Bee health needs to be a priority

This summer, you may have met some native bees going about the important business of gathering pollen. Wild bees, including our 28 native species, don’t live in hives or produce honey the way honeybees do. They tunnel into the soil to build nests, where they lay their eggs and nurture the resulting larvae with pollen and nectar.

As they fly from flower to flower, the bees play a crucial role in pollinating a wide range of wild plant species. Wild bees are also crucial to securing adequate yields in about 85 per cent of food crops around the world.

But local and regional studies suggest wild bee populations are in decline. Habitat loss, disease, competition with exotic species, and the widespread use of chemical sprays are often cited as reasons.

Now a group of researchers publishing in the journal One Earth have attempted, for the first time, to get a handle on the global status of bee populations. The news isn’t good.

Analysing worldwide data sets spanning more than a century, and collected in the Global Biodiversity Information Facility, they found the number of collected bee species have steeply declined from the 1990s. There were 25 per cent fewer species reported between 2006 and 2015 than before the 1990s.

That could be down to changes in how data is collected, but the researchers suggest a more worrying reason. ‘‘It is more likely that these trends reflect existing scenarios of declining bee diversity,’’ they write. ‘‘In the best scenario, this can indicate that thousands of bee species have become too rare, under the worst scenario, they may have already [become] locally or globally extinct.’’

The decline is also evident in the New Zealand data set, which includes 4321 records stretching back to 1909. But lead author, Eduardo E Zattara, an evolutionary biologist from Argentina, says the local data is too sparse to be relied on.

Still, as Stuff reported in 2018, local studies point to a decline in native bee populations as introduced bees are used to produce our prized ma¯ nuka honey. If native bees are being crowded out or declining for other reasons as well, that could have major implications for the health of wild plants and crops alike.

We need to improve monitoring to get a better handle on the issue. Zattara suggests we could also inform the global effort to do so. ‘‘New Zealand would be a fantastic place to test whether the [fuzzy] trends that can be gleaned from these data are actually reflective of the real status of the local bee biodiversity,’’ he says.

As an agricultural nation with unique native wildlife, bee health needs to be made a priority.

There were

25 per cent fewer species reported between

2006 and

2015 than before the

1990s.