their friends. “In certain landscapes, natives can do and are doing the same job as honeybees, if you have a farm with enough habitat on it. We’ve looked at 250 acre farms where this works.” explains Mace Vaughan of the Xerces Society for Invertebrate Conservation. “The farms need a diversity of habitat in and around them. If you look at 250 acres of just blueberries or almonds or any single crop, there’s no diversity.”

Large farms and orchards tend to use monocultures — mile after mile of one single crop. Wildflowers are often dubbed “weeds” and eliminated. This is deadly to native pollinators who need a variety of plants that flower throughout the year. It doesn’t matter if the crops are fruit, vegetables, cotton or any other crop. In monocultures, all the flowers bloom at one time, and usually for only a few weeks. After the bloom there is nothing left for the bees to eat and harvest. To remain in the area is to starve.

Honeybees and managed natives are packed up at the end of a bloom and driven to new locations. Wild natives and honeybees have no such help. The vast acreage of monocultures not only deprives wild pollinators of food and shelter, but it eliminates native plant corridors; without these corridors, the pollinators are unable to leave. With no food, no shelter and no way to exit, native pollinators cannot survive.

Farmers and corporate agricultural interests are aware that they would benefit from a resurgence of wild, free, native pollinators. “The successful growers, big and small, are smart people,” comments Vaughan. “They know what works. It’s just that the larger ones have a system in place and they want to see results before they change.” Vaughan looks to the smaller farms, some comprising 250 acres, to be the first examples of how a diversity of habitats can benefit farm production. “The small farmers and organic farmers have a drive for diversity. They are the early adaptors,” explains Vaughan. “We have to have those early adaptors.”

The Xerces Society, as well as other nonprofit organizations and universities, is also working on restoration projects in agricultural areas, and with small farmers to provide the results large scale agriculture wants to see. Near Sacramento, the Xerces Society has teemed with the Audubon Society, the University of California, Berkeley and the Natural Resources Conservation Service (NRCS) division of the United States Department of Agriculture to restore sloughs in agricultural areas with “specifically chosen plants that will mean an abundance of habitat.”

Vaughan explains, “My guess is that there’s going to be a nice benefit for farmers, but maybe not on the same level as honeybees. In certain situations the native bees can do it all but the honeybees are going to be the workhorse [of pollination].”

The use of natives for commercial pollination has an established history in the United States. The alkali bee, a solitary bee that nests in the soil of western North America, is a natural at pollinating alfalfa. In the 1950s farmers in the United States helped increase the number of alkali bees by creating habitat for them. The bees did well, and alfalfa seed production increased.

Twenty years later alkali bee populations began to fail. It’s suspected that pesticides used on nearby farmlands caused the decline in the bees. The U.S. alfalfa crop, worth $5 billion a year, now depends on the alfalfa leafcutter bee, a nonnative species. These imports fly in light rain and at lower temperatures than most honeybees.

The use of native bees for farm pollination is on the increase. Some small farms are already showing a benefit from a diverse habitat that provides a home for native pollinators. In other areas, habitat restoration is in the initial stages. It will be some time before it can be determined what impact native pollinators in these areas will have on large commercial agriculture. Plants must grow, then the native pollinators need to discover the area and become established before they can increase to the numbers needed for commercial crop pollination.

“It would take several years for the numbers to rebound in a restoration area,” Vaughan points out. “Then you’ve got to make sure the neighbors aren’t spraying pesticides. If the ‘weeds’ next door are sprayed, there go the pollinators.”

Pesticides, which include both herbicides and insecticides, affect all insect pollinators: natives and honeybees. Herbicides can endanger them by removing the plants’ pollinators’ food, shelter and nests. One of the leading herbicides in use in agriculture in the United States is glyphosate, which most gardeners know as “Round-Up” from Monsanto. It is used for a wide variety of crops from fruit orchards, to vineyards, to Douglas firs.

Washington’s Department of Natural Resources (DNR) uses glyphosate to kill all plants that appear after a clear-cut. “It kills what’s existing, but the plants will come back in one year,” says Allison Hitchcock, the regional silvaculturalist for the Northwest Region of the Washington DNR. “By the time they come back, the conifers have grown up and shade them out … . We use glyphosate as a broadcast spray; it’s the main workhorse of forestry.”

It is also one of the most deadly herbicides, absorbed only through the leaves and green stems of the plants it hits. It’s selective about its point of entry, but not to its physical location. Surrounding vegetation can be killed even though it grows 300 feet away from the plants targeted during a broadcast spray. It can effectively remove the food and habitat native pollinators and wild honeybees need for an entire season, possibly for the entire reproductive cycle of the pollinators. The wholesale elimination of native plants can have another detrimental effect for native pollinators: the introduction of invasive species, which offer no sustenance to native pollinators.

“If you want a prescription for nonnative weeds, nuke your natives,” comments Dr. Nan Vance, research plant physiologist at the Pacific Northwest Research Station of the National Forest Service. “What returns is not natives; you can get thistles and brambles.” The Forest Service has “backed off from herbicides nearly completely. We now spot spray for specific plants,” she explains. “There has been a paradigm shift, and now we’re back in balance.” That balance can benefit pollinators. Vance points out that post-WWII use of organophosphates was responsible for a 43 percent drop in bee populations. Glyphosate is an organophosphate.

Herbicides affect pollinators by removing the plants they need. Insecticides kill more directly, and they pack a double-punch since they kill on contact and can continue to kill long after the initial application. Pollen covered with pesticides or pesticides that are encased in microcapsules may be gathered and stored by honeybees for food — a fatal feast.

A sip of pesticide-laced nectar may spell a faster death for native and nonnative pollinators. If the toxins are weaker, the bees may still perish as pesticides can render them unable to fly, completely paralyze the bees, or cause honeybees to become disoriented and lose their way back to their hive.

“Some insect pesticides need to be sprayed when the flowers are in bloom,” says Craig MacConnell, Whatcom County extension agent, of the Washington State Department of Agriculture. “But there are ways to do this so the pollinators aren’t hurt … . It can be an insecticide with a short-term impact on pollinators — so they spray at night, so when the pollinators come in the morning it has no effect.”

“You can reduce your impact,” Vaughan agrees, “but even in that situation [night spraying] honey beekeepers keep their bees out of the fields. You have to apply at the end of the day and take into account the temperature, the humidity and a number of other factors the manufacturer states. Even then there are still going to be active compounds and most natives are smaller than honeybees and thus more affected by pesticides.”

Sometimes even the honeybees don’t escape. Pesticides, when combined with a breeze, have a long reach. Insecticides are usually not sprayed on crops in bloom, but the wind can carry their toxins away from the intended target, to nearby flowering plants where pollinators then harvest death along with pollen and nectar.

The Xerces Society points out that wind drift of insecticides can kill 80 percent of bees that are foraging nearby, and it can continue to be dangerous to pollinators more than a mile away. The death of honeybees due to pesticides over past decades drastically reduced the number of bees in some beekeepers’ colonies, and became one of the reasons for the decline of managed bee colonies in the United States.

In the 1990s, a microencapsulated pesticide, Penncap-M, was used to fight corn rootworm in Washington state, Colorado, Nebraska and North Carolina. Although bees and corn don’t usually meet because corn is wind pollinated, the winds blowing through cornfields carried the pesticide to nearby fields of flowering crops. Honeybees, who treat nearly anything pollen-sized on a flower as pollen, harvested the micropellets. When the toxic food was consumed, the result was a massive die-off of bees.

The toxic chemical Sevin was the culprit responsible in the deaths of thousands of honeybees in Minnesota in 1998. Sevin, a pesticide that can endanger more than 80 species, according to the U.S. Fish and Wildlife Service, had been sprayed on cottonwood trees in an effort to control leaf beetle. The Minnesota Department of Natural Resources and the International Paper Company both sprayed Sevin. What they failed to take into consideration were the nearby honeybees.

Nine years later, the Minnesota DNR paid out over $300,000 in an out-of-court settlement to beekeepers, and agreed to stop using Sevin. The Minnesota Supreme Court has now ruled that landowners who use pesticides on trees could be held liable for damages to beekeepers with hives in the area.

There are no laws that protect native pollinators. “That would only happen if they became a federally listed [endangered] species,” says Vaughan. The laws, rules and guidelines regarding pesticides, are aimed at honeybees. Pesticides have an even greater impact on native bees, due to the natives’ diminutive size and their already declining numbers due to loss of habitat.

Pollinators can be struck down by pesticides in the country and in the city. Arial spraying of medflies, gypsy moths and other pests can devastate honeybees and native pollinators. Urban gardeners apply vast amounts of toxins in their quest for pest-free yards. Surveys conducted by the United States Geologic Survey (USGS) have shown that streams in some urban areas carry more pesticides than streams in agricultural areas.

King County, Washington, which includes Seattle and Tacoma, was found to have more varieties of pesticides in its streams than were found in farm regions, according to a USGS study in 1997. Gardeners in the Puget Sound basin had the dubious distinction of applying more pounds of pesticides per acre than agricultural users of pesticides.

Nearly as devastating to pollinators as gardeners’ use of pesticides is the quest for the perfect green lawn. The elimination of dandelions and other wildflowers, often considered weeds, creates mini versions of the monocultures created in agricultural areas. Honeybees and native pollinators need sources of nectar and pollen to survive. Native pollinators also need a place to live. A rolling green carpet of manicured lawn provides no food, no shelter and no nest sites.

The loss of habitat and the use of pesticides have hit pollinators hard in both city and country over the last 50 years. Those same years have seen an enormous change in our society and way of life. The United States transformed from a rural environment to an urban landscape. Modern technology brought the world closer together with high-speed travel and international trade. It also brought new diseases and parasites that found a wonderful new host in the honeybees established in the western hemisphere. The next article in this series will take a look at that impact. §

Next Month: Diseases and Parasites Come to the Americas