Biodiversity

Non-native bees discovered in Canada may pose serious threat to native mason bee populations

lanthierj — Thu, 08 Dec 2022 17:08:14 +0000

Non-native bees discovered in Canada may pose serious threat to native mason bee populations

lanthierj Thu, 12/08/2022 - 12:08

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Osmia taurus is one of two non-native bee species that have established populations in Canada, �ؿ�ζSM Scarborough researchers say (photo by Don Campbell)

Don Campbell

Topic

Breaking Research

Biodiversity

Environment

Research and Innovation

Sustainability

U of T Scarborough

Researchers at the �ؿ�ζSM Scarborough have discovered the presence of two species of bee in Canada for the first time – one of which could pose a big threat to native mason bees.

The non-native mason bees (Osmia cornifrons and Osmia taurus) originate from northern Asia and were introduced to North America more than 50 years ago as crop pollinators.

The presence of O. taurus is the most concerning, says Scott MacIvor, a professor in the department biological sciences at U of T Scarborough and lead author of the study published in the journal PeerJ Life & Environment.

He referenced a recent study in the United States that found an 800 per cent increase in O. taurus coincided with a 90 per cent decline in six different species of native mason bees. The study was done across multiple mid-Atlantic states over a 13-year period.

“O. taurus, the bee that was brought over completely by accident, has had a negative impact on native mason bees in these states,” says MacIvor, who is an expert on bees, pollination and biodiversity.

“It’s too early to say whether this bee will have the same impact on native mason bees here in Canada, but it’s definitely a strong possibility.”

O. cornifrons (also known as the horned-face bee) was brought to the U.S. starting in the late 1960s to help pollinate fruit crops, but due to its similar appearance, O. taurus was also brought over accidentally around the same time.

While there is no evidence that O. cornifrons has a similar negative impact on native bee populations, MacIvor says non-native bees can be considered invasive when they displace native bees by introducing disease, disrupting nests, or simply outcompeting them for resources.

Professor Scott MacIvor is a expert on bees, pollination and biodiversity (photo by Don Campbell)

Potential pathways

MacIvor says the bees likely crossed natural land borders connecting Michigan and New York to Ontario. While the bees have existed in large numbers in the U.S. for decades, it raises the question: Why have they only appeared recently in Canada?

“Entomologists in southern Ontario have been doing bee surveys for decades and it’s only within the last couple of years that they started to appear,” he says.

One reason could be the recent popularity of bee hotels that people are using to support struggling native bee populations in urban areas. Both bee species are cavity-nesting bees, so they might be thriving due to the recent availability of these hotels.

Another potential way they’ve ended up in Canada could be the online sale of bee cocoons to gardeners and bee hotel owners. MacIvor says it’s possible they could be inadvertently sold non-native species instead of native mason bees. While importing bee cocoons from the U.S. is illegal, he says it’s possible they might have slipped past border inspections. Bee cocoons can also be purchased online from Canadian companies, so over time there is a potential they could be shipped to other parts of Canada.

Interestingly, the researchers discovered that batches of O. cornifrons were also imported into Canada in the 1970s as part of agricultural experiments but given the widespread surveying, there’s no proof those bees were able to survive and reproduce in the wild.

Native mason bee conservation

Protecting native mason bees is critical due to the important role they play in pollinating native plants, as well as spring-flowering orchard crops such as peaches, plums, cherries and apples.

While there’s not much that can be done to stem the flow of non-native mason bees naturally, MacIvor says there are a few things people can do to support native mason bee populations.

“For one, avoid buying bee cocoons online,” he says. “Instead, let local populations colonize bee hotels and other habitats.”

He adds the best way to support native mason bees isn’t necessarily to set up a bee hotel since many native bee species make their nests elsewhere, such as decaying wood or underground. Try focusing on plants that flower in the spring such as lupine, beardtongue, raspberry or redbud. These will attract native mason bees and help them thrive.

“If you are interested in native bee conservation, the best thing to do is build gardens with native flowering plants and pay attention and protect spots where nests develop naturally.”

This research was supported by a grant from the Natural Science and Engineering Research Council of Canada (NSERC).

What happens to wildlife when humans alter their habitat? U of T research sheds some light

ullahnor — Tue, 21 Feb 2017 17:56:33 +0000

What happens to wildlife when humans alter their habitat? U of T research sheds some light

ullahnor Tue, 02/21/2017 - 12:56

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The research found that some bird species were vulnerable to habitat loss in the Thousand Island Lake area of China. The top two bird species survived habitat fragmentation, but the bottom two were left vulnerable (photos by Yuhao Zha and Di Zeng)

Don Campbell

Author legacy

Don Campbell

Topic

What happens to birds living in the wild when you instantly flood an area, roughly the size of Chicago, and forever change their habitat?

According to new U of T research not only is there an overall loss of species, but those that remain also end up being very alike.

“You lose uniqueness – a full gamut of species that have their own distinct feeding strategies, physical characteristics and niches, not to mention genetic diversity,” says Marc Cadotte, an associate professor of biology at U of T Scarborough.

The study, led by Cadotte’s postdoctoral researcher Xingfeng Si and co-supervised by Professor Ping Ding from Zhejiang University, looked at what’s called community disassembly by focusing on birds living in the Thousand Island Lake area of China. The lake itself was formed in 1959 with the opening of the Xin’an River hydroelectric station – an area of continuous forest was instantly changed into a massive lake with more than a thousand islands.

Researchers looked at bird species in the Thousand Island Lake area of China, which was formed in 1959 with the opening of the Xin’an River hydroelectric dam

The goal of the research, which will be published in the Journal of Animal Ecology, is to help researchers predict what kinds of communities will end up living in similar fragmented habitats –environments that have been changed by human activity.

“We have a lot of uninterrupted forests in Canada, but that’s changing,” Cadotte says. “We’re moving further north, tearing up forests, expanding development into new areas, and we should want to know how much biodiversity these altered ecosystems can hold.”

The Thousand Island Lake area of China offers a unique opportunity to study exactly what happens to wildlife when natural habitats are fragmented by human activity, Si says.

“When the area was first flooded a bunch of species would have disappeared from the islands because some birds like the silver pheasant need a large territory,” he says.

For these birds, the newly created islands were too small to maintain a population because of a lack of space for nesting, food or other resources. For birds that rely on foraging for insects, they too wouldn’t have been able to survive.

U of T Scarborough postdoctoral researcher Xingfeng Si (left) and Associate Professor Marc Cadotte studied changes in bird biodiversity in the Thousand Island Lake area of China (photo by Ken Jones)

The result was a significant drop in the number of birds living on these newly created islands. Si says that on the mainland close to the lake there are 55 different species of terrestrial breeding birds in total, but on larger islands that number drops to 44. On smaller islands, it’s about 20, sometimes less.

Cadotte says what ends up happening through disassembly is two forms of biodiversity loss. In addition to losing raw diversity – that is fewer species in general – the ones that remain are very similar to each other.

“That loss of unique species can have all sorts of consequences,” he adds.

He adds that for a lot of habitats, fragmentation is a relatively new arrangement. Human activity is changing areas where habitats used to be continuous and harboured many different types of species.

“A lot of human activity occurs without asking what the natural world will look like after or how biodiversity will be affected,” Cadotte says. “Studies like this can help us answer questions about how much biodiversity the world will hold when we fragment habitats.”