Bees and insect predators can help boost yields and cut losses, but farmers have to provide a good home
Shelterbelts don’t just keep topsoil from blowing way.
They also provide homes for pollinator species, a group that includes butterflies, beetles, birds, wasps, flies – and even monkeys in some countries.
But far and away the most effective of all are the bees, said Mark Wonneck, an ecologist with Agriculture and Agri-Food Canada.
“They are designed to do pollination. About half of all agricultural crops depend to some extent on bees,” said Wonneck, in a presentation on enhancing pollinator habitat with windbreaks at the recent joint U.S.-Canadian Great Plains Windbreak Renovation and Innovation Conference.
To make habitat for bees, it’s necessary to understand what they need to survive and thrive.
First, most wild bee species are solitary, unlike their domesticated counterparts.
Instead of hives, they live in nests, 70 per cent of which are underground tunnels such as gopher and mice holes and under rocks and logs. The rest nest above ground from materials they find in the environment such as mud, leaves or rotten old trees.
Second, they need adequate pollen and nectar from flowers that is available throughout the spring, summer and fall.
Wild bees are “nest-centric foragers,” which means that they tend to tap food sources close to the nest, unlike honeybees, which can travel up to 14 km from their hive.
Bumblebees, the ultimate pollinator due to their fuzzy hair coat and “buzz pollination” method, live in quasi-colonies numbering 50-400 individuals, and cover a “trapline” of potentially productive flowers stretching about one kilometre from their nest.
Smaller bee species may range only 200 metres from the nest, which means that suitable habitats must have a wide variety of plant species to cover their needs during the frost-free period.
Canola provides a lot of flowers, but its short bloom window isn’t long enough to sustain bee populations on its own. Saskatoon, wild rose, pin cherry and other shrubs can extend the buffet season.
Shelterbelts also provide protection from pesticides by offering an alternative foraging location during spraying so that a portion of the population can survive.
“They are like bankers. They only work from 10 to 3,” said Wonneck.
Besides pollination, shelterbelts also provide habitat for natural pest control agents.
“There are guesses from the literature that natural pest suppression is in the range of 90 per cent. If that’s true, then you might want to pay attention and not lose too much of that,” said Wonneck.