While we’ve been busy fighting wasps, we’ve turned a blind eye to another invader. Farah Hancock looks at the ecological impact of New Zealand’s lucrative honey bee.
Long taken for granted, the hardworking honey bee is experiencing its moment in the sun. Honey prices are rising and with global numbers reported to be in decline and feral populations decimated by Varroa mite, there have been concerted efforts to save them.
For the past few years New Zealanders have been doing just that: planting bee-friendly flowers in gardens, carefully considering pesticide use, taking up beekeeping as a hobby, and killing wasps with impunity to give the bees a chance.
These efforts might be misguided. In New Zealand, honey bees are more livestock than they are wildlife.
Imported in 1839, honey bees were introduced to pollinate exotic crops and produce honey. New Zealand’s 28 native bee species do pollinate flowers, but do not produce honey. They also can’t be farmed in hives the same way honeybees can.
A proliferation of farmed honey bees could endanger native species by taking food sources, disrupting the pollination of flowers and spreading disease.
Some of our indigenous bee species are now rare or in decline. There are at least 224 indigenous plant species honey bees collect nectar or pollen from. These are the same food sources used by native bees and insects, however, compared to our native pollinating insects, farmed honey bees can be an elite invading force.
While native bees live in solitary burrows or holes in twigs or logs, honey bees are transported en masse in hives, often arriving just as flowers emerge and moved on when the pollen is depleted.
Studies in New Zealand and other countries show solitary and semi-social bees are often poor competitors with the social honey bee, however, there’s scant research into exactly how honey bees interact with most native species. As well as insects, bats, reptiles and birds also rely on the nectar or pollen of some of the same plants honey bees feed on.
Some indigenous plant species require birds for pollination and honey bees are the wrong size for these flowers. In some cases, they are able to rob the nectar without accessing the stamen of the flower to pollinate it. This is a concern for species such as kākābeak and giant-flowered broom which honey bees seek out. They are limited in number and honey bees do not pollinate them when they feed.
A proliferation of farmed honey bees could endanger native species by taking food sources, disrupting the pollination of flowers and spreading disease.
With export revenue climbing to $315 million in 2017, higher honey bee densities may be on the cards. Both the amount, and price, of honey has increased —since 2011, New Zealand doubled honey production, adding more 400,000 new hives.
Hives are dotted throughout the country and beekeepers are always on the look-out for where to place their bees. Some beekeepers are buying land, others rent spots on farms.
Another option is to put hives on the 8.6 million hectares of public conservation land the Department of Conservation (DOC) manages.
The number of hives on conservation land has steadily increased. In 1996 there were 2036 hives, by 2015 the number had grown to 14,850. Facing an application to put 58,000 hives across the central North Island, DOC decided to review its stance on allocation.
In 2015, DOC science advisor Dr Catherine Beard completed a risk analysis on honey bees on conservation land, looking at food source competition, pollination issues, weed spread caused by honey bees pollinating weeds, and disease spread.
Her analysis concludes by saying it is clear honey bees are a possible threat to our indigenous biodiversity, but more research is needed to clearly understand the impact.
“That whole area of research has been quite difficult to make any progress in. It’s not only expensive, it requires skilled experts.
“It’s just such a complex and difficult-to-study area of research, because we are dealing with systems where we might have information about birds and the odd mammal, but we have next-to-no information about invertebrate species.”
The review Beard created the risk analysis for brought about a new set of guidelines for managing honey bee hive allocation on conservation land. Despite the possible threat to native species, commercial beekeeping on DOC land is still permitted.
“Ecologically speaking, the ideal would be not to have bees on conservation land but that’s not practical and that’s not acceptable to the general public either,” said Beard.
About a third of conservation land has been classified as high value, and moves are being made to exclude commercial beekeeping from that land.
1.5 million hectares has been selected as being suitable for hives, with a maximum number of one hive per three hectares set by DOC. Without enough research to base a number of hives in an area on scientific evidence, Beard said they looked at commercial rates of one hive per hectare and took a conservative approach.
This would amount to a possible addition of over 500,000 hives to conservation land. Currently the total number of registered hives in New Zealand is 825,630.
Applications are individually reassessed by DOC before being and the Beard said the guidelines would be reviewed regularly as research was completed.
