Habitat loss a big buzz kill for B.C.’s wild bees

That’s one of the recommendations of SFU biologists Elizabeth Elle and Julie Wray in a report to Metro Vancouver that outlines the threats to bees.

“The main reason that wild pollinators are declining is loss of habitat,” Elle said in a recent presentation to Metro directors. “They’re losing their food and they’re losing their nests.”

Bees need nectar-producing flowers and while commercial blueberry fields are one source, it’s a monoculture crop that blooms for only a few weeks, leaving vast areas devoid of food the rest of the time.

Wild bees aren’t transported from field to field in boxes like imported pollinator honeybees and they require flowers that bloom at various times all year long.

More of that kind of habitat could be created by cities in parks and even by households and businesses in yards and other urban areas, Elle said.

She noted Metro Vancouver has already been planting diverse wildflowers and other native plants that bloom throughout the year in some regional parks.

Researchers have measured a 25 per cent increase in both the abundance and diversity of pollinators at those sites, she said.

Wild species nest in the ground, in trees or other areas and that habitat is also being lost to urban development or other ecosystem disruption.

Elle noted invasive species are a particular problem.

The Himalayan blackberry, she noted, can cover large areas where other flowers are effectively forced out and no nectar is available for most of the year.

Solitary bees only survive four to six weeks, so that species won’t survive in an area if food isn’t available when they come out.

Much public attention has focused on the threat to bees from farm pesticides, including neonicotinoids – there have been repeated calls to ban the neuro-toxic insecticides that have been found to kill beneficial insects.

Elle said the chemicals are linked to colony decline and even when they don’t kill bees outright they can hurt their ability to survive and thrive.

“Just smelling a fungicide reduces the ability of a bumble bee to find food and to collect it quickly and bring it back home,” she said. “What this means is they’re not provisioning a colony very quickly and the colony is not growing – just by smelling agro-chemicals.”

Some municipalities still allow cosmetic pesticide use, she noted, but said most exposure comes from farms.

Exposure to one pesticide can worsen the effects of another one on bees, she added, while imported European honeybees used to pollinate crops can be a source of diseases that spread to wild species and the managed bees also crowd out wild species.

She pointed to climate change as another source of trouble.

In high alpine areas, she said, wild flowers like the glacier lily are flowering earlier than they used to because the snowpack melts faster.

“Their main pollinator is a type of bumble bee that just isn’t active yet when the plants are blooming,” she said, adding that has limited the reproduction of the lillies, which no longer grow to the same extent.

The bottom line, Elle said, is bees are under pressure on multiple fronts.

“People want to know ‘What’s the one thing we can do?’ But it’s not a simple problem. It’s not just one thing that we can fix.”

However, Elle said even reducing one threat is likely to help bees and slow the declines.

More than 100 of the 450 bee species identified in B.C. live in the Lower Mainland but Elle believes many of them could go extinct and some may already be gone.

The local poster child for bee decline is the Western bumble bee.

They used to be commonly seen on blueberry farms in the 1980s but became very scarce about 10 years ago, Elle said. They haven’t been spotted on a farm in four years.

Gerda Peachey ·  Top Commenter · University of the Fraser Valley

Thanks for printing this article. There are some things we can do to mitigate the decline of pollinators. Great credit to the Abbotsford Board of Education for altering their approach to weed control on public school grounds, in an attempt to diminish the use of Casaron and Roundup. On the other hand the City of Abbotsford allows landowners to diminish the set-backs too much, so that on many new developments, almost no land remains for trees, bushes or flowers. Buildings and parking lots maximize their footprints to the exclusion of any space for habitat. That may increase profits for the owner but in the long run the city becomes less attractive, and less fit for all life. What is badly needed is leadership at all levels of government, even to hold the line on the regulations that already exist, like the buffers around waterways being left unsprayed. You can see chemical burns that clearly show violations are the norm. Farmers used to understand the value of hedgerows, as windbreaks but also as a habitat for the myriad life forms that live in those buffer zones. Mono-cropping and maximizing every square inch of land to reap a few more dollars will continue unless politicians understand the interdependence of all living things. But understanding the fragile balance of nature isn’t enough, politicians also need courage to implement and enforce common-sense guardianship of the land. But we all have influence in our own small spheres, and as this article says so well, lets provide flowers for the pollinators, even on balconies and window ledges, and wherever possible, decrease the use of pesticides.

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