Synopsis : Honey bees compete with native bees. How many hives are too many, resulting in damage to native bee populations? Probably fewer than you think.
Introduction
Several years ago I visited Montréal to speak at an international symposium. It was a big conference with a very busy programme but I still managed to sneak away and see the city. We had a week or so of stunning Indian summer weather so I walked almost everywhere; along the banks of the St Lawrence and Prairies Rivers, through the Botanic Gardens and the Mount Royal 1 Park.
Montréal Olympic stadium from the Botanic Gardens
If you’ve not been I can recommend it.
However, I didn’t see a single honey bee.
I wasn’t specifically looking for honey bees, but beekeepers tend to notice these things.
In retrospect that wasn’t too surprising. At that time there were just a couple of hundred hives within the city, which covers an area of 430 km2 .
I did see monarch butterflies (Danaus plexippus) in the gardens, stocking up on nectar before starting their migration back to Central Mexico.
Monarch butterfly, Montréal Botanic Gardens
This was early October. Had there been lots of honey bees in Montréal I’d have expected to see them on the same asters, competing for the nectar with the butterflies, piling in the stores before the coming winter.
And competition isn’t always a good thing.
Save the bees
Scientists have long been aware of the importance of pollinators (many of which are insects) and the global decline of insect populations. The role of insects, and the importance of conserving them can be a difficult thing to ‘sell’ to the general public.
They are often perceived as wriggly, creepy-crawlies, that might sting … urgh!
Without public support many conservation projects will fail.
Increasing public awareness and associated conservation measures, for example banning pesticide sales by garden centres, is needed and a combination of ‘brand awareness’, a widespread fondness for honey and (inevitably) sloppy journalism means that honey bees (Apis mellifera) have become the poster girl for insect pollinators.
Save the bees …
’Save the bees’ as a slogan is a gross oversimplification of ’increase the number and diversity of insects pollinators in the environment’ and is usually taken to mean – or interpreted as – ‘promote honey bees’.
If you’re interested in seeing just how biased this coverage is I recommend Smith and Saunders (2016) who collated press articles on pollinators (in Australia) and quantified the different species featured. The title of their paper neatly defines the problem:
Honey bees: the queens of mass media, despite minority rule among insect pollinators
The beekeeping ‘explosion’
Partly as a consequence of this media coverage there has been an explosion of interest in honey bees and beekeeping over the last 10-15 years … and lots of new beekeepers.
Since over 80% of Canadians live in urban areas a significant proportion of these new beekeepers – and their hives – are in towns and cities.
Between 2013 and 2020 the number of hives in Montréal increased from 283 to ~3000.
Conveniently – for this post and the paper (MacInnes et al., 2023) on which it is primarily based – there was an extensive survey of Montréal’s urban bees in 2013 (Normandin et al., 2017). By repeating the survey in 2020 it was possible to determine the impact of the increase in urban honey bees on wild bees and some of the flowers on which both depend for pollen or nectar.
This ‘before and after’ study showed that the introduction of large numbers of hives reduce wild bee species richness and pollen availability.
“Too many honey bees” … perhaps not what you expected in a beekeeping blog 😉 .
Testable hypotheses
The MacInnes study had three goals, to:
Examine the species richness and composition of wild bee communities along a gradient of honey bee abundances
Assess the influence of honey bee abundance on floral resource (pollen) availability
Compare the richness and composition of the wild bee communities before and after the large increase in the honey bee colonies in Montréal
The 2918 hives in Montréal are not evenly distributed 2. The location of some were known, but in the absence of that information it has to be inferred by the frequency of honey bees sampled in particular locations … if there are lots of honey bees it’s reasonable to assume that hive density within foraging distance is higher than in areas where there are fewer honey bees.
Therefore, by sampling wild bee numbers and species across a range of different sites, as well as counting honey bee numbers, it was possible to determine whether the presence of honey bees influenced the presence, number and population make up of other bees.
Similarly, by comparing the 2020 data with the 2013 survey it was possible to determine the influence of the city-wide 10-fold increase in honey bee numbers.
Competition between bee species – at least in this case – is exploitative.
One bee species exploits a resource that is needed by another bee species. The most obvious things they compete over are the floral resources – pollen and nectar – produced by plants in the area. It’s possible to measure pollen abundance and nectar volume (and sugar concentration, though this should not change in response to bee numbers) and, in this study, pollen was quantified to see if areas with high numbers of honey bees had less pollen.
Study design
I’m not an ecologist so am unqualified to properly judge the study but – to my unqualified eye – it looks pretty reasonable. The paper is freely available so judge for yourself 3. Sampling was conducted at 15 well-spaced sites across Montréal, in forage-rich locations such as community gardens, cemeteries and nature parks. High resolution satellite mapping was used to quantify herbaceous cover and impervious surfaces (concrete, buildings). Bees were collected using pan traps using a standardised sampling procedure for the locations of the traps, their separation, the duration of trapping and the types of day on which trapping was conducted.
Some of Montréal’s impervious surfaces
For example, you cannot meaningfully compare 3 hours of trapping on a wet April afternoon with 6 hours on a gorgeous late summer day. Good foraging days were chosen in June, July (twice), August and September.
In addition to pan traps, aerial trapping (imagine enthusiastic PhD students prancing around swishing butterfly nets) was also conducted in parallel, with samples from each site/date pooled for counting and subsequent identification.
Finally, the same sampling sites were used as were chosen in the 2013 survey (though I think there were a couple of additional sites used as well) to allow relevant comparisons before and after the influx of honey bees.
A few definitions
Honey bees … you know what these are 😉 .
All other bee species were considered ‘wild bees’ i.e. unmanaged, though they acknowledge some Bombus species are managed for pollination services, but did/could not distinguish these from free-living Bombus.
Within these wild bees the authors identified ‘native’ and ‘exotic’ bees; the latter (~12% of the total) being introduced through the activities of man.
The wild bees identified were also separated into two groups – large and small – based upon the inter-tegula span (ITS). This is the distance between the tegulae at the wing bases, and is a very good indicator of body mass and wing musculature which, in turn, is a predictor of foraging range. Bees with a low ITS 4 are small, light and only forage over short distances .
Bee communities (i.e. X% of species A, Y% of species B, Z% of species C, remembering the community might contain several dozen species) were characterised using a number of statistical methods that I’m also not qualified to judge properly (though I’ve published several papers using some of the methods cited … 😉 ). Go on, ’fill your boots’ … check out the paper and decide whether Shannon-Wiener or Simpson’s diversity indices are the right ones to use. These methods are fairly standard and have been applied to the analysis of bee communities in previous studies, so let’s assume they’re OK.
Pollen analysis of white clover (Trifolium repens) was also conducted. Not all bees use this as a pollen resource, but many bees do. Pollen was ethanol extracted, stained and counted under a microscope (imagine unenthusiastic PhD students going cross-eyed with boredom … and cursing their supervisor 😉 ).
Wild bee richness and honey bee abundance
Richness is a measure of the number of species and hence diversity of the wild bee population. The hypothesis was that richness would reduce as honey bee numbers increased if there was competition between the bees for limiting resources.
And that’s exactly what was seen.
Honey bee abundance and wild bee richness.
These graphs plot honey bee numbers (horizontal) against a measure of species richness (vertical), with each dot being a different sample site/sampling date. The overlaid solid line and shaded blue region represents a best fit and 95% confidence limit respectively.
Since the line slopes down from left to right (a negative slope) it indicates that increased abundance of honey bees results in reduced species richness in the wild bee population across Montréal (left hand graph). Large bees and Bombus (bumble bees, which are very large bees) were unaffected by honey bee abundance (not shown), but small wild bees (right hand graph) decreased significantly.
The wild bee community make up – the range of species and the number of each – is slightly more difficult to explain. Essentially sites with high numbers of honey bees were more similar to each other in their wild bee communities. Sites with low or medium levels of honey bees were more diverse. This suggests that only some wild bees can compete in the face of high honey bee abundance.
The impact of beekeeping on wild bee communities
Unsurprisingly, in light of the results presented above, the ten-fold increase in honey bee hive numbers in Montréal between 2013 and 2020 also negatively impacted wild bee richness.
Honey bee increases from 2013 to 202 and wild bee richness
These graphs plot the difference in honey bee numbers at each sampled site between 2013 and 2020 (horizontal axis) versus wild bee richness. The solid black line represents the best fit of the scattered data points having taken into account other variables such as sampling period, floral richness, floral density and the amount of impervious surfaces and herbaceous forage.
Again, the downwards (negative) slope of the line as honey bee abundance increases indicates that wild bee community richness decreases if there are more honey bees about. As before, this was not seen in large wild bees or Bombus, but was significant in small wild bees.
If there are increases of generalist bees – such as honey bees – in the environment, the expectation would be that forage plants, like white clover, would be depleted of pollen and nectar … this was the next thing that was tested.
More honey bees = less pollen 🙁
White clover was widely distributed across the sample sites. It is also a flower that a lot of different bees can access for ‘resources’ (pollen and nectar) … no need for a really long tongue, or strong jaws to cut through the sides of the florets.
Easy pickings for lots of different bees.
Unless there are abundant numbers of honey bees in the environment.
Pollen availability is reduced where honey bees are abundant
The residual pollen on white clover significantly decreased with increasing abundance of honey bees. With less than 20 honey bees detected at sampling sites, each clover flower contained ~24,000 pollen grains. With numbers over 20 honey bees the number dropped to ~14,500.
This decrease was unrelated to other variables tested e.g. the numbers of Bombus at each sampling site.
The assumption here is that the increased numbers of honey bees exploit the available pollen to the detriment of other bees that would otherwise forage on clover.
Is it all bad news?
Unfortunately, yes.
I think that this is one of the better studies of honey bee competition with wild bee populations that I’ve read 5.
It’s worth noting some of the limitations of the study.
There was no sampling early in the season. The size of honey bee colonies in April/May probably makes them fearsome competitors when compared with solitary queens emerging after a winter’s hibernation. It’s likely that omission of early season samples underestimates the negative impact of honey bees on wild bee populations.
Although the only variable measured that influenced wild bee richness was honey bee abundance, perhaps the former declined because of changes in an unmeasured variable. For example, perhaps the floral diversity/community dramatically changed between 2013 and 2020. This data wasn’t collected in 2013 (but was in 2016) but it seems unlikely that it would be dramatically different.
Botanic gardens and urban planting usually contain large amounts of exotic flowers i.e. non-native. Since native wild bees have co-evolved with native flowers, this exotic planting is usually considered to benefit exotic bees more.
Of the 120 bee species identified, 15 were exotic. However, the 13 species missing from sites where honey bees were most abundant were all native bees.
The introduction of large numbers of ‘exotic’ honey bees was particularly detrimental to native wild bee populations rather than other exotic bees. Small native bees (~60% of all species) were the most adversely affected. This is likely due to their very limited foraging range (100’s of metres, rather than kilometres).
’Safe’ colony densities
In the conclusion of the paper the authors briefly discuss the honey bee ‘carrying capacity’ of an environment i.e. the number of colonies that can be introduced without detrimentally affecting native bee populations.
This carrying capacity will vary according to the floral resources available and – although not discussed – will not be constant throughout the season.
Honey bees decrease floral resources available (red shaded area)
Total pollen/nectar availability (blue line) varies during the season 6. Increasing numbers of honey bees in an environment (red shaded area) effectively reduce what is available.
But this is a gross oversimplification … it assumes that all floral resources are equivalent. Generalists can exploit all these resources.
Some bees are specialists; emerging, maturing, mating, laying and dying during the flowering of a single species or genus of plants (cyan line). If honey bees can use the same resource, particularly if it flowers when there is a shortage of other forage, it could severely limit what is available for the specialist native bee.
MacInnes et al., cite two studies which suggest that 3 or 3.5 hives per km2 is the precautionary recommended colony density that reduces negative interspecies interactions (Steffan-Dewenter and Tscharntke, 2000; Torné-Noguera et al., 2016).
I’ve read these two papers and neither are studies of urban bee populations – one is on the thyme- and rosemary-rich scrubland in the Garraf Natural Park (Barcelona) 7, the other on the calcareous grasslands around Göttingen in Germany. Neither convinced me that the suggested 3-3.5 hives/km2 were based upon evidence that necessarily made them ‘transferrable’ to other environments.
But let’s assume that they are …
Environmental colony densities
The 2918 colonies in Montréal were spread unevenly around 430 km2 i.e. a colony density approaching 7 hives/km2. Remember, there may have been undocumented hives that would increase this number.
I’m unaware of meaningful available equivalent data on hive densities in the UK.
The National Bee Unit (NBU) keep a record of apiary and hive numbers of registered beekeepers (assuming records are up-to-date) but – irritatingly – only publish the apiary numbers. When you register an apiary you can see the number but not location of other apiaries within 10 km.
Beebase shows the ‘density’ of apiaries within 10 km
I’ve had apiaries where the NBU “<10km apiary number” is as low as 1 (remote west coast) or as high as 275 (Midlands). My current apiaries on the east coast have ~60 apiaries within 10 km.
A circle of radius 10 km covers an area of 314 km2 . Assuming you know the apiary numbers 8, how many hives would there have to be in each apiary to give a density of 3 or 3.5/km2?
Apiary number and hive density table
Don’t trust my maths (!) but I think the figures above are correct.
My Midlands apiary, with 275 other apiaries within 10 km would have been in an area with over 3.5 hives/km2 if the other apiaries contained an average of ~4 hives each. Based upon my wanderings around the Warwickshire fields I’ve usually estimated that rural apiaries actually average ~5 hives each.
Check your NBU Beebase-registered apiaries. How many other apiaries are there within 10 km? Do your bees forage in an environment with hive numbers above or below 3.5/km2 ?
How about urban apiary and hive densities?
This is getting silly …
I did a quick check of apiary numbers in London, Cardiff, Glasgow and Edinburgh. Central locations in Cardiff, Glasgow and Edinburgh had 196, 144 and 210 apiaries respectively within 10 km.
Perhaps wrongly I’ve always assumed that hive numbers per apiary are less in urban than in rural locations.
People are busy working, gardens are small, balconies are cramped and who wants to carry 36 supers onto a flat roof?
If you assume there are 3 hives per apiary in these cities then the hive densities are well below the suggested 3.5/km2 threshold.
But London is a different matter altogether.
I checked both outer and central London … both locations I was familiar with. Outer London had 441 apiaries within 10 km and the central location I chose had an eye-watering 719 🙁 .
Unless these apiaries contain only one or two hives each it’s likely that the 3.5/km2 hive threshold is exceeded.
If you are an urban beekeeper check the apiary numbers where your hives are registered. There will be considerable geographic variation – even over quite short distances – depending what’s ‘in range’.
Conclusions
As I’ve said before, beekeepers have a responsibility to their bees and to the environment in which we keep bees.
If we behave in a way that is detrimental to the environment it will, eventually, be detrimental to our bees. But that selfish justification shouldn’t be needed … there should be no satisfaction in swamping an area with hives if it results in the loss of native bees and other pollinators.
It seems as though this summer has been poor in terms of honey yields … not everywhere of course, but in many locations. If our bees are struggling just imagine the impact the presence of our colonies are having on the native pollinators that they share the environment with.
And remember, the environment is being depleted, denuded and degraded; hedges are being grubbed out, field margins ploughed up, flower meadows converted to silage production, pesticides are widely used and native habitats are concreted over as urban areas expand.
It’s already tough out there for the hundreds of other bee species which our bees now compete with.
When it comes to enhancing pollinator numbers and diversity, honey bees probably aren’t the solution … but they might well be part of the problem.
Notes
For those of you who have coastal or lakeside apiaries remember that the NBU ’10 km radius’ probably isn’t smart enough to take the water into account. One of my east coast apiaries has about 130 km2 of North Sea within 10 km, almost all of which appears to be devoid of bees of any sort 😉 .
I’m aware of the deficiencies in my apiary/hive density calculations and will return to this at some point in the future. If you assume honey bees forage 2 km from the apiary, a large apiary (e.g. a shared or association apiary) containing 25 hives will result in a local hive density of 3.5/km2.
High hive densities from overlapping apiary ranges … or just big apiaries
But, if apiary ranges overlap and plant resources are unevenly distributed (which they are) then much lower hive numbers could result in higher local hive densities.
References
MacInnis, G., Normandin, E., and Ziter, C.D. (2023) Decline in wild bee species richness associated with honey bee (Apis mellifera L.) abundance in an urban ecosystem. PeerJ 11: e14699 https://peerj.com/articles/14699. Accessed June 6, 2023.
Normandin, É., Vereecken, N.J., Buddle, C.M., and Fournier, V. (2017) Taxonomic and functional trait diversity of wild bees in different urban settings. PeerJ 5: e3051 https://peerj.com/articles/3051. Accessed August 17, 2023.
Smith, T.J., and Saunders, M.E. (2016) Honey bees: the queens of mass media, despite minority rule among insect pollinators. Insect Conservation and Diversity 9: 384–390 https://onlinelibrary.wiley.com/doi/abs/10.1111/icad.12178. Accessed August 16, 2023.
Steffan-Dewenter, I., and Tscharntke, T. (2000) Resource overlap and possible competition between honey bees and wild bees in central Europe. Oecologia 122: 288–296 https://doi.org/10.1007/s004420050034. Accessed August 16, 2023.
Torné-Noguera, A., Rodrigo, A., Osorio, S., and Bosch, J. (2016) Collateral effects of beekeeping: Impacts on pollen-nectar resources and wild bee communities. Basic and Applied Ecology 17: 199–209 https://www.sciencedirect.com/science/article/pii/S1439179115001504. Accessed August 16, 2023.
Footnotes
- Hence Montréal … think of the French.
- These are known hives, there may be unknowns as well.
- Particularly if you are an ecologist.
- In this study 2.25 mm, but take care when reading other studies as not all standardise on this.
- Or perhaps it’s just one of the more understandable ones … ecology is difficult, there are a lot of variables and – over multiple seasons – a lot of stuff changes.
- Note that the data is made up on this graph.
- A lovely environment.
- And that they are accurate … they’re not. They are an underestimate. Perhaps by 30-40%?
I know some London beekeepers do say central London companies like law firms are too keen to appear environmentally friendly by plonking a hive or two on their roof
Hi Emily
Greenwashing, or beewashing, is the correct term for that I think. Just like we’re seeing for some of the carbon offsetting schemes I think there will be a backlash against this type of tokenism. Remember that some of the beekeeping associations have run ‘sponsor a hive’ programmes that have exploited this ‘save the bee’ sentiment, without really understanding the problem at all 🙁
Cheers
David
They’re creating habitat and clearly from his numbers here, they aren’t the threat. However protecting wild spaces or native-seeding them, or creating a biodiverse habitat rooftop garden that also cools the neighborhood and invites an ecosystem, would be more helpful.
Hi Robin
There are a lot of lawyers! They cluster in particular parts of London … interestingly, well within the 10 km radius I ‘measured’ 700-odd apiaries within for central London. Actually, within foraging range for many of them. I don’t think the roofs there lend themselves to much planting and the parks tend to be rather small and a bit too manicured to be useful.
Cheers
David
I have read the MacInnis study and give it a solid fail. The study illustrates the first rule you learn in Stats 101: correlation is not causation.
We should include this paper in Apprentice Beekeeping as an example of how a paper can both make insinuations that are not supported by data, and how the media can compound that error in their reporting.
In short, the paper skips over the fact that for 500 years, honey bees and wild, native pollinators throve together in abundance, and that since the mid-1900’s, ALL N. American insects have suffered catastrophic declines. It goes on to imply that the rise in urban bee populations is responsible for the declines in urban native pollinator numbers (via rapacious foraging), while noting that beekeepers feed their bees, and ignoring forage loss/degradation, habitat loss and garden/agri-spray effects.
The problem with targeting honey bees as a non-native species is that the preoccupation with what was native to the Americas pre-Contact distracts us from what has to be done, which is restore habitat and forage, and stop spraying pesticides etc. all over the place. That rising tide would float all pollinator boats.
This honey bee bashing is now quite fashionable, and I liken it to the seals vs. salmon debates here on the NW Pacific coast. Fishermen both commercial and recreational want the seals shot to “protect” salmon stocks, which ignores the fact that these two populations also throve in abundance together for millennia. Shooting all the seals would not help the salmon, who need spawning habitat restoration, forage restoration and relief from relentless over-fishing.
Ditto the honey bee and wild pollinators. They often feed on different things (another point the study ignores). Native bees and pollinators often have incredibly short ranges and very specific nesting requirements. They cannot weather even small dearths in their localities. As has been demonstrated in England with bumblebees, the populations rebound when abundant forage patches are provided, separated by no more than the flight range of the target species.
It would be interesting to see how the study repeats if it were done somewhere like Portland, which has made a big effort to make the city a pollinator buffet.
Hi Janet
Whilst I agree that some of the results are clearly correlative rather than causative, that does not rule out that they could be causative.
I certainly agree that habitat loss and a shortage of forage massively exacerbates any competitive disadvantage that native bees have when faced with an influx of honey bees. Improve the habitat, plant more season-round/long forage, use less pesticides etc. and a whole lot of things improve.
None of which means that honey bees aren’t part of the problem. Any environment – whether rich or depleted in resources – has a carrying capacity. We could still overwhelm a rich environment by placing too many hives there, to the detriment of other species sharing the environment.
It’s worth noting that the study looked specifically at species richness, not abundance. What they see is a city-wide reduction in small native bee species diversity where honey bees are abundant, or when 2013 vs 2020 are compared. This ignores any background reduction in insect numbers, but you’d have to argue that these adversely affected small native bees and not larger solitary bees or bumble bees.
The pollen study is also correlative, but would be relatively easy to repeat in a way that would definitely show whether an influx of honey bees resulted in a reduction of available forage.
I’m certainly not saying that the study is perfect, but I don’t think it’s as bad as you suggest … it largely ignores some of the major drivers of the ‘insect apocalypse’, but that doesn’t mean that the results are not valid.
I’d also love to see this done somewhere like Portland …
Cheers
David
Thank you for this. I call it #BeeBlame.
and tell folks, “bee bashing one bee isn’t going to save any species of bee.” Humans need to focus on humans and they’ve created this impact on native bees.
Certainly, humans spraying pesticides are going to make an impact.
But human encroachment on habitat is limiting resources that creates more competition for pollinators. An increasing number of apiaries is encroachment and the hundreds of years of native and honey bees coexisting is meaningless when you add more apiaries or more humans eating salmon.
Humans (including beekeepers) need to take responsibility, not blame bees.
Hi Robin
It’s worth remembering that the likely ‘wild’ density of honey bees in the environment is very much lower than beekeepers achieve. The studies by Thomas Seeley show density in the forest is about 1 colony per square kilometre. However, as with everything, there are caveats … these bees have Varroa; colony size, fecundity and survival may all be influenced by the mites, which in turn may change colony density.
I think that balance needs to be better achieved … if you’re going to put more hives into an environment then perhaps you should also be planting meaningful amounts of forage – either for the honey bees, or the potentially displaced natives. A handful of wildflower seeds is a start, a hundred trees is better … and that’s for starters.
Cheers
David
I loved your answer! You are spot on!
Very interesting. Almost but not quite related to one of my worries which is whether hive numbers locally (or density) can out-run the available forage and lead to reported poor honey crops. I have no evidence either way, but when most of an association start moaning at the same time (in years where there’s no OSR around) it makes me wonder….
Hi Duncan
I think it’s reasonably certain that a poor season, where the colonies are unable to collect sufficient honey to overwinter (assuming that honey was left for them) means that there are more bees in that environment than it can support. One colony might be OK, but 20 would end up starving.
I don’t know an easy way to determine this – honey yield is dependent upon more than just available forage; consider how much better really strong colonies do than moderate or weak ones.
But, if there are too many honey bees for the hives to collect surplus honey … what’s happening to the native bees that they share the environment with?
Cheers
David
Ah, what we are witnessing is evolution/survival of the fittest. There is a finite amount of forage for pollen and nectar-eating insects. However honeybees have been ‘clever’ in ‘learning’ to store honey. Along comes man who likes honey so he places beehives liberally in forage areas. Win-win for both honeybees and man – but to the detriment of other pollinators
Hi Giles
But it’s slightly worse than that … there’s seasonal variation, some years are good and some are poor. Native bees have fluctuating success depending upon whether it’s a good season or not, but the minimum capacity of the environment is determined by the poor years. The beekeeper adds to the demand on the environment, but in the poor years s/he feeds the honey bees enabling them to survive periods of dearth. They have a considerable advantage.
With improved forage and a less-depleted environment a lot of these concerns would be hugely reduced.
Cheers
David
Its hardly the survival of the fittest, but instead the most-human aided. We can breed honey bee queens to feed them and recover populations.
Like lab-raised bumble bees we’ve inflated their populations unnaturally, increasing their impact (competition, spread of disease to other native bees).
And we move hives, put them on trucks, ship bumble bees… if hundreds of insects show up in a garden suddenly, we call that infestation. But for honey bees we call it “pollination.”
Hardly the survival of the fittest, but the most-human aided.
see http://www.lbka.org.uk/london for a similar analysis in London
Hello Simon
I’ve read the LBKA stuff and some of the linked articles … it would be interesting to know if there was any follow-up action, like surveying the actual hive density, or quantifying honey yields in areas with different colony densities, or recommending limits on colony numbers.
Perhaps the locations I chose had abnormally high colony densities, but I’d be amazed if 5-10 colonies per square kilometre was sustainable in the centre of London.
Cheers
David
Very interesting. Thank you
As I have said in a statement in a bee magazine. We “the community” worry too much about the bees. Hobbyists, sideliners, and commercial can handle the bee population. It is the shortage of food that know one seems to work on. When is the last time you have seen a pollinator while running Arends?
Hello Joe
The shortage of forage is clearly critical … I don’t disagree. If it were limitless then any number of bees could be accommodated. It’s not, even when bountiful, which means that there’s still a chance it could be competitively exploited by honey bees at the expense of other bees.
There’s a lot of science done on providing additional forage for bees – both native and managed – some of which I’ll cover in the future. As Janet Wilson says in her comment (which I have yet to get to but which will appear here shortly) some cities – like Portland in the US – are making city-wide progress in improving forage … it’ll be interesting to see how (and if) this improves things.
Cheers
David
It is a difficukty that the NBU figures include all apiaries (including seasonal ones eg for heather) whether there are colonies there or not.
Hi Jeremy
They do … we provide all this information and I’d love to see some proper analysis of hive densities done. Maybe they’ve done it, but that’s not much help to beekeepers if it’s not be published.
Presumably the city figures generally are ‘static’ apiaries … I don’t think there’s much migratory beekeeping in cities, though perhaps some beekeepers take their hives from the city to the heather or for top fruit pollination?
Cheers
David
Brilliant post as usual, on a question that’s been sitting in the back of my mind since picking up beekeeping some years ago – is this hobby potentially further damaging my local biodiversity already under grave threat?
While I agree on the environment being depleted and degraded, I do believe (well… hope, naively perhaps?) the specific issues you call out around loss of hedges, ploughing, field margins and meadows, and to a certain extent use of damaging pesticides have somewhat peaked in this country. These agri habits were learned in the post-WW2 rush to scale up production, however I do believe farmers (and society as a whole) are finally beginning to wake up to the longer term (and now very noticeable) detrimental impacts of such activities.
Personally, I find great hope in the momentum and enthusiasm I see building around the regenerative agriculture movement and its potential to help restore our countryside, shifting the balance back from production-volumes-at-all-costs in favour of promoting biodiversity and working with nature to produce sustainably as the generations did for millennia before us (whilst also greatly improving the razor-thin margins of farming enterprises today – win win win).
These days driving through the countryside I can’t help but notice new native hedgerows being planted, strips of native wildflowers popping up in unexpected places, and an increase in clover-rich multi-species swards and ‘traditional’ meadows where previously only monocrops of high-yield ryegrass were grown. All of these required a significant amount of investment to restore – heritage grass & wildflower seed can be insanely costly per acre, not to mention the time/effort required in ground prep & ongoing maintenance to get them to a level of self-sustainability. It’s reassuring to see traction building here despite the high outlays, now the challenge of improving the commercials and scaling up…
15 years ago, a 100 mile drive between my local cities would require a serious amount of scrubbing dead insects off my car window and numberplate. These days, I could return from a 200 mile trip with an entirely clean car – the sheer rate of noticeable change is terrifying when you sit and consider the small everyday indicators that are easily missed. Let’s hope we see some much more positive changes over the next couple of decades.
Hi Alistair
I think some of the things you are seeing are generally improving, but I think there’s a lot of regional variation. A few years ago the wide field margins one of my apiaries was in – rich in wild flowers, badger setts and birdlife – was ploughed into extinction, to within 15 cm of the hive stands. Undoubtedly this coincided with the presence or absence of a subsidy for biodiversity or increased production; the extra couple of acres added to the field made it financially worthwhile. I also think there’s increasing awareness of the decreases in biodiversity and insect life generally.
However, we’ve still got a long way to go … when I travel to Spain or France I’m always struck by the wealth of wildlife and the much more natural habitat. Not everywhere of course, and I tend not to visit the more agricultural deserts, but it is notable.
I’d love to see hundreds of acres more like this (scene from Spain) in the British countryside 🙂
Remember that sampling methods determine the outcome of scientific experiments … cars are now more aerodynamic than they were a decade or two ago. Your ‘dead insect’ count would only be valid if you were driving the same car 😉
I certainly agree that we need to see more positive changes over the next decade or two … or hopefully sooner.
Cheers
David
In the latest BBC Attenborough series (Wild Isles), the great man (or his script writer) declares – twice – that we have lost 60% of our insects over the last 20 years.
I looked around to see if I could find the source of this claim. It looks like it might be this study: The Bugs Matter Citizen Science survey: counting insect ‘splats’ on number plates reveals a 58.5% reduction in the abundance of actively flying insects in the UK between 2004 and 2021.
https://cdn.buglife.org.uk/2022/05/Bugs-Matter-2021-National-Report.pdf
It seems to me as a layman to be a very nuanced piece of research. The researchers are at pains to point out the limitations of their research, and the very limited scope for extrapolation from their results. They write:
‘Whilst there is growing evidence of potentially catastrophic declines in insect diversity and abundance, care must be taken to not extrapolate too far, with potential consequences for undermining public confidence in research. We recognise and stress that the results we have reported here do not constitute a trend, and advocate strongly for data collection over extended timeframes to enable conclusions about trends in insect populations to be drawn.’
There is one finding in this study that might be surprising. Although people often say that the reduction in the number of insect splats on our cars may to some extent be a consequence of efficient streamlining of modern cars, it was the newest models of cars that had the highest rates of splatter in the 2021 survey!
Hi Archie
Newer cars are driven faster … so gaining more ‘splats’ 😉
Charlotte Outhwaite’s study published in Nature in 2022 shows numbers slashed by up to 50% and species reduced by 27% in some areas. I should write about this (though it’s all a bit depressing 🙁 ) though I risk turning this beekeeping blog into an environmental ecology blog.
Actually, back to the ‘splats’ … for the data to be properly controlled you’d need to somehow take into account both the speed the car was being driven at and the types of roads it was driven along. Maybe new cars spend more time bombing up and down dual carriageways at 70 mph, whereas older ones are just used to pootle around town?
To be fair … I’ve not looked at the study, so perhaps should 😉
Cheers
David
I get asked a lot about what people can do to “save the bees” and I try to emphasize that it’s other species of bees that we’re more concerned about.
I do wonder how easy it is to tease out the decline in pollinator species from the decline in insects more generally. its my understanding that flying insect numbers generally have reduced significantly. Are you aware if this has been addressed at all in the literature on pollinator loss? I’m afraid that making sense of scientific inquiry has never been my strong point.
Hello Stephen
Yes, it has been covered in some of the literature and it’s clearly something that scientists are aware of. In this study they’re looking at wild bee richness, not abundance. How do honey bees influence the range and types of other bees they share the environment with? Abundance would also be influenced by sampling effort that differed.
I’ll be returning to this topic in the future … but I’ve got to get the summer honey off first 😉
Cheers
David
It’s all of them we need to save, because ALL of them are up against climate warming.
Pollen proteins are HALF what they used to be.
If you want to make help, know your food and your farmer’s name for everything in your cupboard and your fridge. Don’t buy out if season, or anything grown more than 24-hours drive.
And no indoor-pollinated strawberries or tomatoes if you don’t want to imprison sentient bumble bees.
Hi Robin
Thanks for the reminder … I’ve been meaning to write about bumble bee pollination and genetic spillover.
Not sure where the evidence is that pollen proteins (which I understand to mean the protein content per pollen grain) are reduced. I’ve not seen any research that suggest this, though there’s a limitless amount of stuff I’ve not read, and it doesn’t make sense to me from an evolutionary aspect.
Unless of course it’s a crop plant that has been genetically selected to be wind pollinated in which case all bets are off.
Cheers
David
Are there similar studies for any countryside areas. Here, in West Devon, England, bee keeping seems to have exploded in popularity. My friend is promoting and breeding for native rather than imported honey bees. However, she is very aware that there may now be too many honey bees “out of town.”
Hello Sian
I cite two in the post – the studies on the Garraf National Park and the German grasslands. There are lots of others but some reach a very different conclusion. I’ll cover some of this science in the future. These ecological studies are complicated by the huge variation in environments and annual changes that we are well aware of. Some environments are likely to be so forage-rich that they can support lots of hives (perhaps heather moors in late August in a good season would be an example here), but others are so poor that beekeeping would have a negative impact, on both native pollinators and honey bees (for example, heather moors in early May where there’s little alternative forage).
At the very least, beekeepers need to have an awareness of the potential impact of their activities.
Cheers
David
Excellent post David. The impact of hived bee populations on the wider natural environment, and the knock on effects, isn’t recognised, considered, or discussed nearly enough in beekeeping circles. I doubt that it is even considered relevant in current beekeeping training and certification (I stand corrected if that’s not the case!), and it is not as far I can see on any authority radar, although it should be. It’s the tip of an environmental awareness iceberg that will no doubt challenge many in beekeeping and honey farming communities.
More!
Iain 😉
Hi Iain
I think you’re right about it not being discussed in beekeeping circles, but it certainly is elsewhere. Unfortunately, the science is complicated and not at all clear cut. I could have chosen another paper that came to diametrically opposing conclusions (and will post on one like this in the future). There’s a comment waiting to be moderated by Janet Wilson which considers the results in this paper are correlative, not causative. It’s about 15 comments on from this and I’ll get to it later today. I don’t necessarily disagree but I do think beekeepers need to think about these things and perhaps be pro-active in addressing the question of “too many hives”. For example, engaging with scientists (or even funding the science – via the beekeeping charities, or association sponsorship) to help develop responsible and sustainable practices.
Yes … that’s a bit like turkeys voting for Christmas, but there are potential outcomes such as regulation and restriction that could be imposed which may be to the detriment of beekeeping and the environment.
Cheers
David
Shouldn’t we expect species diversity and abundance to be seriously changed in Urban environments. In cities where many of us live our decision to be here dooms in most cases once pristine landscapes to concrete, asphalt, vacant and occupied lands. Our houses and buildings willingly replaced all of the cities former natural habitats. Along with it species diversity and richness. We can never expect that to return. Honeybees are no different than us – just opportunists and in good company. Starlings, rats, raccoon, coyotes and all sorts of invasive species from around the world have replaced native species. Outside the city it is not much different. Homes, car parks, asphalt, concrete, airports all with enormous impact on native plant and animal species. Its endless, agricultural land, dredging, and dykes that shrink wetlands and estuaries. We are humans. At the top of the food chain. Are we not all in ewe at just how far we have come. Indeed how much we have changed our native environments. Flying anywhere in the world and looking down – what do we see – endless array of sparkling lights. Small yellow-white dots litter the landscape like stars. One group after another morphs into a huge splash of light as we fly over great cities and small towns. Only over Russia, Northern Canada, Himalaya, and oceans do we see land without human produced light. We have indeed changed the world and along with it what makes up species diversity and richness. Its not by just our friends the honeybee.
Hi Vince
Yes, of course we should expect them to change. What’s notable here is that the urban environment with or without honey bees appears to be very different in terms of the other bees it can accommodate. Does this matter? Does any of the biodiversity lost due to anthropogenic activities matter? Yes, of course it does. At the very least it makes the world a whole lot less interesting. Somewhat more significantly it means that whole environments may collapse due to a lack of buffering activity, to the inevitable monoculture that would follow and then the nightmare scenario such as hand pollinating fruit trees due to a lack of native pollinators:
We might be at the top of the food chain (though a man-eating lion may beg to differ) but if we don’t look after that food chain we will eventually end up going hungry …
Cheers
David
David & Robin Jones
“Its hardly the survival of the fittest, but instead the most-human aided.”
Ah again, that’s my point. Homo sapiens are but another result of survival of the fittest. Darwinially we are no different from the other millions of species on the planet. H.sap exploit honeybees who in turn compete with bumblebees just as ants nurture sugar-secreting aphids, doubtless to the detriment of aphids that have not been ‘clever’ enough to evolve this asset…..
Thanks for putting down clearly something I’ve been doing back-of-envelope with people at various times when asked about honey bee densities, BeeBase apiary counts and competition with other pollinators!
An extension to this subject is looking at not only hive density, but also bee subspecies and management techniques. A strong hybrid colony may at times have 100% more bees in it than a native/local strain – meaning doubling the effective density.
Competition is likely to be more pronounced at certain times of year – early spring, June gap, late Autumn – especially for pollen. For example strong colonies built up for OSR will have been consuming more than their fair share of pollen to raise the necessary foragers in early spring, potentially at a cost to other pollinators who then fail to get up and running.
Additionally feeding colonies through times of scarcity not only maintains excessive strength, but allows non-thrifty genetics to survive in situations where they would otherwise struggle. Personally I would always suggest feeding no more syrup than equivalent weight of honey removed (the idea being that if the colony can’t survive on that, then they would have starved anyway). But many beekeepers are reluctant to apply selection pressure to their colonies, and prefer a belt-and-braces approach, even if it leads to promoting ‘poor’ bees.
Finally, in case you haven’t seen them, Api:Cultural has a number of blog posts on similar topics, especially in relation to London: https://www.apicultural.co.uk/the-need-for-adequate-forage-and-nutrition-for-honey-bees
Hi Matt
Thanks for the Api:Cultural link. I wasn’t aware of that and will have a read.
The seasonal variation in forage availability is certainly true. OSR gives colonies a massive boost. My east coast bees are probably twice as strong at the end of May as those in the OSR-free west coast (though there are other differences as well as OSR). Once the OSR finishes that’s a lot of hungry mouths to feed from an already-depleted environment. If there’s a marked June gap beekeepers typically feed … but all the other pollinators in the shared environment are suffering the same June gap without the benefit of 2 litres of thin syrup to tide them over.
Whether the strength is ‘excessive’ depends upon whether you’re a beekeeper or an ecologist interested in pollinators more generally. For the former the strength isn’t excessive, it’s what is needed to properly exploit the summer nectar flows.
This whole area is a bit of a minefield. I’m not suggesting beekeepers restrict themselves to just two colonies, or that honey bees alone are responsible for the demise in other pollinator numbers. What I’d like to see are beekeepers discussing the topic and thinking about ways to mitigate the impact our bees might have … because you can be sure that others are wanting to reduce this impact and they may choose to achieve it in ways that are detrimental to bees or beekeeping.
But the first thing to try and agree on is just how great the impact is, and what the carrying capacity of an environment is – both maximal and minimal.
Cheers
David
Very useful analysis which confirms my worries. I live in North Devon, area almost exactly 1000 km2. It is sparsely populated but contains a handful of urban areas, the rest given over to cattle, dairy, sheep, some arable farming. I find it impossible to get even an approximate number of hives. Our local beekeeper association in North Devon has about 130 members. Maybe on average, they each keep 3 hives. Some, I hope the majority, are registered on Bee Base, but I know not all are. There is another association, not affiliated to BBKA that is quite popular but I do not know their member numbers. Within my own parish, as a registered beekeeper I am very much in the minority. Of the other 8 beekeepers that I know personally within my small rural neighborhood, none are registered and none belong to the local beekeeping association so are effectively invisible.
I am going to take a wild guess that there are 3 times as many non-beekeeping association members as there are members. So 520 beekeepers, each with 3 hives, maybe 1500 hives. Add to this the large commercial honeybee farmer, Quince, and several smaller honeybee farmers and perhaps that number is doubled so hitting the 3 hives per square kilometer in a very poorly biodiverse area.
How can this be better managed other than the association taking an active step to discourage beekeeping and new beekeepers?
Honeybee numbers were not mentioned in the National Pollinator Strategy (and I have seen nothing to suggest that this initiative has produced any positive outcomes in the last 9 years other than a total reliance on the work of volunteer organisations and individuals).
Compulsory registration or effectively, licencing, might be useful if introduced primarily with the aim of protecting the future of the honey production industry to control honeybee disease ilike small hive beetle. A second aim could be to place limits on total numbers of hives in an area, putting wild pollinators before commercial honey production. That would go down like a lead balloon and Defra would not stand the cost of policing it but if you had to produce your licence issued by a local authority, in order to buy any beekeeping paraphernalia, that would make “illegal” beekeeping difficult. Like keeping illegal firearms. Effect might be to drive amateur beekeeping underground with no disease control and synthetic honey could really take off (more).
I am sure you will give us the answers in a subsequent blog! Please.
Hi Julian
I certainly don’t know the answers. Registration/regulation seems like a recipe for disaster … it would probably be costly to implement and of dubious benefit for the reasons you mention. Commercials might do it because they’re high profile and have large numbers of boxes, but an amateur with two hives at the bottom of a private garden (who already baulks at paying a few quid for miticides) … forget it.
There are States in the US where ‘beeyards’ (apiaries) have to be located a certain distance from other beeyards. Three miles perhaps? This would certainly reduce the pressure on some parts of the environment, though this could be nullified if the apiaries had 50 colonies in each one. However, they have a lot more space per beekeeper in the US … population density there is ~88 per square mile compared with ~270 per square mile in the UK. Having a minimum distance between apiaries would almost certainly drive the creation of shared apiaries (which have issues for disease management) or force beekeepers to travel significant distances which – and I speak here from experience – can be problematic for a pastime that is so demanding of space.
Could registration be made more attractive? Yes, certainly. You could envisage a scheme where registered beekeepers also ‘bought’ their miticides, perhaps with control of Apistan so it was only available every 3-5 years, and so helped offset resistance. Obviously this is fraught with problems – not least for those that do not treat (though registration would also help get some better statistics on treatment and overwintering success perhaps) – but it doesn’t have to be £10 for a piece of worthless paper rubber stamped from the government, with no penalties for not registering and no benefits from doing so.
I’d like to think that the National Bee Unit have a better idea of how representative or otherwise your experience is. My private conversations with them suggest they are aware of the issue, but perhaps aren’t aware of how great it is in some areas. It must contribute to the problems controlling foulbroods (and presumably Asian hornet etc.).
I wrote the post largely to trigger the conversation and to raise an awareness with beekeepers of the situation. Clearly the problem is multi-factorial. With an unspoiled environment the carrying capacity for hives would be much greater (though they would still inevitably compete with natives), but most of us live in a pesticide-riddled, degraded environment where more or less everything is already struggling.
I’ve been meaning to write something about the National Pollinator Strategy (and the Bee Health Strategy), so thank you for the reminder.
Cheers
David