Newstrom-Lloyd, a pollination biologist and research associate at Landcare Research, Lincoln, told the recent Eastwoodhill Trees for Bees conference in Gisborne few flowers were available for bees in spring and even fewer in autumn.
Spring-flowering plants helped build bee colonies and autumn-flowering plants helped prepare bees for winter survival, she said.
Her recent research for the Bee Friendly Farming Group found that many plant species can fill the gaps in spring.
Led by Amberley farmer Ross Little, the group includes scientists, beekeepers and farmers, whose objective is to improve honey bee health by increasing pollen sources for bees at critical times.
Newstrom-Lloyd said in spring it was important for bees to increase from small, winter populations to reach peak numbers to provide pollination services and harvest honey.
If there was not enough pollen diversity and abundance in August, September and October, the bee colony would not reach its peak size by mid-November and poor pollination would result.
Without enough pollen the bees would lack protein and would become malnourished and could starve, she said.
The second critical time was when the bees prepared for winter. In summer bees lived for only nine weeks, but bees born in autumn needed to survive through winter, she said.
To live that long they needed pollen and honey stored in the hive.
“Weak bees with insufficient food stored will lead to collapse of colonies because bees just don’t survive the winter.
“These two periods are very critical but there is very little on farms that bees can use for pollen.”
In New Zealand many good pollen sources for bees, such as gorse, broom and willow, were being eliminated because they were unwanted, weedy species.
Farmers were also removing shelter belts and there was a general loss of plant diversity on farms, she said.
“Beekeepers need to have good, strong colonies with peak population size, but that’s not possible if you don’t have food for the bees.”
Newstrom-Lloyd said the problem was serious and was getting worse as farming became more intensive, with reduced plant diversity.
She cited several farming trends, including intensive dairying, as a particular problem for bees. Because dairy farmers did not want clover in pastures they were removing shelterbelts to enable pivot irrigation and were eliminating weed species.
“Farms in NZ used to be much more mixed and diverse, with more flowering trees and shrubs. The biggest issue is the loss of both diversity and abundance of pollen on farms.”
Linda Newstrom-Lloyd
pollination biologist
“Farms in NZ used to be much more mixed and diverse, with more flowering trees and shrubs. The biggest issue is the loss of both diversity and abundance of pollen on farms.
“Our project aims to solve that problem. For example, there is a gap in pollen supply right after willows finish flowering and before clover starts flowering, but it is a completely artificial gap.”
The team’s studies at Eastwoodhill Arboretum in Gisborne show many species, including maples, ash, oaks and photinia, can fill that spring gap.
“We have found our native plants are fantastic for providing pollen and nectar. Flax has very high protein, all the pittosporums are good for spring, and the lacebark tree has good protein in autumn.”
The Trees for Bees NZ team has measured protein levels on 120 species, of which 10 are native species, and many have high-protein content in the pollen.
“Five finger is a very high priority because it flowers in late winter, early spring. If farmers wanted to have a native bush area with the right sequence of flowering that would be a great thing for bees.
“Exotics can also help in winter and early spring, such as Eucalyptus leucoxylon Rosea and tree lucerne.”
Another option was to plant durable Eucalyptus trees, which gave an economic return, she said.
“We don’t want farmers to take land out of production. That is not the answer.
“There are corners, waste places, gullies, marginal bits and riparian strips where they need species for other reasons, such as erosion control, and stock fodder such as willow.
“That’s an opportunity to stick in some trees that the bees will thrive on.”
When planting, farmers should think about a feed budget for bees to provide food for every month of the year to match the demands of the colony.
Summer was easy, because many species were available and neither pollen nor nectar were in short supply.
The group received a grant from the Ministry for Primary Industry’s Sustainable Farming Fund for this research. The fund is a collaboration between Landcare Research, AsureQuality and GNS Science.
It has been sponsored by councils and the beekeeping and honey industry and supported by Federated Farmers, the National Beekeepers Association and the Foundation for Arable Research.
“We have two demonstration plots on arable farms in Canterbury, two in Gisborne, and we are setting up a plot with the Hawke’s Bay Regional Council at Lake Tutira. These demonstration plots are important to show how the selected species work together to feed the bees.”
Newstrom-Lloyd said bee plant guides were available on the website www.treesforbeesnz.org and through Federated Farmers, with new additions to the plant list to be available in the next few months.
