Wayback Wednesday - Pollinator Sanctuary Study Indicates that If You Build it, They Will Come

From the Fall 2019 Farming Smarter Magazine

If you build it, they will come - take a pivot corner, a fence line or a ditch and turn those into a bed and breakfast for bees.

Farming Smarter set out to determine what blend of plants would turn marginal farmland into suitable habitat for both domestic and wild pollinators. With the right seed blend creating a long flowering season, farmers could have a significant impact on recovering struggling pollinator populations.

Farming Smarter secured funding for a one-year Pollinator Sanctuary Study through the Canadian Agricultural Program. Field Researcher Saikat Basu is the lead on this project.

"(Basu) took a shining to pollinators in general and, in particular, whether there are mixes of species that we can grow that will provide an extended flower season for various wild pollinators," said Farming Smarter Manager Ken Coles. "This could create good habitat on marginal areas on the farm and provide an ecosystem service."

Smaller initiatives are popular now with packets of wildflower seeds given out to the public by various companies. These are helpful, and great for promoting public awareness of the challenge pollinators face. However, to make a big impact on recovering pollinators, Basu feels farmers need to get involved.

"You can do a little backyard wildflower patch, you can grow them in your lawns, we can have a bit in our city parks and municipal gardens," said Basu.  "All initiatives toward bee conservation are appreciable, but I always felt that this is not actually filling in that niche because the farmers are not attracted."

Basu wants to encourage farmers to create pollinator sanctuaries in areas not usually used for agronomic purposes on farms - perimeter areas; around center pivots; salinity impacted areas; or other areas not used commercially.

It was quickly apparent that rather than looking at a pure wildflower mix for larger scale planting, a blend of different types of plants would be ideal.

"I found that the cost of the bee production seed is too high," said Basu. "We were looking for an alternative and I thought one of the easiest solutions would be including our cover crop species. We have a lot of crops that go throughout the season including legumes, brassicas and clovers."

Many of these also function as forage crops.

"If I can mix various combinations of crops that are early season to late season, they sequentially flower," said Basu. "It increases the bee foraging period."

The aim was to find a blend of plants that will attract domestic bees and a variety of wild pollinators, provide an extended flowering season, improve soil conditions and require little to no labour beyond planting. The seed also must be affordable, which is not the case with pure wildflower blends.

Basu considers four uses for the plant species going into the pollinator sanctuary:

First, they act as a pollinator sanctuary, but even more than that, a wildlife sanctuary. They act as a little niche that provides homes for small mammals, birds, lizards and frogs. Second, they should be an excellent cover crop. This aids in preventing weeds and increases soil and water conservation. Third, the mixes could be excellent for soil remediation, including in areas where salinity is a concern. Finally, they could function as forage for producers who want to graze stock on the pollinator sanctuaries.

The current study is on Farming Smarter land. It is marginal land near a wetland that can't be used for much of anything else. There are five different treatments, each on a four by six meter plot with four replications of each treatment. They were seeded at two times, early and late, to see how it affects the length of flowering season. The plots are no till and received no fertilizer, irrigation, pesticides or herbicides.

The five treatments used were:

Straight Annual mix

Straight Perennial mix

Annual/Perennial mix

A commercial pollinator mix

A wildflower mix available from nurseries

Preliminary results aren't surprising Basu - The more diverse the stand of plants, the higher the diversity of insects that are visiting them.

Basu kept records of which plants were flowering or fruiting throughout the season, developing a floral calendar. By selecting the right combinations, the different plants should flower sequentially, giving the pollinators continual access to flowers.

At the same time, he systematically sampled the insects. Basu utilized sweep netting, sticky cards and image capture to record the insects in each plot.

"I'm sampling, collecting and storing them," said Basu. "They will be sent to an expert for identification and then we will prepare a biodiversity report of the insects attracted to our plots."

He's found honeybees and many other wild bees, but the variety of pollinators is broad, including various species of pollinator flies, beetles, moths and butterflies.

"We do see pest insects coming in too," explained Basu, "but they haven't done significant damage other than flea leaf beetle; which are attracted in large numbers to the mustard crops or the canola family crops that we have."

Saikat explained that with a similar experiment with another group last year, the brassicas came into flower and went to seed early, but they attracted flea beetles and sustained significant damage. The plants recovered, though, and provided further benefit to the bees.

"As soon as the cold weather sets in their leaves come back one more time because it's too cold for the flea beetle to be active," explained Basu. "They have a secondary round of flowering sometimes and they attract bees again."

Weeds are of course a concern, particularly when introducing a mix of plants to an area that will not be sprayed. The researchers were careful selecting the species to be used. 

"We checked with the Invasive Species Council and examined any risks and concerns," explained Coles. "We removed some of the species that we were originally going to plant."

"Wherever the plot has been thin with lots of patches in between, the weeds have moved in, creating more weed competition on those plots," said Basu, explaining further that dense seeding deters weeds.

Additionally, pre and post crop soil samples were obtained to examine any changes to the soils that occur under the varying crop compositions.

The plan going forward is to expand the study across differing climatic regions and various latitudes in Alberta in both dry land and irrigated applications.

The hope is to make large scale pollinator sanctuaries a possibility with the cooperation of farmers. "This could make a significant impact in bee conservation in the long run," said Basu.