Category Archives: Pollination

Urban areas as a refuge for insect pollinators: conservation for the city

Urban conservation ecology is a fast growing field that has mainly focused on how towns and cities can support populations of plants, animals and fungi that may be declining or threatened in the surrounding rural environment. That is, the city for wildlife conservation. In a new essay in the journal Conservation Biology, written with colleagues from across the world, we argue that conservation for the city (an idea originally conceived, I believe, by Steward Pickett) should also be a focus of future research and management activities.

Conservation, or ecology, for the city in essence means that plants, animals and fungi, as well as being supported by the city (see our recent urban bees example), play a role in supporting the city itself through the provision of ecosystem services such as decomposition, flood alleviation, and crop pollination.

It’s pollinators and pollination that we particualrly focus on in this essay – here’s the abstract:

Urban ecology research is changing how we view the biological value and ecological importance of cities. Lagging behind this revised image of the city are natural resource management agencies’ urban conservation programs that historically have invested in education and outreach rather than programs designed to achieve high-priority species conservation results. This essay synthesizes research on urban bee species diversity and abundance to suggest how urban conservation can be repositioned to better align with a newly unfolding image of urban landscapes. We argue that pollinators put high-priority and high-impact urban conservation within reach. In a rapidly urbanizing world, transforming how environmental managers view the city can improve citizen engagement while exploring more sustainable practices of urbanization.

I’m happy to send the PDF to anyone who wants a copy; here’s the full citation:

Hall, D.M., Camilo, G.D., Tonietto, R.K., Ollerton, J., Ahrné, K., Arduser, M., Ascher, J.S., Baldock, K.C.R., Fowler, R.E., Frankie, G.W., Goulson, D., Gunnarsson, B., Hanley, M.E., Jackson, J.I., Langellotto, G., Lowenstein, D., Minor, E.S., Philpott, S.M., Potts, S.G., Sirohi, M.H., Spevak, E.M., Stone, G., Threlfall, C. (2016) The city as a refuge for insect pollinators. Conservation Biology (in press)

The macroecology of animal versus wind pollination – a new study just published

Release today of the IPBES Summary for Policymakers of the Assessment Report on Pollinators, Pollination and Food Production

2 Replies

Inula at Ravensthorpe 20160710_145426 Following on from the press release earlier this year announcing of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) assessment of pollinators, pollination and food production (which I reported on in February) it looks as though the full report may shortly be published. A Summary for Policymakers has just been released by IPBES and can be downloaded by following this link. I’ll put up a link to the full report once it becomes becomes available.

Bees and pesticides – a major new study just published – UPDATED

5 Replies

Male B lap on Salvia cropped P1120309

An important new study about the effects of neonicotinoid pesticides on wild bees has just been published in the journal Nature Communications – here’s the details and a link to the paper, which is open access:

Woodcock, B. A. et al. (2016) Impacts of neonicotinoid use on long-term population changes in wild bees in England. Nat. Commun. 7:12459 doi: 10.1038/ncomms12459

As I’ve previously discussed on this blog (e.g. here and here) there are widespread concerns amongst environmentalists, and some scientists, about the impact that these relatively new pesticides are having on pollinators and other biodiversity. The Woodcock et al. paper is a major contribution to this discussion as it uses a huge dataset to model the changes in populations of 62 wild bee species that are known to forage on oilseed rape (canola) over 18 years. These changes can be related to the spatial extent of oilseed rape cultivation and the authors found that whilst bees “….foraging on oilseed rape benefit from the…[nectar and pollen provided by]….this crop….[they]….were on average three times more negatively affected by exposure to neonicotinoids than…” bees which didn’t forage on the crop.

The authors further conclude that “This study provides the first evidence for community level national scale impacts on the persistence of wild bee populations resulting from exposure to neonicotinoid treated oilseed rape crops.”

Neonicotinoid pesticides are, of course, not the whole story when it comes to understanding declines in pollinator diversity and abundance. But these pesticides are the latest in a long history of changes to British agriculture that have had significant consequences for the biodiversity of our country (as we showed in our study of bee and wasp extinctions).

Reactions to the study have been, well, predictable. A long feature on the BBC News website* quoted a representative from Bayer as saying:

“we believe….[the study’s]….findings would be more correctly headlined that intensive agriculture is causing some issues with pollinators….. Whether this is due to the use of insecticides is not clear; a lack of nesting sites and pollen and nectar sources in these areas may also be critical factors.”

Which rather ignores the fact that this was a comparative study of bees that forage on oilseed rape versus those that don’t.

Likewise the National Farmer’s Union’s position was that:

“While this study claims to provide an important contribution to the evidence base underpinning the current EU moratorium on some uses of neonicotinoids, experts reviewing all the evidence have concluded that there are still major gaps in our knowledge and a limited evidence base to guide policymakers”

Which sounds to me like a statement designed to fudge the issue: the “experts reviewing all the evidence” would not have reviewed this particular study! And which begs the question – how much evidence and how many studies would be enough for the NFU?

The study’s authors do not make any suggestions as to what the next step should be in this continuing saga but are quoted as saying that “simplistic solutions” such as banning these pesticides are not the answer because this will encourage use of pesticides that are even more damaging. That may be the case but it’s clear that an independent root-and-branch reassessment of the use of pesticides (and herbicides) in UK agriculture is long overdue.

*As an aside, this BBC News piece wrongly states that bumblebees were not included in the study, which is not the case.

UPDATE: After I published this post I noticed that Manu Saunders has also written about the bee study, plus a second study that I’d not seen linking neonicotinoid use to declining butterfly populations in California. Here’s a link to Manu’s blog.

Just published: A horizon scan of future threats and opportunities for pollinators and pollination

The influence of floral traits on specialization and modularity of plant–pollinator networks in a biodiversity hotspot in the Peruvian Andes – Watts et al. (2016)

2 Replies

Watts et al Figure 1

The second paper from the PhD thesis of my former student Dr Stella Watts has just been published in Annals of Botany – here’s a link to the journal’s website. It summarises the major findings from her field work on plant-pollinator interactions in the high Andes of Peru:

Watts, S., Dormann, C.F., Martín González, A.M. & Ollerton, J. (2016) The influence of floral traits on specialization and modularity of plant–pollinator networks in a biodiversity hotspot in the Peruvian Andes. Annals of Botany doi: 10.1093/aob/mcw114

This paper represents a major piece of research, including extensive field data collection over multiple sites in a challenging environment at altitude; state-of-the-art data analysis; and then summarising all of this into a single, digestible paper, with some great figures. I’m very proud to have been part of it!

Here’s the abstract; please email me or Stella if you’d like a copy of the full PDF:

Background and Aims: Modularity is a ubiquitous and important structural property of ecological networks which describes the relative strengths of sets of interacting species and gives insights into the dynamics of ecological communities. However, this has rarely been studied in species-rich, tropical plant–pollinator networks. Working in a biodiversity hotspot in the Peruvian Andes we assessed the structure of quantitative plant–pollinator networks in nine valleys, quantifying modularity among networks, defining the topological roles of species and the influence of floral traits on specialization.

Methods: A total of 90 transects were surveyed for plants and pollinators at different altitudes and across different life zones. Quantitative modularity (QuanBiMo) was used to detect modularity and six indices were used to quantify specialization.

Key Results: All networks were highly structured, moderately specialized and significantly modular regardless of size. The strongest hubs were Baccharis plants, Apis mellifera, Bombus funebris and Diptera spp., which were the most ubiquitous and abundant species with the longest phenologies. Species strength showed a strong association with the modular structure of plant–pollinator networks. Hubs and connectors were the most centralized participants in the networks and were ranked highest (high generalization) when quantifying specialization with most indices. However, complementary specialization d’ quantified hubs and connectors as moderately specialized. Specialization and topological roles of species were remarkably constant across some sites, but highly variable in others. Networks were dominated by ecologically and functionally generalist plant species with open access flowers which are closely related taxonomically with similar morphology and rewards. Plants associated with hummingbirds had the highest level of complementary specialization and exclusivity in modules (functional specialists) and the longest corollas.

Conclusions: We have demonstrated that the topology of networks in this tropical montane environment was non-random and highly organized. Our findings underline that specialization indices convey different concepts of specialization and hence quantify different aspects, and that measuring specialization requires careful consideration of what defines a specialist.

Third International Conference on Pollinator Biology, Health and Policy – Pennsylvania – 18-20 July, 2016

Bees’ Needs week (9th to 17th July) #BeesNeeds

11 Replies

Inula at Ravensthorpe 20160710_145426.png

In the current political turmoil around the Chilcot Enquiry, Brexit, leadership challenges and a change of Prime Minister you’d be forgiven for having missed the fact that 9th to 17th July 2016 has been designated “Bees’ Knees” week, as a follow on to the Pollinator Awareness Week of 2015.

Here’s the link to the Defra press release.

Unlike last year I’ve no specific plans to do any regular posts on the topic, but I will provide links to relevant items as and when I see them, starting with these two:

Why insects are declining globally, and why it matters.

Dave Goulson is trying to crowdfund a project to look at pesticides in plants from garden centres.

How to deal with bumblebees in your roof [UPDATED]

58 Replies

Bombus hypnorum

This week I’ve had two enquiries from colleagues at the University of Northampton asking advice on what to do about colonies of bumblebees that have set up home in their roofs. In both cases these were nests of the Tree Bumblebee (Bombus hypnorum), a species that only colonised the British Isles in 2001 and has since spread rapidly (see this post from last year for a more detailed account). Because of their association with human settlements they are significant pollinators of garden produce: over the past few weeks I’ve been watching them pollinating the raspberries in our garden and we now have a large crop.

But having a bee nest in your home is, for many people, a real concern. I thought it might be useful to discuss the issue by quoting from the email correspondence I had with my first colleague, Paul.

Paul wrote: I wonder if you can give me some advice. I returned home from holiday on Saturday to find that a colony of bees had taken up residence in a roof space above my front porch. The bees are not domestic honey bees but large bumblebees with white rears. I am not sure how many there are, they buzz furiously when I close the door….. They are not in the house and I cannot see them from my loft…..so they are not causing a problem at the moment other than a moderate dead rabbit smell in the porch.

I am considering contacting the local council pest controllers, but fear they may just gas and kill them as they are not honey bees. What would your advice be, would it be safe to leave them alone, if so how long are they likely to stay, how large is the colony likely to become, are they likely to cause any damage or mess?

Here’s my response: From your description they are almost certainly Tree Bumblebees which often use loft spaces, bird boxes, etc. As the name suggests they naturally nest in holes in trees. The colony is not likely to get much bigger though over the next few weeks you may find males patrolling the front of the nest, waiting for the virgin females to emerge so that they can mate. That sometimes makes the colony seem larger than it actually is – there are not likely to be more than about 150 bees in there.

I’ve had Tree Bumblebees in my roof a few times and they’ve never caused any damage. All bumblebee colonies die over the winter and the newly-mated females fly off and hibernate. So by late August or September (perhaps earlier if the weather ever gets warmer….) the bees should have gone. At that time you could seal the entrance to the roof space, though they are unlikely to return next year (although it’s not unknown).

Yes, a pest controller would kill the colony. But they are unlikely to be aggressive unless you stick your fingers in the nest hole! My advice is to let them be and take pride in your own bee colony – they are very discerning and don’t nest just anywhere 🙂

So there you have it: my advice is, leave them alone. Of course if you or your family have a particular sensitivity to bee stings you may need to think carefully about this advice, but in my experience bumblebees are only aggressive if they feel directly threatened. In over 25 years of field work focused on bees and other pollinators, I’ve only ever been stung a few times, and mainly by honey bees.

UPDATE: A commenter on Facebook had a great suggestion, that I provide a link to Dave Goulson’s nice little video showing what the inside of a bumblebee nest looks like – so here it is.

Silver Medal for the BES’s pollinator’s display at RHS Chelsea Flower Show!

5 Replies

RHS Silver Medal

An early train to London yesterday got me to the RHS Chelsea Flower Show in time for the gates opening at 8am. I’d agreed to spend the day staffing the British Ecological Society’s Animal Attraction: The garden and beyond display, which deals with the relationships between plants and their pollinators – see my recent posts here and here.

The first thing I noticed as I approached the display was how impressive and well designed it looked, with some wonderful planting to complement the simple, bold scientific information. The second thing I noticed was that we had won a Silver Medal! The whole team was very pleased – it’s the third year that the BES has been represented at Chelsea, but the first time that it’s won a medal. I’m proud to have made a small contribution to that by advising on the plants and the scientific content, but the main kudos goes to the BES’s staff and to the garden designer Emily Darby.

Over the course of a long day we talked to hundreds of visitors about the display, what it represented, and the different ways that flowers are adapted to their pollinators. There was a huge amount of public interest and support, very gratifying to see. Here’s some pictures from the day:

RHS display

RHS crowd

RHS crowd with fig

RHS Jeff

RHS display