Dr Dara Stanley of University College Dublin shares her thoughts from a recent workshop ‘Assessing competition between domesticated bees and wild pollinators’.
Uncovering threats to bees
Bees are facing many threats, from habitat loss to pesticide use and climate change. Recently, another debate has centred around the potential competition for food resources between wild pollinators and managed honeybees. This was the subject of a workshop hosted in January 2022 by Aarhus University in Denmark.
Held over two days, the workshop brought together over 60 scientists and stakeholders, aiming to review the available scientific evidence and propose a roadmap for future work. Denmark was ideally placed to lead this discussion, as in recent years it has been at the centre of intense debate about potential honeybee competition with wild bees between beekeepers and conservationists.
Reviewing the research
The workshop began with an acknowledgement of the importance of both managed and wild bees as pollinators. This was followed by a reiteration of the core challenge: to assess potential areas of competition between wild and managed bees, and to find ways of mitigating any issues that emerge from these findings so that all bees can coexist and continue to benefit biodiversity and beekeeping.
The first keynote came from Sandra Lindström of Lund University, Sweden. She presented findings of a recent report for the Swedish Ministry of Agriculture about honeybee competition with wild bees. The report found that so far, there has been little research into competition between managed honeybees and wild bees in Europe, with only 33 studies matching their criteria.
Is there competition?
For competition to exist, honeybees and wild bees need to forage on the same flowers. This would therefore have an impact on the resources either group could collect, ultimately effecting their reproduction or survival. Lindström reported that most studies looked at the impact of honeybees on the diversity or abundance of wild bees; fewer had looked at effects on resource intake or overlap in resources; and very few had studied effects on their reproduction or survival. Wild bee reproduction and survival is difficult to measure as it requires the comparison of landscapes with and without honeybees, the latter of which are hard to come by.
The keynote was followed by a series of talks about ongoing research into honeybee competition, with some examples from France and California of sites where managed honeybees are brought to semi-natural or mountainous regions due to resource shortages on farmland after crop flowering.
Most of the research presented in the workshop showed that honeybees had some impact on wild bees, but the effect on survival rates was often unknown. One talk I particularly enjoyed showed that plants vary in how quickly they can replenish nectar when it is removed by pollinators, suggesting that faster-replenishing plants might be good choices for planting in areas where competition may be present.
Other sessions included a talk about the socio-ecological implications of addressing competition between managed and wild pollinators, and breakout discussions of current methods of assessing competition, and what we might need to develop in the future.
What can we do?
If competition exists, what can we do about it? Several ideas were discussed in the workshop, including increasing the availability of floral resources in the landscape so there is more to go around. Other suggestions included adjusting the distance between apiaries and protected areas, such as national parks or nature reserves, or avoiding placing managed honeybees in protected areas as a precautionary measure. This seems sensible while the risks haven’t been fully identified, particularly in areas with threatened bee species or where wild bees have high overlap in resources with honeybees.
These were my key takeaway messages from the workshop:
- We don’t know enough about competition between managed honeybees and wild bees. Given the potential threat to wild bee populations, more work needs to be done to fully assess the risks of competition.
- We know almost nothing about competition with other non-bee pollinators such as hoverflies.
- Competition is more likely to exist in areas where there are fewer floral resources.
- It would be useful to estimate the ‘carrying capacity’ each habitat, i.e. how many managed honeybees it can support. However, this is difficult as it depends on a variety of factors.
- We don’t know how important competition is compared to other threats.
- The focus of the workshop was on competition for floral resources; this is the most likely way in which honeybees and wild bees may compete. However, managed honeybees may also affect wild bees through transfer of disease. This could have strong implications, particularly for rarer bees. This was not covered in the workshop but would benefit from further discussion.
- Managed honeybees and wild bees are all important. Perhaps in some cases the biggest issues are between groups of humans rather than the bees themselves
What does this mean for Ireland?
Right now, we have no evidence from Ireland on the levels of competition between managed honeybees and wild bees, and it is certainly an area that deserves further attention. My lab at UCD have one study on this issue that is near completion, so watch this space!
At present, beekeeping in Ireland is largely at a small scale so we may have less to worry about than other countries with a higher density of beekeeping. Placement of managed honeybees is often not encouraged in protected areas in Ireland, which makes a lot of sense as a precautionary measure.
Either way, we are lucky in Ireland that the All-Ireland Pollinator Plan considers all bees and brings together both beekeepers and those interested in wild species, paving the way for finding solutions to any issues related to competition. All bees are important for the health of our ecosystems and crops, and after all joint efforts to benefit bees have greater potential to be successful.
Dr Dara Stanley is a Lecturer in Applied Entomology in the School of Agriculture and Food Science, and Earth Institute at University College Dublin.
https://people.ucd.ie/dara.stanley/about
https://www.stanleyecologylab.org